const path = require('path')
const fs = require('fs')
const crypto = require('crypto')
const Database = require('better-sqlite3')
const { initCrypto, dec, ensureDecrypted } = require('./weekly_crypto')

const cfgPath = path.join(process.cwd(), 'config', 'weekly_embed.json')
if (!fs.existsSync(path.dirname(cfgPath))) fs.mkdirSync(path.dirname(cfgPath), { recursive: true })
if (!fs.existsSync(cfgPath)) {
  fs.writeFileSync(cfgPath, JSON.stringify({ machine_salt: crypto.randomBytes(16).toString('hex'), access_key: 'K049876543' }, null, 2))
}
const getConfig = () => {
  try { return JSON.parse(fs.readFileSync(cfgPath, 'utf-8')) } catch { return {} }
}
const cfg = getConfig()

const passphrase = process.env.SYSTEM_AUTH_PASS_93220 || process.env.WEEKLY_PASSWORD || ''
const salt = cfg.machine_salt || 'salt'
initCrypto(passphrase, salt)

const dataDir = path.join(process.cwd(), 'data')
const dbPath = path.join(dataDir, 'weekly.db')
const sealPath = path.join(dataDir, 'weekly.enc')

let db = null
const getDB = () => {
  if (db) return db
  if (!fs.existsSync(dataDir)) fs.mkdirSync(dataDir, { recursive: true })
  ensureDecrypted(dbPath, sealPath)
  db = new Database(dbPath, { readonly: true })
  try { db.pragma('journal_mode = WAL') } catch {}
  try { db.pragma('synchronous = NORMAL') } catch {}
  try { db.pragma('busy_timeout = 4000') } catch {}
  return db
}

const weekIdForDate = (dateStr) => {
  try {
    const d = new Date(dateStr)
    const day = d.getUTCDay()
    const diffToMon = (day + 6) % 7
    const mon = new Date(Date.UTC(d.getUTCFullYear(), d.getUTCMonth(), d.getUTCDate() - diffToMon))
    const firstDay = new Date(Date.UTC(mon.getUTCFullYear(), 0, 1))
    const firstDayWeekday = (firstDay.getUTCDay() + 6) % 7
    const days = Math.floor((mon - firstDay) / 86400000) + firstDayWeekday + 1
    const week = Math.ceil(days / 7)
    return `${mon.getUTCFullYear()}-W${String(week).padStart(2, '0')}`
  } catch {
    return `${new Date().getUTCFullYear()}-W01`
  }
}

const weeksForYear = (year) => {
  const y = parseInt(year, 10)
  const tz = 'Asia/Shanghai'
  const dateInTZ = (d) => new Date(d)
  const firstThursday = new Date(Date.UTC(y, 0, 4))
  const day = firstThursday.getUTCDay()
  const diffToMon = (day + 6) % 7
  let mon = new Date(Date.UTC(y, 0, 4 - diffToMon))
  const out = []
  let weekNum = 1
  while (weekNum <= 53) {
    const thu = new Date(Date.UTC(mon.getUTCFullYear(), mon.getUTCMonth(), mon.getUTCDate() + 3))
    const isoYear = thu.getUTCFullYear()
    if (isoYear !== y) break
    const sun = new Date(Date.UTC(mon.getUTCFullYear(), mon.getUTCMonth(), mon.getUTCDate() + 6))
    const weekLabel = `${y}-W${String(weekNum).padStart(2, '0')}`
    const startStr = new Intl.DateTimeFormat('zh-CN', { timeZone: tz, year: 'numeric', month: '2-digit', day: '2-digit' }).format(dateInTZ(mon)).replace(/\//g, '-')
    const endStr = new Intl.DateTimeFormat('zh-CN', { timeZone: tz, year: 'numeric', month: '2-digit', day: '2-digit' }).format(dateInTZ(sun)).replace(/\//g, '-')
    out.push({ week_id: weekLabel, start: startStr, end: endStr })
    mon = new Date(Date.UTC(mon.getUTCFullYear(), mon.getUTCMonth(), mon.getUTCDate() + 7))
    weekNum++
  }

  try {
    const db = getDB()
    const reports = db.prepare(`SELECT id, week_id FROM reports WHERE week_id LIKE ?`).all(`${y}-%`)
    const reportMap = new Map()
    reports.forEach(r => reportMap.set(r.week_id, r.id))
    if (reports.length > 0) {
      const placeholders = reports.map(() => '?').join(',')
      const reportIds = reports.map(r => r.id)
      const eventRows = db.prepare(`SELECT DISTINCT report_id FROM events WHERE report_id IN (${placeholders})`).all(...reportIds)
      const eventSet = new Set(eventRows.map(r => r.report_id))
      out.forEach(w => {
        const rid = reportMap.get(w.week_id)
        w.has_report = !!rid
        w.has_events = rid ? eventSet.has(rid) : false
      })
    } else {
      out.forEach(w => { w.has_report = false; w.has_events = false })
    }
  } catch {}

  return out
}

const getReportByWeek = (week_id) => {
  const row = getDB().prepare(`SELECT * FROM reports WHERE week_id=? ORDER BY id DESC LIMIT 1`).get(week_id)
  if (!row) return null
  return {
    id: row.id,
    week_id: row.week_id,
    title: dec(row.title_enc, row.title_iv, row.title_tag),
    summary: dec(row.summary_enc, row.summary_iv, row.summary_tag),
    content: dec(row.content_enc, row.content_iv, row.content_tag),
    created_at: row.created_at,
    updated_at: row.updated_at
  }
}

const listEvents = (report_id) => {
  const rows = getDB().prepare(`SELECT * FROM events WHERE report_id=? ORDER BY id ASC`).all(parseInt(report_id, 10))
  return rows.map(r => ({
    id: r.id,
    report_id: r.report_id,
    title: dec(r.title_enc, r.title_iv, r.title_tag),
    content: dec(r.content_enc, r.content_iv, r.content_tag),
    status_code: r.status_code,
    status: dec(r.status_enc, r.status_iv, r.status_tag),
    deadline: r.deadline,
    parent_event_id: r.parent_event_id,
    completed_at: r.completed_at,
    push_required: !!r.push_required,
    created_at: r.created_at,
    updated_at: r.updated_at
  }))
}

const bindRoutes = (app) => {
  const accessKey = String(cfg.access_key || 'K049876543')
  const mustKey = (req, res) => {
    const key = String(req.get('X-Weekly-Embed-Key') || req.query.key || '')
    if (!key || key !== accessKey) {
      res.status(403).json({ ok: false, error: 'forbidden' })
      return false
    }
    return true
  }

  app.use('/api/weekly_embed', (req, res, next) => {
    res.set('Cache-Control', 'no-store, no-cache, must-revalidate, proxy-revalidate')
    res.set('Pragma', 'no-cache')
    res.set('Expires', '0')
    res.set('Surrogate-Control', 'no-store')
    if (!mustKey(req, res)) return
    next()
  })

  app.get('/api/weekly_embed/years', (req, res) => {
    try {
      const trace = []
      trace.push('打开只读周报数据库')
      const db = getDB()
      trace.push('查询可用年份')
      const rows = db.prepare(`SELECT DISTINCT SUBSTR(week_id,1,4) AS y FROM reports WHERE week_id IS NOT NULL AND LENGTH(week_id)>=4 ORDER BY y DESC`).all()
      trace.push(`返回年份 ${rows.length} 条`)
      const years = rows.map(r => parseInt(String(r.y), 10)).filter(y => y > 0)
      res.json({ ok: true, years, trace })
    } catch (e) {
      res.status(500).json({ ok: false, error: String(e && e.message ? e.message : e) })
    }
  })

  app.get('/api/weekly_embed/weeks', (req, res) => {
    const trace = []
    const year = parseInt(String(req.query.year || new Date().getFullYear()), 10)
    trace.push(`计算 ${year} 年 ISO 周列表`)
    const weeks = weeksForYear(year)
    trace.push(`合并周报/事件存在标记 ${weeks.length} 条`)
    const currentWeekId = weekIdForDate(new Date().toISOString())
    trace.push(`定位当前周 ${currentWeekId}`)
    res.json({ ok: true, weeks, currentWeekId, trace })
  })

  app.get('/api/weekly_embed/report', (req, res) => {
    const trace = []
    const weekId = String(req.query.week_id || '')
    trace.push(`按 week_id 读取周报 ${weekId}`)
    const report = weekId ? getReportByWeek(weekId) : null
    trace.push(report ? `读取到周报 id=${report.id}` : '未找到周报')
    res.json({ ok: true, report, trace })
  })

  app.get('/api/weekly_embed/events', (req, res) => {
    const trace = []
    const reportId = String(req.query.report_id || '')
    if (!reportId) return res.json({ ok: true, events: [], rows: [], trace: ['缺少 report_id，返回空列表'] })
    trace.push(`按 report_id=${reportId} 读取事件列表`)
    const events = listEvents(reportId)
    trace.push(`事件数量 ${events.length}`)
    res.json({ ok: true, events, rows: events, trace })
  })
}

module.exports = { bindRoutes }