// ==UserScript==
// @name         AO3 阅读历史增强导出器（提速 + 评论修复 + 稳定增强版）
// @namespace    https://github.com/KWzhabing/ao3-reading-exporter
// @version      1.8-enhanced
// @description  一键导出 AO3 阅读历史为 JSON。
// @author       KWzhabing (优化 by Qwen)
// @match        https://archiveofourown.org/users/*/readings*
// @icon         https://archiveofourown.org/favicon.ico
// @grant        none
// @license      MIT
// ==/UserScript==

(function () {
  'use strict';

  const username = window.location.pathname.split('/')[2];
  if (!username) return;

  // === 检查是否已登录（通过是否存在用户名链接）===
  const userLink = document.querySelector(`a[href="/users/${username}"]`);
  if (!userLink) {
    alert('⚠️ 请先登录 AO3 账号再使用此工具！');
    return;
  }

  // 创建按钮容器
  const container = document.createElement('div');
  container.style.margin = '1rem 0';
  container.innerHTML = `
    <button id="ao3-export-basic" style="
      margin-right: 10px; padding: 8px 16px;
      background: #4CAF50; color: white; border: none; border-radius: 4px;
      cursor: pointer;">📤 快速导出（仅基础数据）</button>
    <button id="ao3-export-full" style="
      padding: 8px 16px;
      background: #2196F3; color: white; border: none; border-radius: 4px;
      cursor: pointer;">🚀 完整导出（含字数/Kudos/评论）</button>
  `;
  const readingsList = document.querySelector('#main > dl, #main > ul, .reading-list');
  if (readingsList) {
    readingsList.parentNode.insertBefore(container, readingsList);
  } else {
    document.querySelector('#main')?.prepend(container);
  }

  // ========== 工具函数：提取 work_id ==========
  function extractWorkIdFromUrl(url) {
    const match = url.match(/\/works\/(\d+)/);
    return match ? match[1] : null;
  }

  // ========== 带重试的 fetch 封装 ==========
  async function fetchWithRetry(url, options = {}, maxRetries = 3, baseDelay = 800) {
    for (let i = 0; i <= maxRetries; i++) {
      try {
        const res = await fetch(url, { credentials: 'include', ...options });
        if (res.status === 429) {
          const retryAfter = parseInt(res.headers.get('Retry-After')) || baseDelay * (i + 1);
          console.warn(`⚠️ 429 Too Many Requests. Waiting ${retryAfter}ms...`);
          await new Promise(r => setTimeout(r, retryAfter));
          continue;
        }
        if (!res.ok) throw new Error(`HTTP ${res.status}`);
        return res;
      } catch (err) {
        if (i === maxRetries) throw err;
        const delay = baseDelay * Math.pow(2, i); // 指数退避
        console.warn(`🔁 重试 (${i + 1}/${maxRetries}) ${url}: ${err.message}. 等待 ${delay}ms...`);
        await new Promise(r => setTimeout(r, delay));
      }
    }
  }

  // ========== 获取评论并检测是否评论过（带重试）==========
  async function fetchAllCommentsHtml(workId, username) {
    if (!workId) return false;
    try {
      const commentUrl = `https://archiveofourown.org/comments/show_comments?work_id=${workId}`;
      const res = await fetchWithRetry(commentUrl, {}, 2, 1000);
      const html = await res.text();
      const lowerHtml = html.toLowerCase();
      const lowerUser = username.toLowerCase();
      return (
        lowerHtml.includes(`>${lowerUser}<`) ||
        lowerHtml.includes(`by ${lowerUser}`) ||
        lowerHtml.includes(`comment by ${lowerUser}`)
      );
    } catch (err) {
      console.warn(`💬 评论检测失败 (work_id=${workId}):`, err.message);
      return false;
    }
  }

  // ========== 快速导出 ==========
  async function exportBasicReadingHistory(btnEl) {
    const originalText = btnEl.textContent;
    btnEl.disabled = true;
    btnEl.textContent = '导出中...';

    try {
      const baseUrl = `https://archiveofourown.org/users/${username}/readings`;
      const parser = new DOMParser();
      let allReadings = [];
      let page = 1;

      while (true) {
        const url = page === 1 ? baseUrl : `${baseUrl}?page=${page}`;
        const res = await fetchWithRetry(url);
        const text = await res.text();
        const doc = parser.parseFromString(text, 'text/html');

        const readings = Array.from(doc.querySelectorAll('li.reading')).map(item => {
          const titleEl = item.querySelector('h4 a');
          const authorEl = item.querySelector('.byline a');
          const dateEl = item.querySelector('.datetime');
          if (!titleEl || !dateEl) return null;
          return {
            title: titleEl.textContent.trim(),
            url: 'https://archiveofourown.org' + titleEl.getAttribute('href'),
            authors: authorEl ? authorEl.textContent.trim() : '',
            date: dateEl.title || dateEl.textContent.trim()
          };
        }).filter(Boolean);

        if (readings.length === 0) break;
        allReadings.push(...readings);
        page++;
      }

      downloadJson(allReadings, 'ao3_reading_history_basic');
    } catch (err) {
      console.error(err);
      alert('快速导出失败：' + err.message);
    } finally {
      btnEl.disabled = false;
      btnEl.textContent = originalText;
    }
  }

  // ========== 完整导出 ==========
  async function exportFullReadingHistory(btnEl) {
    const originalText = btnEl.textContent;
    btnEl.disabled = true;
    btnEl.textContent = '准备中...';

    try {
      const baseUrl = `https://archiveofourown.org/users/${username}/readings`;
      const parser = new DOMParser();
      let allReadings = [];
      let page = 1;

      while (true) {
        const url = page === 1 ? baseUrl : `${baseUrl}?page=${page}`;
        const res = await fetchWithRetry(url);
        const text = await res.text();
        const doc = parser.parseFromString(text, 'text/html');

        const readings = Array.from(doc.querySelectorAll('li.reading')).map(item => {
          const titleEl = item.querySelector('h4 a');
          const authorEl = item.querySelector('.byline a');
          const dateEl = item.querySelector('.datetime');
          if (!titleEl || !dateEl) return null;
          return {
            title: titleEl.textContent.trim(),
            url: 'https://archiveofourown.org' + titleEl.getAttribute('href'),
            authors: authorEl ? authorEl.textContent.trim() : '',
            date: dateEl.title || dateEl.textContent.trim()
          };
        }).filter(Boolean);

        if (readings.length === 0) break;
        allReadings.push(...readings);
        page++;
      }

      if (allReadings.length === 0) {
        alert('未找到任何阅读记录');
        return;
      }

      // 去重（防止同一篇作品出现在多页）
      const seenUrls = new Set();
      const uniqueReadings = allReadings.filter(r => {
        if (seenUrls.has(r.url)) return false;
        seenUrls.add(r.url);
        return true;
      });

      const MAX_CONCURRENT = 5;     // 保守并发
      const total = uniqueReadings.length;
      let completed = 0;
      const results = [];

      const updateProgress = () => {
        const percent = Math.min(100, Math.round((completed / total) * 100));
        btnEl.textContent = `导出中... ${percent}% (${completed}/${total})`;
      };

      // ========== 抓取单篇作品详情（带重试 + 健壮解析）==========
      async function fetchWorkDetails(reading) {
        try {
          const workRes = await fetchWithRetry(reading.url, {}, 2, 1200);
          const workText = await workRes.text();
          const workDoc = new DOMParser().parseFromString(workText, 'text/html');

          // 字数：支持多种格式
          let words = null;
          const wordEls = [
            workDoc.querySelector('dd.words'),
            ...Array.from(workDoc.querySelectorAll('p.meta')).find(p => p.textContent.includes('Words:'))
          ].filter(Boolean);
          if (wordEls.length) {
            const text = wordEls[0].textContent;
            const match = text.match(/[\d,]+/);
            if (match) words = parseInt(match[0].replace(/,/g, ''), 10);
          }

          // 标签
          const tags = Array.from(workDoc.querySelectorAll('.tag'))
            .map(el => el.textContent.trim())
            .filter(t => t && t !== 'No tags');

          // Kudos：检查是否在 kudos 列表中
          const kudos_given = !!workDoc.querySelector(`#kudos a[href="/users/${username}"]`);

          // 评论检测
          const workId = extractWorkIdFromUrl(reading.url);
          const commented = workId ? await fetchAllCommentsHtml(workId, username) : false;

          return { ...reading, words, tags, kudos_given, commented };
        } catch (err) {
          console.error(`❌ 跳过作品 ${reading.title} (${reading.url}):`, err.message);
          return { ...reading, words: null, tags: [], kudos_given: false, commented: false };
        } finally {
          completed++;
          updateProgress();
        }
      }

      // 并发处理（带批次延迟）
      const queue = [...uniqueReadings];
      while (queue.length > 0) {
        const batch = queue.splice(0, MAX_CONCURRENT);
        const promises = batch.map(fetchWorkDetails);
        const batchResults = await Promise.all(promises);
        results.push(...batchResults);
        if (queue.length > 0) await new Promise(r => setTimeout(r, 800)); // 批次间延迟
      }

      downloadJson(results, 'ao3_reading_history_enhanced');
      console.log('✅ 导出完成！共处理', results.length, '篇作品');
    } catch (err) {
      console.error(err);
      alert('完整导出失败：' + err.message);
    } finally {
      btnEl.disabled = false;
      btnEl.textContent = originalText;
    }
  }

  // ========== 事件绑定 ==========
  document.getElementById('ao3-export-basic').addEventListener('click', function () {
    exportBasicReadingHistory(this);
  });

  document.getElementById('ao3-export-full').addEventListener('click', function () {
    exportFullReadingHistory(this);
  });

  // ========== 下载函数 ==========
  function downloadJson(data, prefix) {
    const jsonStr = JSON.stringify(data, null, 2);
    const blob = new Blob([jsonStr], { type: 'application/json;charset=utf-8' });
    const url = URL.createObjectURL(blob);
    const filename = `${prefix}_${new Date().toISOString().slice(0, 10)}.json`;

    const a = document.createElement('a');
    a.href = url;
    a.download = filename;
    document.body.appendChild(a);
    a.click();
    document.body.removeChild(a);

    const fallbackLink = document.createElement('a');
    fallbackLink.href = url;
    fallbackLink.download = filename;
    fallbackLink.textContent = `⬇️ 如果未自动下载，请点此保存：${filename}`;
    fallbackLink.style.cssText = `
      position: fixed; bottom: 20px; left: 20px; padding: 10px 16px;
      background: #ff9800; color: white; border-radius: 4px; z-index: 10000;
      text-decoration: none; font-family: sans-serif; box-shadow: 0 2px 8px rgba(0,0,0,0.3);
    `;
    document.body.appendChild(fallbackLink);
    setTimeout(() => {
      if (fallbackLink.parentNode) fallbackLink.parentNode.removeChild(fallbackLink);
      URL.revokeObjectURL(url);
    }, 5000);
  }
})();