import fs from 'node:fs';

import { buildPublicUrl } from '../../user-publish.mjs';
import {
  findLatestNewsMorningPage,
  isNewsMorningPageForToday,
} from '../../wechat-news-morning-draft.mjs';
import { resolveNewsMorningPushConfig } from './news-morning-delivery.mjs';

function stripHtml(value) {
  return String(value ?? '')
    .replace(/<br\s*\/?>/gi, '\n')
    .replace(/<[^>]+>/g, '')
    .replace(/\s+/g, ' ')
    .trim();
}

function truncateText(value, maxChars = 96) {
  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 extractDivBlock(html, className) {
  const source = String(html ?? '');
  const openRe = new RegExp(`<div class="${className}"[^>]*>`, 'i');
  const openMatch = openRe.exec(source);
  if (!openMatch) return '';
  let pos = openMatch.index + openMatch[0].length;
  let depth = 1;
  while (pos < source.length && depth > 0) {
    const nextOpen = source.indexOf('<div', pos);
    const nextClose = source.indexOf('</div>', pos);
    if (nextClose === -1) break;
    if (nextOpen !== -1 && nextOpen < nextClose) {
      depth += 1;
      pos = nextOpen + 4;
    } else {
      depth -= 1;
      pos = nextClose + 6;
    }
  }
  return source.slice(openMatch.index, pos);
}

function extractClassDivBlocks(parentHtml, classPrefix) {
  const source = String(parentHtml ?? '');
  const blocks = [];
  const openRe = new RegExp(`<div class="${classPrefix}[^"]*"[^>]*>`, 'gi');
  let openMatch = openRe.exec(source);
  while (openMatch) {
    const start = openMatch.index;
    let pos = start + openMatch[0].length;
    let depth = 1;
    while (pos < source.length && depth > 0) {
      const nextOpen = source.indexOf('<div', pos);
      const nextClose = source.indexOf('</div>', pos);
      if (nextClose === -1) break;
      if (nextOpen !== -1 && nextOpen < nextClose) {
        depth += 1;
        pos = nextOpen + 4;
      } else {
        depth -= 1;
        pos = nextClose + 6;
      }
    }
    blocks.push(source.slice(start, pos));
    openMatch = openRe.exec(source);
  }
  return blocks;
}

export function extractDailyNewsSectionHtml(html, sectionId) {
  const source = String(html ?? '');
  const id = String(sectionId ?? '').trim();
  if (!id) return '';
  const sectionRe = new RegExp(
    `<div class="section" id="${id}"[\\s\\S]*?(?=<div class="section" id=|<div class="footer"|<footer|</body>)`,
    'i',
  );
  return source.match(sectionRe)?.[0] ?? '';
}

export function extractDailyNewsHeroDate(html) {
  return stripHtml(
    String(html).match(/<div class="date-badge"[^>]*>([\s\S]*?)<\/div>/i)?.[1]
    ?? String(html).match(/<span class="date"[^>]*>([\s\S]*?)<\/span>/i)?.[1]
    ?? '',
  );
}

export function extractCardsFromHtmlFragment(html) {
  const parts = String(html ?? '').split(/<div class="card(?:\s|")/i).slice(1);
  return parts.map((block, index) => {
    const title = stripHtml(
      block.match(/<h3[^>]*>([\s\S]*?)<\/h3>/i)?.[1]
      ?? block.match(/<h2[^>]*>([\s\S]*?)<\/h2>/i)?.[1]
      ?? '',
    );
    const tag = stripHtml(
      block.match(/<span class="[^"]*\btag\b[^"]*"[^>]*>([\s\S]*?)<\/span>/i)?.[1] ?? '',
    );
    const paragraphs = [...block.matchAll(/<p[^>]*>([\s\S]*?)<\/p>/gi)]
      .map((item) => stripHtml(item[1]))
      .filter(Boolean);
    const context = paragraphs[0] ?? '';
    return {
      index: index + 1,
      title,
      tag,
      context: truncateText(context, 120),
    };
  }).filter((item) => item.title);
}

export function extractKnowledgeItemsFromHtml(html) {
  const sectionHtml = extractDailyNewsSectionHtml(html, 'knowledge');
  const blocks = extractClassDivBlocks(sectionHtml, 'knowledge-item');
  return blocks.map((block, index) => {
    const icon = stripHtml(block.match(/<div class="k-icon"[^>]*>([\s\S]*?)<\/div>/i)?.[1] ?? '');
    const title = stripHtml(block.match(/<h4[^>]*>([\s\S]*?)<\/h4>/i)?.[1] ?? '');
    const body = truncateText(
      stripHtml(block.match(/<p[^>]*>([\s\S]*?)<\/p>/i)?.[1] ?? ''),
      180,
    );
    if (!title) return null;
    return { index: index + 1, title: icon ? `${icon} ${title}` : title, body };
  }).filter(Boolean);
}

export function extractCardsFromSectionIds(html, sectionIds = []) {
  const cards = [];
  for (const sectionId of sectionIds) {
    const sectionHtml = extractDailyNewsSectionHtml(html, sectionId);
    if (!sectionHtml) continue;
    cards.push(...extractCardsFromHtmlFragment(sectionHtml));
  }
  return cards.map((card, index) => ({ ...card, index: index + 1 }));
}

export function buildSectionCardsPushText({
  emoji,
  label,
  dateLabel = '',
  cards = [],
  maxItems = 5,
  includeSummary = false,
  publicUrl = '',
  cancelId,
  unavailableText = '内容正在整理中，稍后会推送到本服务号。',
}) {
  const lines = [`${emoji} ${label}${dateLabel ? ` · ${dateLabel}` : ''}`];
  const picked = cards.slice(0, Math.max(1, Math.min(10, Number(maxItems) || 5)));

  if (!picked.length) {
    lines.push('', unavailableText);
  } else {
    lines.push('');
    for (const card of picked) {
      const prefix = card.tag ? `[${card.tag}] ` : '';
      if (includeSummary && card.context) {
        lines.push(`${card.index}. ${prefix}${card.title}`, `   ${card.context}`, '');
      } else {
        lines.push(`${card.index}. ${prefix}${card.title}`);
      }
    }
    if (includeSummary) {
      while (lines.at(-1) === '') lines.pop();
    }
  }

  if (publicUrl) lines.push('', `👉 阅读全文：${publicUrl}`);
  if (cancelId) lines.push('', `回复「取消${cancelId}」关闭推送`);
  return lines.join('\n');
}

export async function loadTodayNewsMorningHtml({
  now = Date.now(),
  timezone = 'Asia/Shanghai',
  env = process.env,
  h5Root = process.cwd(),
  pool = null,
} = {}) {
  const config = await resolveNewsMorningPushConfig({ pool, env });
  const effectiveTimezone = config.timezone || timezone;
  if (!config.sourceUserId) {
    return { html: null, config, dateLabel: '', publicUrl: '' };
  }

  const page = findLatestNewsMorningPage({
    h5Root,
    userId: config.sourceUserId,
    slugPattern: config.pageSlugPattern,
    date: new Date(now),
    timezone: effectiveTimezone,
  });

  if (
    !page?.localPath
    || !fs.existsSync(page.localPath)
    || !isNewsMorningPageForToday(page, { date: new Date(now), timezone: effectiveTimezone })
  ) {
    return { html: null, config, dateLabel: '', publicUrl: '' };
  }

  const html = fs.readFileSync(page.localPath, 'utf8');
  return {
    html,
    config,
    dateLabel: extractDailyNewsHeroDate(html),
    publicUrl: buildPublicUrl(config.publicBaseUrl, config.sourceUserId, page.relativePath),
  };
}