// BLE protocol: frame encoding/decoding, checksum, constants

var PROTOCOL_MODE = 'vendor_33'

var SERVICE = {
  DEVICE_INFO: 'FFE0',
  DATA_COMM: 'FFE1',
  OTA: 'FFE2'
}

var CHAR = {
  DEVICE_INFO: 'FFE3',
  COMMAND: 'FFE1',
  STATUS: 'FFE4',
  BOND_INFO: 'FFE6',
  OTA_CONTROL: 'FFE7',
  OTA_DATA: 'FFE8',
  OTA_STATUS: 'FFE9'
}

var CMD = {
  SET_PARAMS: 0x01,
  START: 0x02,
  STOP: 0x03,
  QUERY_STATUS: 0x04,
  BIND: 0x05,
  UNBIND: 0x06
}

var NOTIFY = {
  STATUS_REPORT: 0x21,
  ACK: 0x22,
  TREATMENT_COMPLETE: 0x31,
  EXCEPTION: 0x32,
  BIND_SUCCESS: 0x33
}

var MODE_STATE = {
  IDLE: 0x00,
  SCANNING: 0x01,
  ACTIVE: 0x02,
  PAUSED: 0x03,
  COMPLETED: 0x04,
  ERROR: 0x05,
  OTA: 0x06
}

var WAVELENGTH = {
  IR: 1,
  R: 2,
  UV: 3,
  Y: 4
}

var TREAT_MODE = {
  NORMAL: 0,
  SMART: 1
}

// 区域 = IO↔物理位置（果果 2026-07-28 真机实测）：右=IO1(0x01) 左=IO2(0x02) 上=IO3(0x04)
// 中=IO4(0x08) 下=IO5(0x10)。此前口头给的"纵列左IO1/中上IO2…"实测不符，以本表为准。
var REGION = {
  RIGHT: 0x01,
  LEFT: 0x02,
  TOP: 0x04,
  MIDDLE: 0x08,
  BOTTOM: 0x10,
  FULL_FACE: 0x1F
}

var REGION_NAMES = ['right', 'left', 'top', 'middle', 'bottom']

// FFE4 Byte17 高三位 = 扫描时光色指示（协议简述-添加扫描时光色.docx 2026-07）：
// 001=红光 010=红外 011=紫外(蓝) 100=暖黄。注意与下发命令的 WAVELENGTH 编码
// (IR=1,R=2,UV=3,Y=4) 不同——1/2 正好是红与红外互换，绝不能复用那套常量。
var SCAN_WAVE_KEY = { 1: 'red', 2: 'ir', 3: 'uv', 4: 'yellow' }

var DEVICE_ERR = {
  0x00: 'SUCCESS',
  0x01: 'ERR_REGION_INVALID',
  0x02: 'ERR_REGION_EMPTY',
  0x03: 'ERR_BRIGHTNESS_INVALID',
  0x04: 'ERR_DURATION_INVALID',
  0x05: 'ERR_NOT_BOUND',
  0x06: 'ERR_NO_SUBSCRIPTION',
  0x07: 'ERR_TEMP_HIGH',
  0x08: 'ERR_BATTERY_LOW',
  0x09: 'ERR_ALREADY_RUNNING',
  0x0A: 'ERR_NOT_RUNNING',
  0x0B: 'ERR_OTA_FAILED',
  0x0C: 'ERR_BLE_DISCONNECTED'
}

// --- byte utilities ---

function bufferToBytes(buffer) {
  var arr = new Uint8Array(buffer)
  var bytes = []
  for (var i = 0; i < arr.length; i++) {
    bytes.push(arr[i])
  }
  return bytes
}

function bytesToBuffer(bytes) {
  var buffer = new ArrayBuffer(bytes.length)
  var view = new Uint8Array(buffer)
  for (var i = 0; i < bytes.length; i++) {
    view[i] = bytes[i]
  }
  return buffer
}

function xorChecksum(bytes) {
  var result = 0
  for (var i = 0; i < bytes.length; i++) {
    result ^= bytes[i]
  }
  return result
}

function clampByte(value) {
  var n = parseInt(value, 10)
  if (isNaN(n)) n = 0
  return Math.max(0, Math.min(255, n))
}

function clampUInt16(value) {
  var n = parseInt(value, 10)
  if (isNaN(n)) n = 0
  return Math.max(0, Math.min(65535, n))
}

function uint32ToBytes(value) {
  return [
    (value >> 24) & 0xFF,
    (value >> 16) & 0xFF,
    (value >> 8) & 0xFF,
    value & 0xFF
  ]
}

function bytesToUint32(bytes, offset) {
  return (bytes[offset] << 24) | (bytes[offset + 1] << 16) | (bytes[offset + 2] << 8) | bytes[offset + 3]
}

function hexToBytes(hex) {
  var bytes = []
  for (var i = 0; i < hex.length; i += 2) {
    bytes.push(parseInt(hex.substr(i, 2), 16))
  }
  return bytes
}

function bytesToHex(bytes) {
  var hex = ''
  for (var i = 0; i < bytes.length; i++) {
    hex += ('0' + bytes[i].toString(16)).slice(-2)
  }
  return hex.toUpperCase()
}

// --- vendor 34-byte command protocol ---
// Byte1-30: IO1~IO5 (6B each: R, IR, UV, Y, GainH, GainL)
// Byte31-32: hold time (seconds, big-endian)
// Byte33: control (0=IDLE, 1=scan, 2=treat)
// Byte34: XOR checksum of Byte1-33

var CONTROL = {
  IDLE: 0x00,
  SCAN: 0x01,
  TREAT: 0x02
}

// 每 IO 6 字节，颜色格顺序 [红][红外][紫外][暖黄]（厂商原表，新版协议简述再次确认）。
// 两种调用方式：
//   单色广播（旧）：{ region_mask, wavelength(编码), brightness, ... }
//   分区差异化（新）：{ plan: [{ mask, wave:'red'|'ir'|'uv'|'yellow', brightness }], hold_time, control }
//     —— 同一条命令里不同区可用不同颜色不同亮度（协议本身就支持 5 IO × 4 色独立）。
var WAVE_BYTE_OFFSET = { red: 0, ir: 1, uv: 2, yellow: 3 }

// 安全包线（builder 层硬上限，纵深防御——即使服务端 diagnosis_config 误配也不可突破）：
// 治疗亮度 ≤204(80%)，单次时长 ≤600s(10min)。固件侧安全机制大多未实现，此处是最后防线。
var MAX_TREAT_BRIGHTNESS = 204
var MAX_HOLD_SECONDS = 600

function buildVendorCommand(options) {
  options = options || {}
  var gain = clampUInt16(options.current_gain === undefined ? 0 : options.current_gain)
  var durationMs = options.duration_ms || 600000
  var holdSeconds = clampUInt16(options.hold_time === undefined ? Math.round(durationMs / 1000) : options.hold_time)
  var control = options.control !== undefined ? options.control : CONTROL.TREAT
  if (holdSeconds > MAX_HOLD_SECONDS) holdSeconds = MAX_HOLD_SECONDS
  var isTreat = control === CONTROL.TREAT
  function clampTreat(b) {
    b = clampByte(b)
    return isTreat && b > MAX_TREAT_BRIGHTNESS ? MAX_TREAT_BRIGHTNESS : b
  }
  // IO1..IO5 物理槽位 = bit 升序（Byte n*6 对应 mask 1<<n）。直接用字面量，不依赖
  // REGION 常量名——区域↔mask 语义调整时这里必须始终是 0x01,0x02,0x04,0x08,0x10。
  var ioMasks = [0x01, 0x02, 0x04, 0x08, 0x10] // IO1=右 IO2=左 IO3=上 IO4=中 IO5=下
  var bytes = []
  var i, j

  if (options.plan && options.plan.length) {
    for (i = 0; i < ioMasks.length; i++) {
      var slot = [0, 0, 0, 0]
      for (j = 0; j < options.plan.length; j++) {
        var p = options.plan[j]
        if ((p.mask & ioMasks[i]) === 0) continue
        var off = WAVE_BYTE_OFFSET[p.wave]
        if (off === undefined) continue
        slot[off] = clampTreat(p.brightness === undefined ? 200 : p.brightness)
      }
      bytes.push(slot[0], slot[1], slot[2], slot[3], (gain >> 8) & 0xFF, gain & 0xFF)
    }
  } else {
    var regionMask = options.region_mask || REGION.FULL_FACE
    var wavelength = options.wavelength || WAVELENGTH.R
    var brightness = clampTreat(options.brightness === undefined ? 200 : options.brightness)
    for (i = 0; i < ioMasks.length; i++) {
      var enabled = (regionMask & ioMasks[i]) !== 0
      var red = 0
      var infrared = 0
      var uv = 0
      var warmYellow = 0
      if (enabled) {
        if (wavelength === WAVELENGTH.R) red = brightness
        if (wavelength === WAVELENGTH.IR) infrared = brightness
        if (wavelength === WAVELENGTH.UV) uv = brightness
        if (wavelength === WAVELENGTH.Y) warmYellow = brightness
      }
      bytes.push(red, infrared, uv, warmYellow, (gain >> 8) & 0xFF, gain & 0xFF)
    }
  }

  bytes.push((holdSeconds >> 8) & 0xFF, holdSeconds & 0xFF)
  bytes.push(control & 0xFF)
  bytes.push(xorChecksum(bytes))
  return bytes
}

function parseVendorStatus(buffer) {
  var bytes = bufferToBytes(buffer)
  if (bytes.length === 1) {
    return { type: 'heartbeat', heartbeat: bytes[0], is_heartbeat: true, raw_hex: bytesToHex(bytes) }
  }
  if (bytes.length === 19) {
    var checksum19 = xorChecksum(bytes.slice(0, 18))
    var pds19 = []
    for (var p = 0; p < 7; p++) {
      pds19.push(bytes[p * 2] | (bytes[p * 2 + 1] << 8))
    }
    // Byte17 复用：低位=贴合状态(0/1)，高三位=扫描时光色指示（0 表示无标识/非扫描态或旧固件）。
    // Byte18 运行状态：0=IDLE 1=检测 2=治疗 0xFF=故障。
    var scanWaveCode = (bytes[16] >> 5) & 0x07
    return {
      type: 'adc',
      is_heartbeat: false,
      pd: pds19,
      vbat: bytes[14] | (bytes[15] << 8),
      fitting: bytes[16] & 0x1F,
      scan_wave: SCAN_WAVE_KEY[scanWaveCode] || null,
      run_state: bytes[17],
      is_fault: bytes[17] === 0xFF,
      checksum_ok: checksum19 === bytes[18],
      raw_hex: bytesToHex(bytes)
    }
  }
  if (bytes.length === 34) {
    var ios34 = []
    for (var j = 0; j < 5; j++) {
      var off34 = j * 6
      ios34.push({
        red: bytes[off34], infrared: bytes[off34 + 1],
        uv: bytes[off34 + 2], warm_yellow: bytes[off34 + 3],
        gain: (bytes[off34 + 4] << 8) | bytes[off34 + 5]
      })
    }
    var expected34 = xorChecksum(bytes.slice(0, 33))
    return {
      type: 'params',
      is_heartbeat: false,
      ios: ios34,
      hold_time: (bytes[30] << 8) | bytes[31],
      control: bytes[32],
      checksum: bytes[33],
      checksum_ok: expected34 === bytes[33],
      raw_hex: bytesToHex(bytes)
    }
  }
  return { type: 'unknown', is_heartbeat: false, raw_bytes: bytes, raw_hex: bytesToHex(bytes) }
}

// --- frame encoding/decoding ---

function buildFrame(type, payload) {
  var len = payload ? payload.length : 0
  var frame = [0xAA, 0x55, len, type]
  if (payload && payload.length > 0) {
    frame = frame.concat(payload)
  }
  var checkBytes = frame.slice(0)
  frame.push(xorChecksum(checkBytes))
  return bytesToBuffer(frame)
}

function parseFrame(buffer) {
  var bytes = bufferToBytes(buffer)
  if (bytes.length < 5) return null
  if (bytes[0] !== 0xAA || bytes[1] !== 0x55) return null
  var len = bytes[2]
  if (bytes.length < 5 + len) return null
  var type = bytes[3]
  var payload = bytes.slice(4, 4 + len)
  var checksum = bytes[4 + len]
  var expected = xorChecksum(bytes.slice(0, 4 + len))
  if (checksum !== expected) return null
  return { type: type, payload: payload, seq: payload.length > 0 ? payload[payload.length - 1] : 0 }
}

// --- notification parsing ---

function parseStatusReport(payload) {
  if (payload.length < 14) return null
  return {
    mode_state: payload[0],
    region_mask: payload[1],
    wavelength: payload[2],
    brightness: payload[3],
    remaining_ms: bytesToUint32(payload, 4),
    error_code: payload[8],
    command_seq: payload[9],
    battery: payload[10],
    temperature: payload[11],
    bind_status: payload[12],
    subscription: payload[13]
  }
}

function parseAck(payload) {
  return {
    seq: payload[0],
    error_code: payload.length > 1 ? payload[1] : 0,
    error_msg: DEVICE_ERR[payload.length > 1 ? payload[1] : 0] || 'UNKNOWN'
  }
}

function parseTreatmentComplete(payload) {
  return {
    session_id: bytesToHex(payload.slice(0, 8)),
    regions: payload[8],
    total_duration_ms: bytesToUint32(payload, 9),
    avg_pd: payload[13]
  }
}

function parseException(payload) {
  return {
    error_code: payload[0],
    error_msg: DEVICE_ERR[payload[0]] || 'UNKNOWN',
    temperature: payload.length > 1 ? payload[1] : 0
  }
}

// --- display helpers ---

// 掩码 = IO 纵列布局（与 REGION 常量一致）。注意：此处为硬编码中文（历史遗留，
// history/treatment-done 在用）；新页面请改用 i18n common.regions.* 取标签。
function getRegionName(mask) {
  var names = []
  var bits = [
    [0x01, '右区'], [0x02, '左区'], [0x04, '上区'],
    [0x08, '中区'], [0x10, '下区']
  ]
  for (var i = 0; i < bits.length; i++) {
    if (mask & bits[i][0]) names.push(bits[i][1])
  }
  return names
}

function getWavelengthName(code) {
  var map = { 1: '红外 850nm', 2: '红光 630nm', 3: '紫光 405nm', 4: '黄光 590nm' }
  return map[code] || '未知'
}

function getModeStateName(code) {
  var map = {
    0x00: '空闲', 0x01: '扫描中', 0x02: '使用中',
    0x03: '已暂停', 0x04: '已完成', 0x05: '异常', 0x06: 'OTA升级中'
  }
  return map[code] || '未知'
}

module.exports = {
  PROTOCOL_MODE: PROTOCOL_MODE,
  SERVICE: SERVICE,
  CHAR: CHAR,
  CMD: CMD,
  NOTIFY: NOTIFY,
  MODE_STATE: MODE_STATE,
  WAVELENGTH: WAVELENGTH,
  TREAT_MODE: TREAT_MODE,
  REGION: REGION,
  REGION_NAMES: REGION_NAMES,
  SCAN_WAVE_KEY: SCAN_WAVE_KEY,
  CONTROL: CONTROL,
  DEVICE_ERR: DEVICE_ERR,

  bufferToBytes: bufferToBytes,
  bytesToBuffer: bytesToBuffer,
  xorChecksum: xorChecksum,
  uint32ToBytes: uint32ToBytes,
  bytesToUint32: bytesToUint32,
  hexToBytes: hexToBytes,
  bytesToHex: bytesToHex,
  buildVendorCommand: buildVendorCommand,

  buildFrame: buildFrame,
  parseFrame: parseFrame,
  parseVendorStatus: parseVendorStatus,
  parseStatusReport: parseStatusReport,
  parseAck: parseAck,
  parseTreatmentComplete: parseTreatmentComplete,
  parseException: parseException,

  getRegionName: getRegionName,
  getWavelengthName: getWavelengthName,
  getModeStateName: getModeStateName
}