import { useState, useCallback } from 'react';
import { View, Text } from '@tarojs/components';
import { useDidShow } from '@tarojs/taro';
import { BLEManager } from '@/services/ble/BLEManager';
import { XiaomiBandAdapter } from '@/services/ble/adapters/XiaomiBandAdapter';
import { uploadReadings } from '@/services/device-sync';
import { useAuthStore } from '@/stores/auth';
import type { BLEDevice, NormalizedReading } from '@/services/ble/types';
import './index.scss';

const bleManager = new BLEManager({ scanTimeout: 10000, retryCount: 3 });
bleManager.registerAdapter(XiaomiBandAdapter);

type PageState = 'idle' | 'scanning' | 'connecting' | 'connected' | 'syncing' | 'done' | 'error';

export default function DeviceSync() {
  const { currentPatient } = useAuthStore();
  const [pageState, setPageState] = useState<PageState>('idle');
  const [devices, setDevices] = useState<BLEDevice[]>([]);
  const [selectedDevice, setSelectedDevice] = useState<BLEDevice | null>(null);
  const [liveReadings, setLiveReadings] = useState<NormalizedReading[]>([]);
  const [syncCount, setSyncCount] = useState(0);
  const [errorMsg, setErrorMsg] = useState('');

  useDidShow(() => {
    bleManager.setOnConnectionChange(() => {});
    bleManager.setOnReadings((readings) => {
      setLiveReadings((prev) => [...prev, ...readings]);
    });

    return () => {
      bleManager.destroy();
    };
  });

  const handleScan = useCallback(async () => {
    setPageState('scanning');
    setDevices([]);
    setErrorMsg('');
    try {
      const found = await bleManager.scanDevices();
      setDevices(found);
      if (found.length === 0) {
        setErrorMsg('未发现支持的设备，请确认手环已开启蓝牙并靠近手机');
      }
      setPageState('idle');
    } catch (e: any) {
      setErrorMsg(e.message || '扫描失败');
      setPageState('error');
    }
  }, []);

  const handleConnect = useCallback(async (device: BLEDevice) => {
    setSelectedDevice(device);
    setPageState('connecting');
    setErrorMsg('');
    try {
      await bleManager.connect(device);
      setPageState('connected');
    } catch (e: any) {
      setErrorMsg(e.message || '连接失败');
      setPageState('error');
    }
  }, []);

  const handleSync = useCallback(async () => {
    if (!currentPatient || !selectedDevice) return;

    setPageState('syncing');
    setErrorMsg('');

    try {
      const result = await bleManager.syncToServer(async (readings) => {
        return uploadReadings(
          currentPatient.id,
          selectedDevice.deviceId,
          selectedDevice.name,
          readings,
        );
      });

      if (result.success) {
        setSyncCount(result.uploadedCount);
        setPageState('done');
      } else {
        setErrorMsg(result.error || '同步失败');
        setPageState('error');
      }
    } catch (e: any) {
      setErrorMsg(e.message || '同步失败');
      setPageState('error');
    }
  }, [currentPatient, selectedDevice]);

  const handleDisconnect = useCallback(async () => {
    await bleManager.disconnect();
    setPageState('idle');
    setSelectedDevice(null);
    setLiveReadings([]);
    setSyncCount(0);
    setErrorMsg('');
  }, []);

  const renderIdle = () => (
    <View className="sync-section">
      <View className="sync-hero">
        <Text className="sync-hero-icon">⌚</Text>
        <Text className="sync-hero-title">设备同步</Text>
        <Text className="sync-hero-desc">连接智能手环，自动采集健康数据</Text>
      </View>

      <View className="sync-action" onClick={handleScan}>
        <Text className="sync-action-text">扫描设备</Text>
      </View>

      {devices.length > 0 && (
        <View className="sync-device-list">
          <Text className="sync-section-title">发现的设备</Text>
          {devices.map((d) => (
            <View
              key={d.deviceId}
              className="sync-device-item"
              onClick={() => handleConnect(d)}
            >
              <View className="sync-device-info">
                <Text className="sync-device-name">{d.name}</Text>
                <Text className="sync-device-adapter">{d.adapter?.name}</Text>
              </View>
              <Text className="sync-device-rssi">信号 {d.RSSI > -60 ? '强' : d.RSSI > -80 ? '中' : '弱'}</Text>
            </View>
          ))}
        </View>
      )}
    </View>
  );

  const renderConnected = () => (
    <View className="sync-section">
      <View className="sync-status-card">
        <Text className="sync-status-dot sync-status-dot--connected" />
        <Text className="sync-status-text">已连接: {selectedDevice?.name}</Text>
      </View>

      {liveReadings.length > 0 && (
        <View className="sync-readings-panel">
          <Text className="sync-section-title">实时数据</Text>
          {liveReadings.slice(-5).reverse().map((r, i) => (
            <View key={i} className="sync-reading-item">
              <Text className="sync-reading-type">
                {r.device_type === 'heart_rate' ? '心率' : r.device_type}
              </Text>
              <Text className="sync-reading-value">
                {r.device_type === 'heart_rate'
                  ? `${r.values.heart_rate} bpm`
                  : JSON.stringify(r.values)}
              </Text>
            </View>
          ))}
          <Text className="sync-readings-count">
            已采集 {liveReadings.length} 条数据
          </Text>
        </View>
      )}

      <View className="sync-actions-row">
        <View className="sync-action sync-action--primary" onClick={handleSync}>
          <Text className="sync-action-text">上传数据</Text>
        </View>
        <View className="sync-action sync-action--danger" onClick={handleDisconnect}>
          <Text className="sync-action-text">断开连接</Text>
        </View>
      </View>
    </View>
  );

  const renderDone = () => (
    <View className="sync-section">
      <View className="sync-result-card">
        <Text className="sync-result-icon">✓</Text>
        <Text className="sync-result-title">同步完成</Text>
        <Text className="sync-result-count">成功上传 {syncCount} 条数据</Text>
      </View>
      <View className="sync-action" onClick={handleDisconnect}>
        <Text className="sync-action-text">完成</Text>
      </View>
    </View>
  );

  return (
    <View className="device-sync-page">
      <View className="sync-header">
        <Text className="sync-header-title">设备同步</Text>
      </View>

      {errorMsg && (
        <View className="sync-error">
          <Text className="sync-error-text">{errorMsg}</Text>
        </View>
      )}

      {(pageState === 'scanning' || pageState === 'connecting' || pageState === 'syncing') && (
        <View className="sync-loading">
          <Text className="sync-loading-text">
            {pageState === 'scanning' && '正在扫描设备...'}
            {pageState === 'connecting' && '正在连接设备...'}
            {pageState === 'syncing' && '正在上传数据...'}
          </Text>
        </View>
      )}

      {(pageState === 'idle' || pageState === 'error') && renderIdle()}
      {pageState === 'connected' && renderConnected()}
      {pageState === 'done' && renderDone()}
    </View>
  );
}