import React, { memo } from 'react';
import {
  View,
  FlatList,
  ActivityIndicator,
  RefreshControl,
  StyleSheet,
  Image,
  TouchableOpacity,
  Platform
} from 'react-native';
import { VideoPlayer } from '@/components/video/video-player';
import { ThemedText } from '@/components/themed-text';
import MaterialIcons from '@expo/vector-icons/MaterialIcons';
import { useColorScheme } from '@/hooks/use-color-scheme';
import { router } from 'expo-router';
import type { TemplateGeneration } from '@/lib/api/template-generations';

/**
 * 根据文件 URL 后缀名判断媒体类型
 */
function getMediaType(url: string): 'image' | 'video' | 'unknown' {
  if (!url) return 'unknown';

  const extension = url.split('.').pop()?.toLowerCase() || '';

  const imageExts = ['jpg', 'jpeg', 'png', 'gif', 'webp', 'bmp', 'svg'];
  const videoExts = ['mp4', 'webm', 'avi', 'mov', 'mkv', 'flv', 'm4v'];

  if (imageExts.includes(extension)) return 'image';
  if (videoExts.includes(extension)) return 'video';
  return 'unknown';
}

export function ContentGallery({
  generations,
  isRefreshing,
  onRefresh,
  isLoadingMore,
  hasMore,
  onLoadMore,
  ListHeaderComponent,
}: {
  generations: TemplateGeneration[];
  isRefreshing: boolean;
  onRefresh: () => void;
  isLoadingMore: boolean;
  hasMore: boolean;
  onLoadMore: () => void;
  ListHeaderComponent?: React.ComponentType<any> | React.ReactElement | null;
}) {
  const colorScheme = useColorScheme();
  const palette = colorScheme === 'dark' ? darkPalette : lightPalette;

  const renderItem = ({ item }: { item: TemplateGeneration }) => (
    <ContentItem palette={palette} generation={item} />
  );

  const renderFooter = () => {
    if (isLoadingMore) {
      return (
        <View style={[styles.loadingMoreContainer, { backgroundColor: palette.background }]}>
          <ActivityIndicator size="small" color={palette.accent} />
          <ThemedText style={[styles.loadingMoreText, { color: palette.textSecondary }]}>
            加载更多...
          </ThemedText>
        </View>
      );
    }

    if (!hasMore && generations.length > 0) {
      return (
        <View style={[styles.noMoreContainer, { backgroundColor: palette.background }]}>
          <ThemedText style={[styles.noMoreText, { color: palette.textSecondary }]}>
            没有更多内容了
          </ThemedText>
        </View>
      );
    }

    return null;
  };

  return (
    <FlatList
      data={generations}
      renderItem={renderItem}
      ListHeaderComponent={ListHeaderComponent}
      ListFooterComponent={renderFooter}
      numColumns={2}
      keyExtractor={(item) => item.id}
      columnWrapperStyle={styles.columnWrapper}
      showsVerticalScrollIndicator={false}
      refreshControl={
        <RefreshControl
          refreshing={isRefreshing}
          onRefresh={onRefresh}
          tintColor={palette.accent}
          colors={[palette.accent]}
        />
      }
      onEndReached={onLoadMore}
      onEndReachedThreshold={0.5}
      contentContainerStyle={styles.contentContainer}
      removeClippedSubviews={true}
      maxToRenderPerBatch={6}
      updateCellsBatchingPeriod={50}
      windowSize={10}
    />
  );
}

const ContentItem = memo(function ContentItem({
  palette,
  generation,
}: {
  palette: any;
  generation: TemplateGeneration;
}) {
  const formatDate = (dateString: string) => {
    const date = new Date(dateString);
    return date.toLocaleDateString('en-US', {
      month: 'short',
      day: 'numeric',
    });
  };

  const renderMedia = () => {
    const mediaUrl = generation.resultUrl[0];

    if (!mediaUrl) {
      return (
        <View style={[styles.mediaContainer, styles.placeholderContainer]}>
          <ThemedText style={styles.placeholderText}>
            {generation.type === 'VIDEO' ? '🎬' : generation.type === 'IMAGE' ? '🖼️' : '📝'}
          </ThemedText>
        </View>
      );
    }

    const mediaType = getMediaType(mediaUrl);

    if (mediaType === 'video') {
      if (Platform.OS === 'web') {
        return (
          <View style={styles.mediaContainer}>
            <video
              src={mediaUrl}
              style={{
                width: '100%',
                height: '100%',
                objectFit: 'cover' as any,
              }}
              muted
              playsInline
              preload="metadata"
            />
          </View>
        );
      } else {
        return (
          <View style={styles.mediaContainer}>
            <VideoPlayer
              source={{ uri: mediaUrl }}
              style={styles.mediaVideo}
              shouldPlay={false}
              isLooping={true}
              isMuted={true}
              useNativeControls={false}
              showPoster={true}
              maxHeight={300}
            />
          </View>
        );
      }
    }

    return (
      <View style={styles.mediaContainer}>
        <Image
          source={{ uri: mediaUrl }}
          style={styles.mediaImage}
          resizeMode="cover"
        />
      </View>
    );
  };

  return (
    <TouchableOpacity
      style={[
        styles.contentItem,
        {
          backgroundColor: palette.surface,
        },
      ]}
      onPress={() => router.push(`/result?generationId=${generation.id}`)}
      activeOpacity={0.9}
    >
      {renderMedia()}
      <View style={styles.contentInfo}>
        <ThemedText
          style={[styles.contentTitle, { color: palette.textPrimary }]}
          numberOfLines={1}
        >
          {generation.template.title}
        </ThemedText>
        <View style={styles.contentMeta}>
          <View style={styles.metaItem}>
            <MaterialIcons name="schedule" size={14} color={palette.textSecondary} />
            <ThemedText style={[styles.metaText, { color: palette.textSecondary }]}>
              {formatDate(generation.createdAt)}
            </ThemedText>
          </View>
          {generation.status !== 'completed' && (
            <View style={styles.statusBadge}>
              <ThemedText style={[styles.statusText, { color: palette.textSecondary }]}>
                {generation.status}
              </ThemedText>
            </View>
          )}
        </View>
      </View>
    </TouchableOpacity>
  );
});

const darkPalette = {
  background: '#050505',
  surface: '#121216',
  border: '#1D1E24',
  textPrimary: '#F6F7FA',
  textSecondary: '#8E9098',
  accent: '#B7FF2F',
};

const lightPalette = {
  background: '#F7F8FB',
  surface: '#FFFFFF',
  border: '#E2E5ED',
  textPrimary: '#0F1320',
  textSecondary: '#5E6474',
  accent: '#405CFF',
};

const styles = StyleSheet.create({
  contentContainer: {
    paddingBottom: 120,
    paddingHorizontal: 12,
  },
  columnWrapper: {
    justifyContent: 'space-between',
  },
  contentItem: {
    flex: 1,
    borderRadius: 12,
    marginBottom: 12,
    overflow: 'hidden',
    marginHorizontal: 6,
  },
  mediaContainer: {
    width: '100%',
    aspectRatio: 1,
    backgroundColor: '#000',
  },
  placeholderContainer: {
    backgroundColor: '#1A1A1A',
    justifyContent: 'center',
    alignItems: 'center',
  },
  placeholderText: {
    fontSize: 48,
  },
  mediaImage: {
    width: '100%',
    height: '100%',
  },
  mediaVideo: {
    width: '100%',
    height: '100%',
  },
  contentInfo: {
    padding: 12,
  },
  contentTitle: {
    fontSize: 15,
    fontWeight: '600',
    marginBottom: 8,
  },
  contentMeta: {
    flexDirection: 'row',
    alignItems: 'center',
  },
  metaItem: {
    flexDirection: 'row',
    alignItems: 'center',
    marginRight: 12,
  },
  metaText: {
    fontSize: 12,
    marginLeft: 4,
  },
  statusBadge: {
    paddingHorizontal: 8,
    paddingVertical: 4,
    borderRadius: 4,
    backgroundColor: 'rgba(0, 0, 0, 0.1)',
  },
  statusText: {
    fontSize: 11,
    fontWeight: '600',
    textTransform: 'capitalize' as const,
  },
  loadingMoreContainer: {
    paddingVertical: 20,
    alignItems: 'center',
    flexDirection: 'row',
    justifyContent: 'center',
    gap: 12,
  },
  loadingMoreText: {
    fontSize: 14,
  },
  noMoreContainer: {
    paddingVertical: 20,
    alignItems: 'center',
  },
  noMoreText: {
    fontSize: 14,
  },
});