import React, { useState, useEffect, useRef, useCallback } from 'react';
import { View, Text, TouchableOpacity, ActivityIndicator, StyleSheet } from 'react-native';
import { useVideoPlayer, VideoView } from 'expo-video';
import { LinearGradient } from 'expo-linear-gradient';
import { Ionicons } from '@expo/vector-icons';
import { colors, gradients, spacing, radius } from '../../../theme';
import { useVideoCache } from '../hooks';


export interface ChatVideoPlayerProps {
    /** Signed URL for the video */
    signedUrl: string | null;
    /** Storage path for caching */
    storagePath: string;
    /** Whether there was an error loading the URL */
    urlError: boolean;
    /** Callback when fullscreen is requested */
    onFullScreen: (uri: string) => void;
}

const ACCENT = colors.premium.gold;

/**
 * Video player component with native-like tap behavior.
 * Supports play/pause, fullscreen, caching, and loading states.
 */
const ChatVideoPlayerComponent: React.FC<ChatVideoPlayerProps> = ({
    signedUrl,
    storagePath,
    urlError,
    onFullScreen,
}) => {
    const [isPlaying, setIsPlaying] = useState(false);
    const [hasEnded, setHasEnded] = useState(false);
    const [isLoading, setIsLoading] = useState(true);

    // Use video cache hook
    const { cachedUri, cacheVideoFile } = useVideoCache(storagePath, signedUrl);

    // For encrypted media, signedUrl is already the decrypted local file URI
    // Skip the cache lookup for local file URIs
    const isLocalFile = signedUrl?.startsWith('file://');
    const videoSource = isLocalFile ? signedUrl : (cachedUri || signedUrl);

    const player = useVideoPlayer(videoSource ? { uri: videoSource } : null, (setupPlayer) => {
        setupPlayer.loop = false;
    });

    // Swap the player source when the cached local file becomes available,
    // without reloading on the initial mount (useVideoPlayer already loaded it).
    const mountedSourceRef = useRef(videoSource);
    useEffect(() => {
        if (videoSource && videoSource !== mountedSourceRef.current) {
            mountedSourceRef.current = videoSource;
            player.replace({ uri: videoSource });
        }
    }, [videoSource, player]);

    // Handle playback status updates
    useEffect(() => {
        const statusSubscription = player.addListener('statusChange', ({ status, error }) => {
            if (status === 'error') {
                if (error) {
                    console.error(`[ChatVideoPlayer] Video load error:`, error);
                }
                setIsLoading(false);
                return;
            }
            setIsLoading(status === 'loading');
        });

        const playingSubscription = player.addListener('playingChange', ({ isPlaying: playing }) => {
            setIsPlaying(playing);
        });

        const endSubscription = player.addListener('playToEnd', () => {
            setHasEnded(true);
            setIsPlaying(false);

            // Cache in background if not already cached (only for remote URLs)
            if (signedUrl && !cachedUri && !isLocalFile) {
                cacheVideoFile();
            }
        });

        return () => {
            statusSubscription.remove();
            playingSubscription.remove();
            endSubscription.remove();
        };
    }, [player, signedUrl, cachedUri, isLocalFile, cacheVideoFile]);

    // Toggle play/pause with native-like behavior
    const handleTapToPlay = useCallback(() => {
        if (isPlaying) {
            player.pause();
            setIsPlaying(false);
        } else {
            if (hasEnded) {
                player.replay();
                setHasEnded(false);
            }
            player.play();
            setIsPlaying(true);

            // Start caching when playback starts
            if (signedUrl && !cachedUri) {
                cacheVideoFile();
            }
        }
    }, [isPlaying, hasEnded, player, signedUrl, cachedUri, cacheVideoFile]);

    // Handle full screen
    const handleFullScreen = useCallback(() => {
        const uri = cachedUri || signedUrl;
        if (uri) {
            if (isPlaying) {
                player.pause();
                setIsPlaying(false);
            }
            onFullScreen(uri);
        }
    }, [cachedUri, signedUrl, isPlaying, player, onFullScreen]);

    if (urlError || !videoSource) {
        return (
            <View style={[styles.video, styles.errorContainer]}>
                <Ionicons name="videocam-outline" size={32} color={colors.textSecondary} />
                <Text style={styles.errorText}>Video unavailable</Text>
            </View>
        );
    }

    return (
        <TouchableOpacity
            activeOpacity={0.9}
            onPress={handleTapToPlay}
            onLongPress={handleFullScreen}
            delayLongPress={300}
            style={styles.container}
        >
            <VideoView
                player={player}
                style={styles.video}
                contentFit="cover"
                nativeControls={false}
            />

            {/* Loading indicator */}
            {isLoading && (
                <View style={styles.loadingOverlay}>
                    <ActivityIndicator color={ACCENT} size="small" />
                </View>
            )}

            {/* Play/Replay overlay */}
            {!isPlaying && !isLoading && (
                <View style={styles.playOverlay}>
                    <LinearGradient
                        colors={gradients.premiumGold as [string, string]}
                        style={styles.playButton}
                        start={{ x: 0, y: 0 }}
                        end={{ x: 1, y: 1 }}
                    >
                        <Ionicons
                            name={hasEnded ? 'refresh' : 'play'}
                            size={24}
                            color={colors.text}
                            style={hasEnded ? undefined : { marginLeft: 3 }}
                        />
                    </LinearGradient>
                </View>
            )}

            {/* Full screen button */}
            {!isPlaying && !isLoading && (
                <TouchableOpacity
                    style={styles.fullScreenButton}
                    onPress={handleFullScreen}
                    activeOpacity={0.7}
                >
                    <Ionicons name="expand-outline" size={16} color={colors.text} />
                </TouchableOpacity>
            )}

            {/* Cached indicator */}
            {cachedUri && !isPlaying && (
                <View style={styles.cachedBadge}>
                    <Ionicons name="download-outline" size={10} color={colors.textSecondary} />
                </View>
            )}
        </TouchableOpacity>
    );
};

// Wrap with React.memo for performance
export const ChatVideoPlayer = React.memo(ChatVideoPlayerComponent);

const styles = StyleSheet.create({
    container: {
        width: '100%',
        aspectRatio: 16 / 9,
        borderRadius: radius.lg,
        overflow: 'hidden',
    },
    video: {
        width: '100%',
        height: '100%',
        backgroundColor: colors.background,
    },
    errorContainer: {
        justifyContent: 'center',
        alignItems: 'center',
        backgroundColor: 'rgba(0, 0, 0, 0.3)',
    },
    errorText: {
        color: colors.textSecondary,
        fontSize: 12,
        marginTop: spacing.xs,
    },
    loadingOverlay: {
        ...StyleSheet.absoluteFill,
        justifyContent: 'center',
        alignItems: 'center',
        backgroundColor: 'rgba(0, 0, 0, 0.3)',
    },
    playOverlay: {
        ...StyleSheet.absoluteFill,
        justifyContent: 'center',
        alignItems: 'center',
    },
    playButton: {
        width: 56,
        height: 56,
        borderRadius: 28,
        justifyContent: 'center',
        alignItems: 'center',
    },
    fullScreenButton: {
        position: 'absolute',
        bottom: spacing.sm,
        right: spacing.sm,
        width: 32,
        height: 32,
        borderRadius: 16,
        backgroundColor: 'rgba(0, 0, 0, 0.5)',
        justifyContent: 'center',
        alignItems: 'center',
    },
    cachedBadge: {
        position: 'absolute',
        top: spacing.xs,
        left: spacing.xs,
        width: 20,
        height: 20,
        borderRadius: 10,
        backgroundColor: 'rgba(0, 0, 0, 0.5)',
        justifyContent: 'center',
        alignItems: 'center',
    },
});