import fs from 'node:fs';

import { wechatDailyNewsInlineInternals } from '../../wechat-daily-news-inline.mjs';
import {
  findLatestNewsMorningPage,
  isNewsMorningPageForToday,
} from '../../wechat-news-morning-draft.mjs';
import { resolveNewsMorningPushConfig } from './news-morning-delivery.mjs';

const DEFAULT_WEATHER_CITY = '北京';

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

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;
}

function normalizeWeatherCity(raw) {
  return stripInlineText(raw).replace(/市$/u, '').trim();
}

function parseWeatherCard(cardHtml) {
  const city = normalizeWeatherCity(
    cardHtml.match(/<span class="w-city">([\s\S]*?)<\/span>/i)?.[1]
      ?? cardHtml.match(/<div class="wc">([\s\S]*?)<\/div>/i)?.[1]
      ?? '',
  );
  const cond = stripInlineText(
    cardHtml.match(/<span class="w-cond">([\s\S]*?)<\/span>/i)?.[1]
      ?? cardHtml.match(/<div class="we">([\s\S]*?)<\/div>/i)?.[1]
      ?? '',
  );
  const temp = stripInlineText(
    cardHtml.match(/<span class="w-temp">([\s\S]*?)<\/span>/i)?.[1]
      ?? cardHtml.match(/<div class="wt">([\s\S]*?)<\/div>/i)?.[1]
      ?? '',
  );
  if (!city) return null;
  return { city, cond, temp };
}

function extractWeatherCardsFromHtml(html) {
  const grid = extractDivBlock(html, 'weather-grid');
  const cards = extractClassDivBlocks(grid, 'weather-card')
    .map(parseWeatherCard)
    .filter(Boolean);
  if (cards.length > 0) return cards;

  const { selectTouristWeatherCards } = wechatDailyNewsInlineInternals;
  return selectTouristWeatherCards(extractClassDivBlocks(html, 'weather-card'))
    .map(parseWeatherCard)
    .filter(Boolean);
}

function extractWeatherTodaySummary(html) {
  const todayBlock = extractDivBlock(html, 'weather-today');
  if (!todayBlock) return '';
  return stripInlineText(todayBlock).slice(0, 120);
}

export function normalizePushWeatherCity(raw, { defaultCity = DEFAULT_WEATHER_CITY } = {}) {
  const city = normalizeWeatherCity(raw);
  if (!city) return defaultCity;
  if (wechatDailyNewsInlineInternals.isPopularTouristCityName(city)) return city;
  if (/^[\u4e00-\u9fff]{2,6}$/u.test(city)) return city;
  return defaultCity;
}

function buildDressingAdvice({ cond = '', temp = '' }) {
  const text = `${cond} ${temp}`;
  if (/雨|雪/u.test(text)) return '建议带伞，穿防水外套。';
  if (/冷|冰|0°|1°|2°|3°|4°|5°/u.test(text)) return '偏冷，注意保暖，外套加厚。';
  if (/30|31|32|33|34|35|36/u.test(text)) return '偏热，轻薄透气，注意防晒补水。';
  if (/晴/u.test(text)) return '晴好天气，适合户外，记得防晒。';
  if (/阴|云/u.test(text)) return '温差可能较大，建议洋葱式穿衣。';
  return '根据体感增减衣物，出门前再看一眼实时预报。';
}

export function buildWeatherPushTextFromHtml(
  html,
  { city = DEFAULT_WEATHER_CITY, manageHint = '回复「取消3」关闭推送' } = {},
) {
  const normalizedCity = normalizePushWeatherCity(city);
  const cards = extractWeatherCardsFromHtml(html);
  const matched = cards.find((item) => normalizeWeatherCity(item.city) === normalizedCity)
    ?? cards[0]
    ?? null;
  const todaySummary = extractWeatherTodaySummary(html);
  const lines = [`🌤 每日天气 · ${normalizedCity}`];

  if (matched) {
    const detail = [matched.cond, matched.temp].filter(Boolean).join(' · ');
    lines.push('', detail || '详见下方概览');
    lines.push('', `穿衣建议：${buildDressingAdvice(matched)}`);
  } else if (todaySummary) {
    lines.push('', todaySummary);
  } else {
    lines.push('', '今日天气数据正在更新，请稍后再看。');
  }

  if (cards.length > 1 && matched) {
    const others = cards
      .filter((item) => normalizeWeatherCity(item.city) !== normalizedCity)
      .slice(0, 3)
      .map((item) => `${item.city} ${[item.cond, item.temp].filter(Boolean).join(' ')}`.trim());
    if (others.length) {
      lines.push('', `周边速览：${others.join(' · ')}`);
    }
  }

  if (manageHint) lines.push('', manageHint);
  return lines.join('\n');
}

export async function formatWeatherPushDelivery({
  city = DEFAULT_WEATHER_CITY,
  now = Date.now(),
  timezone = 'Asia/Shanghai',
  env = process.env,
  h5Root = process.cwd(),
  pool = null,
} = {}) {
  const normalizedCity = normalizePushWeatherCity(city);
  const config = await resolveNewsMorningPushConfig({ pool, env });
  const effectiveTimezone = config.timezone || timezone;

  if (!config.sourceUserId) {
    return {
      text: `🌤 每日天气 · ${normalizedCity}\n\n天气数据暂不可用，请稍后再试。\n\n回复「取消3」关闭推送`,
      verifiedHtmlUrls: [],
    };
  }

  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 {
      text: `🌤 每日天气 · ${normalizedCity}\n\n今日天气正在整理中，稍后会推送到本服务号。\n\n回复「取消3」关闭推送`,
      verifiedHtmlUrls: [],
    };
  }

  const html = fs.readFileSync(page.localPath, 'utf8');
  return {
    text: buildWeatherPushTextFromHtml(html, { city: normalizedCity }),
    verifiedHtmlUrls: [],
  };
}