import { extractPageTitle } from './wechat/verify/share-preview-repair.mjs';

const MAX_WECHAT_CONTENT_CHARS = 20000;
const MAX_WECHAT_CONTENT_TARGET_CHARS = 19600;
const DEFAULT_PORTAL_URL = 'https://m.tkmind.cn';

const CARD_VARIANTS = {
  'highlight-box': {
    wrap: 'background:linear-gradient(135deg,#b71c1c,#d32f2f);border-radius:12px;padding:14px;margin:0 0 10px;color:#fff;',
    title: 'margin:0 0 6px;font-size:16px;font-weight:700;color:#fff;line-height:1.5;',
    body: 'margin:0 0 6px;font-size:14px;line-height:1.7;color:#ffcdd2;',
    source: 'margin:0;font-size:12px;color:#90caf4;',
    tag: 'display:inline-block;font-size:11px;padding:2px 8px;border-radius:4px;margin:0 0 6px;background:rgba(255,255,255,.18);color:#fff;',
  },
  'highlight-box-orange': {
    wrap: 'background:linear-gradient(135deg,#e65100,#bf360c);border-radius:12px;padding:14px;margin:0 0 10px;color:#fff;',
    title: 'margin:0 0 6px;font-size:16px;font-weight:700;color:#fff;line-height:1.5;',
    body: 'margin:0 0 6px;font-size:14px;line-height:1.7;color:#ffe0b2;',
    source: 'margin:0;font-size:12px;color:#ffcdd2;',
    tag: 'display:inline-block;font-size:11px;padding:2px 8px;border-radius:4px;margin:0 0 6px;background:rgba(255,255,255,.18);color:#fff;',
  },
  'highlight-box-gold': {
    wrap: 'background:linear-gradient(135deg,#0d47a1,#1565c0);border-radius:12px;padding:14px;margin:0 0 10px;color:#fff;',
    title: 'margin:0 0 6px;font-size:16px;font-weight:700;color:#fff;line-height:1.5;',
    body: 'margin:0 0 6px;font-size:14px;line-height:1.7;color:#bbdefb;',
    source: 'margin:0;font-size:12px;color:#bbdefb;',
    tag: 'display:inline-block;font-size:11px;padding:2px 8px;border-radius:4px;margin:0 0 6px;background:rgba(255,255,255,.18);color:#fff;',
  },
  'highlight-box-teal': {
    wrap: 'background:linear-gradient(135deg,#004d40,#00695c);border-radius:12px;padding:14px;margin:0 0 10px;color:#fff;',
    title: 'margin:0 0 6px;font-size:16px;font-weight:700;color:#fff;line-height:1.5;',
    body: 'margin:0 0 6px;font-size:14px;line-height:1.7;color:#b2dfdb;',
    source: 'margin:0;font-size:12px;color:#b2dfdb;',
    tag: 'display:inline-block;font-size:11px;padding:2px 8px;border-radius:4px;margin:0 0 6px;background:rgba(255,255,255,.18);color:#fff;',
  },
  default: {
    wrap: 'background:#fff;border-radius:12px;padding:14px;margin:0 0 10px;',
    title: 'margin:0 0 4px;font-size:16px;font-weight:600;color:#1a202c;line-height:1.5;',
    body: 'margin:0 0 6px;font-size:14px;color:#4a5568;line-height:1.7;',
    source: 'margin:0;font-size:12px;color:#a0aec0;',
    tag: 'display:inline-block;font-size:11px;padding:2px 8px;border-radius:4px;margin:0 0 6px;background:#ffebee;color:#b71c1c;',
  },
};

const TAG_CLASS_COLORS = {
  'tag-red': 'background:#ffcdd2;color:#b71c1c;',
  'tag-blue': 'background:#bbdefb;color:#0d47a1;',
  'tag-green': 'background:#c8e6c9;color:#1b5e20;',
  'tag-purple': 'background:#e1bee7;color:#6a1b9a;',
  'tag-orange': 'background:#ffe0b2;color:#e65100;',
  'tag-teal': 'background:#b2dfdb;color:#004d40;',
  'tag-pink': 'background:#f8bbd0;color:#880e4f;',
  'tag-gray': 'background:#e0e0e0;color:#424242;',
  'tag-amber': 'background:#ffecb3;color:#ff6f00;',
};

function extractMetaDescription(html) {
  const match = String(html ?? '').match(
    /<meta[^>]+name=["']description["'][^>]+content=["']([^"']*)["']/i,
  );
  return match?.[1]?.trim() ?? '';
}

function stripScripts(html) {
  return String(html ?? '').replace(/<script[\s\S]*?<\/script>/gi, '');
}

function sanitizeInlineHtml(html) {
  return stripScripts(String(html ?? ''))
    .replace(/<(?!\/?(a\b|br\b|strong\b|span\b|b\b|em\b|i\b)\b)[^>]+>/gi, '')
    .replace(/\son\w+="[^"]*"/gi, '')
    .trim();
}

function extractInnerHtml(block, pattern) {
  const match = String(block ?? '').match(pattern);
  return match?.[1] ? sanitizeInlineHtml(match[1]) : '';
}

function detectCardVariant(cardHtml) {
  if (/highlight-box-orange/u.test(cardHtml)) return 'highlight-box-orange';
  if (/highlight-box-gold/u.test(cardHtml)) return 'highlight-box-gold';
  if (/highlight-box-teal/u.test(cardHtml)) return 'highlight-box-teal';
  if (/highlight-box/u.test(cardHtml)) return 'highlight-box';
  return 'default';
}

function renderTagHtml(cardHtml, styles) {
  const tagMatch = String(cardHtml).match(/<span class="tag([^"]*)"[^>]*(?:style="([^"]*)")?[^>]*>([\s\S]*?)<\/span>/i);
  if (!tagMatch) return '';
  const className = tagMatch[1]?.trim() ?? '';
  const inlineStyle = tagMatch[2]?.trim() ?? '';
  const label = sanitizeInlineHtml(tagMatch[3]);
  if (!label) return '';
  const colorStyle = TAG_CLASS_COLORS[className.replace(/^\s+/, '')] ?? '';
  const style = inlineStyle || colorStyle || styles.tag;
  return `<span style="${style}">${label}</span>`;
}

function renderCard(cardHtml) {
  const variant = detectCardVariant(cardHtml);
  const styles = CARD_VARIANTS[variant] ?? CARD_VARIANTS.default;
  const tag = renderTagHtml(cardHtml, styles);
  const title = extractInnerHtml(cardHtml, /<h3[^>]*>([\s\S]*?)<\/h3>/i);
  const body = extractInnerHtml(cardHtml, /<p[^>]*>([\s\S]*?)<\/p>/i);
  const sourceRaw = extractInnerHtml(cardHtml, /<div class="source"[^>]*>([\s\S]*?)<\/div>/i);
  const source = sourceRaw.replace(/^来源：?/u, '').trim();
  if (!title) return '';

  const parts = [
    `<section style="${styles.wrap}">`,
    tag ? `<p style="margin:0 0 6px;">${tag}</p>` : '',
    `<p style="${styles.title}"><strong>${title}</strong></p>`,
    body ? `<p style="${styles.body}">${body}</p>` : '',
    source ? `<p style="${styles.source}">来源：${source}</p>` : '',
    '</section>',
  ];
  return parts.filter(Boolean).join('');
}

function renderSectionTitle(titleHtml) {
  const text = sanitizeInlineHtml(titleHtml).replace(/<span class="icon"[^>]*>([\s\S]*?)<\/span>/gi, '$1');
  if (!text) return '';
  return `<p style="margin:0 0 12px;padding:12px 0 6px;border-bottom:3px solid #0d47a1;font-size:18px;font-weight:700;color:#b71c1c;line-height:1.4;">${text}</p>`;
}

function renderHero(html) {
  const title = sanitizeInlineHtml(String(html).match(/<h1[^>]*>([\s\S]*?)<\/h1>/i)?.[1] ?? '') || '📰 每日新闻早报';
  const dateBadge = sanitizeInlineHtml(String(html).match(/<div class="date-badge"[^>]*>([\s\S]*?)<\/div>/i)?.[1] ?? '');
  const subtitle = sanitizeInlineHtml(String(html).match(/<div class="subtitle"[^>]*>([\s\S]*?)<\/div>/i)?.[1] ?? '');
  return [
    '<section style="text-align:center;padding:24px 14px;background:linear-gradient(135deg,#b71c1c,#d32f2f 50%,#0d47a1);color:#fff;margin:0 0 12px;border-radius:12px;">',
    `<p style="margin:0 0 10px;font-size:24px;font-weight:700;line-height:1.35;">${title}</p>`,
    dateBadge ? `<p style="margin:0 0 8px;font-size:14px;opacity:.92;">${dateBadge}</p>` : '',
    subtitle ? `<p style="margin:0;font-size:14px;opacity:.88;line-height:1.7;">${subtitle}</p>` : '',
    '</section>',
  ].filter(Boolean).join('');
}

function renderReadOriginalTop(publicUrl) {
  if (!publicUrl) return '';
  return [
    '<section style="margin:0 0 16px;text-align:center;">',
    `<a href="${publicUrl}" style="display:inline-block;padding:11px 22px;background:linear-gradient(135deg,#b71c1c,#d32f2f);color:#fff;font-size:14px;font-weight:600;text-decoration:none;border-radius:999px;letter-spacing:.02em;box-shadow:0 3px 10px rgba(183,28,28,.22);">📖 点击阅读原文</a>`,
    '<p style="margin:8px 0 0;font-size:12px;color:#a0aec0;line-height:1.6;">查看完整排版、图片与更多栏目</p>',
    '</section>',
  ].join('');
}

function renderCreatePortalCTA(portalUrl = DEFAULT_PORTAL_URL) {
  return `<p style="margin:18px 0 0;font-size:14px;color:#718096;text-align:center;line-height:1.7;">✨ 一起创作 → <a href="${portalUrl}" style="color:#e53935;font-weight:600;text-decoration:underline;">点我</a></p>`;
}

function renderFollowMpSection(qrcodeImageUrl = '') {
  if (qrcodeImageUrl) {
    return [
      '<section style="text-align:center;padding:22px 16px 18px;margin:18px 0 8px;background:linear-gradient(180deg,#fff8f8,#fff);border:1px solid #ffcdd2;border-radius:12px;">',
      '<p style="margin:0 0 6px;font-size:16px;font-weight:700;color:#b71c1c;line-height:1.5;">📣 关注 TKMind 服务号</p>',
      '<p style="margin:0 0 14px;font-size:13px;color:#666;line-height:1.7;">长按扫描关注，每日早报不错过</p>',
      `<img src="${qrcodeImageUrl}" alt="TKMind 服务号二维码" style="width:168px;height:168px;display:block;margin:0 auto;border-radius:10px;border:1px solid #eee;" />`,
      '<p style="margin:12px 0 0;font-size:12px;color:#a0aec0;">长按扫描关注</p>',
      '</section>',
    ].join('');
  }
  return [
    '<section style="text-align:center;padding:20px 16px;margin:18px 0 8px;background:#fafafa;border:1px dashed #e0e0e0;border-radius:12px;">',
    '<p style="margin:0 0 6px;font-size:15px;font-weight:600;color:#333;">📣 关注 TKMind 服务号</p>',
    '<p style="margin:0;font-size:13px;color:#888;line-height:1.7;">推送草稿时将嵌入公众号二维码</p>',
    '</section>',
  ].join('');
}

function renderWeatherSection(sectionHtml) {
  const title = extractInnerHtml(sectionHtml, /<div class="section-title"[^>]*>([\s\S]*?)<\/div>/i);
  const summary = extractInnerHtml(sectionHtml, /<div class="weather-today"[^>]*>([\s\S]*?)<\/div>/i);
  const cityCards = [...String(sectionHtml).matchAll(/<div class="weather-card[^"]*"[^>]*>[\s\S]*?<span class="w-city">([\s\S]*?)<\/span>[\s\S]*?<span class="w-cond">([\s\S]*?)<\/span>[\s\S]*?<span class="w-temp">([\s\S]*?)<\/span>/gi)]
    .map((item) => `${sanitizeInlineHtml(item[1])}${sanitizeInlineHtml(item[2])} ${sanitizeInlineHtml(item[3])}`)
    .slice(0, 12);
  const footer = extractInnerHtml(sectionHtml, /<p style="font-size:12px;color:#a0aec0;">([\s\S]*?)<\/p>/i);

  const parts = [renderSectionTitle(title)];
  parts.push('<section style="background:linear-gradient(135deg,#e3f2fd,#bbdefb);border:1px solid #90caf9;border-radius:12px;padding:14px 16px;margin-bottom:12px;">');
  if (summary) {
    parts.push(`<p style="margin:0 0 8px;font-size:14px;color:#0d47a1;line-height:1.75;">${summary.replace(/<div[^>]*>/gi, ' ').replace(/<\/div>/gi, ' ')}</p>`);
  }
  if (cityCards.length > 0) {
    parts.push(`<p style="margin:0;font-size:13px;color:#1565c0;line-height:1.8;">${cityCards.join(' · ')}</p>`);
  }
  parts.push('</section>');
  if (footer) {
    parts.push(`<p style="margin:0 0 16px;font-size:12px;color:#a0aec0;line-height:1.6;">${footer}</p>`);
  }
  return parts.join('');
}

function splitSections(html) {
  const body = String(html ?? '').match(/<body>([\s\S]*?)<\/body>/i)?.[1] ?? String(html ?? '');
  return body
    .split(/<div class="section"[^>]*>/i)
    .slice(1)
    .map((chunk) => {
      const id = chunk.match(/^[^>]*id="([^"]+)"/i)?.[1] ?? '';
      const htmlChunk = `<div class="section"${chunk.split(/<div class="section"|<div class="footer"/i)[0]}`;
      const title = stripInlineText(extractInnerHtml(htmlChunk, /<div class="section-title"[^>]*>([\s\S]*?)<\/div>/i));
      return { id, title, html: htmlChunk };
    });
}

function stripInlineText(value) {
  return sanitizeInlineHtml(String(value ?? ''))
    .replace(/<span class="icon"[^>]*>([\s\S]*?)<\/span>/gi, '$1')
    .replace(/<[^>]+>/g, '')
    .replace(/\s+/g, ' ')
    .trim();
}

const DEFAULT_SECTION_CARD_LIMITS = {
  headlines: 6,
  world: 3,
  domestic: 3,
  google: 2,
  finance: 3,
  tech: 3,
  sports: 2,
  technews: 2,
  hot: 1,
};

const TRIM_PROFILES = [
  { skipHistory: true, sectionCardLimits: null, maxBodyChars: null },
  {
    skipHistory: true,
    sectionCardLimits: DEFAULT_SECTION_CARD_LIMITS,
    maxBodyChars: 120,
  },
  {
    skipHistory: true,
    sectionCardLimits: { ...DEFAULT_SECTION_CARD_LIMITS, headlines: 5, world: 2, domestic: 2 },
    maxBodyChars: 90,
  },
  {
    skipHistory: true,
    sectionCardLimits: { headlines: 4, world: 2, domestic: 2, google: 2, finance: 2, tech: 2, sports: 1, technews: 1, hot: 1 },
    maxBodyChars: 72,
  },
  {
    skipHistory: true,
    sectionCardLimits: { headlines: 3, world: 2, domestic: 2, google: 2, finance: 2, tech: 2, sports: 1, technews: 0, hot: 1 },
    maxBodyChars: 64,
  },
  {
    skipHistory: true,
    sectionCardLimits: { headlines: 3, world: 2, domestic: 2, google: 1, finance: 2, tech: 2, sports: 1, technews: 0, hot: 0 },
    maxBodyChars: 56,
  },
];

function buildFallbackTrimProfiles() {
  const profiles = [];
  for (let headlines = 3; headlines >= 2; headlines -= 1) {
    for (let maxBodyChars = 56; maxBodyChars >= 24; maxBodyChars -= 8) {
      for (const skipWeather of [false, true]) {
        profiles.push({
          skipHistory: true,
          skipWeather,
          sectionCardLimits: {
            headlines,
            world: 2,
            domestic: 2,
            google: 1,
            finance: 2,
            tech: 2,
            sports: 1,
            technews: 0,
            hot: 0,
          },
          maxBodyChars,
        });
      }
    }
  }
  return profiles;
}

function resolveSectionCardLimit(section, sectionCardLimits) {
  if (!sectionCardLimits) return null;
  return sectionCardLimits[section.id] ?? 3;
}

function estimateQrcodeUrlForLayout(qrcodeImageUrl = '') {
  const url = String(qrcodeImageUrl ?? '');
  if (!url) return '';
  if (url.length >= 180) return url;
  return `${url}${'x'.repeat(180 - url.length)}`;
}

function estimateFixedLayoutLength({ publicUrl = '', qrcodeImageUrl = '', portalUrl = DEFAULT_PORTAL_URL } = {}) {
  const qrcodeForEstimate = estimateQrcodeUrlForLayout(qrcodeImageUrl);
  return (
    (publicUrl ? renderReadOriginalTop(publicUrl).length : 0)
    + renderFollowMpSection(qrcodeForEstimate).length
    + renderCreatePortalCTA(portalUrl).length
  );
}

function buildWechatInlineContent(html, {
  publicUrl = '',
  qrcodeImageUrl = '',
  portalUrl = DEFAULT_PORTAL_URL,
  trimProfile = TRIM_PROFILES[0],
  includeFixedLayout = true,
} = {}) {
  const sections = splitSections(html);
  const bodyParts = [renderHero(html)];

  for (const section of sections) {
    if (trimProfile.skipHistory && shouldSkipSection(section, trimProfile)) {
      continue;
    }
    if (resolveSectionCardLimit(section, trimProfile.sectionCardLimits) === 0) {
      continue;
    }
    if (section.id === 'weather') {
      if (!trimProfile.skipWeather) {
        bodyParts.push(renderWeatherSection(section.html));
      }
      continue;
    }
    bodyParts.push(renderGenericSection(section.html, {
      maxCards: resolveSectionCardLimit(section, trimProfile.sectionCardLimits),
      maxBodyChars: trimProfile.maxBodyChars,
    }));
  }

  bodyParts.push(renderFooter(html));

  const ordered = [...bodyParts];
  if (includeFixedLayout) {
    if (publicUrl) ordered.splice(1, 0, renderReadOriginalTop(publicUrl));
    ordered.push(renderFollowMpSection(qrcodeImageUrl));
    ordered.push(renderCreatePortalCTA(portalUrl));
  }

  return {
    content: ordered.join(''),
    sectionCount: sections.length,
    renderedSectionCount: sections.filter((section) => {
      if (trimProfile.skipHistory && shouldSkipSection(section, trimProfile)) return false;
      if (resolveSectionCardLimit(section, trimProfile.sectionCardLimits) === 0) return false;
      return true;
    }).length,
  };
}

function truncatePlainText(value, maxChars) {
  const text = String(value ?? '').replace(/\s+/g, ' ').trim();
  if (!maxChars || text.length <= maxChars) return text;
  return `${text.slice(0, Math.max(0, maxChars - 1))}…`;
}

function shouldSkipSection(section, trimProfile) {
  if (!section) return true;
  if (['history', 'knowledge'].includes(section.id)) return true;
  if (trimProfile?.skipSectionIds?.includes(section.id)) return true;
  return /历史上的今天|近7天新闻早报/u.test(section.title);
}

function renderGenericSection(sectionHtml, { maxCards = null, maxBodyChars = null } = {}) {
  const title = extractInnerHtml(sectionHtml, /<div class="section-title"[^>]*>([\s\S]*?)<\/div>/i);
  if (/近7天新闻早报/u.test(stripInlineText(title))) return '';
  const cards = sectionHtml.split(/<div class="card(?:\s|")/i).slice(1);
  const parts = [renderSectionTitle(title)];
  const limit = maxCards == null ? cards.length : Math.min(maxCards, cards.length);
  for (let index = 0; index < limit; index += 1) {
    let cardChunk = cards[index];
    if (maxBodyChars) {
      cardChunk = cardChunk.replace(/<p[^>]*>([\s\S]*?)<\/p>/i, (match, body) => {
        const plain = body.replace(/<[^>]+>/g, '').replace(/\s+/g, ' ').trim();
        return match.replace(body, truncatePlainText(plain, maxBodyChars));
      });
    }
    const rendered = renderCard(`<div class="card ${cardChunk}`);
    if (rendered) parts.push(rendered);
  }
  return parts.join('');
}

function renderFooter(html) {
  const footer = String(html).match(/<div class="footer"[^>]*>([\s\S]*?)<\/div>/i)?.[1] ?? '';
  if (!footer) return '';
  const lines = [...footer.matchAll(/<p[^>]*>([\s\S]*?)<\/p>/gi)]
    .map((item) => sanitizeInlineHtml(item[1]))
    .filter(Boolean)
    .slice(0, 3);
  if (lines.length === 0) return '';
  return [
    '<section style="text-align:center;padding:20px 12px 8px;color:#a0aec0;">',
    ...lines.map((line) => `<p style="margin:0 0 8px;font-size:13px;line-height:1.7;color:#718096;">${line}</p>`),
    '</section>',
  ].join('');
}

export function convertDailyNewsHtmlToWechatInlineArticle(html, {
  publicUrl = '',
  qrcodeImageUrl = '',
  portalUrl = DEFAULT_PORTAL_URL,
} = {}) {
  const title = (extractPageTitle(html) || '每日新闻早报').slice(0, 32);
  const digest = (extractMetaDescription(html) || title).slice(0, 120);
  let built = null;
  let trimLevel = 0;
  let usedFallback = false;
  const allProfiles = [...TRIM_PROFILES, ...buildFallbackTrimProfiles()];

  const fixedLayoutLength = estimateFixedLayoutLength({ publicUrl, qrcodeImageUrl, portalUrl });
  const trimTargetChars = Math.max(12000, MAX_WECHAT_CONTENT_CHARS - fixedLayoutLength - 800);

  for (const [index, trimProfile] of allProfiles.entries()) {
    built = buildWechatInlineContent(html, {
      publicUrl,
      qrcodeImageUrl,
      portalUrl,
      trimProfile,
      includeFixedLayout: false,
    });
    trimLevel = index;
    usedFallback = index >= TRIM_PROFILES.length;
    if (built.content.length <= trimTargetChars) {
      break;
    }
  }

  let selectedProfile = allProfiles[trimLevel] ?? allProfiles[allProfiles.length - 1];
  if (built) {
    built = buildWechatInlineContent(html, {
      publicUrl,
      qrcodeImageUrl,
      portalUrl,
      trimProfile: selectedProfile,
      includeFixedLayout: true,
    });
    let tightenGuard = 0;
    while (built.content.length > MAX_WECHAT_CONTENT_CHARS && tightenGuard < 24) {
      tightenGuard += 1;
      const limits = {
        world: 2,
        domestic: 2,
        google: 1,
        tech: 2,
        sports: 1,
        technews: 0,
        hot: 0,
        headlines: selectedProfile.sectionCardLimits?.headlines ?? 3,
        finance: selectedProfile.sectionCardLimits?.finance ?? 2,
      };
      const maxBody = selectedProfile.maxBodyChars ?? 64;
      if (maxBody > 16) {
        selectedProfile.maxBodyChars = maxBody - 4;
      } else if (limits.headlines > 2) {
        limits.headlines -= 1;
      } else if (limits.finance > 1) {
        limits.finance -= 1;
      } else {
        break;
      }
      selectedProfile = {
        ...selectedProfile,
        skipHistory: true,
        skipWeather: true,
        maxBodyChars: selectedProfile.maxBodyChars ?? maxBody,
        sectionCardLimits: limits,
      };
      built = buildWechatInlineContent(html, {
        publicUrl,
        qrcodeImageUrl,
        portalUrl,
        trimProfile: selectedProfile,
        includeFixedLayout: true,
      });
      usedFallback = true;
    }
  }

  if (!built || built.content.length > MAX_WECHAT_CONTENT_CHARS) {
    throw new Error(
      `微信正文超过 ${MAX_WECHAT_CONTENT_CHARS} 字符（当前 ${built?.content.length ?? 0}），请缩短 HTML 页面后重试`,
    );
  }

  return {
    title,
    digest,
    content: built.content,
    contentSourceUrl: publicUrl || undefined,
    contentMode: 'inline_html',
    contentLength: built.content.length,
    sectionCount: built.sectionCount,
    renderedSectionCount: built.renderedSectionCount,
    trimLevel,
    trimmed: trimLevel > 0,
    usedFallbackTrim: usedFallback,
  };
}

export const wechatDailyNewsInlineInternals = {
  renderCard,
  renderHero,
  buildWechatInlineContent,
  TRIM_PROFILES,
  MAX_WECHAT_CONTENT_CHARS,
};