import {bytesToHex, bytesToMac} from '../utils/hex'
import {joinLowHigh, readUint16LE, toUint8Array} from '../utils/bytes'

/**
 * 解析 UUID_STATE 的状态字节，转为有符号 8bit。
 */
export function parseStateCode(payload) {
  const bytes = toUint8Array(payload)
  if (!bytes.length) {
    return null
  }

  return bytes[0] > 127 ? bytes[0] - 256 : bytes[0]
}

/**
 * 解析 UUID_MSG 设备信息（ED713/ED719 通用字段优先）。
 */
export function parseDeviceInfo(payload) {
  const bytes = toUint8Array(payload)

  if (!bytes.length) {
    return {
      raw: bytes,
      mac: '',
      bindStatus: null,
      productId: null,
      deviceType: null,
      wifiStatus: null,
      cellularStatus: null
    }
  }

  const macBytes = bytes.slice(0, 6)
  const bindStatus = bytes.length > 6 ? bytes[6] : null
  const productId = bytes.length > 10 ? joinLowHigh(bytes[10], bytes[9]) : null
  const deviceType = bytes.length > 14 ? bytes[14] : null
  const wifiStatus = bytes.length > 15 ? bytes[15] : null
  const cellularStatus = bytes.length > 16 ? bytes[16] : null

  return {
    raw: bytes,
    mac: bytesToMac(macBytes),
    bindStatus,
    productId,
    deviceType,
    wifiStatus,
    cellularStatus,
    baseBoardVersion: bytes.length > 11 ? bytes[11] : null,
    coreBoardVersion: bytes.length > 12 ? bytes[12] : null
  }
}

/**
 * ED713 雷达数据解析。
 * 协议帧长度不足时返回 valid:false，交由上层决定是否忽略。
 */
export function parseEd713Radar(payload) {
  const bytes = toUint8Array(payload)

  if (bytes.length < 60) {
    return {
      type: 'ED713',
      valid: false,
      reason: 'LENGTH_LT_60',
      raw: bytes
    }
  }

  return {
    type: 'ED713',
    valid: true,
    raw: bytes,
    peopleCount: bytes[24],
    peopleLocalDecimeter: bytes[25],
    peopleState: bytes[26],
    heartRate: bytes[28],
    respRate: bytes[29],
    activityState: bytes[30],
    moveIndex: bytes[35],
    waveNum: bytes[37],
    respWave: Array.from(bytes.slice(38, 58)),
    narrowFlag: bytes[59]
  }
}

/**
 * ED719 雷达数据解析。
 * 屏蔽区数量由 shieldNum 控制，每块固定 9 字节。
 */
export function parseEd719Radar(payload) {
  const bytes = toUint8Array(payload)

  if (bytes.length < 24) {
    return {
      type: 'ED719',
      valid: false,
      reason: 'LENGTH_LT_24',
      raw: bytes
    }
  }

  const shieldNum = bytes[27] || 0
  const shieldStart = 28
  const shieldBlockLength = Math.min(Math.max(shieldNum, 0), 4) * 9

  return {
    type: 'ED719',
    valid: true,
    raw: bytes,
    eventState: bytes[4],
    peopleState: bytes[5],
    peopleNum: bytes[6],
    installHeight: readUint16LE(bytes, 8),
    installMode: bytes[10],
    beeperOn: bytes[11],
    leftDist: readUint16LE(bytes, 12),
    rightDist: readUint16LE(bytes, 14),
    frontDist: readUint16LE(bytes, 16),
    backDist: readUint16LE(bytes, 18),
    sensitive: bytes[20],
    stateDelay: readUint16LE(bytes, 22),
    shieldNum,
    shieldZoneRaw: Array.from(bytes.slice(shieldStart, shieldStart + shieldBlockLength)),
    wallOption: bytes[shieldStart + shieldBlockLength] ?? null
  }
}