Pixiv Downloader のソースコード

Pixiv Downloader

下载 Pixiv 插画、漫画、小说和完整小说系列。
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// ==UserScript==
// @name         Pixiv Downloader
// @namespace    https://www.pixiv.net/
// @version      1.0.0
// @description  下载 Pixiv 插画、漫画、小说和完整小说系列。
// @author       Local
// @match        https://www.pixiv.net/*
// @run-at       document-idle
// @require      https://cdn.jsdelivr.net/npm/[email protected]/dist/jszip.min.js
// @grant        GM_xmlhttpRequest
// @grant        GM_addStyle
// @grant        GM_getValue
// @grant        GM_setValue
// @grant        GM_registerMenuCommand
// @grant        GM_notification
// @connect      i.pximg.net
// ==/UserScript==

(() => {
  'use strict';

  const SCRIPT_NAME = 'PixivDownloader';
  const SCRIPT_VERSION = '1.0.0';
  const VERIFIED_DATE = '2026-08-08';
  const TEST_MODE = typeof globalThis !== 'undefined' && Boolean(globalThis.__PIXIV_DOWNLOADER_TEST__);

  const Config = Object.freeze({
    settingsKey: 'pixiv-downloader-settings-v1',
    routePollIntervalMs: 1500,
    maxSeriesPages: 1000,
    seriesPageSize: 30,
    seriesRequestConcurrency: 2,
    seriesRequestIntervalMs: 350,
    embeddedResolveBatchSize: 20,
    defaultSettings: Object.freeze({
      debug: false,
      imageConcurrency: 3,
      retryCount: 3,
      requestTimeoutMs: 30000,
      novelFormat: 'txt',
      seriesFormat: 'both',
      downloadEmbeddedImages: false,
      notifications: true,
      showFloatingButton: true,
      imageFilenameTemplate: '{author} - {title} - {id}',
      novelFilenameTemplate: '{author} - {title} - {id}',
      seriesFilenameTemplate: '{author} - {series} - {seriesId}'
    })
  });

  class PixivDownloaderError extends Error {
    constructor(code, message, options = {}) {
      super(message);
      this.name = 'PixivDownloaderError';
      this.code = code;
      this.status = options.status || 0;
      this.retryable = Boolean(options.retryable);
      this.retryAfterMs = Number(options.retryAfterMs) || 0;
      this.context = options.context || '';
      if (options.cause) this.cause = options.cause;
    }
  }

  const ErrorUtils = {
    abortError(message = '用户已取消下载') {
      if (typeof DOMException === 'function') return new DOMException(message, 'AbortError');
      const error = new Error(message);
      error.name = 'AbortError';
      return error;
    },

    isAbort(error) {
      return Boolean(error && error.name === 'AbortError');
    },

    toUserMessage(error) {
      if (this.isAbort(error)) return '下载已取消。';
      const messages = {
        LOGIN_REQUIRED: '当前内容需要登录后访问，请先在 Pixiv 正常登录。',
        FORBIDDEN: 'Pixiv 拒绝了请求。请确认当前账号有权查看该内容。',
        NOT_FOUND: '作品不存在、已删除，或当前账号无法访问。',
        RATE_LIMIT: 'Pixiv 返回 429，下载速度已受限；请稍后重试。',
        SERVER_ERROR: 'Pixiv 服务器暂时异常，请稍后重试。',
        NETWORK: '网络请求失败，请检查网络连接后重试。',
        TIMEOUT: '请求超时。可在设置中延长超时时间后重试。',
        INVALID_JSON: 'Pixiv 返回了无法解析的数据，网站接口可能已改变。',
        API_ERROR: 'Pixiv 数据接口返回错误。',
        API_SCHEMA_CHANGED: 'Pixiv 返回的数据结构与已验证版本不一致，请检查 PixivDataAdapter。',
        ORIGINAL_UNAVAILABLE: 'Original 原图地址不可用；脚本不会静默降级到压缩图。',
        SERIES_INCOMPLETE: '未能取得完整系列目录，已停止以避免生成缺章文件。',
        ZIP_UNAVAILABLE: 'JSZip 未加载，无法生成 ZIP。',
        ZIP_FAILED: 'ZIP 生成失败，可能是浏览器内存不足。',
        DOWNLOAD_FAILED: '浏览器未能保存下载文件。',
        UNSUPPORTED_IMAGE_HOST: '图片地址不在已授权的 i.pximg.net 域名。',
        INVALID_ID: '页面中的作品 ID 无效。',
        CONTENT_UNAVAILABLE: '作品正文或资源当前不可用。'
      };
      if (error instanceof PixivDownloaderError) {
        const base = messages[error.code] || error.message || '下载失败。';
        return error.context ? `${base}（${error.context}）` : base;
      }
      return error && error.message ? error.message : '发生未知错误。';
    },

    serializable(error) {
      return {
        name: error && error.name ? String(error.name) : 'Error',
        code: error && error.code ? String(error.code) : '',
        status: error && error.status ? Number(error.status) : 0,
        message: error && error.message ? String(error.message) : '未知错误'
      };
    }
  };

  const Utils = {
    clamp(value, min, max) {
      const number = Number(value);
      if (!Number.isFinite(number)) return min;
      return Math.min(max, Math.max(min, number));
    },

    sleep(ms, signal) {
      if (signal && signal.aborted) return Promise.reject(ErrorUtils.abortError());
      return new Promise((resolve, reject) => {
        const timer = setTimeout(() => {
          cleanup();
          resolve();
        }, Math.max(0, ms));
        const onAbort = () => {
          clearTimeout(timer);
          cleanup();
          reject(ErrorUtils.abortError());
        };
        const cleanup = () => {
          if (signal) signal.removeEventListener('abort', onAbort);
        };
        if (signal) signal.addEventListener('abort', onAbort, { once: true });
      });
    },

    normalizeLineEndings(value) {
      return String(value == null ? '' : value).replace(/\r\n?/g, '\n');
    },

    toCrlf(value) {
      return this.normalizeLineEndings(value).replace(/\n/g, '\r\n');
    },

    htmlToText(html) {
      const source = String(html == null ? '' : html)
        .replace(/<br\s*\/?>/gi, '\n')
        .replace(/<\/p\s*>/gi, '\n\n');
      if (typeof document !== 'undefined' && document.createElement) {
        const template = document.createElement('template');
        template.innerHTML = source;
        return (template.content.textContent || '').replace(/\u00a0/g, ' ').trim();
      }
      return source
        .replace(/<[^>]*>/g, '')
        .replace(/&lt;/g, '<')
        .replace(/&gt;/g, '>')
        .replace(/&quot;/g, '"')
        .replace(/&#39;/g, "'")
        .replace(/&amp;/g, '&')
        .trim();
    },

    formatBytes(bytes) {
      const value = Number(bytes) || 0;
      if (value < 1024) return `${value} B`;
      const units = ['KB', 'MB', 'GB', 'TB'];
      let size = value;
      let index = -1;
      do {
        size /= 1024;
        index += 1;
      } while (size >= 1024 && index < units.length - 1);
      return `${size >= 100 ? size.toFixed(0) : size.toFixed(1)} ${units[index]}`;
    },

    textByteLength(value) {
      if (typeof TextEncoder === 'function') return new TextEncoder().encode(String(value)).byteLength;
      return unescape(encodeURIComponent(String(value))).length;
    },

    formatDate(value) {
      if (!value) return '';
      const date = new Date(value);
      if (Number.isNaN(date.getTime())) return String(value);
      const pad = (number) => String(number).padStart(2, '0');
      return `${date.getFullYear()}-${pad(date.getMonth() + 1)}-${pad(date.getDate())} ${pad(date.getHours())}:${pad(date.getMinutes())}:${pad(date.getSeconds())}`;
    },

    escapeMarkdownText(value) {
      return String(value == null ? '' : value).replace(/([\\`*_[\]<>])/g, '\\$1');
    },

    saveBlob(blob, filename) {
      if (typeof document === 'undefined' || typeof URL === 'undefined' || !URL.createObjectURL) {
        throw new PixivDownloaderError('DOWNLOAD_FAILED', '当前环境不支持浏览器下载。');
      }
      const url = URL.createObjectURL(blob);
      const anchor = document.createElement('a');
      anchor.href = url;
      anchor.download = filename;
      anchor.style.display = 'none';
      document.body.appendChild(anchor);
      try {
        anchor.click();
      } catch (error) {
        URL.revokeObjectURL(url);
        anchor.remove();
        throw new PixivDownloaderError('DOWNLOAD_FAILED', '浏览器拒绝了下载。', { cause: error });
      }
      anchor.remove();
      setTimeout(() => URL.revokeObjectURL(url), 60000);
    },

    uniqueBy(items, keySelector) {
      const seen = new Set();
      const result = [];
      for (const item of items) {
        const key = keySelector(item);
        if (seen.has(key)) continue;
        seen.add(key);
        result.push(item);
      }
      return result;
    },

    assertNotAborted(signal) {
      if (signal && signal.aborted) throw ErrorUtils.abortError();
    }
  };

  const FilenameUtils = {
    cleanUnicode(value) {
      let output = '';
      const input = String(value == null ? '' : value);
      for (let index = 0; index < input.length; index += 1) {
        const code = input.charCodeAt(index);
        if (code >= 0xd800 && code <= 0xdbff) {
          const next = input.charCodeAt(index + 1);
          if (next >= 0xdc00 && next <= 0xdfff) {
            output += input[index] + input[index + 1];
            index += 1;
          } else {
            output += '\ufffd';
          }
        } else if (code >= 0xdc00 && code <= 0xdfff) {
          output += '\ufffd';
        } else {
          output += input[index];
        }
      }
      return output;
    },

    truncate(value, maxLength) {
      const points = Array.from(String(value));
      return points.length <= maxLength ? points.join('') : points.slice(0, maxLength).join('');
    },

    sanitizeFilename(value, options = {}) {
      const maxLength = Utils.clamp(options.maxLength == null ? 160 : options.maxLength, 16, 220);
      const fallback = String(options.fallback || 'untitled');
      let result = this.cleanUnicode(value);
      if (typeof result.normalize === 'function') result = result.normalize('NFC');
      result = result
        .replace(/[\x00-\x1f\x7f]/g, ' ')
        .replace(/[\\/:*?"<>|]/g, '_')
        .replace(/\s+/g, ' ')
        .trim()
        .replace(/[. ]+$/g, '');
      if (!result) result = fallback;
      if (/^(con|prn|aux|nul|com[1-9]|lpt[1-9])(?:\..*)?$/i.test(result)) result = `_${result}`;
      result = this.truncate(result, maxLength).replace(/[. ]+$/g, '');
      return result || fallback;
    },

    formatFilename(template, metadata, options = {}) {
      const requiredToken = options.requiredToken || 'id';
      const requiredValue = String(options.requiredValue == null ? metadata[requiredToken] || '' : options.requiredValue);
      const maxLength = options.maxLength || 160;
      const sourceTemplate = String(template || `{title} - {${requiredToken}}`);
      let rendered = sourceTemplate.replace(/\{([a-zA-Z][a-zA-Z0-9]*)\}/g, (match, key) => {
        return Object.prototype.hasOwnProperty.call(metadata, key) ? String(metadata[key] == null ? '' : metadata[key]) : match;
      });
      if (!sourceTemplate.includes(`{${requiredToken}}`) && requiredValue) rendered += ` - ${requiredValue}`;
      let safe = this.sanitizeFilename(rendered, { maxLength });
      if (requiredValue && !safe.includes(requiredValue)) {
        const suffix = ` - ${this.sanitizeFilename(requiredValue, { maxLength: 40 })}`;
        const prefixLength = Math.max(1, maxLength - Array.from(suffix).length);
        safe = `${this.truncate(safe, prefixLength).replace(/[. ]+$/g, '')}${suffix}`;
      }
      return safe;
    },

    getNumberPadding(totalCount, minimum = 2) {
      return Math.max(minimum, String(Math.max(1, Number(totalCount) || 1)).length);
    },

    extensionFromUrl(url, fallback = 'bin') {
      try {
        const match = new URL(url).pathname.match(/\.([a-zA-Z0-9]{1,8})$/);
        if (!match) return fallback;
        const extension = match[1].toLowerCase();
        return extension === 'jpeg' ? 'jpg' : extension;
      } catch (_) {
        return fallback;
      }
    },

    extensionFromContentType(contentType) {
      const type = String(contentType || '').split(';')[0].trim().toLowerCase();
      const map = {
        'image/jpeg': 'jpg',
        'image/png': 'png',
        'image/gif': 'gif',
        'image/webp': 'webp',
        'image/avif': 'avif',
        'application/zip': 'zip',
        'application/x-zip-compressed': 'zip'
      };
      return map[type] || '';
    },

    chooseExtension(url, contentType, fallback = 'bin') {
      return this.extensionFromContentType(contentType) || this.extensionFromUrl(url, fallback);
    }
  };

  class Logger {
    constructor(enabled = false) {
      this.enabled = Boolean(enabled);
    }

    setEnabled(enabled) {
      this.enabled = Boolean(enabled);
    }

    info(message, data) {
      if (!this.enabled) return;
      if (data === undefined) console.info(`[${SCRIPT_NAME}][INFO] ${message}`);
      else console.info(`[${SCRIPT_NAME}][INFO] ${message}`, data);
    }

    warn(message, data) {
      if (!this.enabled) return;
      if (data === undefined) console.warn(`[${SCRIPT_NAME}][WARN] ${message}`);
      else console.warn(`[${SCRIPT_NAME}][WARN] ${message}`, data);
    }

    error(message, error) {
      const safe = error ? ErrorUtils.serializable(error) : undefined;
      if (safe === undefined) console.error(`[${SCRIPT_NAME}][ERROR] ${message}`);
      else console.error(`[${SCRIPT_NAME}][ERROR] ${message}`, safe);
    }
  }

  class SettingsManager {
    constructor() {
      this.settings = { ...Config.defaultSettings };
      this.listeners = new Set();
    }

    load() {
      let stored = {};
      try {
        if (typeof GM_getValue === 'function') stored = GM_getValue(Config.settingsKey, {}) || {};
      } catch (_) {
        stored = {};
      }
      this.settings = this.validate({ ...Config.defaultSettings, ...stored });
      return this.get();
    }

    get() {
      return { ...this.settings };
    }

    validate(input) {
      const novelFormats = new Set(['txt', 'markdown', 'both']);
      const seriesFormats = new Set(['merged-txt', 'chapter-zip', 'both']);
      return {
        debug: Boolean(input.debug),
        imageConcurrency: Math.round(Utils.clamp(input.imageConcurrency, 1, 5)),
        retryCount: Math.round(Utils.clamp(input.retryCount, 0, 5)),
        requestTimeoutMs: Math.round(Utils.clamp(input.requestTimeoutMs, 10000, 120000)),
        novelFormat: novelFormats.has(input.novelFormat) ? input.novelFormat : Config.defaultSettings.novelFormat,
        seriesFormat: seriesFormats.has(input.seriesFormat) ? input.seriesFormat : Config.defaultSettings.seriesFormat,
        downloadEmbeddedImages: Boolean(input.downloadEmbeddedImages),
        notifications: Boolean(input.notifications),
        showFloatingButton: Boolean(input.showFloatingButton),
        imageFilenameTemplate: String(input.imageFilenameTemplate || Config.defaultSettings.imageFilenameTemplate).slice(0, 240),
        novelFilenameTemplate: String(input.novelFilenameTemplate || Config.defaultSettings.novelFilenameTemplate).slice(0, 240),
        seriesFilenameTemplate: String(input.seriesFilenameTemplate || Config.defaultSettings.seriesFilenameTemplate).slice(0, 240)
      };
    }

    save(nextSettings) {
      this.settings = this.validate({ ...this.settings, ...nextSettings });
      if (typeof GM_setValue === 'function') GM_setValue(Config.settingsKey, this.settings);
      for (const listener of this.listeners) listener(this.get());
      return this.get();
    }

    subscribe(listener) {
      this.listeners.add(listener);
      return () => this.listeners.delete(listener);
    }
  }

  const PageDetector = {
    detect(input) {
      let url;
      try {
        url = input instanceof URL ? input : new URL(String(input), 'https://www.pixiv.net/');
      } catch (_) {
        return { type: 'other', key: 'other' };
      }
      const path = url.pathname.replace(/^\/(?:[a-z]{2}(?:-[a-z]{2})?)\//i, '/');
      let match = path.match(/^\/artworks\/(\d+)(?:\/|$)/);
      if (match) return { type: 'artwork', id: match[1], key: `artwork:${match[1]}` };

      match = path.match(/^\/novel\/series\/(\d+)\/contents\/(\d+)(?:\/|$)/);
      if (match) {
        return {
          type: 'novel-series-content',
          seriesId: match[1],
          contentOrder: Number(match[2]),
          key: `novel-series-content:${match[1]}:${match[2]}`
        };
      }

      match = path.match(/^\/novel\/series\/(\d+)(?:\/|$)/);
      if (match) return { type: 'novel-series', seriesId: match[1], key: `novel-series:${match[1]}` };

      if (path === '/novel/show.php') {
        const id = url.searchParams.get('id');
        if (/^\d+$/.test(id || '')) return { type: 'novel', id, key: `novel:${id}` };
      }
      return { type: 'other', key: 'other' };
    }
  };

  class RouteObserver {
    constructor(options = {}) {
      this.pollIntervalMs = options.pollIntervalMs || Config.routePollIntervalMs;
      this.callback = null;
      this.lastHref = '';
      this.timer = null;
      this.pollTimer = null;
      this.eventName = `${SCRIPT_NAME}:location-change`;
      this.originalPushState = null;
      this.originalReplaceState = null;
      this.boundCheck = () => this.scheduleCheck();
    }

    start(callback) {
      if (this.callback || typeof window === 'undefined') return;
      this.callback = callback;
      this.lastHref = window.location.href;
      this.originalPushState = history.pushState;
      this.originalReplaceState = history.replaceState;
      const dispatch = () => window.dispatchEvent(new Event(this.eventName));
      history.pushState = (...args) => {
        const result = this.originalPushState.apply(history, args);
        dispatch();
        return result;
      };
      history.replaceState = (...args) => {
        const result = this.originalReplaceState.apply(history, args);
        dispatch();
        return result;
      };
      window.addEventListener(this.eventName, this.boundCheck);
      window.addEventListener('popstate', this.boundCheck);
      this.pollTimer = setInterval(this.boundCheck, this.pollIntervalMs);
      callback(PageDetector.detect(window.location.href));
    }

    scheduleCheck() {
      clearTimeout(this.timer);
      this.timer = setTimeout(() => this.check(), 60);
    }

    check() {
      if (!this.callback || window.location.href === this.lastHref) return;
      this.lastHref = window.location.href;
      this.callback(PageDetector.detect(this.lastHref));
    }

    stop() {
      if (typeof window === 'undefined') return;
      clearTimeout(this.timer);
      clearInterval(this.pollTimer);
      window.removeEventListener(this.eventName, this.boundCheck);
      window.removeEventListener('popstate', this.boundCheck);
      if (this.originalPushState) history.pushState = this.originalPushState;
      if (this.originalReplaceState) history.replaceState = this.originalReplaceState;
      this.callback = null;
    }
  }

  function parseRetryAfter(value) {
    if (!value) return 0;
    const seconds = Number(value);
    if (Number.isFinite(seconds)) return Math.max(0, seconds * 1000);
    const date = new Date(value).getTime();
    return Number.isFinite(date) ? Math.max(0, date - Date.now()) : 0;
  }

  function mapHttpStatus(status, context = '', retryAfterMs = 0) {
    const options = { status, context, retryAfterMs };
    if (status === 401) return new PixivDownloaderError('LOGIN_REQUIRED', '需要登录。', options);
    if (status === 403) return new PixivDownloaderError('FORBIDDEN', '请求被拒绝。', options);
    if (status === 404) return new PixivDownloaderError('NOT_FOUND', '资源不存在。', options);
    if (status === 429) return new PixivDownloaderError('RATE_LIMIT', '请求过于频繁。', { ...options, retryable: true });
    if (status >= 500) return new PixivDownloaderError('SERVER_ERROR', `服务器返回 ${status}。`, { ...options, retryable: true });
    return new PixivDownloaderError('API_ERROR', `请求返回 HTTP ${status}。`, options);
  }

  class RequestManager {
    constructor(options = {}) {
      this.baseUrl = options.baseUrl || 'https://www.pixiv.net';
      this.timeoutProvider = options.timeoutProvider || (() => Config.defaultSettings.requestTimeoutMs);
      this.retryProvider = options.retryProvider || (() => 0);
      this.retryBaseDelayMs = Math.max(0, Number(options.retryBaseDelayMs == null ? 1000 : options.retryBaseDelayMs));
      this.fetchImpl = options.fetchImpl || (typeof fetch === 'function' ? fetch.bind(globalThis) : null);
      this.logger = options.logger || new Logger(false);
    }

    async requestJson(path, options = {}) {
      const retryCount = Math.round(Utils.clamp(
        options.retries == null ? this.retryProvider() : options.retries,
        0,
        5
      ));
      let lastError = null;
      for (let attempt = 0; attempt <= retryCount; attempt += 1) {
        try {
          return await this.requestJsonOnce(path, options);
        } catch (error) {
          lastError = error;
          if (ErrorUtils.isAbort(error) || !error.retryable || attempt >= retryCount) throw error;
          const exponential = Math.min(30000, this.retryBaseDelayMs * (2 ** attempt));
          const jitter = exponential * 0.2 * ((Math.random() * 2) - 1);
          let delay = Math.max(0, Math.round(exponential + jitter));
          if (error.code === 'RATE_LIMIT') delay = Math.max(delay, error.retryAfterMs || 10000);
          this.logger.warn('Pixiv JSON 请求等待重试', {
            path: new URL(path, this.baseUrl).pathname,
            attempt: attempt + 1,
            delay
          });
          await Utils.sleep(delay, options.signal);
        }
      }
      throw lastError;
    }

    async requestJsonOnce(path, options = {}) {
      if (!this.fetchImpl) throw new PixivDownloaderError('NETWORK', 'Fetch API 不可用。');
      const url = new URL(path, this.baseUrl).toString();
      const externalSignal = options.signal;
      Utils.assertNotAborted(externalSignal);
      const controller = new AbortController();
      const timeoutMs = Number(options.timeoutMs) || Number(this.timeoutProvider()) || Config.defaultSettings.requestTimeoutMs;
      let timedOut = false;
      const onExternalAbort = () => controller.abort();
      if (externalSignal) externalSignal.addEventListener('abort', onExternalAbort, { once: true });
      const timer = setTimeout(() => {
        timedOut = true;
        controller.abort();
      }, timeoutMs);
      this.logger.info('请求 Pixiv JSON', { path: new URL(url).pathname });
      try {
        const response = await this.fetchImpl(url, {
          method: 'GET',
          credentials: 'include',
          cache: 'no-store',
          headers: { Accept: 'application/json' },
          signal: controller.signal
        });
        const status = Number(response.status) || 0;
        if (!(status >= 200 && status < 300)) {
          const retryAfter = response.headers && response.headers.get ? parseRetryAfter(response.headers.get('Retry-After')) : 0;
          throw mapHttpStatus(status, new URL(url).pathname, retryAfter);
        }
        const text = await response.text();
        try {
          return JSON.parse(text);
        } catch (error) {
          throw new PixivDownloaderError('INVALID_JSON', 'JSON 解析失败。', {
            context: new URL(url).pathname,
            cause: error
          });
        }
      } catch (error) {
        if (ErrorUtils.isAbort(error)) {
          if (externalSignal && externalSignal.aborted) throw ErrorUtils.abortError();
          if (timedOut) {
            throw new PixivDownloaderError('TIMEOUT', '请求超时。', {
              retryable: true,
              context: new URL(url).pathname,
              cause: error
            });
          }
          throw ErrorUtils.abortError();
        }
        if (error instanceof PixivDownloaderError) throw error;
        throw new PixivDownloaderError('NETWORK', '网络请求失败。', {
          retryable: true,
          context: new URL(url).pathname,
          cause: error
        });
      } finally {
        clearTimeout(timer);
        if (externalSignal) externalSignal.removeEventListener('abort', onExternalAbort);
      }
    }

    async getBody(path, options = {}) {
      const payload = await this.requestJson(path, options);
      if (!payload || typeof payload !== 'object') {
        throw new PixivDownloaderError('API_SCHEMA_CHANGED', '响应不是对象。', { context: path });
      }
      if (payload.error) {
        const message = String(payload.message || 'Pixiv API error');
        const lower = message.toLowerCase();
        if (lower.includes('login')) throw new PixivDownloaderError('LOGIN_REQUIRED', message, { context: path });
        if (lower.includes('not found') || lower.includes('deleted')) {
          throw new PixivDownloaderError('NOT_FOUND', message, { context: path });
        }
        throw new PixivDownloaderError('API_ERROR', message, { context: path });
      }
      if (!Object.prototype.hasOwnProperty.call(payload, 'body') || payload.body == null) {
        throw new PixivDownloaderError('API_SCHEMA_CHANGED', '响应缺少 body。', { context: path });
      }
      return payload.body;
    }
  }

  // Pixiv adapter boundary. Verified against the live site on 2026-08-08.
  // If Pixiv changes its internal JSON, update this class before touching downloaders or UI code.
  class PixivDataAdapter {
    constructor(requestManager, logger = new Logger(false)) {
      this.request = requestManager;
      this.logger = logger;
      this.cache = new Map();
    }

    normalizeId(value, label = 'ID') {
      const id = String(value == null ? '' : value);
      if (!/^\d+$/.test(id)) throw new PixivDownloaderError('INVALID_ID', `${label} 无效。`);
      return id;
    }

    memo(key, loader, force = false) {
      if (!force && this.cache.has(key)) return this.cache.get(key);
      const promise = Promise.resolve().then(loader).catch((error) => {
        this.cache.delete(key);
        throw error;
      });
      this.cache.set(key, promise);
      return promise;
    }

    async getArtworkInfo(id, options = {}) {
      const artworkId = this.normalizeId(id, '作品 ID');
      return this.memo(`artwork:${artworkId}`, async () => {
        const raw = await this.request.getBody(`/ajax/illust/${artworkId}`, options);
        const typeNumber = Number(raw.illustType);
        const type = typeNumber === 2 ? 'ugoira' : typeNumber === 1 ? 'manga' : 'illustration';
        if (!raw.illustTitle || !raw.userId || !raw.userName || !Number.isFinite(Number(raw.pageCount))) {
          throw new PixivDownloaderError('API_SCHEMA_CHANGED', '插画基本字段缺失。', {
            context: 'PixivDataAdapter.getArtworkInfo'
          });
        }
        return {
          id: String(raw.illustId || raw.id || artworkId),
          title: String(raw.illustTitle || raw.title),
          description: Utils.htmlToText(raw.illustComment || raw.description || ''),
          author: String(raw.userName),
          authorId: String(raw.userId),
          pageCount: Number(raw.pageCount),
          type,
          typeNumber,
          width: Number(raw.width) || 0,
          height: Number(raw.height) || 0,
          createDate: raw.createDate || '',
          updateDate: raw.uploadDate || '',
          tags: this.mapTags(raw.tags),
          isLoginOnly: Boolean(raw.isLoginOnly),
          firstOriginalUrl: raw.urls && raw.urls.original ? String(raw.urls.original) : ''
        };
      }, options.force);
    }

    async getArtworkPages(id, options = {}) {
      const artworkId = this.normalizeId(id, '作品 ID');
      return this.memo(`artwork-pages:${artworkId}`, async () => {
        const body = await this.request.getBody(`/ajax/illust/${artworkId}/pages`, options);
        if (!Array.isArray(body)) {
          throw new PixivDownloaderError('API_SCHEMA_CHANGED', '插画 pages 不是数组。', {
            context: 'PixivDataAdapter.getArtworkPages'
          });
        }
        return body.map((page, index) => ({
          index,
          originalUrl: page && page.urls && page.urls.original ? String(page.urls.original) : '',
          extension: page && page.urls && page.urls.original ? FilenameUtils.extensionFromUrl(page.urls.original, 'bin') : '',
          width: Number(page && page.width) || 0,
          height: Number(page && page.height) || 0
        }));
      }, options.force);
    }

    async getUgoiraMeta(id, options = {}) {
      const artworkId = this.normalizeId(id, '作品 ID');
      return this.memo(`ugoira:${artworkId}`, async () => {
        const raw = await this.request.getBody(`/ajax/illust/${artworkId}/ugoira_meta`, options);
        if (!raw.originalSrc || !Array.isArray(raw.frames)) {
          throw new PixivDownloaderError('API_SCHEMA_CHANGED', 'Ugoira 元数据缺失。', {
            context: 'PixivDataAdapter.getUgoiraMeta'
          });
        }
        return {
          originalSrc: String(raw.originalSrc),
          previewSrc: raw.src ? String(raw.src) : '',
          mimeType: raw.mime_type ? String(raw.mime_type) : 'application/zip',
          frames: raw.frames.map((frame, index) => ({
            index,
            file: String(frame.file || ''),
            delay: Number(frame.delay) || 0
          }))
        };
      }, options.force);
    }

    async getNovelInfo(id, options = {}) {
      const novelId = this.normalizeId(id, '小说 ID');
      return this.memo(`novel:${novelId}`, async () => {
        const raw = await this.request.getBody(`/ajax/novel/${novelId}`, options);
        return this.mapNovel(raw, 'PixivDataAdapter.getNovelInfo');
      }, options.force);
    }

    async getNovelBySeriesContent(seriesId, contentOrder, options = {}) {
      const normalizedSeriesId = this.normalizeId(seriesId, 'Series ID');
      const order = Number(contentOrder);
      if (!Number.isInteger(order) || order < 1) throw new PixivDownloaderError('INVALID_ID', '章节顺序无效。');
      return this.memo(`novel-series-content:${normalizedSeriesId}:${order}`, async () => {
        const raw = await this.request.getBody(`/ajax/novel/series/${normalizedSeriesId}/contents/${order}`, options);
        return this.mapNovel(raw, 'PixivDataAdapter.getNovelBySeriesContent');
      }, options.force);
    }

    mapNovel(raw, context) {
      if (!raw || !raw.id || !raw.title || !raw.userId || !raw.userName || typeof raw.content !== 'string') {
        if (raw && raw.isLoginOnly) {
          throw new PixivDownloaderError('LOGIN_REQUIRED', '登录限定小说正文不可用。', { context });
        }
        throw new PixivDownloaderError('API_SCHEMA_CHANGED', '小说基本字段或正文缺失。', { context });
      }
      const uploadedImages = {};
      if (raw.textEmbeddedImages && typeof raw.textEmbeddedImages === 'object') {
        for (const [key, image] of Object.entries(raw.textEmbeddedImages)) {
          uploadedImages[String(key)] = {
            id: String((image && image.novelImageId) || key),
            originalUrl: image && image.urls && image.urls.original ? String(image.urls.original) : ''
          };
        }
      }
      const series = raw.seriesNavData && raw.seriesNavData.seriesId ? raw.seriesNavData : null;
      return {
        id: String(raw.id),
        title: String(raw.title),
        author: String(raw.userName),
        authorId: String(raw.userId),
        description: Utils.htmlToText(raw.description || ''),
        tags: this.mapTags(raw.tags),
        createDate: raw.createDate || '',
        updateDate: raw.uploadDate || '',
        characterCount: Number(raw.characterCount) || 0,
        wordCount: Number(raw.wordCount) || 0,
        useWordCount: Boolean(raw.useWordCount),
        readingTime: Number(raw.readingTime) || 0,
        text: String(raw.content),
        rawText: String(raw.content),
        seriesId: series ? String(series.seriesId) : '',
        seriesTitle: series ? String(series.title || '') : '',
        seriesOrder: series ? Number(series.order) || 0 : 0,
        uploadedImages,
        isLoginOnly: Boolean(raw.isLoginOnly),
        language: raw.language ? String(raw.language) : ''
      };
    }

    mapTags(rawTags) {
      if (!rawTags) return [];
      const list = Array.isArray(rawTags) ? rawTags : Array.isArray(rawTags.tags) ? rawTags.tags : [];
      return list.map((tag) => String(typeof tag === 'string' ? tag : tag && tag.tag ? tag.tag : '')).filter(Boolean);
    }

    async getNovelSeriesInfo(seriesId, options = {}) {
      const id = this.normalizeId(seriesId, 'Series ID');
      return this.memo(`novel-series:${id}`, async () => {
        const raw = await this.request.getBody(`/ajax/novel/series/${id}`, options);
        if (!raw || !raw.id || !raw.title || !raw.userId || !raw.userName) {
          throw new PixivDownloaderError('API_SCHEMA_CHANGED', '系列基本字段缺失。', {
            context: 'PixivDataAdapter.getNovelSeriesInfo'
          });
        }
        const total = Number(raw.displaySeriesContentCount || raw.publishedContentCount || raw.total) || 0;
        return {
          id: String(raw.id),
          title: String(raw.title),
          author: String(raw.userName),
          authorId: String(raw.userId),
          description: Utils.htmlToText(raw.caption || ''),
          tags: Array.isArray(raw.tags) ? raw.tags.map(String) : [],
          total,
          publishedContentCount: Number(raw.publishedContentCount) || 0,
          displaySeriesContentCount: Number(raw.displaySeriesContentCount) || 0,
          createDate: raw.createDate || raw.createdTimestamp || '',
          updateDate: raw.updateDate || raw.updatedTimestamp || '',
          isConcluded: Boolean(raw.isConcluded),
          language: raw.language ? String(raw.language) : ''
        };
      }, options.force);
    }

    async getNovelSeriesWorks(seriesId, options = {}) {
      const id = this.normalizeId(seriesId, 'Series ID');
      const expectedTotal = Number(options.expectedTotal) || 0;
      try {
        const titles = await this.request.getBody(`/ajax/novel/series/${id}/content_titles`, options);
        const primary = this.validateContentTitles(titles, expectedTotal);
        this.logger.info('系列目录使用 content_titles', { seriesId: id, count: primary.length });
        if (typeof options.onPage === 'function') options.onPage({ source: 'content_titles', count: primary.length, done: true });
        return primary;
      } catch (error) {
        if (ErrorUtils.isAbort(error)) throw error;
        this.logger.warn('content_titles 不可用，改用分页接口', ErrorUtils.serializable(error));
      }
      return this.getNovelSeriesWorksPaginated(id, { ...options, expectedTotal });
    }

    validateContentTitles(body, expectedTotal = 0) {
      if (!Array.isArray(body) || body.length === 0) {
        throw new PixivDownloaderError('API_SCHEMA_CHANGED', 'content_titles 为空或不是数组。', {
          context: 'PixivDataAdapter.getNovelSeriesWorks'
        });
      }
      const works = body.map((item, index) => ({
        index: index + 1,
        novelId: item && item.id ? String(item.id) : '',
        title: item && item.title ? String(item.title) : `第 ${index + 1} 章`,
        available: !item || item.available !== false,
        contentOrder: index + 1
      }));
      const ids = works.map((work) => work.novelId).filter(Boolean);
      if (ids.length !== works.length || new Set(ids).size !== ids.length) {
        throw new PixivDownloaderError('SERIES_INCOMPLETE', 'content_titles 包含空 ID 或重复 ID。');
      }
      if (expectedTotal > 0 && works.length !== expectedTotal) {
        throw new PixivDownloaderError('SERIES_INCOMPLETE', `目录数量 ${works.length} 与系列总数 ${expectedTotal} 不一致。`);
      }
      return works;
    }

    async getNovelSeriesWorksPaginated(seriesId, options = {}) {
      const expectedTotal = Number(options.expectedTotal) || 0;
      const works = [];
      const seenIds = new Set();
      let lastOrder = 0;
      let terminated = false;
      for (let pageIndex = 0; pageIndex < Config.maxSeriesPages; pageIndex += 1) {
        Utils.assertNotAborted(options.signal);
        const path = `/ajax/novel/series_content/${seriesId}?limit=${Config.seriesPageSize}&last_order=${lastOrder}&order_by=asc`;
        const body = await this.request.getBody(path, options);
        const pageWorks = body && body.page && Array.isArray(body.page.seriesContents) ? body.page.seriesContents : null;
        if (!pageWorks) {
          throw new PixivDownloaderError('API_SCHEMA_CHANGED', 'series_content 缺少 page.seriesContents。', {
            context: 'PixivDataAdapter.getNovelSeriesWorks'
          });
        }
        if (pageWorks.length === 0) {
          terminated = true;
          break;
        }
        let added = 0;
        let maxOrder = lastOrder;
        for (const item of pageWorks) {
          const novelId = item && item.id ? String(item.id) : '';
          const contentOrder = Number(item && item.series && item.series.contentOrder);
          if (!novelId || !Number.isInteger(contentOrder) || contentOrder < 1) continue;
          maxOrder = Math.max(maxOrder, contentOrder);
          if (seenIds.has(novelId)) continue;
          seenIds.add(novelId);
          works.push({
            index: contentOrder,
            novelId,
            title: String(item.title || `第 ${contentOrder} 章`),
            available: true,
            contentOrder
          });
          added += 1;
        }
        works.sort((left, right) => left.contentOrder - right.contentOrder);
        if (typeof options.onPage === 'function') {
          options.onPage({ source: 'series_content', page: pageIndex + 1, count: works.length, done: false });
        }
        if (expectedTotal > 0 && works.length >= expectedTotal) {
          terminated = true;
          break;
        }
        if (added === 0 || maxOrder <= lastOrder) {
          throw new PixivDownloaderError('SERIES_INCOMPLETE', '系列分页没有新增章节，已终止以避免无限请求。');
        }
        lastOrder = maxOrder;
        if (pageWorks.length < Config.seriesPageSize) {
          terminated = true;
          break;
        }
      }
      if (!terminated) {
        throw new PixivDownloaderError('SERIES_INCOMPLETE', `系列分页超过安全上限 ${Config.maxSeriesPages}。`);
      }
      if (expectedTotal > 0 && works.length !== expectedTotal) {
        throw new PixivDownloaderError('SERIES_INCOMPLETE', `仅取得 ${works.length}/${expectedTotal} 章。`);
      }
      if (works.length === 0) throw new PixivDownloaderError('SERIES_INCOMPLETE', '系列目录为空。');
      return works.map((work, index) => ({ ...work, index: index + 1 }));
    }

    async resolveNovelEmbeddedImages(novel, options = {}) {
      const references = NovelParser.extractImageReferences(novel.rawText);
      const resolved = new Map();
      const pixivReferences = [];
      for (const reference of references) {
        if (reference.kind === 'uploaded') {
          const uploaded = novel.uploadedImages[reference.imageId];
          resolved.set(reference.key, {
            ...reference,
            available: Boolean(uploaded && uploaded.originalUrl),
            originalUrl: uploaded && uploaded.originalUrl ? uploaded.originalUrl : '',
            unavailableReason: uploaded && uploaded.originalUrl ? '' : '上传图片 Original URL 缺失'
          });
        } else {
          pixivReferences.push(reference);
        }
      }

      for (let offset = 0; offset < pixivReferences.length; offset += Config.embeddedResolveBatchSize) {
        Utils.assertNotAborted(options.signal);
        const batch = pixivReferences.slice(offset, offset + Config.embeddedResolveBatchSize);
        const params = new URLSearchParams();
        for (const reference of batch) params.append('id[]', reference.citationId);
        try {
          const body = await this.request.getBody(`/ajax/novel/${novel.id}/insert_illusts?${params.toString()}`, options);
          for (const reference of batch) {
            const item = body && body[reference.citationId];
            const originalUrl = item && item.visible && item.illust && item.illust.images && item.illust.images.original
              ? String(item.illust.images.original)
              : '';
            resolved.set(reference.key, {
              ...reference,
              available: Boolean(originalUrl),
              originalUrl,
              unavailableReason: originalUrl ? '' : String((item && item.unavailableType) || '引用插画不可用')
            });
          }
        } catch (error) {
          if (ErrorUtils.isAbort(error)) throw error;
          for (const reference of batch) {
            resolved.set(reference.key, {
              ...reference,
              available: false,
              originalUrl: '',
              unavailableReason: ErrorUtils.toUserMessage(error)
            });
          }
        }
      }
      return references.map((reference) => resolved.get(reference.key) || {
        ...reference,
        available: false,
        originalUrl: '',
        unavailableReason: '未能解析图片引用'
      });
    }
  }

  class NovelParser {
    static extractImageReferences(rawText) {
      const source = String(rawText == null ? '' : rawText);
      const references = [];
      const seen = new Set();
      const pattern = /\[(uploadedimage|pixivimage):([^\]]+)\]/g;
      let match;
      while ((match = pattern.exec(source))) {
        if (match[1] === 'uploadedimage') {
          if (!/^\d+$/.test(match[2])) continue;
          const key = `uploaded:${match[2]}`;
          if (seen.has(key)) continue;
          seen.add(key);
          references.push({
            key,
            kind: 'uploaded',
            imageId: match[2],
            raw: match[0]
          });
          continue;
        }
        const parsed = match[2].match(/^(\d+)(?:-(\d+))?$/);
        if (!parsed) continue;
        const citationId = parsed[2] ? `${parsed[1]}-${parsed[2]}` : parsed[1];
        const key = `pixiv:${citationId}`;
        if (seen.has(key)) continue;
        seen.add(key);
        references.push({
          key,
          kind: 'pixiv',
          illustId: parsed[1],
          pageNumber: parsed[2] ? Number(parsed[2]) : 1,
          citationId,
          raw: match[0]
        });
      }
      return references;
    }

    static tokenize(rawText) {
      const source = Utils.normalizeLineEndings(rawText);
      const tokens = [];
      let textBuffer = '';
      const flushText = () => {
        if (!textBuffer) return;
        tokens.push({ type: 'text', value: textBuffer });
        textBuffer = '';
      };
      const addToken = (token) => {
        flushText();
        tokens.push(token);
      };

      for (let index = 0; index < source.length;) {
        if (source[index] !== '[') {
          textBuffer += source[index];
          index += 1;
          continue;
        }

        if (source.startsWith('[newpage]', index)) {
          addToken({ type: 'newpage', raw: '[newpage]' });
          index += '[newpage]'.length;
          continue;
        }

        if (source.startsWith('[[', index)) {
          const end = source.indexOf(']]', index + 2);
          if (end >= 0) {
            const raw = source.slice(index, end + 2);
            const inner = source.slice(index + 2, end);
            const prefixes = [
              ['jumpuri:', 'jumpuri'],
              ['rb:', 'ruby'],
              ['emphasismark:', 'emphasis']
            ];
            let matched = false;
            for (const [prefix, type] of prefixes) {
              if (!inner.startsWith(prefix)) continue;
              const body = inner.slice(prefix.length);
              let divider = body.indexOf(' > ');
              let dividerLength = 3;
              if (divider < 0) {
                divider = body.indexOf('>');
                dividerLength = 1;
              }
              if (divider >= 0) {
                addToken({
                  type,
                  left: body.slice(0, divider).trim(),
                  right: body.slice(divider + dividerLength).trim(),
                  raw
                });
                index = end + 2;
                matched = true;
              }
              break;
            }
            if (matched) continue;
          }
        }

        const end = source.indexOf(']', index + 1);
        if (end >= 0) {
          const raw = source.slice(index, end + 1);
          const inner = source.slice(index + 1, end);
          let match = inner.match(/^chapter:(.*)$/s);
          if (match) {
            addToken({ type: 'chapter', value: match[1], raw });
            index = end + 1;
            continue;
          }
          match = inner.match(/^pixivimage:(\d+)(?:-(\d+))?$/);
          if (match) {
            const citationId = match[2] ? `${match[1]}-${match[2]}` : match[1];
            addToken({
              type: 'pixivimage',
              illustId: match[1],
              pageNumber: match[2] ? Number(match[2]) : 1,
              citationId,
              key: `pixiv:${citationId}`,
              raw
            });
            index = end + 1;
            continue;
          }
          match = inner.match(/^uploadedimage:(\d+)$/);
          if (match) {
            addToken({ type: 'uploadedimage', imageId: match[1], key: `uploaded:${match[1]}`, raw });
            index = end + 1;
            continue;
          }
          match = inner.match(/^jump:(\d+)$/);
          if (match) {
            addToken({ type: 'jump', pageNumber: Number(match[1]), raw });
            index = end + 1;
            continue;
          }
          match = inner.match(/^([bi]):(.*)$/s);
          if (match) {
            addToken({ type: match[1] === 'b' ? 'bold' : 'italic', value: match[2], raw });
            index = end + 1;
            continue;
          }
        }

        textBuffer += source[index];
        index += 1;
      }
      flushText();
      return tokens;
    }

    static render(rawText, mode = 'plain', resourceMap = new Map()) {
      const context = { mode, resourceMap, currentPage: 1 };
      return this.renderTokens(this.tokenize(rawText), context);
    }

    static renderTokens(tokens, context) {
      let output = '';
      for (const token of tokens) {
        switch (token.type) {
          case 'text':
            output += token.value;
            break;
          case 'newpage':
            context.currentPage += 1;
            output += context.mode === 'markdown'
              ? `\n\n<a id="page-${context.currentPage}"></a>\n\n---\n\n`
              : '\n\n==================== 分页 ====================\n\n';
            break;
          case 'chapter':
            output += context.mode === 'markdown'
              ? `\n\n## ${token.value}\n\n`
              : `\n\n【${token.value}】\n\n`;
            break;
          case 'pixivimage':
          case 'uploadedimage':
            output += this.renderImageToken(token, context);
            break;
          case 'jump':
            output += context.mode === 'markdown'
              ? `[跳转到第 ${token.pageNumber} 页](#page-${token.pageNumber})`
              : `（跳转到第 ${token.pageNumber} 页）`;
            break;
          case 'jumpuri': {
            const title = token.left || token.right;
            if (context.mode === 'markdown' && /^https?:\/\//i.test(token.right)) {
              output += `[${Utils.escapeMarkdownText(title)}](${token.right.replace(/\s/g, '%20')})`;
            } else {
              output += token.right ? `${title}（${token.right}）` : title;
            }
            break;
          }
          case 'ruby':
            output += context.mode === 'markdown'
              ? `<ruby>${this.escapeHtmlText(token.left)}<rt>${this.escapeHtmlText(token.right)}</rt></ruby>`
              : `${token.left}（${token.right}）`;
            break;
          case 'emphasis':
            output += context.mode === 'markdown'
              ? `<span data-emphasis-mark="${this.escapeHtmlAttribute(token.right)}">${this.escapeHtmlText(token.left)}</span>`
              : `${token.left}（强调符号：${token.right}）`;
            break;
          case 'bold': {
            const inner = this.renderTokens(this.tokenize(token.value), context);
            output += context.mode === 'markdown' ? `**${inner}**` : inner;
            break;
          }
          case 'italic': {
            const inner = this.renderTokens(this.tokenize(token.value), context);
            output += context.mode === 'markdown' ? `*${inner}*` : inner;
            break;
          }
          default:
            output += token.raw || '';
        }
      }
      return output;
    }

    static renderImageToken(token, context) {
      const resource = context.resourceMap instanceof Map ? context.resourceMap.get(token.key) : null;
      const localPath = typeof resource === 'string' ? resource : resource && resource.localPath;
      const label = token.type === 'pixivimage'
        ? `Pixiv 作品 ${token.illustId}${token.pageNumber > 1 ? ` 第 ${token.pageNumber} 页` : ''}`
        : `上传图片 ${token.imageId}`;
      if (context.mode === 'markdown') {
        if (localPath) return `\n\n![${label}](${localPath})\n\n`;
        if (token.type === 'pixivimage') {
          return `\n\n[插图：${label}](https://www.pixiv.net/artworks/${token.illustId})\n\n`;
        }
        return `\n\n[插图：${label}]\n\n`;
      }
      return `\n\n【插图：${label}】\n\n`;
    }

    static escapeHtmlAttribute(value) {
      return String(value == null ? '' : value)
        .replace(/&/g, '&amp;')
        .replace(/"/g, '&quot;')
        .replace(/</g, '&lt;')
        .replace(/>/g, '&gt;');
    }

    static escapeHtmlText(value) {
      return String(value == null ? '' : value)
        .replace(/&/g, '&amp;')
        .replace(/</g, '&lt;')
        .replace(/>/g, '&gt;');
    }
  }

  class DownloadQueue {
    constructor(options = {}) {
      this.concurrency = Math.round(Utils.clamp(options.concurrency || 3, 1, 5));
      this.retryCount = Math.round(Utils.clamp(options.retryCount == null ? 3 : options.retryCount, 0, 10));
      this.baseDelayMs = Math.max(0, Number(options.baseDelayMs == null ? 1000 : options.baseDelayMs));
      this.maxDelayMs = Math.max(this.baseDelayMs, Number(options.maxDelayMs || 30000));
      this.jitterRatio = Utils.clamp(options.jitterRatio == null ? 0.2 : options.jitterRatio, 0, 1);
      this.minStartIntervalMs = Math.max(0, Number(options.minStartIntervalMs) || 0);
      this.random = typeof options.random === 'function' ? options.random : Math.random;
      this.onProgress = typeof options.onProgress === 'function' ? options.onProgress : () => {};
      this.externalSignal = options.signal || null;
      this.controller = new AbortController();
      this.state = 'idle';
      this.tasks = [];
      this.results = [];
      this.failures = [];
      this.nextIndex = 0;
      this.completed = 0;
      this.succeeded = 0;
      this.failed = 0;
      this.bytes = 0;
      this.active = new Map();
      this.startedAt = 0;
      this.nextStartAt = 0;
      this.startGate = Promise.resolve();
      this.resumePromise = Promise.resolve();
      this.resumeResolver = null;
      this.externalAbortHandler = () => this.cancel();
    }

    async run(tasks) {
      if (this.state !== 'idle') throw new Error('DownloadQueue 只能运行一次。');
      this.tasks = Array.from(tasks || []);
      this.results = new Array(this.tasks.length);
      this.startedAt = Date.now();
      if (this.externalSignal) {
        if (this.externalSignal.aborted) this.controller.abort();
        else this.externalSignal.addEventListener('abort', this.externalAbortHandler, { once: true });
      }
      if (this.controller.signal.aborted) throw ErrorUtils.abortError();
      this.state = 'running';
      this.notify('state');
      if (this.tasks.length === 0) {
        this.state = 'completed';
        this.notify('state');
        return this.outcome();
      }
      const workerCount = Math.min(this.concurrency, this.tasks.length);
      try {
        await Promise.all(Array.from({ length: workerCount }, () => this.worker()));
        if (this.controller.signal.aborted) throw ErrorUtils.abortError();
        this.state = 'completed';
        this.notify('state');
        return this.outcome();
      } catch (error) {
        if (this.controller.signal.aborted || ErrorUtils.isAbort(error)) {
          this.state = 'cancelled';
          this.notify('state');
          throw ErrorUtils.abortError();
        }
        this.state = 'failed';
        this.notify('state', { error });
        throw error;
      } finally {
        if (this.externalSignal) this.externalSignal.removeEventListener('abort', this.externalAbortHandler);
      }
    }

    async worker() {
      while (true) {
        await this.waitIfPaused();
        Utils.assertNotAborted(this.controller.signal);
        const index = this.nextIndex;
        this.nextIndex += 1;
        if (index >= this.tasks.length) return;
        const task = this.tasks[index];
        this.active.set(index, task.label || task.id || `任务 ${index + 1}`);
        this.notify('task-claimed', { index, task });
        let value;
        let finalError = null;
        for (let attempt = 0; attempt <= this.retryCount; attempt += 1) {
          await this.waitIfPaused();
          await this.reserveStartSlot();
          await this.waitIfPaused();
          Utils.assertNotAborted(this.controller.signal);
          this.notify('task-start', { index, task, attempt });
          try {
            value = await task.run({
              signal: this.controller.signal,
              attempt,
              index,
              task
            });
            finalError = null;
            break;
          } catch (error) {
            if (ErrorUtils.isAbort(error) || this.controller.signal.aborted) throw ErrorUtils.abortError();
            finalError = error;
            const retryable = Boolean(error && error.retryable) || (typeof task.shouldRetry === 'function' && task.shouldRetry(error));
            if (!retryable || attempt >= this.retryCount) break;
            const delay = this.retryDelay(attempt, error);
            this.notify('retry', { index, task, attempt: attempt + 1, delay, error });
            await Utils.sleep(delay, this.controller.signal);
          }
        }

        this.active.delete(index);
        this.completed += 1;
        if (finalError) {
          this.failed += 1;
          const failure = { index, task, error: finalError };
          this.results[index] = { status: 'rejected', reason: finalError, task };
          this.failures.push(failure);
          this.notify('task-failure', failure);
        } else {
          this.succeeded += 1;
          const resultBytes = this.resultBytes(value);
          this.bytes += resultBytes;
          this.results[index] = { status: 'fulfilled', value, task };
          this.notify('task-success', { index, task, value, bytes: resultBytes });
        }
      }
    }

    retryDelay(attempt, error) {
      const exponential = Math.min(this.maxDelayMs, this.baseDelayMs * (2 ** attempt));
      const jitter = exponential * this.jitterRatio * ((this.random() * 2) - 1);
      let delay = Math.max(0, Math.round(exponential + jitter));
      if (error && error.code === 'RATE_LIMIT') delay = Math.max(delay, error.retryAfterMs || 10000);
      return delay;
    }

    async reserveStartSlot() {
      let release;
      const previous = this.startGate;
      this.startGate = new Promise((resolve) => { release = resolve; });
      await previous;
      try {
        const waitMs = Math.max(0, this.nextStartAt - Date.now());
        if (waitMs > 0) await Utils.sleep(waitMs, this.controller.signal);
        this.nextStartAt = Date.now() + this.minStartIntervalMs;
      } finally {
        release();
      }
    }

    waitIfPaused() {
      if (this.state !== 'paused') return Promise.resolve();
      return new Promise((resolve, reject) => {
        const signal = this.controller.signal;
        const onAbort = () => {
          cleanup();
          reject(ErrorUtils.abortError());
        };
        const cleanup = () => signal.removeEventListener('abort', onAbort);
        signal.addEventListener('abort', onAbort, { once: true });
        this.resumePromise.then(() => {
          cleanup();
          if (signal.aborted) reject(ErrorUtils.abortError());
          else resolve();
        });
      });
    }

    pause() {
      if (this.state !== 'running') return false;
      this.state = 'paused';
      this.resumePromise = new Promise((resolve) => { this.resumeResolver = resolve; });
      this.notify('state');
      return true;
    }

    resume() {
      if (this.state !== 'paused') return false;
      this.state = 'running';
      const resolver = this.resumeResolver;
      this.resumeResolver = null;
      if (resolver) resolver();
      this.notify('state');
      return true;
    }

    cancel() {
      if (this.controller.signal.aborted || ['completed', 'cancelled'].includes(this.state)) return false;
      this.controller.abort();
      if (this.resumeResolver) this.resumeResolver();
      return true;
    }

    resultBytes(value) {
      if (!value) return 0;
      if (Number.isFinite(Number(value.bytes))) return Number(value.bytes);
      if (Number.isFinite(Number(value.byteLength))) return Number(value.byteLength);
      if (value.data && Number.isFinite(Number(value.data.byteLength))) return Number(value.data.byteLength);
      return 0;
    }

    snapshot() {
      const elapsedSeconds = Math.max(0.001, (Date.now() - this.startedAt) / 1000);
      return {
        state: this.state,
        total: this.tasks.length,
        completed: this.completed,
        succeeded: this.succeeded,
        failed: this.failed,
        bytes: this.bytes,
        speed: this.bytes / elapsedSeconds,
        percent: this.tasks.length ? Math.round((this.completed / this.tasks.length) * 100) : 100,
        activeLabels: Array.from(this.active.values())
      };
    }

    notify(type, detail = {}) {
      try {
        this.onProgress({ type, ...detail, snapshot: this.snapshot() });
      } catch (_) {
        // Progress rendering must never break the queue.
      }
    }

    outcome() {
      return {
        results: this.results.slice(),
        failures: this.failures.slice(),
        succeeded: this.succeeded,
        failed: this.failed,
        bytes: this.bytes
      };
    }
  }

  class BinaryFetcher {
    constructor(options = {}) {
      this.timeoutProvider = options.timeoutProvider || (() => Config.defaultSettings.requestTimeoutMs);
      this.gmRequest = options.gmRequest || (typeof GM_xmlhttpRequest === 'function' ? GM_xmlhttpRequest : null);
    }

    fetch(url, options = {}) {
      let parsed;
      try {
        parsed = new URL(url);
      } catch (error) {
        return Promise.reject(new PixivDownloaderError('UNSUPPORTED_IMAGE_HOST', '图片 URL 无效。', { cause: error }));
      }
      if (parsed.protocol !== 'https:' || parsed.hostname !== 'i.pximg.net') {
        return Promise.reject(new PixivDownloaderError('UNSUPPORTED_IMAGE_HOST', parsed.hostname || '未知域名'));
      }
      if (!this.gmRequest) {
        return Promise.reject(new PixivDownloaderError('NETWORK', 'GM_xmlhttpRequest 不可用。'));
      }
      const signal = options.signal;
      if (signal && signal.aborted) return Promise.reject(ErrorUtils.abortError());
      const timeout = Number(options.timeoutMs) || Number(this.timeoutProvider()) || Config.defaultSettings.requestTimeoutMs;

      return new Promise((resolve, reject) => {
        let settled = false;
        let requestHandle = null;
        const cleanup = () => {
          if (signal) signal.removeEventListener('abort', onAbort);
        };
        const finishResolve = (value) => {
          if (settled) return;
          settled = true;
          cleanup();
          resolve(value);
        };
        const finishReject = (error) => {
          if (settled) return;
          settled = true;
          cleanup();
          reject(error);
        };
        const onAbort = () => {
          try {
            if (requestHandle && typeof requestHandle.abort === 'function') requestHandle.abort();
          } catch (_) {
            // Ignore abort transport errors; the promise still rejects as cancelled.
          }
          finishReject(ErrorUtils.abortError());
        };

        requestHandle = this.gmRequest({
          method: 'GET',
          url: parsed.toString(),
          headers: {
            Referer: 'https://www.pixiv.net/',
            Accept: 'image/avif,image/webp,image/apng,image/svg+xml,image/*,*/*;q=0.8'
          },
          responseType: 'arraybuffer',
          timeout,
          onprogress: (event) => {
            if (typeof options.onProgress === 'function') {
              options.onProgress({
                loaded: Number(event.loaded) || 0,
                total: Number(event.total) || 0,
                lengthComputable: Boolean(event.lengthComputable)
              });
            }
          },
          onload: (response) => {
            const status = Number(response.status) || 0;
            if (!(status >= 200 && status < 300)) {
              const retryAfter = parseRetryAfter(this.headerValue(response.responseHeaders, 'retry-after'));
              finishReject(mapHttpStatus(status, parsed.pathname, retryAfter));
              return;
            }
            if (!(response.response instanceof ArrayBuffer)) {
              finishReject(new PixivDownloaderError('API_SCHEMA_CHANGED', '图片响应不是 ArrayBuffer。', {
                context: parsed.pathname
              }));
              return;
            }
            finishResolve({
              data: response.response,
              bytes: response.response.byteLength,
              contentType: this.headerValue(response.responseHeaders, 'content-type'),
              finalUrl: response.finalUrl || parsed.toString()
            });
          },
          ontimeout: () => finishReject(new PixivDownloaderError('TIMEOUT', '图片请求超时。', {
            retryable: true,
            context: parsed.pathname
          })),
          onerror: () => finishReject(new PixivDownloaderError('NETWORK', '图片请求失败。', {
            retryable: true,
            context: parsed.pathname
          })),
          onabort: () => {
            if (signal && signal.aborted) finishReject(ErrorUtils.abortError());
            else finishReject(new PixivDownloaderError('NETWORK', '图片请求被中止。', {
              retryable: true,
              context: parsed.pathname
            }));
          }
        });
        if (signal) signal.addEventListener('abort', onAbort, { once: true });
      });
    }

    headerValue(rawHeaders, name) {
      const target = String(name).toLowerCase();
      for (const line of String(rawHeaders || '').split(/\r?\n/)) {
        const index = line.indexOf(':');
        if (index < 0) continue;
        if (line.slice(0, index).trim().toLowerCase() === target) return line.slice(index + 1).trim();
      }
      return '';
    }
  }

  class ZipManager {
    constructor() {
      const ZipClass = typeof JSZip !== 'undefined'
        ? JSZip
        : typeof globalThis !== 'undefined'
          ? globalThis.JSZip
          : null;
      if (typeof ZipClass !== 'function') throw new PixivDownloaderError('ZIP_UNAVAILABLE', 'JSZip 不可用。');
      this.zip = new ZipClass();
    }

    normalizePath(path) {
      return String(path)
        .replace(/\\/g, '/')
        .split('/')
        .filter((part) => part && part !== '.' && part !== '..')
        .join('/');
    }

    addBinary(path, data) {
      this.zip.file(this.normalizePath(path), data, { binary: true, compression: 'STORE' });
    }

    addText(path, text, options = {}) {
      const withBom = options.bom !== false;
      const content = `${withBom ? '\ufeff' : ''}${String(text)}`;
      this.zip.file(this.normalizePath(path), content, { compression: 'DEFLATE' });
    }

    async generate(options = {}) {
      try {
        return await this.zip.generateAsync({
          type: 'blob',
          compression: 'DEFLATE',
          compressionOptions: { level: 6 },
          streamFiles: true
        }, (metadata) => {
          Utils.assertNotAborted(options.signal);
          if (typeof options.onProgress === 'function') options.onProgress(metadata.percent || 0, metadata.currentFile || '');
        });
      } catch (error) {
        if (ErrorUtils.isAbort(error)) throw error;
        if (error instanceof PixivDownloaderError) throw error;
        throw new PixivDownloaderError('ZIP_FAILED', 'ZIP 生成失败。', { cause: error });
      }
    }

    dispose() {
      this.zip = null;
    }
  }

  const ReportUtils = {
    failureLines(failures) {
      return failures.map((failure, index) => {
        const label = failure.label || (failure.task && (failure.task.label || failure.task.id)) || `任务 ${index + 1}`;
        const error = failure.error || failure.reason;
        return `${index + 1}. ${label}\n   ${ErrorUtils.toUserMessage(error)}`;
      });
    },

    failureReport(title, failures) {
      const lines = [title, '', `失败数量：${failures.length}`, '', ...this.failureLines(failures)];
      return Utils.toCrlf(lines.join('\n'));
    },

    queueFailures(outcome) {
      return outcome.failures.map((failure) => ({
        label: failure.task && (failure.task.label || failure.task.id) ? String(failure.task.label || failure.task.id) : `任务 ${failure.index + 1}`,
        error: failure.error
      }));
    }
  };

  const NovelFormatter = {
    plain(novel, resourceMap = new Map()) {
      const metadata = [
        `标题：${novel.title}`,
        `作者：${novel.author}`,
        `作者 ID：${novel.authorId}`,
        `Pixiv Novel ID：${novel.id}`
      ];
      if (novel.seriesTitle) metadata.push(`系列：${novel.seriesTitle}`);
      if (novel.seriesId) metadata.push(`Pixiv Series ID：${novel.seriesId}`);
      if (novel.seriesOrder) metadata.push(`系列顺序：${novel.seriesOrder}`);
      if (novel.tags.length) metadata.push(`标签：${novel.tags.join('、')}`);
      if (novel.createDate) metadata.push(`发布时间：${Utils.formatDate(novel.createDate)}`);
      if (novel.updateDate) metadata.push(`更新时间：${Utils.formatDate(novel.updateDate)}`);
      if (novel.characterCount) metadata.push(`字符数：${novel.characterCount}`);
      if (novel.wordCount) metadata.push(`字数：${novel.wordCount}`);
      if (novel.description) metadata.push('', '简介：', novel.description);
      return [
        ...metadata,
        '',
        '========================================',
        '',
        NovelParser.render(novel.rawText, 'plain', resourceMap)
      ].join('\n').trimEnd();
    },

    markdown(novel, resourceMap = new Map()) {
      const lines = [
        `# ${novel.title}`,
        '',
        `- 作者：${novel.author}`,
        `- 作者 ID：${novel.authorId}`,
        `- Pixiv Novel ID：${novel.id}`
      ];
      if (novel.seriesTitle) lines.push(`- 系列：${novel.seriesTitle}`);
      if (novel.seriesId) lines.push(`- Pixiv Series ID：${novel.seriesId}`);
      if (novel.seriesOrder) lines.push(`- 系列顺序：${novel.seriesOrder}`);
      if (novel.tags.length) lines.push(`- 标签：${novel.tags.map((tag) => `\`${tag.replace(/`/g, '\\`')}\``).join(' ')}`);
      if (novel.createDate) lines.push(`- 发布时间：${Utils.formatDate(novel.createDate)}`);
      if (novel.updateDate) lines.push(`- 更新时间：${Utils.formatDate(novel.updateDate)}`);
      if (novel.characterCount) lines.push(`- 字符数：${novel.characterCount}`);
      if (novel.wordCount) lines.push(`- 字数：${novel.wordCount}`);
      if (novel.description) lines.push('', '## 简介', '', novel.description);
      lines.push('', '## 正文', '', NovelParser.render(novel.rawText, 'markdown', resourceMap));
      return lines.join('\n').trimEnd();
    }
  };

  const SeriesFormatter = {
    info(series, works, chapterFailures = []) {
      const lines = [
        `系列名称：${series.title}`,
        `作者：${series.author}`,
        `作者 ID：${series.authorId}`,
        `Pixiv Series ID：${series.id}`,
        `章节总数：${works.length}`
      ];
      if (series.tags.length) lines.push(`标签：${series.tags.join('、')}`);
      if (series.createDate) lines.push(`创建时间：${Utils.formatDate(series.createDate)}`);
      if (series.updateDate) lines.push(`更新时间：${Utils.formatDate(series.updateDate)}`);
      lines.push(`状态：${series.isConcluded ? '已完结' : '连载中'}`);
      if (series.description) lines.push('', '简介：', series.description);
      lines.push('', '章节目录：');
      const padding = FilenameUtils.getNumberPadding(works.length, 2);
      const failedIds = new Set(chapterFailures.map((failure) => failure.novelId).filter(Boolean));
      for (const work of works) {
        const suffix = failedIds.has(work.novelId) ? ' [下载失败]' : '';
        lines.push(`${String(work.index).padStart(padding, '0')}  ${work.title}  (Novel ID: ${work.novelId})${suffix}`);
      }
      return lines.join('\n');
    },

    merged(series, works, novelsById, chapterFailures = []) {
      const padding = FilenameUtils.getNumberPadding(works.length, 2);
      const failureById = new Map(chapterFailures.map((failure) => [failure.novelId, failure]));
      const lines = [
        `系列名称：${series.title}`,
        `作者：${series.author}`,
        `作者 ID：${series.authorId}`,
        `Pixiv Series ID：${series.id}`,
        `章节总数：${works.length}`
      ];
      if (series.description) lines.push('', '简介：', series.description);
      lines.push('');
      for (const work of works) {
        const number = String(work.index).padStart(padding, '0');
        lines.push('========================================', '', `第${number}章 ${work.title}`, '');
        const novel = novelsById.get(work.novelId);
        if (novel) {
          lines.push(NovelParser.render(novel.rawText, 'plain'));
        } else {
          const failure = failureById.get(work.novelId);
          lines.push(`【本章下载失败：${failure ? ErrorUtils.toUserMessage(failure.error) : '正文不可用'}】`);
        }
        lines.push('');
      }
      return lines.join('\n').trimEnd();
    },

    readme(series, works, chapterFailures = []) {
      const lines = [
        `# ${series.title}`,
        '',
        `- 作者：${series.author}`,
        `- 作者 ID：${series.authorId}`,
        `- Pixiv Series ID：${series.id}`,
        `- 章节总数：${works.length}`
      ];
      if (series.description) lines.push('', '## 简介', '', series.description);
      lines.push('', '## 目录', '');
      const padding = FilenameUtils.getNumberPadding(works.length, 2);
      const failedIds = new Set(chapterFailures.map((failure) => failure.novelId).filter(Boolean));
      for (const work of works) {
        const number = String(work.index).padStart(padding, '0');
        const title = Utils.escapeMarkdownText(work.title);
        const suffix = failedIds.has(work.novelId) ? '（下载失败）' : '';
        lines.push(`- ${number} - ${title}${suffix}`);
      }
      return lines.join('\n');
    }
  };

  class DownloadContext {
    constructor(app, controller) {
      this.app = app;
      this.controller = controller;
      this.signal = controller.signal;
      this.settings = app.settingsManager.get();
      this.queue = null;
      this.warnings = [];
      this.failures = [];
    }

    setTitle(title) {
      this.app.ui.setOperationTitle(title);
    }

    setStatus(status) {
      this.app.ui.setStatus(status);
    }

    warn(message) {
      if (!message || this.warnings.includes(message)) return;
      this.warnings.push(message);
      this.app.ui.setWarnings(this.warnings);
    }

    addFailures(failures) {
      this.failures.push(...failures);
      this.app.ui.setFailures(this.failures);
    }

    setPhaseProgress(percent, label = '') {
      this.app.ui.setPhaseProgress(percent, label);
    }

    createQueue(options = {}) {
      const queue = new DownloadQueue({
        concurrency: options.concurrency || this.settings.imageConcurrency,
        retryCount: options.retryCount == null ? this.settings.retryCount : options.retryCount,
        baseDelayMs: options.baseDelayMs == null ? 1000 : options.baseDelayMs,
        maxDelayMs: options.maxDelayMs || 30000,
        minStartIntervalMs: options.minStartIntervalMs || 0,
        signal: this.signal,
        onProgress: (event) => this.app.ui.updateQueue(event)
      });
      this.queue = queue;
      this.app.attachQueue(queue);
      return queue;
    }

    saveBlob(blob, filename) {
      Utils.assertNotAborted(this.signal);
      Utils.saveBlob(blob, filename);
    }
  }

  class ArtworkDownloader {
    constructor(adapter, binaryFetcher, logger) {
      this.adapter = adapter;
      this.binaryFetcher = binaryFetcher;
      this.logger = logger;
    }

    async download(route, context) {
      context.setStatus('正在获取作品信息...');
      const artwork = await this.adapter.getArtworkInfo(route.id, { signal: context.signal });
      context.setTitle(artwork.title);
      if (artwork.type === 'ugoira') return this.downloadUgoira(artwork, context);

      context.setStatus('正在获取全部 Original 页面...');
      const pages = await this.adapter.getArtworkPages(artwork.id, { signal: context.signal });
      if (pages.length === 0 || (artwork.pageCount > 0 && pages.length !== artwork.pageCount)) {
        throw new PixivDownloaderError('API_SCHEMA_CHANGED', `pages 返回 ${pages.length}/${artwork.pageCount} 页。`, {
          context: 'PixivDataAdapter.getArtworkPages'
        });
      }
      const missing = pages.filter((page) => !page.originalUrl);
      if (missing.length) {
        const reason = artwork.isLoginOnly ? '登录限定作品的 Original URL 为空' : `第 ${missing.map((page) => page.index + 1).join('、')} 页缺少 Original URL`;
        throw new PixivDownloaderError('ORIGINAL_UNAVAILABLE', reason, { context: reason });
      }

      if (pages.length >= 100) {
        context.warn(`此作品包含 ${pages.length} 张原图。JSZip 会在内存中保存全部内容，请确保浏览器有足够内存。`);
      }
      if (pages.length === 1 && artwork.type !== 'manga') return this.downloadSingle(artwork, pages[0], context);
      return this.downloadMultiple(artwork, pages, context);
    }

    metadata(artwork) {
      return {
        author: artwork.author,
        authorId: artwork.authorId,
        title: artwork.title,
        id: artwork.id,
        date: String(artwork.createDate || '').slice(0, 10)
      };
    }

    async downloadSingle(artwork, page, context) {
      context.setStatus('正在下载 Original 原图...');
      const queue = context.createQueue({ concurrency: 1 });
      const outcome = await queue.run([{
        id: `${artwork.id}:0`,
        label: `Original 第 1 页`,
        run: ({ signal }) => this.binaryFetcher.fetch(page.originalUrl, { signal })
      }]);
      if (outcome.failed) throw outcome.failures[0].error;
      const binary = outcome.results[0].value;
      const extension = FilenameUtils.chooseExtension(binary.finalUrl || page.originalUrl, binary.contentType, page.extension || 'bin');
      const base = FilenameUtils.formatFilename(context.settings.imageFilenameTemplate, this.metadata(artwork), {
        requiredToken: 'id',
        requiredValue: artwork.id
      });
      const blob = new Blob([binary.data], { type: binary.contentType || 'application/octet-stream' });
      context.saveBlob(blob, `${base}.${extension}`);
      return { message: `Original 原图下载完成（${Utils.formatBytes(binary.bytes)}）。`, failures: [] };
    }

    async downloadMultiple(artwork, pages, context) {
      const zip = new ZipManager();
      const folder = FilenameUtils.sanitizeFilename(artwork.title, { maxLength: 120, fallback: artwork.id });
      const padding = FilenameUtils.getNumberPadding(pages.length, 3);
      context.setStatus(`正在下载 ${pages.length} 张 Original 原图...`);
      const queue = context.createQueue({ concurrency: context.settings.imageConcurrency });
      const tasks = pages.map((page) => {
        const number = String(page.index + 1).padStart(padding, '0');
        return {
          id: `${artwork.id}:${page.index}`,
          label: `${number}.${page.extension || 'img'}`,
          run: async ({ signal }) => {
            const binary = await this.binaryFetcher.fetch(page.originalUrl, { signal });
            const extension = FilenameUtils.chooseExtension(binary.finalUrl || page.originalUrl, binary.contentType, page.extension || 'bin');
            const filename = `${number}.${extension}`;
            zip.addBinary(`${folder}/${filename}`, binary.data);
            return { bytes: binary.bytes, filename };
          }
        };
      });
      const outcome = await queue.run(tasks);
      if (outcome.succeeded === 0) {
        zip.dispose();
        throw outcome.failures[0].error;
      }
      const failures = ReportUtils.queueFailures(outcome);
      if (failures.length) {
        zip.addText(`${folder}/下载失败.txt`, ReportUtils.failureReport('以下 Original 页面下载失败', failures));
        context.addFailures(failures);
      }
      context.setStatus('正在生成 ZIP...');
      const blob = await zip.generate({
        signal: context.signal,
        onProgress: (percent, currentFile) => context.setPhaseProgress(percent, currentFile ? `压缩：${currentFile}` : '正在压缩')
      });
      const base = FilenameUtils.formatFilename(context.settings.imageFilenameTemplate, this.metadata(artwork), {
        requiredToken: 'id',
        requiredValue: artwork.id
      });
      context.saveBlob(blob, `${base}.zip`);
      zip.dispose();
      return {
        message: `ZIP 下载完成：成功 ${outcome.succeeded}，失败 ${outcome.failed}。`,
        failures
      };
    }

    async downloadUgoira(artwork, context) {
      context.warn('Ugoira 将保存 Pixiv 原始帧 ZIP 与帧延时元数据，不转换为 GIF 或视频。');
      context.setStatus('正在获取 Ugoira 帧元数据...');
      const metadata = await this.adapter.getUgoiraMeta(artwork.id, { signal: context.signal });
      const queue = context.createQueue({ concurrency: 1 });
      context.setStatus('正在下载 Ugoira 原始帧 ZIP...');
      const outcome = await queue.run([{
        id: `${artwork.id}:ugoira`,
        label: 'Ugoira 原始帧 ZIP',
        run: ({ signal }) => this.binaryFetcher.fetch(metadata.originalSrc, { signal })
      }]);
      if (outcome.failed) throw outcome.failures[0].error;
      const binary = outcome.results[0].value;
      const zip = new ZipManager();
      const folder = FilenameUtils.sanitizeFilename(artwork.title, { maxLength: 120, fallback: artwork.id });
      zip.addBinary(`${folder}/frames-original.zip`, binary.data);
      zip.addText(`${folder}/animation.json`, JSON.stringify({
        pixivIllustId: artwork.id,
        title: artwork.title,
        frameCount: metadata.frames.length,
        frames: metadata.frames,
        format: 'Pixiv Ugoira original frame archive',
        verifiedAdapterDate: VERIFIED_DATE
      }, null, 2), { bom: false });
      zip.addText(`${folder}/README.txt`, Utils.toCrlf([
        '此文件保存 Pixiv 提供的 Ugoira 原始帧 ZIP。',
        'animation.json 中记录每一帧的文件名和延时（毫秒）。',
        '当前版本不进行 GIF 或视频转换。'
      ].join('\n')));
      context.setStatus('正在生成 Ugoira 外层 ZIP...');
      const blob = await zip.generate({
        signal: context.signal,
        onProgress: (percent, currentFile) => context.setPhaseProgress(percent, currentFile || '正在压缩')
      });
      const base = FilenameUtils.formatFilename(context.settings.imageFilenameTemplate, this.metadata(artwork), {
        requiredToken: 'id',
        requiredValue: artwork.id
      });
      context.saveBlob(blob, `${base} - Ugoira.zip`);
      zip.dispose();
      return { message: `Ugoira 原始帧包下载完成，共 ${metadata.frames.length} 帧。`, failures: [] };
    }
  }

  class NovelDownloader {
    constructor(adapter, binaryFetcher) {
      this.adapter = adapter;
      this.binaryFetcher = binaryFetcher;
    }

    async getNovel(route, signal) {
      if (route.type === 'novel-series-content') {
        return this.adapter.getNovelBySeriesContent(route.seriesId, route.contentOrder, { signal });
      }
      return this.adapter.getNovelInfo(route.id, { signal });
    }

    metadata(novel) {
      return {
        author: novel.author,
        authorId: novel.authorId,
        title: novel.title,
        id: novel.id,
        series: novel.seriesTitle,
        seriesId: novel.seriesId,
        date: String(novel.createDate || '').slice(0, 10)
      };
    }

    async download(route, context) {
      context.setStatus('正在获取完整小说正文...');
      const novel = await this.getNovel(route, context.signal);
      context.setTitle(novel.title);
      const base = FilenameUtils.formatFilename(context.settings.novelFilenameTemplate, this.metadata(novel), {
        requiredToken: 'id',
        requiredValue: novel.id
      });
      if (!context.settings.downloadEmbeddedImages) return this.downloadTextOnly(novel, base, context);
      return this.downloadWithImages(novel, base, context);
    }

    async downloadTextOnly(novel, base, context) {
      const format = context.settings.novelFormat;
      const plain = format !== 'markdown' ? NovelFormatter.plain(novel) : '';
      const markdown = format !== 'txt' ? NovelFormatter.markdown(novel) : '';
      if (format === 'txt') {
        const blob = new Blob(['\ufeff', Utils.toCrlf(plain)], { type: 'text/plain;charset=utf-8' });
        context.saveBlob(blob, `${base}.txt`);
        return { message: '小说 TXT 下载完成。', failures: [] };
      }
      if (format === 'markdown') {
        const blob = new Blob([markdown], { type: 'text/markdown;charset=utf-8' });
        context.saveBlob(blob, `${base}.md`);
        return { message: '小说 Markdown 下载完成。', failures: [] };
      }
      const zip = new ZipManager();
      const folder = FilenameUtils.sanitizeFilename(novel.title, { maxLength: 120, fallback: novel.id });
      zip.addText(`${folder}/${FilenameUtils.sanitizeFilename(novel.title, { maxLength: 110 })}.txt`, Utils.toCrlf(plain));
      zip.addText(`${folder}/${FilenameUtils.sanitizeFilename(novel.title, { maxLength: 110 })}.md`, markdown, { bom: false });
      context.setStatus('正在生成 TXT + Markdown ZIP...');
      const blob = await zip.generate({
        signal: context.signal,
        onProgress: (percent, currentFile) => context.setPhaseProgress(percent, currentFile || '正在压缩')
      });
      context.saveBlob(blob, `${base}.zip`);
      zip.dispose();
      return { message: '小说 TXT 与 Markdown 下载完成。', failures: [] };
    }

    async downloadWithImages(novel, base, context) {
      context.setStatus('正在解析小说内嵌图片...');
      const descriptors = await this.adapter.resolveNovelEmbeddedImages(novel, { signal: context.signal });
      const zip = new ZipManager();
      const folder = FilenameUtils.sanitizeFilename(novel.title, { maxLength: 120, fallback: novel.id });
      const imageMap = new Map();
      const unavailable = [];
      const downloadable = descriptors.filter((descriptor) => {
        if (descriptor.available && descriptor.originalUrl) return true;
        unavailable.push({
          label: descriptor.kind === 'pixiv' ? `Pixiv 插图 ${descriptor.citationId}` : `上传图片 ${descriptor.imageId}`,
          error: new PixivDownloaderError('CONTENT_UNAVAILABLE', descriptor.unavailableReason || '图片不可用')
        });
        return false;
      });
      const padding = FilenameUtils.getNumberPadding(descriptors.length, 3);
      context.setStatus(`正在下载 ${downloadable.length} 张小说内嵌图片...`);
      const queue = context.createQueue({ concurrency: context.settings.imageConcurrency });
      const tasks = downloadable.map((descriptor) => {
        const sourceIndex = descriptors.findIndex((item) => item.key === descriptor.key);
        const number = String(sourceIndex + 1).padStart(padding, '0');
        return {
          id: descriptor.key,
          label: `images/${number}`,
          run: async ({ signal }) => {
            const binary = await this.binaryFetcher.fetch(descriptor.originalUrl, { signal });
            const extension = FilenameUtils.chooseExtension(binary.finalUrl || descriptor.originalUrl, binary.contentType, 'bin');
            const localPath = `images/${number}.${extension}`;
            zip.addBinary(`${folder}/${localPath}`, binary.data);
            imageMap.set(descriptor.key, { localPath });
            return { bytes: binary.bytes, localPath };
          }
        };
      });
      const outcome = await queue.run(tasks);
      const failures = [...unavailable, ...ReportUtils.queueFailures(outcome)];
      if (failures.length) {
        zip.addText(`${folder}/图片下载失败.txt`, ReportUtils.failureReport('以下小说内嵌图片未能保存', failures));
        context.addFailures(failures);
      }
      const plain = NovelFormatter.plain(novel, imageMap);
      const markdown = NovelFormatter.markdown(novel, imageMap);
      const safeTitle = FilenameUtils.sanitizeFilename(novel.title, { maxLength: 110, fallback: novel.id });
      zip.addText(`${folder}/${safeTitle}.md`, markdown, { bom: false });
      if (context.settings.novelFormat !== 'markdown') {
        zip.addText(`${folder}/${safeTitle}.txt`, Utils.toCrlf(plain));
      }
      context.setStatus('正在生成小说 ZIP...');
      const blob = await zip.generate({
        signal: context.signal,
        onProgress: (percent, currentFile) => context.setPhaseProgress(percent, currentFile || '正在压缩')
      });
      context.saveBlob(blob, `${base}.zip`);
      zip.dispose();
      return {
        message: `小说 ZIP 下载完成：图片成功 ${outcome.succeeded}，失败 ${failures.length}。`,
        failures
      };
    }
  }

  class NovelSeriesDownloader {
    constructor(adapter, binaryFetcher) {
      this.adapter = adapter;
      this.binaryFetcher = binaryFetcher;
    }

    metadata(series) {
      return {
        author: series.author,
        authorId: series.authorId,
        title: series.title,
        series: series.title,
        seriesId: series.id,
        id: series.id,
        date: String(series.createDate || '').slice(0, 10)
      };
    }

    async download(route, context) {
      context.setStatus('正在获取系列信息...');
      const series = await this.adapter.getNovelSeriesInfo(route.seriesId, { signal: context.signal });
      context.setTitle(series.title);
      context.setStatus('正在获取完整系列目录...');
      const works = await this.adapter.getNovelSeriesWorks(series.id, {
        signal: context.signal,
        expectedTotal: series.total,
        onPage: (progress) => {
          if (progress.source === 'series_content') context.setStatus(`正在获取系列目录：已找到 ${progress.count} 章...`);
        }
      });
      if (works.length >= 100) {
        context.warn(`该系列包含 ${works.length} 章。请求会限速执行，生成 ZIP 时需要足够浏览器内存。`);
      }

      const padding = FilenameUtils.getNumberPadding(works.length, 2);
      context.setStatus(`正在下载 ${works.length} 章完整正文...`);
      const chapterQueue = context.createQueue({
        concurrency: Config.seriesRequestConcurrency,
        minStartIntervalMs: Config.seriesRequestIntervalMs
      });
      const chapterOutcome = await chapterQueue.run(works.map((work) => ({
        id: work.novelId,
        label: `${String(work.index).padStart(padding, '0')} - ${work.title}`,
        run: async ({ signal }) => {
          const novel = await this.adapter.getNovelInfo(work.novelId, { signal, retries: 0 });
          return { novel, bytes: Utils.textByteLength(novel.rawText) };
        }
      })));
      if (chapterOutcome.succeeded === 0) throw chapterOutcome.failures[0].error;

      const novelsById = new Map();
      for (const result of chapterOutcome.results) {
        if (result && result.status === 'fulfilled') novelsById.set(result.value.novel.id, result.value.novel);
      }
      const chapterFailures = chapterOutcome.failures.map((failure) => ({
        label: failure.task.label,
        error: failure.error,
        novelId: failure.task.id,
        index: failure.index + 1
      }));
      if (chapterFailures.length) context.addFailures(chapterFailures);

      const base = FilenameUtils.formatFilename(context.settings.seriesFilenameTemplate, this.metadata(series), {
        requiredToken: 'seriesId',
        requiredValue: series.id
      });
      if (context.settings.seriesFormat === 'merged-txt' && !context.settings.downloadEmbeddedImages) {
        const merged = SeriesFormatter.merged(series, works, novelsById, chapterFailures);
        const blob = new Blob(['\ufeff', Utils.toCrlf(merged)], { type: 'text/plain;charset=utf-8' });
        context.saveBlob(blob, `${base}.txt`);
        return {
          message: `系列合并 TXT 下载完成：成功 ${chapterOutcome.succeeded}，失败 ${chapterOutcome.failed}。`,
          failures: chapterFailures
        };
      }
      return this.buildSeriesZip(series, works, novelsById, chapterFailures, base, context);
    }

    async buildSeriesZip(series, works, novelsById, chapterFailures, base, context) {
      const zip = new ZipManager();
      const folder = FilenameUtils.sanitizeFilename(series.title, { maxLength: 120, fallback: series.id });
      const padding = FilenameUtils.getNumberPadding(works.length, 2);
      zip.addText(`${folder}/000 - 系列信息.txt`, Utils.toCrlf(SeriesFormatter.info(series, works, chapterFailures)));

      for (const work of works) {
        const number = String(work.index).padStart(padding, '0');
        const safeTitle = FilenameUtils.sanitizeFilename(work.title, { maxLength: 100, fallback: work.novelId });
        const novel = novelsById.get(work.novelId);
        const body = novel
          ? NovelFormatter.plain(novel)
          : `标题：${work.title}\r\nPixiv Novel ID：${work.novelId}\r\n\r\n【本章下载失败，请在 Pixiv 中检查访问权限后重试。】`;
        zip.addText(`${folder}/${number} - ${safeTitle}.txt`, Utils.toCrlf(body));
      }

      if (context.settings.seriesFormat === 'both' || context.settings.seriesFormat === 'merged-txt') {
        const merged = SeriesFormatter.merged(series, works, novelsById, chapterFailures);
        zip.addText(`${folder}/系列全文.txt`, Utils.toCrlf(merged));
      }

      const imageFailures = [];
      if (context.settings.downloadEmbeddedImages) {
        await this.addSeriesMarkdownAndImages(zip, folder, series, works, novelsById, chapterFailures, imageFailures, context);
      }

      const allFailures = [...chapterFailures, ...imageFailures];
      if (allFailures.length) {
        zip.addText(`${folder}/下载失败汇总.txt`, ReportUtils.failureReport('系列下载中的失败任务', allFailures));
        if (imageFailures.length) context.addFailures(imageFailures);
      }
      context.setStatus('正在生成系列 ZIP...');
      const blob = await zip.generate({
        signal: context.signal,
        onProgress: (percent, currentFile) => context.setPhaseProgress(percent, currentFile || '正在压缩')
      });
      context.saveBlob(blob, `${base}.zip`);
      zip.dispose();
      return {
        message: `系列 ZIP 下载完成：章节成功 ${novelsById.size}，章节失败 ${chapterFailures.length}，图片失败 ${imageFailures.length}。`,
        failures: allFailures
      };
    }

    async addSeriesMarkdownAndImages(zip, folder, series, works, novelsById, chapterFailures, imageFailures, context) {
      const successfulWorks = works.filter((work) => novelsById.has(work.novelId));
      const padding = FilenameUtils.getNumberPadding(works.length, 2);
      context.setStatus('正在解析各章内嵌图片...');
      const resolveQueue = context.createQueue({
        concurrency: Config.seriesRequestConcurrency,
        minStartIntervalMs: Config.seriesRequestIntervalMs
      });
      const resolveOutcome = await resolveQueue.run(successfulWorks.map((work) => ({
        id: work.novelId,
        label: `${String(work.index).padStart(padding, '0')} - 解析图片`,
        run: async ({ signal }) => {
          const novel = novelsById.get(work.novelId);
          const descriptors = await this.adapter.resolveNovelEmbeddedImages(novel, { signal });
          return { work, descriptors };
        }
      })));

      const descriptorsByNovel = new Map();
      for (const result of resolveOutcome.results) {
        if (result && result.status === 'fulfilled') {
          descriptorsByNovel.set(result.value.work.novelId, result.value.descriptors);
        }
      }
      for (const failure of ReportUtils.queueFailures(resolveOutcome)) imageFailures.push(failure);

      const resourceMaps = new Map();
      const imageTasks = [];
      for (const work of successfulWorks) {
        const descriptors = descriptorsByNovel.get(work.novelId) || [];
        const resourceMap = new Map();
        resourceMaps.set(work.novelId, resourceMap);
        const imagePadding = FilenameUtils.getNumberPadding(descriptors.length, 3);
        descriptors.forEach((descriptor, index) => {
          const number = String(index + 1).padStart(imagePadding, '0');
          if (!descriptor.available || !descriptor.originalUrl) {
            imageFailures.push({
              label: `第 ${work.index} 章图片 ${number}`,
              error: new PixivDownloaderError('CONTENT_UNAVAILABLE', descriptor.unavailableReason || '图片不可用')
            });
            return;
          }
          imageTasks.push({
            id: `${work.novelId}:${descriptor.key}`,
            label: `第 ${work.index} 章图片 ${number}`,
            run: async ({ signal }) => {
              const binary = await this.binaryFetcher.fetch(descriptor.originalUrl, { signal });
              const extension = FilenameUtils.chooseExtension(binary.finalUrl || descriptor.originalUrl, binary.contentType, 'bin');
              const relativePath = `images/chapter${String(work.index).padStart(padding, '0')}/${number}.${extension}`;
              zip.addBinary(`${folder}/${relativePath}`, binary.data);
              resourceMap.set(descriptor.key, { localPath: relativePath });
              return { bytes: binary.bytes, localPath: relativePath };
            }
          });
        });
      }

      context.setStatus(`正在下载系列内嵌图片（${imageTasks.length} 张）...`);
      const imageQueue = context.createQueue({ concurrency: context.settings.imageConcurrency });
      const imageOutcome = await imageQueue.run(imageTasks);
      imageFailures.push(...ReportUtils.queueFailures(imageOutcome));

      zip.addText(`${folder}/README.md`, SeriesFormatter.readme(series, works, chapterFailures), { bom: false });
      for (const work of works) {
        const number = String(work.index).padStart(padding, '0');
        const safeTitle = FilenameUtils.sanitizeFilename(work.title, { maxLength: 100, fallback: work.novelId });
        const novel = novelsById.get(work.novelId);
        const markdown = novel
          ? NovelFormatter.markdown(novel, resourceMaps.get(work.novelId) || new Map())
          : `# ${work.title}\n\n本章下载失败，请在 Pixiv 中检查访问权限后重试。`;
        zip.addText(`${folder}/${number} - ${safeTitle}.md`, markdown, { bom: false });
      }
    }
  }

  class UIManager {
    constructor(settingsManager) {
      this.settingsManager = settingsManager;
      this.settings = settingsManager.get();
      this.handlers = {};
      this.route = { type: 'other', key: 'other' };
      this.busy = false;
      this.startedAt = 0;
      this.elements = {};
      this.mounted = false;
    }

    mount(handlers = {}) {
      if (this.mounted || typeof document === 'undefined') return;
      this.handlers = handlers;
      this.injectStyles();
      const root = document.createElement('div');
      root.id = 'pdl-root';
      root.innerHTML = `
        <button id="pdl-action" type="button" aria-label="下载当前 Pixiv 作品">
          <span class="pdl-action-icon" aria-hidden="true">↓</span>
          <span id="pdl-action-label">下载当前作品</span>
        </button>
        <section id="pdl-panel" aria-live="polite" hidden>
          <header class="pdl-panel-header">
            <div class="pdl-panel-heading">
              <strong>Pixiv Downloader</strong>
              <span id="pdl-operation-title"></span>
            </div>
            <div class="pdl-header-actions">
              <button id="pdl-settings-button" class="pdl-icon-button" type="button" title="设置" aria-label="设置">⚙</button>
              <button id="pdl-hide-button" class="pdl-icon-button" type="button" title="隐藏" aria-label="隐藏">−</button>
            </div>
          </header>
          <div class="pdl-panel-body">
            <div id="pdl-status">准备下载</div>
            <div class="pdl-progress-track" role="progressbar" aria-valuemin="0" aria-valuemax="100" aria-valuenow="0">
              <div id="pdl-progress-bar"></div>
            </div>
            <div class="pdl-stats">
              <span id="pdl-count">0 / 0</span>
              <span id="pdl-percent">0%</span>
              <span id="pdl-bytes">0 B</span>
              <span id="pdl-speed">0 B/s</span>
            </div>
            <div id="pdl-current" class="pdl-current"></div>
            <ul id="pdl-warnings" class="pdl-message-list pdl-warning-list" hidden></ul>
            <ul id="pdl-failures" class="pdl-message-list pdl-failure-list" hidden></ul>
          </div>
          <footer class="pdl-panel-footer">
            <button id="pdl-pause-button" type="button" disabled>暂停</button>
            <button id="pdl-cancel-button" class="pdl-danger-button" type="button" disabled>取消</button>
          </footer>
        </section>
        <div id="pdl-modal-backdrop" hidden>
          <form id="pdl-settings-form" aria-label="Pixiv Downloader 设置">
            <header class="pdl-settings-header">
              <strong>Pixiv Downloader 设置</strong>
              <button id="pdl-settings-close" class="pdl-icon-button" type="button" title="关闭" aria-label="关闭">×</button>
            </header>
            <div class="pdl-settings-body">
              <label>图片质量
                <select disabled><option>Original（固定）</option></select>
              </label>
              <div class="pdl-field-row">
                <label>图片并发
                  <input name="imageConcurrency" type="number" min="1" max="5" step="1">
                </label>
                <label>失败重试
                  <input name="retryCount" type="number" min="0" max="5" step="1">
                </label>
              </div>
              <label>请求超时（秒）
                <input name="requestTimeoutSeconds" type="number" min="10" max="120" step="5">
              </label>
              <div class="pdl-field-row">
                <label>单篇小说格式
                  <select name="novelFormat">
                    <option value="txt">TXT</option>
                    <option value="markdown">Markdown</option>
                    <option value="both">TXT + Markdown ZIP</option>
                  </select>
                </label>
                <label>系列格式
                  <select name="seriesFormat">
                    <option value="merged-txt">合并 TXT</option>
                    <option value="chapter-zip">分章 ZIP</option>
                    <option value="both">分章 ZIP + 合并 TXT</option>
                  </select>
                </label>
              </div>
              <label class="pdl-check"><input name="downloadEmbeddedImages" type="checkbox">下载小说内嵌图片</label>
              <label class="pdl-check"><input name="notifications" type="checkbox">完成后发送通知</label>
              <label class="pdl-check"><input name="showFloatingButton" type="checkbox">显示右下角下载按钮</label>
              <label class="pdl-check"><input name="debug" type="checkbox">启用 DEBUG 日志</label>
              <label>图片文件名模板
                <input name="imageFilenameTemplate" type="text" maxlength="240">
              </label>
              <label>小说文件名模板
                <input name="novelFilenameTemplate" type="text" maxlength="240">
              </label>
              <label>系列文件名模板
                <input name="seriesFilenameTemplate" type="text" maxlength="240">
              </label>
            </div>
            <footer class="pdl-settings-footer">
              <button id="pdl-settings-reset" type="button">恢复默认</button>
              <div>
                <button id="pdl-settings-cancel" type="button">取消</button>
                <button class="pdl-primary-button" type="submit">保存</button>
              </div>
            </footer>
          </form>
        </div>`;
      document.body.appendChild(root);
      this.elements = {
        root,
        action: root.querySelector('#pdl-action'),
        actionLabel: root.querySelector('#pdl-action-label'),
        panel: root.querySelector('#pdl-panel'),
        title: root.querySelector('#pdl-operation-title'),
        status: root.querySelector('#pdl-status'),
        progressTrack: root.querySelector('.pdl-progress-track'),
        progressBar: root.querySelector('#pdl-progress-bar'),
        count: root.querySelector('#pdl-count'),
        percent: root.querySelector('#pdl-percent'),
        bytes: root.querySelector('#pdl-bytes'),
        speed: root.querySelector('#pdl-speed'),
        current: root.querySelector('#pdl-current'),
        warnings: root.querySelector('#pdl-warnings'),
        failures: root.querySelector('#pdl-failures'),
        pause: root.querySelector('#pdl-pause-button'),
        cancel: root.querySelector('#pdl-cancel-button'),
        hide: root.querySelector('#pdl-hide-button'),
        settingsButton: root.querySelector('#pdl-settings-button'),
        modal: root.querySelector('#pdl-modal-backdrop'),
        settingsForm: root.querySelector('#pdl-settings-form'),
        settingsClose: root.querySelector('#pdl-settings-close'),
        settingsCancel: root.querySelector('#pdl-settings-cancel'),
        settingsReset: root.querySelector('#pdl-settings-reset')
      };
      this.bindEvents();
      this.syncSettingsForm(this.settings);
      this.mounted = true;
      this.applyActionVisibility();
    }

    injectStyles() {
      const css = `
        #pdl-root, #pdl-root * { box-sizing: border-box; letter-spacing: 0; }
        #pdl-root { --pdl-bg: #ffffff; --pdl-surface: #f4f5f7; --pdl-border: #d8dce2; --pdl-text: #20242a; --pdl-muted: #66717e; --pdl-blue: #0096fa; --pdl-blue-hover: #007fd6; --pdl-red: #d9363e; --pdl-red-hover: #b82b32; --pdl-amber: #9a6200; --pdl-amber-bg: #fff4d6; font: 13px/1.45 Arial, "Microsoft YaHei", sans-serif; color: var(--pdl-text); }
        #pdl-action { position: fixed; right: 24px; bottom: 24px; z-index: 2147483644; display: inline-flex; align-items: center; gap: 8px; min-height: 42px; max-width: calc(100vw - 32px); padding: 0 16px; border: 0; border-radius: 8px; color: #fff; background: var(--pdl-blue); box-shadow: 0 4px 16px rgba(0,0,0,.22); font: 600 14px/1 Arial, "Microsoft YaHei", sans-serif; cursor: pointer; }
        #pdl-action:hover { background: var(--pdl-blue-hover); }
        #pdl-action:disabled { cursor: wait; opacity: .65; }
        .pdl-action-icon { font-size: 20px; line-height: 1; }
        #pdl-panel { position: fixed; right: 24px; bottom: 78px; z-index: 2147483644; width: 370px; max-width: calc(100vw - 32px); overflow: hidden; border: 1px solid var(--pdl-border); border-radius: 8px; background: var(--pdl-bg); box-shadow: 0 10px 34px rgba(0,0,0,.24); }
        #pdl-panel[hidden], #pdl-modal-backdrop[hidden], #pdl-action[hidden] { display: none !important; }
        .pdl-panel-header, .pdl-settings-header { display: flex; align-items: center; justify-content: space-between; gap: 12px; min-height: 48px; padding: 8px 12px; border-bottom: 1px solid var(--pdl-border); }
        .pdl-panel-heading { display: grid; min-width: 0; }
        .pdl-panel-heading strong { font-size: 14px; }
        #pdl-operation-title { overflow: hidden; color: var(--pdl-muted); font-size: 12px; text-overflow: ellipsis; white-space: nowrap; }
        .pdl-header-actions { display: flex; gap: 4px; flex: 0 0 auto; }
        .pdl-icon-button { display: inline-grid; place-items: center; width: 30px; height: 30px; padding: 0; border: 1px solid transparent; border-radius: 6px; color: var(--pdl-text); background: transparent; font-size: 17px; cursor: pointer; }
        .pdl-icon-button:hover { border-color: var(--pdl-border); background: var(--pdl-surface); }
        .pdl-panel-body { padding: 12px; }
        #pdl-status { min-height: 20px; font-weight: 600; overflow-wrap: anywhere; }
        .pdl-progress-track { height: 8px; margin-top: 10px; overflow: hidden; border-radius: 4px; background: #dfe3e8; }
        #pdl-progress-bar { width: 0; height: 100%; background: var(--pdl-blue); transition: width .15s ease; }
        .pdl-stats { display: grid; grid-template-columns: 1fr 52px 74px 84px; gap: 6px; margin-top: 8px; color: var(--pdl-muted); font-variant-numeric: tabular-nums; }
        .pdl-stats span { min-width: 0; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
        .pdl-stats span:not(:first-child) { text-align: right; }
        .pdl-current { min-height: 18px; margin-top: 8px; overflow: hidden; color: var(--pdl-muted); text-overflow: ellipsis; white-space: nowrap; }
        .pdl-message-list { max-height: 104px; margin: 10px 0 0; padding: 8px 8px 8px 26px; overflow: auto; border-radius: 6px; overflow-wrap: anywhere; }
        .pdl-warning-list { color: var(--pdl-amber); background: var(--pdl-amber-bg); }
        .pdl-failure-list { color: #a9232a; background: #ffe9ea; }
        .pdl-panel-footer, .pdl-settings-footer { display: flex; align-items: center; justify-content: flex-end; gap: 8px; min-height: 48px; padding: 8px 12px; border-top: 1px solid var(--pdl-border); background: var(--pdl-surface); }
        #pdl-root button:not(.pdl-icon-button):not(#pdl-action) { min-height: 32px; padding: 0 13px; border: 1px solid var(--pdl-border); border-radius: 6px; color: var(--pdl-text); background: var(--pdl-bg); font: 600 13px/1 Arial, "Microsoft YaHei", sans-serif; cursor: pointer; }
        #pdl-root button:not(.pdl-icon-button):not(#pdl-action):hover { background: var(--pdl-surface); }
        #pdl-root button:disabled { cursor: default; opacity: .45; }
        #pdl-root .pdl-danger-button { color: #fff !important; border-color: var(--pdl-red) !important; background: var(--pdl-red) !important; }
        #pdl-root .pdl-danger-button:hover { background: var(--pdl-red-hover) !important; }
        #pdl-root .pdl-primary-button { color: #fff !important; border-color: var(--pdl-blue) !important; background: var(--pdl-blue) !important; }
        #pdl-modal-backdrop { position: fixed; inset: 0; z-index: 2147483646; display: grid; place-items: center; padding: 16px; background: rgba(0,0,0,.48); }
        #pdl-settings-form { width: 560px; max-width: calc(100vw - 32px); min-width: 0; max-height: calc(100vh - 32px); overflow: hidden; border: 1px solid var(--pdl-border); border-radius: 8px; background: var(--pdl-bg); box-shadow: 0 16px 50px rgba(0,0,0,.32); }
        .pdl-settings-body { display: grid; gap: 12px; max-height: calc(100vh - 150px); padding: 14px; overflow: auto; }
        .pdl-settings-body label { display: grid; gap: 5px; min-width: 0; color: var(--pdl-muted); font-weight: 600; }
        .pdl-field-row { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; min-width: 0; }
        .pdl-settings-body input[type="text"], .pdl-settings-body input[type="number"], .pdl-settings-body select { width: 100%; min-width: 0; height: 34px; padding: 0 9px; border: 1px solid var(--pdl-border); border-radius: 6px; color: var(--pdl-text); background: var(--pdl-bg); font: 13px/1 Arial, "Microsoft YaHei", sans-serif; }
        .pdl-settings-body select:disabled { color: var(--pdl-muted); background: var(--pdl-surface); }
        .pdl-settings-body .pdl-check { display: flex; align-items: center; gap: 8px; color: var(--pdl-text); }
        .pdl-check input { width: 16px; height: 16px; margin: 0; accent-color: var(--pdl-blue); }
        .pdl-settings-footer { justify-content: space-between; }
        .pdl-settings-footer > div { display: flex; gap: 8px; }
        @media (prefers-color-scheme: dark) {
          #pdl-root { --pdl-bg: #24272c; --pdl-surface: #1b1e22; --pdl-border: #424850; --pdl-text: #f2f4f7; --pdl-muted: #aeb7c2; --pdl-blue: #00a4f5; --pdl-blue-hover: #24b4fa; --pdl-amber: #ffd269; --pdl-amber-bg: #493810; }
          .pdl-progress-track { background: #4a5058; }
          .pdl-failure-list { color: #ffb6ba; background: #54262a; }
        }
        @media (max-width: 520px) {
          #pdl-action { right: 16px; bottom: 16px; }
          #pdl-panel { right: 16px; bottom: 68px; }
          .pdl-field-row { grid-template-columns: 1fr; }
          .pdl-stats { grid-template-columns: 1fr 44px 68px; }
          #pdl-speed { display: none; }
        }
      `;
      if (typeof GM_addStyle === 'function') GM_addStyle(css);
      else {
        const style = document.createElement('style');
        style.textContent = css;
        document.head.appendChild(style);
      }
    }

    bindEvents() {
      this.elements.action.addEventListener('click', () => {
        if (typeof this.handlers.onAction === 'function') this.handlers.onAction();
      });
      this.elements.pause.addEventListener('click', () => {
        if (typeof this.handlers.onPauseToggle === 'function') this.handlers.onPauseToggle();
      });
      this.elements.cancel.addEventListener('click', () => {
        if (typeof this.handlers.onCancel === 'function') this.handlers.onCancel();
      });
      this.elements.hide.addEventListener('click', () => { this.elements.panel.hidden = true; });
      this.elements.settingsButton.addEventListener('click', () => this.showSettings());
      this.elements.settingsClose.addEventListener('click', () => this.hideSettings());
      this.elements.settingsCancel.addEventListener('click', () => this.hideSettings());
      this.elements.modal.addEventListener('click', (event) => {
        if (event.target === this.elements.modal) this.hideSettings();
      });
      this.elements.settingsReset.addEventListener('click', () => this.syncSettingsForm({ ...Config.defaultSettings }));
      this.elements.settingsForm.addEventListener('submit', (event) => {
        event.preventDefault();
        const form = new FormData(this.elements.settingsForm);
        const next = {
          imageConcurrency: Number(form.get('imageConcurrency')),
          retryCount: Number(form.get('retryCount')),
          requestTimeoutMs: Number(form.get('requestTimeoutSeconds')) * 1000,
          novelFormat: String(form.get('novelFormat')),
          seriesFormat: String(form.get('seriesFormat')),
          downloadEmbeddedImages: form.has('downloadEmbeddedImages'),
          notifications: form.has('notifications'),
          showFloatingButton: form.has('showFloatingButton'),
          debug: form.has('debug'),
          imageFilenameTemplate: String(form.get('imageFilenameTemplate') || ''),
          novelFilenameTemplate: String(form.get('novelFilenameTemplate') || ''),
          seriesFilenameTemplate: String(form.get('seriesFilenameTemplate') || '')
        };
        if (typeof this.handlers.onSaveSettings === 'function') this.handlers.onSaveSettings(next);
        this.hideSettings();
      });
    }

    updateSettings(settings) {
      this.settings = { ...settings };
      this.syncSettingsForm(this.settings);
      this.applyActionVisibility();
    }

    syncSettingsForm(settings) {
      if (!this.elements.settingsForm) return;
      const form = this.elements.settingsForm.elements;
      form.imageConcurrency.value = settings.imageConcurrency;
      form.retryCount.value = settings.retryCount;
      form.requestTimeoutSeconds.value = Math.round(settings.requestTimeoutMs / 1000);
      form.novelFormat.value = settings.novelFormat;
      form.seriesFormat.value = settings.seriesFormat;
      form.downloadEmbeddedImages.checked = settings.downloadEmbeddedImages;
      form.notifications.checked = settings.notifications;
      form.showFloatingButton.checked = settings.showFloatingButton;
      form.debug.checked = settings.debug;
      form.imageFilenameTemplate.value = settings.imageFilenameTemplate;
      form.novelFilenameTemplate.value = settings.novelFilenameTemplate;
      form.seriesFilenameTemplate.value = settings.seriesFilenameTemplate;
    }

    showSettings() {
      this.syncSettingsForm(this.settings);
      this.elements.modal.hidden = false;
    }

    hideSettings() {
      this.elements.modal.hidden = true;
    }

    setRoute(route, label) {
      this.route = route;
      this.elements.actionLabel.textContent = label || '下载当前作品';
      this.applyActionVisibility();
    }

    applyActionVisibility() {
      if (!this.mounted) return;
      this.elements.action.hidden = !this.settings.showFloatingButton || this.route.type === 'other';
      this.elements.action.disabled = this.busy;
    }

    setBusy(busy) {
      this.busy = Boolean(busy);
      this.applyActionVisibility();
    }

    startOperation(label) {
      this.startedAt = Date.now();
      this.setBusy(true);
      this.elements.panel.hidden = false;
      this.elements.title.textContent = label || '';
      this.elements.status.textContent = '正在准备下载...';
      this.elements.current.textContent = '';
      this.elements.count.textContent = '0 / 0';
      this.elements.percent.textContent = '0%';
      this.elements.bytes.textContent = '0 B';
      this.elements.speed.textContent = '0 B/s';
      this.setProgress(0);
      this.setWarnings([]);
      this.setFailures([]);
      this.elements.pause.textContent = '暂停';
      this.elements.pause.disabled = true;
      this.elements.cancel.disabled = false;
    }

    setOperationTitle(title) {
      this.elements.title.textContent = title || '';
    }

    setStatus(status) {
      this.elements.status.textContent = status || '';
    }

    setProgress(percent) {
      const value = Utils.clamp(percent, 0, 100);
      this.elements.progressBar.style.width = `${value}%`;
      this.elements.progressTrack.setAttribute('aria-valuenow', String(Math.round(value)));
      this.elements.percent.textContent = `${Math.round(value)}%`;
    }

    setPhaseProgress(percent, label) {
      this.setProgress(percent);
      if (label) this.elements.current.textContent = label;
      this.elements.count.textContent = '生成文件';
    }

    updateQueue(event) {
      const snapshot = event.snapshot;
      this.setProgress(snapshot.percent);
      this.elements.count.textContent = `${snapshot.completed} / ${snapshot.total}`;
      this.elements.bytes.textContent = Utils.formatBytes(snapshot.bytes);
      this.elements.speed.textContent = `${Utils.formatBytes(snapshot.speed)}/s`;
      const current = event.task && event.task.label
        ? event.task.label
        : snapshot.activeLabels.length
          ? snapshot.activeLabels[snapshot.activeLabels.length - 1]
          : '';
      if (current) this.elements.current.textContent = current;
      if (event.type === 'retry') {
        this.elements.status.textContent = `等待重试（${Math.ceil(event.delay / 1000)} 秒）...`;
      } else if (event.type === 'task-start') {
        this.elements.status.textContent = `正在下载：${current}`;
      }
      this.elements.pause.disabled = !['running', 'paused'].includes(snapshot.state);
      this.elements.pause.textContent = snapshot.state === 'paused' ? '继续' : '暂停';
    }

    setWarnings(warnings) {
      this.renderMessages(this.elements.warnings, warnings);
    }

    setFailures(failures) {
      const messages = failures.map((failure) => {
        const label = failure.label || (failure.task && failure.task.label) || '任务';
        return `${label}：${ErrorUtils.toUserMessage(failure.error || failure.reason)}`;
      });
      this.renderMessages(this.elements.failures, messages, failures.length);
    }

    renderMessages(list, messages, totalCount = messages.length) {
      list.textContent = '';
      list.hidden = messages.length === 0;
      const visible = messages.slice(0, 8);
      for (const message of visible) {
        const item = document.createElement('li');
        item.textContent = message;
        list.appendChild(item);
      }
      if (totalCount > visible.length) {
        const item = document.createElement('li');
        item.textContent = `另有 ${totalCount - visible.length} 项，详见下载包中的失败报告。`;
        list.appendChild(item);
      }
    }

    complete(message, failures = []) {
      this.elements.panel.hidden = false;
      this.elements.status.textContent = message || '下载完成。';
      this.setProgress(100);
      if (failures.length) this.setFailures(failures);
      this.elements.current.textContent = '';
      this.elements.pause.disabled = true;
      this.elements.cancel.disabled = true;
      this.setBusy(false);
    }

    fail(message) {
      this.elements.panel.hidden = false;
      this.elements.status.textContent = message || '下载失败。';
      this.elements.current.textContent = '';
      this.elements.pause.disabled = true;
      this.elements.cancel.disabled = true;
      this.setBusy(false);
    }

    cancelled() {
      this.elements.panel.hidden = false;
      this.elements.status.textContent = '下载已取消。活动请求和后续任务均已停止。';
      this.elements.current.textContent = '';
      this.elements.pause.disabled = true;
      this.elements.cancel.disabled = true;
      this.setBusy(false);
    }
  }

  class App {
    constructor() {
      this.settingsManager = new SettingsManager();
      const settings = this.settingsManager.load();
      this.logger = new Logger(settings.debug);
      this.requestManager = new RequestManager({
        timeoutProvider: () => this.settingsManager.get().requestTimeoutMs,
        retryProvider: () => this.settingsManager.get().retryCount,
        logger: this.logger
      });
      this.adapter = new PixivDataAdapter(this.requestManager, this.logger);
      this.binaryFetcher = new BinaryFetcher({
        timeoutProvider: () => this.settingsManager.get().requestTimeoutMs
      });
      this.ui = new UIManager(this.settingsManager);
      this.routeObserver = new RouteObserver();
      this.artworkDownloader = new ArtworkDownloader(this.adapter, this.binaryFetcher, this.logger);
      this.novelDownloader = new NovelDownloader(this.adapter, this.binaryFetcher);
      this.seriesDownloader = new NovelSeriesDownloader(this.adapter, this.binaryFetcher);
      this.currentRoute = { type: 'other', key: 'other' };
      this.currentController = null;
      this.currentQueue = null;
      this.prefetchToken = 0;
      this.unsubscribeSettings = null;
    }

    start() {
      this.ui.mount({
        onAction: () => this.handleAction(),
        onPauseToggle: () => this.togglePause(),
        onCancel: () => this.cancel(),
        onSaveSettings: (settings) => this.settingsManager.save(settings)
      });
      this.unsubscribeSettings = this.settingsManager.subscribe((settings) => {
        this.logger.setEnabled(settings.debug);
        this.ui.updateSettings(settings);
      });
      this.registerMenuCommands();
      this.routeObserver.start((route) => this.handleRoute(route));
      this.logger.info(`已启动 v${SCRIPT_VERSION}，适配验证日期 ${VERIFIED_DATE}`);
    }

    registerMenuCommands() {
      if (typeof GM_registerMenuCommand !== 'function') return;
      GM_registerMenuCommand('Pixiv Downloader 设置', () => this.ui.showSettings());
      GM_registerMenuCommand('显示下载进度面板', () => { this.ui.elements.panel.hidden = false; });
    }

    handleRoute(route) {
      this.currentRoute = route;
      this.prefetchToken += 1;
      const token = this.prefetchToken;
      this.logger.info('识别页面', { type: route.type, id: route.id || route.seriesId || '' });
      this.ui.setRoute(route, this.routeLabel(route));
      if (route.type !== 'artwork') return;
      this.adapter.getArtworkInfo(route.id).then((artwork) => {
        if (token !== this.prefetchToken || this.currentRoute.key !== route.key) return;
        let label = '下载原图';
        if (artwork.type === 'ugoira') label = '下载 Ugoira 原始包';
        else if (artwork.type === 'manga') label = '下载全部漫画';
        else if (artwork.pageCount > 1) label = '下载全部图片';
        this.ui.setRoute(route, label);
      }).catch((error) => {
        this.logger.warn('作品类型预取失败', ErrorUtils.serializable(error));
      });
    }

    routeLabel(route) {
      if (route.type === 'artwork') return '下载当前作品';
      if (route.type === 'novel' || route.type === 'novel-series-content') return '下载小说';
      if (route.type === 'novel-series') return '下载整个系列';
      return '下载当前作品';
    }

    async handleAction() {
      if (this.currentController || this.currentRoute.type === 'other') return;
      const route = { ...this.currentRoute };
      const controller = new AbortController();
      this.currentController = controller;
      this.currentQueue = null;
      const context = new DownloadContext(this, controller);
      this.ui.startOperation(this.routeLabel(route));
      try {
        let result;
        if (route.type === 'artwork') result = await this.artworkDownloader.download(route, context);
        else if (route.type === 'novel' || route.type === 'novel-series-content') result = await this.novelDownloader.download(route, context);
        else if (route.type === 'novel-series') result = await this.seriesDownloader.download(route, context);
        else throw new PixivDownloaderError('CONTENT_UNAVAILABLE', '当前页面不支持下载。');
        this.ui.complete(result.message, result.failures || []);
        this.notify(result.message);
      } catch (error) {
        if (ErrorUtils.isAbort(error) || controller.signal.aborted) {
          this.ui.cancelled();
        } else {
          this.logger.error('下载失败', error);
          const message = ErrorUtils.toUserMessage(error);
          this.ui.fail(message);
          this.notify(message, true);
        }
      } finally {
        this.currentController = null;
        this.currentQueue = null;
        this.ui.setBusy(false);
        this.ui.setRoute(this.currentRoute, this.routeLabel(this.currentRoute));
        if (this.currentRoute.type === 'artwork') this.handleRoute(this.currentRoute);
      }
    }

    attachQueue(queue) {
      this.currentQueue = queue;
    }

    togglePause() {
      if (!this.currentQueue) return;
      if (this.currentQueue.state === 'paused') this.currentQueue.resume();
      else this.currentQueue.pause();
    }

    cancel() {
      if (this.currentQueue) this.currentQueue.cancel();
      if (this.currentController && !this.currentController.signal.aborted) this.currentController.abort();
    }

    notify(message, isError = false) {
      if (!this.settingsManager.get().notifications || typeof GM_notification !== 'function') return;
      try {
        GM_notification({
          title: isError ? 'Pixiv Downloader - 下载失败' : 'Pixiv Downloader',
          text: String(message),
          timeout: 6000
        });
      } catch (_) {
        // Notifications are optional and must not affect completed downloads.
      }
    }

    stop() {
      this.cancel();
      this.routeObserver.stop();
      if (this.unsubscribeSettings) this.unsubscribeSettings();
    }
  }

  const TestExports = {
    Config,
    PixivDownloaderError,
    ErrorUtils,
    Utils,
    FilenameUtils,
    PageDetector,
    mapHttpStatus,
    RequestManager,
    PixivDataAdapter,
    NovelParser,
    DownloadQueue,
    BinaryFetcher,
    ZipManager,
    NovelFormatter,
    SeriesFormatter
  };

  if (TEST_MODE) {
    if (typeof module !== 'undefined' && module.exports) module.exports = TestExports;
    return;
  }

  if (typeof window === 'undefined' || typeof document === 'undefined') return;
  if (window.top !== window.self) return;
  const startApp = () => {
    const app = new App();
    app.start();
  };
  if (document.body) startApp();
  else window.addEventListener('DOMContentLoaded', startApp, { once: true });
})();