expo-ble-app-demo/hooks/useBlePeripheral.ts

import { useState, useEffect, useCallback, useRef } from 'react';
import { Platform, PermissionsAndroid } from 'react-native';
import { BLE_UUIDS as PROTOCOL_UUIDS } from '../ble/index';
import { BlePeripheralManager, PeripheralEventCallback, DeviceInfo } from '@/ble/manager/BlePeripheralManager';
import { Buffer } from 'buffer';

interface PeripheralState {
  isAdvertising: boolean;
  connectedCentralCount: number;
  logs: string[];
  deviceInfo: DeviceInfo;
  loading: {
    advertising: boolean;
  };
  error: string | null;
}

const MAX_LOGS = 100;

const DEFAULT_DEVICE_INFO: DeviceInfo = {
  devname: 'BLE Test Device',
  version: '2.1.1',
  activated: true,
  brand: 0,
  size: 1,
  allspace: 1024,
  freespace: 512,
};

export const useBlePeripheral = () => {
  const [state, setState] = useState<PeripheralState>({
    isAdvertising: false,
    connectedCentralCount: 0,
    logs: [],
    deviceInfo: DEFAULT_DEVICE_INFO,
    loading: {
      advertising: false,
    },
    error: null,
  });

  // Ref to track peripheral manager
  const peripheralManagerRef = useRef<BlePeripheralManager>(BlePeripheralManager.getInstance());
  
  // Ref to track advertising state for cleanup
  const isAdvertisingRef = useRef(false);
  
  // Ref to track component mount state
  const isMountedRef = useRef(true);

  // Add log message with limit
  const addLog = useCallback((message: string) => {
    const timestamp = new Date().toLocaleTimeString();
    setState(prev => {
      const newLogs = [...prev.logs, `[${timestamp}] ${message}`];
      const trimmedLogs = newLogs.length > MAX_LOGS 
        ? newLogs.slice(-MAX_LOGS) 
        : newLogs;
      return { ...prev, logs: trimmedLogs };
    });
  }, []);

  // Set error with user visibility
  const setError = useCallback((error: string | null) => {
    setState(prev => ({ ...prev, error }));
    if (error) {
      addLog(`ERROR: ${error}`);
    }
  }, [addLog]);

  // Initialize peripheral mode
  useEffect(() => {
    if (Platform.OS === 'web') {
      addLog('BLE peripheral mode not supported on web platform');
      return;
    }

    addLog('BLE Peripheral mode initialized (Real BLE)');
    addLog('Service UUID: ' + PROTOCOL_UUIDS.SERVICE);
    addLog('Write Characteristic UUID: ' + PROTOCOL_UUIDS.WRITE_CHARACTERISTIC);
    addLog('Read Characteristic UUID: ' + PROTOCOL_UUIDS.READ_CHARACTERISTIC);

    // Set up event callbacks
    const callbacks: PeripheralEventCallback = {
      onAdvertisingStateChange: (isAdvertising, error) => {
        if (isMountedRef.current) {
          setState(prev => ({
            ...prev,
            isAdvertising,
            loading: { ...prev.loading, advertising: false },
            error: error || null
          }));
          addLog(`Advertising ${isAdvertising ? 'started' : 'stopped'}${error ? ` with error: ${error}` : ''}`);
        }
      },
      onCentralConnected: (centralId) => {
        if (isMountedRef.current) {
          setState(prev => ({
            ...prev,
            connectedCentralCount: peripheralManagerRef.current.getConnectedCentralsCount()
          }));
          addLog(`Central device connected: ${centralId}`);
        }
      },
      onCentralDisconnected: (centralId) => {
        if (isMountedRef.current) {
          setState(prev => ({
            ...prev,
            connectedCentralCount: peripheralManagerRef.current.getConnectedCentralsCount()
          }));
          addLog(`Central device disconnected: ${centralId}`);
        }
      },
      onCharacteristicRead: (centralId, characteristicUuid, data) => {
        if (isMountedRef.current) {
          addLog(`Characteristic read by ${centralId}: ${characteristicUuid}`);
        }
      },
      onCharacteristicWrite: (centralId, characteristicUuid, data) => {
        if (isMountedRef.current) {
          const jsonString = Buffer.from(data).toString('utf-8');
          addLog(`Characteristic write by ${centralId}: ${characteristicUuid}`);
          addLog(`Data: ${jsonString}`);
        }
      }
    };

    peripheralManagerRef.current.addCallback(callbacks);

    return () => {
      isMountedRef.current = false;
      if (isAdvertisingRef.current) {
        stopAdvertising();
      }
      peripheralManagerRef.current.removeCallback(callbacks);
    };
  }, [addLog]);

  // Check and request necessary permissions for Android 12+
  const checkPermissions = useCallback(async (): Promise<boolean> => {
    if (Platform.OS !== 'android') {
      return true; // iOS handles permissions differently
    }

    try {
      const apiLevel = Platform.Version;
      if (typeof apiLevel === 'number' && apiLevel >= 31) {
        // Android 12+ (API 31+) requires multiple Bluetooth permissions for peripheral mode
        const requiredPermissions = [
          PermissionsAndroid.PERMISSIONS.BLUETOOTH_ADVERTISE,
          PermissionsAndroid.PERMISSIONS.BLUETOOTH_CONNECT,
          PermissionsAndroid.PERMISSIONS.BLUETOOTH_SCAN
        ];
        
        for (const permission of requiredPermissions) {
          const granted = await PermissionsAndroid.check(permission);
          
          if (!granted) {
            const result = await PermissionsAndroid.request(permission, {
              title: 'Bluetooth Permission Required',
              message: 'This app needs Bluetooth permissions to act as a BLE peripheral device.',
              buttonNeutral: 'Ask Me Later',
              buttonNegative: 'Cancel',
              buttonPositive: 'OK',
            });
            
            if (result !== PermissionsAndroid.RESULTS.GRANTED) {
              setError(`${permission} is required for peripheral mode`);
              return false;
            }
          }
        }
      }
      
      return true;
    } catch (error) {
      console.error('Permission check failed:', error);
      setError('Failed to check Bluetooth permissions');
      return false;
    }
  }, [setError]);

  // Start advertising as peripheral (real BLE)
  const startAdvertising = useCallback(async () => {
    if (Platform.OS === 'web') {
      setError('BLE peripheral not supported on web');
      return;
    }

    if (isAdvertisingRef.current) {
      addLog('Already advertising as peripheral');
      return;
    }

    try {
      setError(null);
      setState(prev => ({ 
        ...prev, 
        loading: { ...prev.loading, advertising: true }
      }));

      // Check permissions first
      const hasPermissions = await checkPermissions();
      if (!hasPermissions) {
        if (isMountedRef.current) {
          setState(prev => ({ 
            ...prev, 
            loading: { ...prev.loading, advertising: false }
          }));
        }
        return;
      }

      const currentDeviceInfo = peripheralManagerRef.current.getDeviceInfo();
      addLog('Starting BLE advertising...');
      addLog('Device Name: ' + currentDeviceInfo.devname);
      addLog('Advertising with service UUID: ' + PROTOCOL_UUIDS.SERVICE);
      
      // iOS platform limitation warning
      if (Platform.OS === 'ios') {
        addLog('⚠️  iOS: Advertising will stop when app goes to background');
      }
      peripheralManagerRef
      await peripheralManagerRef.current.startAdvertising(currentDeviceInfo.devname);
      isAdvertisingRef.current = true;
      
    } catch (error) {
      if (isMountedRef.current) {
        const errorMsg = `Failed to start advertising: ${error}`;
        addLog(errorMsg);
        setError(errorMsg);
        setState(prev => ({ 
          ...prev, 
          loading: { ...prev.loading, advertising: false }
        }));
      }
    }
  }, [addLog, setError, checkPermissions]);

  // Stop advertising
  const stopAdvertising = useCallback(async () => {
    if (!isAdvertisingRef.current) {
      addLog('Not currently advertising');
      return;
    }

    try {
      addLog('Stopping BLE advertising...');
      
      await peripheralManagerRef.current.stopAdvertising();
      isAdvertisingRef.current = false;
      setState(prev => ({ 
        ...prev, 
        isAdvertising: false,
        connectedCentralCount: 0
      }));

      addLog('BLE advertising stopped');
    } catch (error) {
      addLog(`Failed to stop advertising: ${error}`);
    }
  }, [addLog]);

  // Get characteristic read value (for testing/debugging: Shows what response will be sent when central reads this characteristic)
  const getCharacteristicReadValue = useCallback((characteristicUuid: string) => {
    if (!isAdvertisingRef.current) {
      addLog('Cannot get read value - not advertising');
      return null;
    }

    addLog(`Getting characteristic read value: ${characteristicUuid}`);
    
    if (characteristicUuid === PROTOCOL_UUIDS.READ_CHARACTERISTIC) {
      // Return device info as JSON - use manager to get latest data instead of stale state
      const response = {
        type: 0x02, // Device info response type
        data: peripheralManagerRef.current.getDeviceInfo()
      };
      addLog('Returning device info response');
      return JSON.stringify(response);
    }

    addLog('Unknown characteristic for read');
    return null;
  }, [addLog]);

  // Update device info
  const updateDeviceInfo = useCallback((updates: Partial<DeviceInfo>) => {
    peripheralManagerRef.current.updateDeviceInfo(updates);
    // Sync state with manager to avoid stale state issues
    setState(prev => ({
      ...prev,
      deviceInfo: peripheralManagerRef.current.getDeviceInfo()
    }));
    addLog('Device info updated');
  }, [addLog]);

  // Reset device info
  const resetDeviceInfo = useCallback(() => {
    peripheralManagerRef.current.resetDeviceInfo();
    // Sync state with manager to avoid stale state issues
    setState(prev => ({
      ...prev,
      deviceInfo: peripheralManagerRef.current.getDeviceInfo()
    }));
    addLog('Device info reset to defaults');
  }, [addLog]);

  // Clear logs
  const clearLogs = useCallback(() => {
    setState(prev => ({ ...prev, logs: [] }));
  }, []);

  return {
    ...state,
    startAdvertising,
    stopAdvertising,
    getCharacteristicReadValue,
    updateDeviceInfo,
    resetDeviceInfo,
    clearLogs,
  };
};