const express = require('express')
const bodyParser = require('body-parser')
const cors = require('cors')
const fs = require('fs').promises
const path = require('path')
const fetch = require('node-fetch')

const PORT = process.env.PORT || 7301
const DATA_DIR = path.join(__dirname, 'data')
const DEVICES_FILE = path.join(DATA_DIR, 'push_devices.json')

async function ensureDataDir() {
  try {
    await fs.mkdir(DATA_DIR, { recursive: true })
    try {
      await fs.access(DEVICES_FILE)
    } catch (e) {
      await fs.writeFile(DEVICES_FILE, '[]', 'utf8')
    }
  } catch (e) {
    console.error('无法创建数据目录:', e)
    process.exit(1)
  }
}

async function readDevices() {
  try {
    const txt = await fs.readFile(DEVICES_FILE, 'utf8')
    return JSON.parse(txt || '[]')
  } catch (e) {
    return []
  }
}

async function writeDevices(devices) {
  await fs.writeFile(DEVICES_FILE, JSON.stringify(devices, null, 2), 'utf8')
}

async function start() {
  await ensureDataDir()
  const app = express()
  app.use(cors())
  app.use(bodyParser.json())

  app.get('/health', (req, res) => res.json({ ok: true }))

  // 注册或更新设备
  app.post('/api/v1/push/register', async (req, res) => {
    const { cid, user_id, platform } = req.body || {}
    if (!cid) return res.status(400).json({ error: 'cid required' })
    const devices = await readDevices()
    let found = devices.find(d => d.cid === cid)
    const now = new Date().toISOString()
    if (found) {
      found.user_id = user_id ?? found.user_id
      found.platform = platform ?? found.platform
      found.updated_at = now
      found.active = true
    } else {
      found = { cid, user_id: user_id ?? null, platform: platform ?? null, created_at: now, updated_at: now, active: true }
      devices.push(found)
    }
    await writeDevices(devices)
    return res.json({ ok: true, cid })
  })

  // 注销设备（可选移除或置为 inactive）
  app.post('/api/v1/push/unregister', async (req, res) => {
    const { cid, user_id } = req.body || {}
    if (!cid && !user_id) return res.status(400).json({ error: 'cid or user_id required' })
    let devices = await readDevices()
    if (cid) {
      devices = devices.map(d => d.cid === cid ? Object.assign({}, d, { active: false, updated_at: new Date().toISOString() }) : d)
    } else if (user_id) {
      devices = devices.map(d => d.user_id === user_id ? Object.assign({}, d, { active: false, updated_at: new Date().toISOString() }) : d)
    }
    await writeDevices(devices)
    return res.json({ ok: true })
  })

  // 列出设备
  app.get('/api/v1/push/devices', async (req, res) => {
    const { user_id, active } = req.query
    let devices = await readDevices()
    if (user_id) devices = devices.filter(d => String(d.user_id) === String(user_id))
    if (active != null) devices = devices.filter(d => String(!!d.active) === String(active === 'true'))
    res.json({ ok: true, total: devices.length, data: devices })
  })

  // 发送推送（mock 或代理到真实 provider，当环境变量 PUSH_PROXY_URL 设置时会代理请求）
  app.post('/api/v1/push/send', async (req, res) => {
    const { cids, user_id, notification, payload } = req.body || {}
    if ((!cids || cids.length === 0) && !user_id) return res.status(400).json({ error: 'cids or user_id required' })

    let targets = []
    if (cids && cids.length > 0) targets = cids
    else if (user_id) {
      const devices = await readDevices()
      targets = devices.filter(d => String(d.user_id) === String(user_id) && d.active).map(d => d.cid)
    }

    // 如果配置了 PUSH_PROXY_URL 则转发到外部推送服务（例如 uni-push2 的服务端 API）
    const proxyUrl = process.env.PUSH_PROXY_URL || ''
    const proxyToken = process.env.PUSH_PROXY_TOKEN || ''
    if (proxyUrl) {
      try {
        const resp = await fetch(proxyUrl, {
          method: 'POST',
          headers: Object.assign({ 'Content-Type': 'application/json' }, proxyToken ? { Authorization: `Bearer ${proxyToken}` } : {}),
          body: JSON.stringify({ targets, notification, payload })
        })
        const data = await resp.text()
        return res.json({ ok: true, proxied: true, status: resp.status, response: data })
      } catch (e) {
        console.warn('代理推送失败:', e)
        return res.status(500).json({ ok: false, error: String(e) })
      }
    }

    // 否则仅记录并返回模拟结果
    console.log('Mock push to', targets.length, 'clients')
    console.log('notification:', notification)
    console.log('payload:', payload)
    return res.json({ ok: true, mocked: true, sent: targets.length })
  })

  app.listen(PORT, () => {
    console.log(`Push server listening on http://localhost:${PORT}`)
  })
}

start().catch(e => {
  console.error('启动失败:', e)
  process.exit(1)
})