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('；'))
  }
}

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。
 */
export function createWifiModule(ble) {
  async function configureWifi(ssid, password, options = {}) {
    const profile = ble.getProfile()
    const targetSsid = String(ssid || '').trim()
    const targetPass = String(password || '').trim()

    validateWifi(profile, targetSsid, targetPass)
    requireAuthorized(ble)

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

    const payload = `${targetSsid}|${targetPass}`

    // 协议要求 WiFi 参数按 0xA7 分包发送到 UUID_WIFI(F401)。
    await writeA7Payload(ble, wifi.uuid, payload, profile.packet, {
      packetInterval: Number(options.packetInterval) || 0
    })

    const stateEvent = await waitForProtocolState(ble, {
      // 仅等待最终态，避免在“连接中(4)”时过早返回导致页面提前结束流程。
      allowedCodes: WIFI_FINAL_STATE_CODES,
      rejectOnUnexpected: false,
      timeout: options.timeout || 12000,
      timeoutMessage: '等待 WiFi 状态超时'
    })

    const stateCode = Number(stateEvent.stateCode)

    return {
      success: stateCode === 3,
      stateCode
    }
  }

  return {
    configureWifi,
    requireAuthorized
  }
}