import { useState, useEffect, useCallback, useRef } from 'react';
import { Platform, Alert } from 'react-native';

// Try to import native module
let ExpoSpeechRecognitionModule: any = null;
let SPEECH_RECOGNITION_AVAILABLE = false;
try {
    const speechRecognition = require('expo-speech-recognition');
    ExpoSpeechRecognitionModule = speechRecognition.ExpoSpeechRecognitionModule;
    if (ExpoSpeechRecognitionModule) {
        SPEECH_RECOGNITION_AVAILABLE = true;
    }
} catch (e) {
    // expo-speech-recognition not available
}

export interface SpeechRecognitionResult {
    transcript: string;
    isFinal: boolean;
}

export interface UseSpeechRecognitionReturn {
    isListening: boolean;
    recognizedText: string;
    startListening: (options?: { continuous?: boolean }) => Promise<void>;
    stopListening: () => void;
    isAvailable: boolean;
    hasPermission: boolean;
    requestPermission: () => Promise<boolean>;
}

export function useSpeechRecognition(): UseSpeechRecognitionReturn {
    const [isListening, setIsListening] = useState(false);
    const [recognizedText, setRecognizedText] = useState('');
    const [hasPermission, setHasPermission] = useState(false);

    // Callbacks
    const onResultRef = useRef<((result: SpeechRecognitionResult) => void) | null>(null);

    useEffect(() => {
        if (!SPEECH_RECOGNITION_AVAILABLE || !ExpoSpeechRecognitionModule) return;

        const subscriptions: any[] = [];

        if (ExpoSpeechRecognitionModule.addListener) {
            subscriptions.push(
                ExpoSpeechRecognitionModule.addListener('start', () => setIsListening(true))
            );
            subscriptions.push(
                ExpoSpeechRecognitionModule.addListener('end', () => setIsListening(false))
            );
            subscriptions.push(
                ExpoSpeechRecognitionModule.addListener('result', (event: any) => {
                    const transcript = event.results?.[0]?.transcript || '';
                    setRecognizedText(transcript);
                    // We expose direct result via component state usually, but for hook we just update state
                })
            );
            subscriptions.push(
                ExpoSpeechRecognitionModule.addListener('error', (event: any) => {
                    setIsListening(false);
                })
            );
        }

        return () => {
            subscriptions.forEach(sub => sub.remove?.());
        };
    }, []);

    const requestPermission = async () => {
        if (!SPEECH_RECOGNITION_AVAILABLE) return false;
        const result = await ExpoSpeechRecognitionModule.requestPermissionsAsync();
        setHasPermission(result.granted);
        return result.granted;
    };

    const startListening = async (options?: { continuous?: boolean }) => {
        if (!SPEECH_RECOGNITION_AVAILABLE) {
            Alert.alert('Not Available', 'Voice recognition is not available on this device.');
            return;
        }

        try {
            // Reset text
            setRecognizedText('');

            await ExpoSpeechRecognitionModule.start({
                lang: 'en-US',
                interimResults: true,
                maxAlternatives: 1,
                continuous: options?.continuous ?? false,
            });
        } catch (e) {
            setIsListening(false);
        }
    };

    const stopListening = () => {
        if (SPEECH_RECOGNITION_AVAILABLE) {
            ExpoSpeechRecognitionModule.stop();
        }
        setIsListening(false);
    };

    return {
        isListening,
        recognizedText,
        startListening,
        stopListening,
        isAvailable: SPEECH_RECOGNITION_AVAILABLE,
        hasPermission,
        requestPermission
    };
}