import { writeA7Payload } from '../core/packet'
import { waitForProtocolState } from '../core/stateWait'

const WIFI_FINAL_STATE_CODES = Object.freeze([1, 2, 3])

/**
 * 校验 WiFi 入参，规则来源于 profile.wifi。
 */
function validateWifi(profile, ssid, password) {
  const errors = []

  if (!ssid || ssid.length > profile.wifi.maxSsidLength) {
    errors.push(`SSID 长度需在 1-${profile.wifi.maxSsidLength} 之间`)
  }

  if (password.length < profile.wifi.minPasswordLength || password.length > profile.wifi.maxPasswordLength) {
    errors.push(`密码长度需在 ${profile.wifi.minPasswordLength}-${profile.wifi.maxPasswordLength} 之间`)
  }

  const invalidChars = profile.wifi.invalidChars || []
  if (invalidChars.some((char) => ssid.includes(char))) {
    errors.push(`SSID 不能包含特殊字符: ${invalidChars.join(' ')}`)
  }

  if (errors.length) {
    throw new Error(errors.join('；'))
  }
}

/** 校验鉴权状态，未完成密钥匹配则抛出异常。 */
function requireAuthorized(ble) {
  const state = ble.getState()

  if (!state.auth || state.auth.keyMatched !== true) {
    throw new Error('请先完成密钥鉴权，再发送 WiFi 配置')
  }
}

/**
 * WiFi 配网模块：负责打包发送 ssid|password，并等待 STATE 回执。
 * 使用前必须先完成密钥鉴权。
 * @param {object} ble createBleCore 实例
 */
export function createWifiModule(ble) {
  function delay(ms) {
    return new Promise((resolve) => setTimeout(resolve, Number(ms) || 0))
  }
  const log = (...args) => { try { console.debug('[BLE][WiFi]', ...args) } catch (e) {} }

  /**
   * 发送WiFi配网指令。
   * 将 ssid|password 按 A7 分包写入 UUID_WIFI，等待 STATE 回执判定结果。
   * @param {string} ssid WiFi名称
   * @param {string} password WiFi密码
   * @param {object} options
   * @param {number} options.timeout 等待状态回执超时(ms)，默认12000
   * @param {number} options.preDelayMs 写入前延迟(ms)，ED713 默认120ms
   * @param {number} options.packetInterval 分包写入间隔(ms)
   * @returns {{ success: boolean, stateCode: number }} stateCode=3 表示连接成功
   */
  async function configureWifi(ssid, password, options = {}) {
    const profile = ble.getProfile()
    const s = String(ssid || '').trim()
    const p = String(password || '').trim()
    validateWifi(profile, s, p)
    requireAuthorized(ble)

    const { wifi } = ble.getState().characteristics
    if (!wifi || !wifi.uuid) {
      throw new Error('未发现 UUID_WIFI 特征值')
    }

    // 先注册 STATE 等待，再写入，确保不漏回执
    const waitPromise = waitForProtocolState(ble, {
      allowedCodes: WIFI_FINAL_STATE_CODES,
      rejectOnUnexpected: false,
      timeout: options.timeout || 12000,
      timeoutMessage: '等待 WiFi 状态超时'
    })

    // ED713 固件需要写入前延迟，否则可能丢包
    const pre = options.preDelayMs ?? (profile.id === 'ED713' ? 120 : 0)
    if (pre) {
      log('preDelay before WiFi write(ms)=', pre)
      await delay(pre)
    }

    log('write WiFi start', { service: ble.getState().serviceId, char: wifi.uuid })
    const sent = await writeA7Payload(ble, wifi.uuid, `${s}|${p}`, profile.packet, {
      packetInterval: Number(options.packetInterval) || 0
    })
    log('write WiFi done, packets=', sent)

    const code = Number((await waitPromise).stateCode)
    log('STATE(final) received for WiFi=', code)

    // STATE=3 表示 WiFi 连接成功
    return { success: code === 3, stateCode: code }
  }

  return { configureWifi, requireAuthorized }
}