import type { DeviceAdapter, NormalizedReading, GenericBLEProfile } from '../types';

// ── Bluetooth SIG 标准 Service UUID ──
const SERVICES: Record<string, { uuid: string; chars: { notify: string; read: string } }> = {
  heart_rate: {
    uuid: '0000180D-0000-1000-8000-00805F9B34FB',
    chars: {
      notify: '00002A37-0000-1000-8000-00805F9B34FB',
      read: '00002A37-0000-1000-8000-00805F9B34FB',
    },
  },
  health_thermometer: {
    uuid: '00001809-0000-1000-8000-00805F9B34FB',
    chars: {
      notify: '00002A1C-0000-1000-8000-00805F9B34FB',
      read: '00002A1C-0000-1000-8000-00805F9B34FB',
    },
  },
  blood_pressure: {
    uuid: '00001810-0000-1000-8000-00805F9B34FB',
    chars: {
      notify: '00002A35-0000-1000-8000-00805F9B34FB',
      read: '00002A35-0000-1000-8000-00805F9B34FB',
    },
  },
  pulse_oximeter: {
    uuid: '00001822-0000-1000-8000-00805F9B34FB',
    chars: {
      // PLX Continuous Measurement — 实时血氧+脉率
      notify: '00002A5F-0000-1000-8000-00805F9B34FB',
      // PLX Spot-Check Measurement — 单次测量
      read: '00002A5E-0000-1000-8000-00805F9B34FB',
    },
  },
};

// ── IEEE 11073 SFLOAT 解析（Bluetooth SIG 医疗 Profile 通用格式） ──

/** 特殊 SFLOAT 值 */
const SFLOAT_NAN = 0x07FF;
const SFLOAT_NRES = 0x0800;
const SFLOAT_POS_INF = 0x07FE;
const SFLOAT_NEG_INF = 0x0802;

function parseSFLOAT(view: DataView, offset: number): number | null {
  if (offset + 2 > view.byteLength) return null;
  const raw = view.getUint16(offset, true);

  if (raw === SFLOAT_NAN || raw === SFLOAT_NRES) return null;
  if (raw === SFLOAT_POS_INF) return Infinity;
  if (raw === SFLOAT_NEG_INF) return -Infinity;

  const signM = (raw >> 15) & 0x01;
  const exp = (raw >> 12) & 0x07;
  const mantissa = raw & 0x0FFF;

  // 指数用 3 位补码表示（0-3 正，4-7 负）
  const exponent = exp >= 4 ? exp - 8 : exp;
  const signedMantissa = signM ? -(mantissa ^ 0x0FFF) - 1 : mantissa;

  return signedMantissa * Math.pow(10, exponent);
}

// ── 解析器 ──

function parseHeartRate(data: ArrayBuffer): NormalizedReading | null {
  const view = new DataView(data);
  if (view.byteLength < 2) return null;

  const flags = view.getUint8(0);
  const isUINT16 = (flags & 0x01) !== 0;
  const hr = isUINT16
    ? (view.byteLength >= 3 ? view.getUint16(1, true) : null)
    : view.getUint8(1);

  if (hr === null || hr <= 0 || hr > 300) return null;

  return {
    device_type: 'heart_rate',
    values: { heart_rate: hr },
    measured_at: new Date().toISOString(),
  };
}

function parseTemperature(data: ArrayBuffer): NormalizedReading | null {
  const view = new DataView(data);
  if (view.byteLength < 4) return null;

  const flags = view.getUint8(0);
  const isFahrenheit = (flags & 0x01) !== 0;

  const mantissa = view.getInt16(1, true);
  const exponent = view.getInt8(3);
  const temp = mantissa * Math.pow(10, exponent);

  const tempCelsius = isFahrenheit ? (temp - 32) * 5 / 9 : temp;

  return {
    device_type: 'temperature',
    values: { value: Math.round(tempCelsius * 10) / 10, unit: '°C' },
    measured_at: new Date().toISOString(),
  };
}

/**
 * 解析 Pulse Oximeter Service 数据
 * PLX Continuous Measurement (0x2A5F) 和 Spot-Check (0x2A5E) 共用
 * 格式: Flags(1B) + SpO2(SFLOAT 2B) + PulseRate(SFLOAT 2B) + optional...
 */
function parsePulseOximeter(data: ArrayBuffer): NormalizedReading[] {
  const view = new DataView(data);
  if (view.byteLength < 5) return [];

  const spO2 = parseSFLOAT(view, 1);
  const pulseRate = parseSFLOAT(view, 3);
  const now = new Date().toISOString();
  const results: NormalizedReading[] = [];

  if (spO2 !== null && spO2 >= 0 && spO2 <= 100) {
    results.push({
      device_type: 'blood_oxygen',
      values: { blood_oxygen: Math.round(spO2), unit: '%' },
      measured_at: now,
    });
  }

  if (pulseRate !== null && pulseRate > 0 && pulseRate <= 300) {
    results.push({
      device_type: 'heart_rate',
      values: { heart_rate: Math.round(pulseRate) },
      measured_at: now,
    });
  }

  return results;
}

// ── 工厂函数 ──

export interface GenericAdapterConfig {
  name: string;
  supportedModels: string[];
  profiles: GenericBLEProfile[];
}

/** 创建通用 BLE 适配器 — 基于 Bluetooth SIG 标准 Health Profile */
export function createGenericBleAdapter(config: GenericAdapterConfig): DeviceAdapter {
  const activeServices = config.profiles
    .map((p) => SERVICES[p])
    .filter(Boolean);

  return {
    name: config.name,
    supportedModels: config.supportedModels,
    serviceUUIDs: activeServices.map((s) => s.uuid),
    notifyCharacteristics: activeServices.map((s) => ({
      service: s.uuid,
      characteristic: s.chars.notify,
    })),
    readCharacteristics: activeServices.map((s) => ({
      service: s.uuid,
      characteristic: s.chars.read,
    })),

    parseNotification(
      _serviceUUID: string,
      charUUID: string,
      data: ArrayBuffer,
    ): NormalizedReading[] {
      const upper = charUUID.toUpperCase();

      // Heart Rate Measurement (0x2A37)
      if (upper.includes('2A37')) {
        const result = parseHeartRate(data);
        return result ? [result] : [];
      }

      // Temperature Measurement (0x2A1C)
      if (upper.includes('2A1C')) {
        const result = parseTemperature(data);
        return result ? [result] : [];
      }

      // Pulse Oximeter Continuous (0x2A5F) / Spot-Check (0x2A5E)
      if (upper.includes('2A5F') || upper.includes('2A5E')) {
        return parsePulseOximeter(data);
      }

      return [];
    },

    parseReadResponse(
      serviceUUID: string,
      charUUID: string,
      data: ArrayBuffer,
    ): NormalizedReading[] {
      return this.parseNotification(serviceUUID, charUUID, data);
    },
  };
}

/**
 * 预配置：通用定制手环（心率 + 体温）
 * 未来定制手环只需在 supportedModels 中加入型号名
 */
export const CustomBandAdapter = createGenericBleAdapter({
  name: 'Custom Health Band',
  supportedModels: [
    'Health Band',
    'Medical Band',
    'Smart Bracelet',
    '健康手环',
  ],
  profiles: ['heart_rate', 'health_thermometer'],
});

/** 华为手环/手表 BLE 适配器 */
export const HuaweiBandAdapter = createGenericBleAdapter({
  name: 'Huawei Band',
  supportedModels: [
    'HUAWEI Band',
    'HUAWEI Watch',
    'Huawei Band',
    'Huawei Watch',
    'HW-B',
    'HUAW',
    '华为手环',
    '华为手表',
  ],
  profiles: ['heart_rate', 'health_thermometer', 'pulse_oximeter'],
});

/**
 * 万能 fallback 适配器 — 匹配所有有名称的设备
 * 尝试标准 BLE 健康协议（心率/体温/血压），设备不支持的服务会被安全跳过
 */
export const FallbackAdapter = createGenericBleAdapter({
  name: '通用设备',
  supportedModels: [],  // 不参与 matchAdapter，仅作为 fallback
  profiles: ['heart_rate', 'health_thermometer', 'blood_pressure'],
});

export default CustomBandAdapter;