// 股票历史K线数据代理 Edge Function
// 主数据源：腾讯财经 fqkline 接口（前复权日K）
// 降级数据源：新浪财经 getKLineData 接口（腾讯返回数据过少时启用，如北交所920开头新股）

function corsHeaders() {
  return {
    'Content-Type': 'application/json; charset=utf-8',
    'Access-Control-Allow-Origin': '*',
    'Access-Control-Allow-Methods': 'GET, OPTIONS',
    'Access-Control-Allow-Headers': 'content-type',
  };
}

// 根据代码推断市场前缀
function getMarketPrefix(code: string): string {
  if (code.startsWith('688') || code.startsWith('60')) return 'sh';
  if (code.startsWith('920') || code.startsWith('8') || code.startsWith('4')) return 'bj';
  return 'sz';
}

// 从腾讯返回数据中提取K线原始数组
function extractTencentKlines(result: any, stockCode: string): any[] {
  const stockData = result?.data?.[stockCode];
  if (!stockData) return [];
  const raw = stockData.qfqday || stockData.day || [];
  return Array.isArray(raw) ? raw : [];
}

// 转换腾讯K线格式：[日期, 开, 收, 高, 低, 量, 额]
function parseTencentKlines(rawKlines: any[]) {
  return rawKlines.map((record: any[]) => ({
    date: record[0],
    open: parseFloat(record[1]) || 0,
    close: parseFloat(record[2]) || 0,
    high: parseFloat(record[3]) || 0,
    low: parseFloat(record[4]) || 0,
    volume: parseInt(record[5]) || 0,
  }));
}

// 新浪财经日K线接口（降级数据源）
// 返回格式：[{ day, open, high, low, close, volume }, ...]
async function fetchSinaKlines(code: string, days: number): Promise<any[]> {
  const market = getMarketPrefix(code);
  const sinaSymbol = `${market}${code}`;
  const url = `https://money.finance.sina.com.cn/quotes_service/api/json_v2.php/CN_MarketData.getKLineData?symbol=${sinaSymbol}&scale=240&ma=no&datalen=${days}`;
  console.log(`[stock-history] 降级新浪接口: ${url}`);
  try {
    const resp = await fetch(url, {
      headers: { 'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36' },
    });
    if (!resp.ok) {
      console.error(`[stock-history] 新浪接口响应异常: ${resp.status}`);
      return [];
    }
    const text = await resp.text();
    if (!text || text.trim() === '' || text.trim() === 'null') return [];
    const arr = JSON.parse(text);
    if (!Array.isArray(arr)) return [];
    return arr.map((item: any) => ({
      date: item.day,
      open: parseFloat(item.open) || 0,
      close: parseFloat(item.close) || 0,
      high: parseFloat(item.high) || 0,
      low: parseFloat(item.low) || 0,
      volume: parseInt(item.volume) || 0,
    }));
  } catch (err) {
    console.error('[stock-history] 新浪接口失败:', err);
    return [];
  }
}

Deno.serve(async (req) => {
  if (req.method === 'OPTIONS') {
    return new Response('ok', { headers: corsHeaders() });
  }

  const url = new URL(req.url);
  const code = url.searchParams.get('code') || '';
  const days = parseInt(url.searchParams.get('days') || '90');

  if (!/^\d{6}$/.test(code)) {
    return new Response(JSON.stringify({ error: '股票代码格式错误，需为6位数字' }), {
      status: 400,
      headers: corsHeaders(),
    });
  }

  const market = getMarketPrefix(code);
  const stockCode = `${market}${code}`;

  try {
    console.log(`[stock-history] 请求股票: ${stockCode}, 天数: ${days}`);

    // 1. 主数据源：腾讯财经日K线接口（前复权）
    const apiUrl = `https://web.ifzq.gtimg.cn/appstock/app/fqkline/get?param=${stockCode},day,,,${days},qfq`;
    console.log(`[stock-history] 腾讯请求URL: ${apiUrl}`);

    const resp = await fetch(apiUrl, {
      headers: {
        'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36',
        'Referer': 'https://stockapp.finance.qq.com/',
      },
    });

    console.log(`[stock-history] 腾讯响应状态: ${resp.status}`);

    let tencentKlines: any[] = [];
    if (resp.ok) {
      const result = await resp.json();
      console.log(`[stock-history] 腾讯返回数据结构:`, JSON.stringify(result).substring(0, 500));
      const rawKlines = extractTencentKlines(result, stockCode);
      console.log(`[stock-history] 腾讯K线数据条数: ${rawKlines.length}`);
      if (rawKlines.length > 0) {
        console.log(`[stock-history] 腾讯首条:`, JSON.stringify(rawKlines[0]));
        console.log(`[stock-history] 腾讯末条:`, JSON.stringify(rawKlines[rawKlines.length - 1]));
        tencentKlines = parseTencentKlines(rawKlines);
      }
    }

    // 2. 腾讯数据充足则直接返回
    if (tencentKlines.length >= 2) {
      console.log(`[stock-history] 腾讯数据充足，返回 ${tencentKlines.length} 条`);
      return new Response(JSON.stringify({
        data: tencentKlines,
        count: tencentKlines.length,
        source: 'tencent',
      }), { headers: corsHeaders() });
    }

    // 3. 腾讯数据过少（新股、北交所920开头等），降级到新浪
    console.log(`[stock-history] 腾讯数据不足(${tencentKlines.length}条)，降级新浪接口`);
    const sinaKlines = await fetchSinaKlines(code, days);
    console.log(`[stock-history] 新浪K线数据条数: ${sinaKlines.length}`);

    if (sinaKlines.length > 0) {
      return new Response(JSON.stringify({
        data: sinaKlines,
        count: sinaKlines.length,
        source: 'sina',
      }), { headers: corsHeaders() });
    }

    // 4. 新浪也无数据，若腾讯至少有1条则返回，否则报错
    if (tencentKlines.length > 0) {
      console.log(`[stock-history] 新浪无数据，返回腾讯的 ${tencentKlines.length} 条`);
      return new Response(JSON.stringify({
        data: tencentKlines,
        count: tencentKlines.length,
        source: 'tencent',
      }), { headers: corsHeaders() });
    }

    return new Response(JSON.stringify({
      error: '未获取到K线数据',
      data: [],
      count: 0,
    }), {
      status: 404,
      headers: corsHeaders(),
    });
  } catch (error) {
    const msg = error instanceof Error ? error.message : String(error);
    console.error('[stock-history] 错误:', msg);
    return new Response(JSON.stringify({
      error: `获取数据失败: ${msg}`,
      data: [],
      count: 0,
    }), {
      status: 500,
      headers: corsHeaders(),
    });
  }
});