/**
 * 艾灸椅 BLE 单例管理器
 *
 * 使用说明:
 *   import bleManager from '@/utils/ble'
 *
 *   // 1. 初始化适配器
 *   await bleManager.init()
 *
 *   // 2. 扫描并连接(按名称)
 *   const device = await bleManager.scan({ namePrefix: 'AJY', timeout: 8000 })
 *   await bleManager.connect(device.deviceId)
 *
 *   // 3. 订阅上报
 *   bleManager.on('report', data => console.log(data))
 *   bleManager.on('state', s  => console.log('状态:', s))
 *
 *   // 4. 发送指令
 *   await bleManager.sendBasic({ power: 1, moxiState: 1, mode: 2, subMode: 1, temperature: 2, duration: 30 })
 */

import EventEmitter from './EventEmitter.js'
import logger from './logger.js'
import {
  DEFAULT_CONFIG, BLE_STATE, BLE_ERROR,
  POWER, MOXI_STATE, MUTE, MODE, SUB_MODE, TEMPERATURE, CHAIR_ANGLE
} from './constants.js'
import {
  encodeBasic, encodeModeParam1, encodeModeParam2, encodeAcupoints,
  bufferToArrayBuffer, arrayBufferToU8, bytesToHex, FrameParser
} from './protocol.js'

class BleManager extends EventEmitter {
  constructor() {
    super()
    this.config = { ...DEFAULT_CONFIG }
    this._state = BLE_STATE.IDLE
    this._device = null         // { deviceId, name, RSSI }
    this._serviceId = null
    this._writeCharId = null
    this._notifyCharId = null
    this._reconnectCount = 0
    this._reconnectTimer = null
    this._parser = new FrameParser(
      (decoded, frame) => this._onFrame(decoded, frame),
      (err, frame)     => logger.warn('frame parse error', err.message, bytesToHex(frame))
    )
    this._writeLock = Promise.resolve() // 写入串行化
    this._bound = false                 // 是否已绑定系统监听
    this._cancelScan = null             // 取消残留扫描的回调
  }

  // ============== 基础 ==============
  /** 获取单例 */
  static getInstance() {
    if (!BleManager._instance) BleManager._instance = new BleManager()
    return BleManager._instance
  }

  /** 覆盖配置 */
  configure(opt = {}) {
    this.config = { ...this.config, ...opt }
    logger.setEnabled(this.config.debug)
  }

  get state() { return this._state }
  get device() { return this._device }
  get isConnected() { return this._state === BLE_STATE.READY_COMM }

  _setState(s) {
    if (this._state === s) return
    this._state = s
    logger.info('state ->', s)
    this.emit('state', s)
  }

  // ============== 初始化 / 释放 ==============
  /** 打开蓝牙适配器 */
  async init() {
    if (this._state !== BLE_STATE.IDLE && this._state !== BLE_STATE.DISCONNECTED) {
		console.log("蓝牙已经初始化不用重复初始化")
      return
    }
    try {
      await this._invoke(uni.openBluetoothAdapter, {})
    } catch (e) {
      logger.error('openBluetoothAdapter fail', e)
      // errCode 10001 = 蓝牙未开启
      const code = e && (e.errCode || e.code)
      throw this._err(code === 10001 ? BLE_ERROR.ADAPTER_OFF : BLE_ERROR.NOT_SUPPORT, e)
    }
    this._bindSystemListeners()
    this._setState(BLE_STATE.READY)
	console.log("蓝牙始化")
  }

  /** 彻底释放 */
  async destroy() {
    this._clearReconnect()
    // 取消残留的扫描
    if (this._cancelScan) { this._cancelScan(); this._cancelScan = null }
    try { await this.disconnect() } catch (_) {}
    try { await this._invoke(uni.closeBluetoothAdapter, {}) } catch (_) {}
    this._unbindSystemListeners()
    this._setState(BLE_STATE.IDLE)
    this.clear()
  }

  _bindSystemListeners() {
    if (this._bound) return
    uni.onBluetoothAdapterStateChange(this._onAdapterStateChange = res => {
      logger.info('adapterStateChange', res)
      this.emit('adapterState', res)
      if (!res.available) {
        this._handleDisconnected(BLE_ERROR.ADAPTER_OFF)
      }
    })
    uni.onBLEConnectionStateChange(this._onConnStateChange = res => {
      logger.info('connectionStateChange', res)
      if (!res.connected && this._device && res.deviceId === this._device.deviceId) {
        this._handleDisconnected(BLE_ERROR.DISCONNECTED)
      }
    })
    uni.onBLECharacteristicValueChange(this._onCharChange = res => {
      const u8 = arrayBufferToU8(res.value)
      logger.log('<=', bytesToHex(u8))
      this._parser.feed(u8)
    })
    this._bound = true
  }

  _unbindSystemListeners() {
    if (!this._bound) return
    try { uni.offBluetoothAdapterStateChange && uni.offBluetoothAdapterStateChange(this._onAdapterStateChange) } catch (_) {}
    try { uni.offBLEConnectionStateChange && uni.offBLEConnectionStateChange(this._onConnStateChange) } catch (_) {}
    try { uni.offBLECharacteristicValueChange && uni.offBLECharacteristicValueChange(this._onCharChange) } catch (_) {}
    this._bound = false
  }

  // ============== 扫描 ==============
  /**
   * 扫描设备
   * @param {Object} opt
   * @param {string} [opt.namePrefix] 名称前缀过滤
   * @param {string} [opt.deviceName] 精确匹配名
   * @param {string[]} [opt.services] 服务UUID过滤(iOS需要)
   * @param {number} [opt.timeout]
   * @param {boolean} [opt.returnAll] 为 true 时返回所有匹配设备数组, 默认返回首个
   * @returns {Promise<Object|Object[]>}
   */
  async scan(opt = {}) {
    // 取消上一次残留的扫描（如 search 页面未正确清理）
    if (this._cancelScan) { this._cancelScan(); this._cancelScan = null }

    await this._ensureReady()
    const {
      namePrefix = this.config.deviceNamePrefix,
      deviceName,
      services,
      timeout   = this.config.scanTimeout,
      returnAll = false
    } = opt

    const devices = new Map()
    const matched = []

    return new Promise(async (resolve, reject) => {
      let finished = false   // 防重入：确保 finish 只执行一次

      const onFound = res => {
        if (finished) return
        for (const d of res.devices) {
          if (devices.has(d.deviceId)) continue
          devices.set(d.deviceId, d)
          const name = d.name || d.localName || ''
          const hit =
            (deviceName  && name === deviceName) ||
            (namePrefix  && name.startsWith(namePrefix)) ||
            (!deviceName && !namePrefix)
          if (hit) {
            matched.push(d)
            this.emit('deviceFound', d)
            if (!returnAll) { finish(null, d); return }
          }
        }
      }

      const timer = setTimeout(() => {
        if (returnAll) finish(null, matched)
        else if (matched.length) finish(null, matched[0])
        else finish(this._err(BLE_ERROR.SCAN_FAIL, { msg: '扫描超时，未发现目标设备' }))
      }, timeout)

      const finish = (err, data) => {
        if (finished) return   // 防重入
        finished = true
        this._cancelScan = null
        clearTimeout(timer)
        uni.offBluetoothDeviceFound && uni.offBluetoothDeviceFound(onFound)
        this._invoke(uni.stopBluetoothDevicesDiscovery, {}).catch(() => {})
        this._setState(BLE_STATE.READY)
        err ? reject(err) : resolve(data)
      }

      // 暴露取消句柄，供 destroy() / 下次 scan() 调用
      this._cancelScan = () => finish(this._err(BLE_ERROR.SCAN_FAIL, { msg: '扫描已取消' }))

      uni.onBluetoothDeviceFound(onFound)
      this._setState(BLE_STATE.SCANNING)

      try {
        await this._invoke(uni.startBluetoothDevicesDiscovery, {
          allowDuplicatesKey: false,
          interval: 0,
          services
        })
      } catch (e) {
        finish(this._err(BLE_ERROR.SCAN_FAIL, e))
      }
    })
  }

  // ============== 连接 ==============
  /**
   * 连接指定设备
   * @param {string} deviceId
   */
  async connect(deviceId) {
    if (!deviceId) throw this._err(BLE_ERROR.CONNECT_FAIL, { msg: 'deviceId 不能为空' })
    await this._ensureReady()
    if (this._state === BLE_STATE.CONNECTING) throw this._err(BLE_ERROR.BUSY)
    this._setState(BLE_STATE.CONNECTING)
    this._device = { deviceId, name: '' }

    try {
      await this._invoke(uni.createBLEConnection, {
        deviceId,
        timeout: this.config.connectTimeout
      })
      this._setState(BLE_STATE.CONNECTED)

      // Android 提升 MTU (忽略失败)
      // #ifdef APP-PLUS
      if (uni.getSystemInfoSync().platform === 'android' && uni.setBLEMTU) {
        try { await this._invoke(uni.setBLEMTU, { deviceId, mtu: 185 }) } catch (_) {}
      }
      // #endif

      await this._discoverAndSubscribe(deviceId)
      this._setState(BLE_STATE.READY_COMM)
      this._reconnectCount = 0
      this.emit('connected', this._device)
    } catch (e) {
      this._setState(BLE_STATE.DISCONNECTED)
      try { await this._invoke(uni.closeBLEConnection, { deviceId }) } catch (_) {}
      const code = e && (e.errCode || e.code)
      if (code === 10003 || code === -1) {
        throw this._err(BLE_ERROR.CONNECT_TIMEOUT, e)
      }
      throw this._err(BLE_ERROR.CONNECT_FAIL, e)
    }
  }

  /** 扫描 + 连接一步到位 */
  async scanAndConnect(opt) {
    const device = await this.scan(opt)
    await this.connect(device.deviceId)
    this._device.name = device.name || device.localName || ''
    return this._device
  }

  /** 主动断开 */
  async disconnect() {
    this._clearReconnect()
    if (!this._device) return
    const { deviceId } = this._device
    try { await this._invoke(uni.closeBLEConnection, { deviceId }) } catch (_) {}
    this._device = null
    this._setState(BLE_STATE.DISCONNECTED)
    this.emit('disconnected', { manual: true })
  }

  /** 发现服务并订阅通知 */
  async _discoverAndSubscribe(deviceId) {
    // 1) 服务列表
    const svcRes = await this._invoke(uni.getBLEDeviceServices, { deviceId })
    const services = svcRes.services || []
    const targetSvc = services.find(s => this._uuidEq(s.uuid, this.config.serviceId)) || services.find(s => s.isPrimary) || services[0]
    if (!targetSvc) throw this._err(BLE_ERROR.SERVICE_NOT_FOUND)
    this._serviceId = targetSvc.uuid

    // 2) 特征值
    const charRes = await this._invoke(uni.getBLEDeviceCharacteristics, {
      deviceId, serviceId: this._serviceId
    })
    const chars = charRes.characteristics || []

    const writeChar = chars.find(c => this._uuidEq(c.uuid, this.config.writeCharId))
      || chars.find(c => c.properties && (c.properties.write || c.properties.writeNoResponse || c.properties.writeDefault))
    const notifyChar = chars.find(c => this._uuidEq(c.uuid, this.config.notifyCharId))
      || chars.find(c => c.properties && (c.properties.notify || c.properties.indicate))

    if (!writeChar)  throw this._err(BLE_ERROR.CHAR_NOT_FOUND, { msg: '未找到写特征' })
    if (!notifyChar) throw this._err(BLE_ERROR.CHAR_NOT_FOUND, { msg: '未找到通知特征' })

    this._writeCharId  = writeChar.uuid
    this._notifyCharId = notifyChar.uuid

    // 3) 开启通知
    await this._invoke(uni.notifyBLECharacteristicValueChange, {
      deviceId,
      serviceId: this._serviceId,
      characteristicId: this._notifyCharId,
      state: true
    })
  }

  _uuidEq(a, b) {
    return String(a || '').toLowerCase() === String(b || '').toLowerCase()
  }

  // ============== 断连处理 & 自动重连 ==============
  _handleDisconnected(reason) {
    if (this._state === BLE_STATE.DISCONNECTED || this._state === BLE_STATE.IDLE) return
    const device = this._device
    this._setState(BLE_STATE.DISCONNECTED)
    this.emit('disconnected', { manual: false, reason })
    this._parser.reset()
    // 尝试自动重连
    this._attemptReconnect(device, reason)
  }

  _attemptReconnect(device, reason) {
    if (!this.config.autoReconnect || !device || this._reconnectCount >= this.config.maxReconnect) {
      if (this._reconnectCount >= this.config.maxReconnect) {
        this.emit('reconnectFailed')
      }
      return
    }
    this._reconnectCount++
    const delay = Math.min(1000 * this._reconnectCount, 5000)
    logger.warn(`reconnect in ${delay}ms (${this._reconnectCount}/${this.config.maxReconnect})`)
    this.emit('reconnecting', { count: this._reconnectCount, max: this.config.maxReconnect })
    this._reconnectTimer = setTimeout(async () => {
      try {
        await this.init()
        await this.connect(device.deviceId)
        this.emit('reconnected', this._device)
      } catch (e) {
        logger.error('reconnect fail', e)
        this._attemptReconnect(device, reason)
      }
    }, delay)
  }

  _clearReconnect() {
    if (this._reconnectTimer) { clearTimeout(this._reconnectTimer); this._reconnectTimer = null }
    this._reconnectCount = 0
  }

  // ============== 收包 ==============
  _onFrame(decoded, frame) {
    // 结构化: { funcCode, payload, parsed }
    this.emit('frame', { ...decoded, raw: frame })
    if (decoded.parsed) this.emit('report', decoded.parsed)
    // 分类事件, 便于精细订阅
    if (decoded.parsed && decoded.parsed.type) {
      this.emit(`report:${decoded.parsed.type}`, decoded.parsed)
    }
  }

  // ============== 发送 ==============
  /** 低层: 写入任意字节 */
  async writeRaw(u8) {
    if (!this.isConnected) throw this._err(BLE_ERROR.DISCONNECTED)
    const payload = bufferToArrayBuffer(u8)
    // 串行写入, 避免并发写同一特征
    this._writeLock = this._writeLock.then(async () => {
      logger.log('=>', bytesToHex(u8))
      try {
        await this._invoke(uni.writeBLECharacteristicValue, {
          deviceId: this._device.deviceId,
          serviceId: this._serviceId,
          characteristicId: this._writeCharId,
          value: payload
        })
      } catch (e) {
        throw this._err(BLE_ERROR.WRITE_FAIL, e)
      }
    })
    return this._writeLock
  }

  /**
   * 发送任意帧 (不等应用层回复, 只等底层 ack)
   * @param {Uint8Array} frame
   */
  send(frame) { return this.writeRaw(frame) }

  // ============== 高层业务接口 ==============
  /** 下发基本功能指令 (0x01) */
  sendBasic(opt) { return this.writeRaw(encodeBasic(opt)) }

  /** 下发模式参数 1 (步骤 1-7) */
  sendModeParam1(opt) { return this.writeRaw(encodeModeParam1(opt)) }

  /** 下发模式参数 2 (步骤 8-14) */
  sendModeParam2(opt) { return this.writeRaw(encodeModeParam2(opt)) }

  /** 下发穴位坐标 (每包 2 个穴位, 可传任意数量, 内部自动分包) */
  async sendAcupoints(points = []) {
    for (let i = 0; i < points.length; i += 2) {
      const pair = points.slice(i, i + 2)
      await this.writeRaw(encodeAcupoints(pair))
    }
  }

  // ---- 常用快捷方法 ----
  powerOn()  { return this.sendBasic({ power: POWER.ON }) }
  powerOff() { return this.sendBasic({ power: POWER.OFF }) }
  startMoxi(opt = {}) { return this.sendBasic({ power: POWER.ON, moxiState: MOXI_STATE.START, ...opt }) }
  pauseMoxi()         { return this.sendBasic({ moxiState: MOXI_STATE.PAUSE }) }
  stopMoxi()          { return this.sendBasic({ moxiState: MOXI_STATE.DONE }) }
  setMute(on)         { return this.sendBasic({ mute: on ? MUTE.ON : MUTE.OFF }) }
  setTemperature(v)   { return this.sendBasic({ temperature: v }) }
  setChairAngle(v)    { return this.sendBasic({ angle: v }) }

  // ============== 工具 ==============
  /** 封装 uni 回调为 Promise */
  _invoke(apiFn, params) {
    return new Promise((resolve, reject) => {
      apiFn({ ...params, success: resolve, fail: reject, complete: () => {} })
    })
  }

  async _ensureReady() {
    if (this._state === BLE_STATE.IDLE) await this.init()
    // 二次校验
    try {
      const res = await this._invoke(uni.getBluetoothAdapterState, {})
      if (!res.available) throw this._err(BLE_ERROR.ADAPTER_OFF)
    } catch (e) {
      if (e && e.code && String(e.code).startsWith('BLE_')) throw e
      throw this._err(BLE_ERROR.ADAPTER_OFF, e)
    }
  }

  _err(code, origin) {
    const err = new Error(code)
    err.code = code
    if (origin) err.origin = origin
    return err
  }
}

export default BleManager