const iconv = require('iconv-lite')
const { fetchYahoo } = require('../../marketsClient')

// State to prevent alert spam
// Map<alertKey, lastAlertTimestamp>
const lastAlertTimes = new Map()

const parseTencentLine = (line) => {
  const m = line.match(/^v_(\w+)="([^"]*)/)
  if (!m) return null
  const symbol = m[1]
  const body = m[2]
  let parts = body.split('~')
  if (parts.length < 3 && body.includes(',')) {
    parts = body.split(',')
  }
  
  // Standard Tencent Format (verified for sh/sz/bj/us/hk):
  // 1: Name
  // 3: Current Price
  // 4: Prev Close
  
  let name = parts[1]
  let price = parseFloat(parts[3])
  let prevClose = parseFloat(parts[4])
  
  if (isNaN(price) || isNaN(prevClose)) return null
  
  const change = price - prevClose
  const pct = prevClose ? (change / prevClose) * 100 : 0
    let captured_at = parts[30] || ''
    if (captured_at.length === 14 && !captured_at.includes('-')) {
      captured_at = captured_at.replace(/^(\d{4})(\d{2})(\d{2})(\d{2})(\d{2})(\d{2})$/, '$1-$2-$3 $4:$5:$6')
    }
  
  return { symbol, name, price, prevClose, change, change_percent: pct, captured_at }
}

const fetchTencent = async (axios, symbols) => {
  if (!symbols || symbols.length === 0) return []
  const url = `http://qt.gtimg.cn/q=${symbols.join(',')}`
  try {
    const res = await axios.get(url, { responseType: 'arraybuffer', timeout: 10000, validateStatus: () => true })
    if (!res || res.status >= 400) return []
    const text = iconv.decode(Buffer.from(res.data), 'gb18030')
    const lines = String(text || '').split(/;\s*/).filter(Boolean)
    const out = []
    for (const line of lines) {
      const r = parseTencentLine(line)
      if (r) out.push({ ...r, source: 'tencent' })
    }
    return out
  } catch (e) {
    return []
  }
}

const checkAlerts = (data, config) => {
  const alerts = []
  
  // Helper to add alert with slot-based cooldown (AM/PM logic)
  const addAlert = (key, title, message, level = 'warning') => {
    // Get current Beijing time
    const d = new Date()
    const utc = d.getTime() + (d.getTimezoneOffset() * 60000)
    const bjDate = new Date(utc + (3600000 * 8))
    
    const year = bjDate.getFullYear()
    const month = String(bjDate.getMonth() + 1).padStart(2, '0')
    const day = String(bjDate.getDate()).padStart(2, '0')
    const hour = bjDate.getHours()
    
    let slot = ''
    if (hour >= 0 && hour < 12) slot = 'am'
    else slot = 'pm' // 12:00 - 23:59
    
    const currentSlotKey = `${year}-${month}-${day}-${slot}`
    const lastSlotKey = lastAlertTimes.get(key)
    
    // Only alert if we haven't alerted in this slot for this specific key
    if (lastSlotKey !== currentSlotKey) {
      alerts.push({ id: key, title, message, level })
      lastAlertTimes.set(key, currentSlotKey)
    }
  }

  // 1. Drop Alerts (Integer steps: 2%, 3%, 4%...)
  if (config.alerts.change_percent_down && data.change_percent <= config.alerts.change_percent_down) {
    // Check integer steps
    const currentDrop = Math.floor(Math.abs(data.change_percent))
    const key = `drop_${currentDrop}`
    if (currentDrop >= Math.abs(config.alerts.change_percent_down)) {
       addAlert(key, `${config.name}跌幅预警`, `当前跌幅 ${data.change_percent.toFixed(2)}% (>= ${currentDrop}%)`)
    }
  }

  // 2. Rise Alerts (Integer steps: 2%, 3%, 4%...)
  if (config.alerts.change_percent_up && data.change_percent >= config.alerts.change_percent_up) {
    const currentRise = Math.floor(data.change_percent)
    const key = `rise_${currentRise}`
    if (currentRise >= config.alerts.change_percent_up) {
      addAlert(key, `${config.name}涨幅预警`, `当前涨幅 ${data.change_percent.toFixed(2)}% (>= ${currentRise}%)`)
    }
  }

  return alerts
}

module.exports = {
  run: async (context, config) => {
    const { axios, logJSON } = context
    let item = null
    if (String(config.source || '').toLowerCase() === 'yahoo_probe') {
      const quotes = await fetchYahoo([config.symbol])
      item = quotes.find(q => q.symbol === config.symbol)
    } else {
      const quotes = await fetchTencent(axios, [config.symbol])
      item = quotes.find(q => q.symbol === config.symbol)
    }

    // Fallback: try Tencent if Yahoo failed, or vice versa
    if (!item) {
      if (String(config.source || '').toLowerCase() === 'yahoo_probe') {
        const fb = await fetchTencent(axios, [config.symbol])
        item = fb.find(q => q.symbol === config.symbol)
      } else {
        const fb = await fetchYahoo([config.symbol])
        item = fb.find(q => q.symbol === config.symbol)
      }
    }

    if (!item) {
      logJSON('skill.fetch.error', { skill: config.name, message: 'Data not found' }, 'market_skills')
      return null
    }

    // Prepare data for DB
    const data = [{
      label: config.name,
      symbol: config.symbol,
      source: config.source,
      name: item.name,
      price: item.price,
      prevClose: item.prevClose,
      change: item.change,
      change_percent: item.change_percent,
      captured_at: item.captured_at,
      market_status: config.market_status
    }]

    // Check alerts
    const alerts = checkAlerts(item, config)

    return { data, alerts }
  }
}