const cron = require('node-cron')
const db = require('./db')
const wx = require('./wx')
const lunar = require('./lunar')

const TEMPLATE_ID = process.env.WX_TEMPLATE_ID
const MINIPROGRAM_STATE = process.env.WX_MINIPROGRAM_STATE || 'formal'

const TYPE_NAMES = {
  birthday: '生日',
  // 老数据 type=lunar_birthday 兼容回显（公历/农历由 isLunar 决定）
  lunar_birthday: '生日',
  wedding: '结婚纪念日',
  engagement: '订婚纪念日',
  other: '其他纪念日'
}

function getTypeName(type, customName) {
  if (type === 'other' && customName) return customName
  return TYPE_NAMES[type] || '纪念日'
}

function formatDate(date) {
  const y = date.getFullYear()
  const m = String(date.getMonth() + 1).padStart(2, '0')
  const d = String(date.getDate()).padStart(2, '0')
  return `${y}年${m}月${d}日`
}

// 算出"距离今年（或明年）这个纪念日还有多少天"
// 农历纪念日按 lunarMonth/lunarDay 计算每年对应的公历日期，否则按 solarMonth/solarDay
function getThisYearDate(anniv) {
  const today = new Date()
  today.setHours(0, 0, 0, 0)

  if (anniv.isLunar && anniv.lunarMonth && anniv.lunarDay) {
    // 闰月生日按 A 方案处理：若当年无对应闰月，lunarToSolar 内部已自动按普通月份算
    const todayLunar = lunar.solarToLunar(today)
    const wantLeap = !!anniv.isLeapMonth
    let target = lunar.lunarToSolar(todayLunar.year, anniv.lunarMonth, anniv.lunarDay, wantLeap)
    target.setHours(0, 0, 0, 0)
    if (target < today) {
      target = lunar.lunarToSolar(todayLunar.year + 1, anniv.lunarMonth, anniv.lunarDay, wantLeap)
      target.setHours(0, 0, 0, 0)
    }
    return target
  }

  let target = new Date(today.getFullYear(), anniv.solarMonth - 1, anniv.solarDay)
  target.setHours(0, 0, 0, 0)
  if (target < today) {
    target = new Date(today.getFullYear() + 1, anniv.solarMonth - 1, anniv.solarDay)
    target.setHours(0, 0, 0, 0)
  }
  return target
}

function daysBetween(target) {
  const today = new Date()
  today.setHours(0, 0, 0, 0)
  return Math.round((target - today) / 86400000)
}

// 检查今天是否已经给这条纪念日发过提醒
function alreadySentToday(anniversaryId) {
  const start = new Date()
  start.setHours(0, 0, 0, 0)
  const row = db.prepare(
    'SELECT COUNT(*) AS n FROM remind_logs WHERE anniversaryId = ? AND sendDate >= ? AND status = ?'
  ).get(anniversaryId, start.getTime(), 'success')
  return row.n > 0
}

const insertLog = db.prepare(`
  INSERT INTO remind_logs (anniversaryId, personName, typeName, daysUntil, sendDate, status, error)
  VALUES (@anniversaryId, @personName, @typeName, @daysUntil, @sendDate, @status, @error)
`)

async function runOnce() {
  console.log('[reminder] 开始扫描纪念日...')

  const list = db.prepare('SELECT * FROM anniversaries WHERE remindEnabled = 1').all()
  console.log(`[reminder] 启用提醒的纪念日 ${list.length} 条`)

  let ok = 0
  let fail = 0

  for (const anniv of list) {
    try {
      const target = getThisYearDate(anniv)
      const daysUntil = daysBetween(target)

      const shouldRemind = (daysUntil === 0) || (daysUntil === (anniv.remindDays || 0))
      if (!shouldRemind) continue

      if (alreadySentToday(anniv.id)) {
        console.log(`[reminder] 今天已发过，跳过: ${anniv.personName}`)
        continue
      }

      const typeName = getTypeName(anniv.type, anniv.customTypeName)

      await wx.sendSubscribeMessage({
        touser: anniv.openid,
        page: 'pages/index/index',
        templateId: TEMPLATE_ID,
        miniprogramState: MINIPROGRAM_STATE,
        data: {
          name1:  { value: anniv.personName },
          thing2: { value: daysUntil === 0 ? '今天' : `还有${daysUntil}天` },
          thing6: { value: formatDate(target) },
          thing5: { value: anniv.remark || '别忘了准备一份礼物哦！' }
        }
      })

      insertLog.run({
        anniversaryId: anniv.id,
        personName: anniv.personName,
        typeName,
        daysUntil,
        sendDate: Date.now(),
        status: 'success',
        error: null
      })
      ok++
      console.log(`[reminder] 发送成功: ${anniv.personName} (${typeName}, ${daysUntil}天)`)
    } catch (err) {
      fail++
      console.error(`[reminder] 发送失败: ${anniv.personName}`, err.message)
      insertLog.run({
        anniversaryId: anniv.id,
        personName: anniv.personName,
        typeName: null,
        daysUntil: null,
        sendDate: Date.now(),
        status: 'failed',
        error: err.message
      })
    }
  }

  console.log(`[reminder] 完成: 成功 ${ok}, 失败 ${fail}`)
  return { total: list.length, ok, fail }
}

function start() {
  const expr = process.env.REMINDER_CRON || '0 9 * * *'
  if (!cron.validate(expr)) {
    console.error(`[reminder] 无效的 cron 表达式: ${expr}，定时任务未启动`)
    return
  }
  cron.schedule(expr, runOnce, { timezone: 'Asia/Shanghai' })
  console.log(`[reminder] 定时任务已注册: ${expr} (Asia/Shanghai)`)
}

module.exports = { start, runOnce }