const express = require('express')
const Database = require('better-sqlite3')
const path = require('path')
const fs = require('fs')

const dataDir = path.join(process.cwd(), 'data')
if (!fs.existsSync(dataDir)) fs.mkdirSync(dataDir, { recursive: true })
const dbPath = path.join(dataDir, 'dlt_draws.db')
const db = new Database(dbPath)

// Initialize Tables
db.exec(`CREATE TABLE IF NOT EXISTS draws (
  issue TEXT PRIMARY KEY,
  date  TEXT,
  front TEXT,
  back  TEXT,
  pool  INTEGER DEFAULT 0,
  created_at TEXT DEFAULT (datetime('now'))
);`)

// Auth Helpers
const readCookieCfg = () => {
  const cfgPath = path.join(process.cwd(), 'public', 'tools', 'dlt_draws', 'assets', 'auth_config.json')
  let name = 'dlt_draws_gate'
  let maxAge = 90 * 24 * 3600 * 1000
  try {
    if (fs.existsSync(cfgPath)) {
      const cfg = JSON.parse(fs.readFileSync(cfgPath, 'utf-8'))
      if (cfg.cookieName) name = String(cfg.cookieName)
      const days = Number(cfg.max_age_days || 0)
      if (Number.isFinite(days) && days > 0) maxAge = Math.min(days, 365) * 24 * 3600 * 1000
    }
  } catch {}
  return { name, maxAge }
}
const parseCookie = (cookieStr) => {
  const out = {}
  String(cookieStr || '').split(/;\s*/).forEach(p => { const idx = p.indexOf('='); if (idx > 0) out[p.slice(0, idx)] = decodeURIComponent(p.slice(idx + 1)) })
  return out
}

const checkAuth = (req, res, next) => {
  try {
    const cookies = parseCookie(req.headers.cookie || '')
    const { name, maxAge } = readCookieCfg()
    if (cookies[name] === '1' || cookies['nav_gate'] === '1') {
      res.cookie(name, '1', { httpOnly: true, sameSite: 'lax', maxAge })
      return next()
    }
  } catch {}
  return res.status(401).json({ error: 'unauthorized' })
}

// Helpers
const pad2 = (n) => String(n).padStart(2, '0')
const arrToCsv = (arr) => (Array.isArray(arr) ? arr : String(arr).split(/[，,\s]+/).filter(Boolean))
  .map((x) => pad2(parseInt(x, 10)))
  .join(',')
const csvToArr = (csv) => String(csv).split(/[，,\s]+/).filter(Boolean).map((x) => parseInt(x, 10))

const bindRoutes = (app) => {
  // Routes prefixed with /api/dlt
  app.get('/auth/handshake', (req, res) => {
    try {
      const cookies = parseCookie(req.headers.cookie || '')
      const { name } = readCookieCfg()
      if (cookies[name] === '1' || cookies['nav_gate'] === '1') return res.json({ ok: true })
      return res.status(401).json({ error: 'unauthorized' })
    } catch (e) {
      res.status(500).json({ ok: false, error: String(e.message || e) })
    }
  })
  app.get('/auth/token', (req, res) => {
    const cookies = parseCookie(req.headers.cookie || '')
    const { name } = readCookieCfg()
    if (cookies[name] === '1' || cookies['nav_gate'] === '1') return res.json({ ok: true })
    return res.status(401).json({ error: 'unauthorized' })
  })
  
  app.get('/api/dlt/health', (req, res) => res.json({ status: 'ok' }))

  app.get('/api/dlt/draws', checkAuth, (req, res) => {
    const limit = Math.max(0, parseInt(req.query.limit || '0', 10) || 0)
    const base = `SELECT issue, date, front, back, pool FROM draws ORDER BY CAST(issue AS INTEGER) ASC`
    const sql = limit ? `${base} LIMIT ?` : base
    try {
      const rows = db.prepare(sql).all(limit ? [limit] : [])
      res.json(rows.map((r) => ({
        issue: r.issue,
        date: r.date,
        front: csvToArr(r.front),
        back: csvToArr(r.back),
        pool: r.pool || 0
      })))
    } catch (err) {
      res.status(500).json({ error: err.message })
    }
  })

  app.post('/api/dlt/draws/merge', checkAuth, (req, res) => {
    const items = Array.isArray(req.body.rows) ? req.body.rows : []
    if (!items.length) return res.status(400).json({ error: 'rows empty' })
    let inserted = 0
    try {
      const insert = db.transaction((rows) => {
        let count = 0
        const stmt = db.prepare('INSERT OR IGNORE INTO draws(issue,date,front,back,pool) VALUES (?,?,?,?,?)')
        for (const it of rows) {
          const issue = String(it.issue || '').trim()
          const date = String(it.date || '').trim()
          const front = arrToCsv(it.front || it.frontArr || [])
          const back = arrToCsv(it.back || it.backArr || [])
          const pool = Number(it.pool || 0)
          if (!issue || csvToArr(front).length !== 5 || csvToArr(back).length !== 2) continue
          const info = stmt.run(issue, date, front, back, pool)
          count += info.changes
        }
        return count
      })
      inserted = insert(items)
      res.json({ inserted })
    } catch (err) {
      res.status(500).json({ error: err.message })
    }
  })

  app.post('/api/dlt/draws/clear', checkAuth, (req, res) => {
    try {
      db.prepare('DELETE FROM draws').run()
      res.json({ cleared: true })
    } catch (err) {
      res.status(500).json({ error: err.message })
    }
  })
}

module.exports = { bindRoutes }