import React, { useState, useRef, useEffect } from 'react';
import { View, Dimensions, Image, ScrollView, NativeSyntheticEvent, NativeScrollEvent } from 'react-native';
import { MyTouchableOpacity, MyText, tw } from 'common-ui';
import { useRouter } from 'expo-router';
import { trpc } from '@/src/trpc-client';
import MaterialIcons from '@expo/vector-icons/MaterialIcons';

const { width: screenWidth } = Dimensions.get('window');

interface Banner {
  id: number;
  name: string;
  imageUrl: string;
  description?: string | null;
  productIds?: number[] | null;
  redirectUrl?: string | null;
  serialNum?: number | null;
  isActive: boolean;
}

export default function BannerCarousel() {
  const router = useRouter();
  const scrollViewRef = useRef<ScrollView>(null);
  const [currentIndex, setCurrentIndex] = useState(0);
  const [isAutoPlaying, setIsAutoPlaying] = useState(true);

  // Fetch banners data
  const { data: bannersData, isLoading, error } = trpc.user.banner.getBanners.useQuery();
  const banners = bannersData?.banners || [];

  // Auto-play functionality
  useEffect(() => {
    if (banners.length <= 1 || !isAutoPlaying) return; // Don't auto-play if conditions not met

    const interval = setInterval(() => {
      setCurrentIndex((prevIndex) => {
        const nextIndex = (prevIndex + 1) % banners.length;
        // Auto-scroll to next slide
        if (scrollViewRef.current) {
          scrollViewRef.current.scrollTo({
            x: nextIndex * (screenWidth - 32),
            animated: true,
          });
        }
        return nextIndex;
      });
    }, 6000); // 6 seconds

    return () => clearInterval(interval); // Cleanup on unmount
  }, [banners.length, isAutoPlaying]);

  if (isLoading) {
    return (
      <View style={tw`px-4 py-4 bg-gradient-to-r from-pink-500 to-rose-500 items-center justify-center h-48`}>
        <MyText style={tw`text-white`}>Loading banners...</MyText>
      </View>
    );
  }

  if (error || !banners || banners.length === 0) return null;

  const handleBannerPress = (banner: Banner) => {
    if (banner.productIds && banner.productIds.length > 0) {
      // Navigate to the first product's detail page
      router.push(`/(drawer)/(tabs)/home/product-detail/${banner.productIds[0]}`);
    } else if (banner.redirectUrl) {
      // Handle external URL - could open in browser or handle deep links
      console.log('Banner redirect URL:', banner.redirectUrl);
    }
    // If no productIds or redirectUrl, banner is just for display
  };

  const handleScroll = (event: NativeSyntheticEvent<NativeScrollEvent>) => {
    const slideSize = screenWidth - 32; // width minus horizontal padding
    const index = Math.round(event.nativeEvent.contentOffset.x / slideSize);
    setCurrentIndex(index);
  };

  const goToSlide = (index: number) => {
    setIsAutoPlaying(false); // Pause auto-play when user manually navigates
    if (scrollViewRef.current) {
      scrollViewRef.current.scrollTo({
        x: index * (screenWidth - 32),
        animated: true,
      });
    }
    setCurrentIndex(index);
    // Resume auto-play after a short delay
    setTimeout(() => setIsAutoPlaying(true), 1000);
  };

  return (
    <View style={tw`px-4 py-4 bg-gradient-to-r from-pink-500 to-rose-500`}>
      <ScrollView
        ref={scrollViewRef}
        horizontal
        showsHorizontalScrollIndicator={false}
        pagingEnabled
        decelerationRate="fast"
        snapToInterval={screenWidth - 32}
        onScroll={handleScroll}
        scrollEventThrottle={16}
        onTouchStart={() => setIsAutoPlaying(false)}
        onTouchEnd={() => setIsAutoPlaying(true)}
        onMomentumScrollEnd={() => setIsAutoPlaying(true)}
      >
        {banners.map((banner: Banner) => (
          <MyTouchableOpacity
            key={banner.id}
            onPress={() => handleBannerPress(banner)}
            style={tw`mr-4 rounded-2xl overflow-hidden`}
            activeOpacity={0.9}
          >
            <Image
              source={{ uri: banner.imageUrl }}
              style={tw`w-[${screenWidth - 64}px] h-48 rounded-2xl`}
              resizeMode="cover"
            />
          </MyTouchableOpacity>
        ))}
      </ScrollView>

      {/* Pagination Dots */}
      {banners.length > 1 && (
        <View style={tw`flex-row justify-center mt-3`}>
          {banners.map((_, index: number) => (
            <MyTouchableOpacity
              key={index}
              onPress={() => goToSlide(index)}
              style={tw`mx-1`}
            >
              <View
                style={tw`w-2 h-2 rounded-full ${
                  index === currentIndex ? 'bg-gray-800' : 'bg-gray-400'
                }`}
              />
            </MyTouchableOpacity>
          ))}
        </View>
      )}
    </View>
  );
}