import React, { useState, useEffect, useCallback } from 'react';
import {
  View,
  Text,
  StyleSheet,
  FlatList,
  Image,
  TouchableOpacity,
  TextInput,
  SafeAreaView,
  StatusBar,
  ActivityIndicator
} from 'react-native';
import Ionicons from '@expo/vector-icons/Ionicons';
import { useNavigation, useRoute } from '@react-navigation/native';
import { NativeStackNavigationProp } from '@react-navigation/native-stack';
import { RouteProp } from '@react-navigation/native';
import { productApi, ProductParams, type Product } from '../services/api/productApi';

// 图标组件 - 使用React.memo优化渲染
const IconComponent = React.memo(({ name, size, color }: { name: string; size: number; color: string }) => {
  const Icon = Ionicons as any;
  return <Icon name={name} size={size} color={color} />;
});


// 路由参数类型
type SearchResultRouteParams = {
  keyword: string;
};

// 产品项组件 - 使用React.memo优化渲染
const ProductItem = React.memo(({ 
  product, 
  onPress 
}: { 
  product: Product; 
  onPress: (product: Product) => void;
}) => (
  <TouchableOpacity 
    style={styles.productCard}
    onPress={() => onPress(product)}
    activeOpacity={0.7}
  >
    <View style={styles.productImageContainer}>
      {product.product_image_urls[0] ? (
        <Image source={{ uri: product.product_image_urls[0] }} style={styles.productImage} resizeMode="cover" />
      ) : (
        <Text style={styles.placeholderText}>product picture</Text>
      )}
    </View>
    <View style={styles.productInfo}>
      <Text style={styles.productPrice}>
        {product.subject}{product.min_price.toFixed(2)}
      </Text>
      <Text style={styles.productTitle} numberOfLines={2}>
        {product.subject_trans}
      </Text>
      <Text style={styles.productSales}>Monthly Sales: {product.min_price}</Text>
    </View>
  </TouchableOpacity>
));

export const SearchResultScreen = () => {
  const navigation = useNavigation<NativeStackNavigationProp<any>>();
  const route = useRoute<RouteProp<Record<string, SearchResultRouteParams>, string>>();
  const [searchText, setSearchText] = useState('');
  const [products, setProducts] = useState<Product[]>([]);
  const [loading, setLoading] = useState(true);

  // 初始化搜索关键字
  useEffect(() => {
    if (route.params?.keyword) {
      setSearchText(route.params.keyword);
      searchProducts(route.params.keyword);
    }
  }, [route.params?.keyword]);

  // 模拟搜索产品的API调用
  const searchProducts = useCallback(async (keyword: string) => {
    setLoading(true);
    try {
      // 这里实际项目中应替换为真实的API调用
      // await apiService.search(keyword)
      const res = await productApi.getSearchProducts({
        keyword,
        page: 1,
        page_size: 20,
        sort_order: 'desc'
      })
        
      setProducts(res.products);
    } catch (error) {
      console.error('Error searching products:', error);
      // 在实际应用中应该显示错误消息
    } finally {
      setLoading(false);
    }
  }, []);

  // 处理搜索提交
  const handleSearch = useCallback(() => {
    if (searchText.trim()) {
      searchProducts(searchText.trim());
    }
  }, [searchText, searchProducts]);

  // 处理点击产品
  const handleProductPress = useCallback((product: Product) => {
    // 导航到产品详情页，并传递产品信息
    navigation.navigate('ProductDetail', { 
      offer_id: product.offer_id,
      searchKeyword: searchText,
      price: product.min_price
    });
  }, [navigation, searchText]);

  // 返回上一页
  const goBack = useCallback(() => {
    navigation.goBack();
  }, [navigation]);

  // 渲染列表为空时的组件
  const renderEmptyList = useCallback(() => (
    <View style={styles.emptyContainer}>
      <IconComponent name="search-outline" size={48} color="#ccc" />
      <Text style={styles.emptyText}>No results found for "{searchText}"</Text>
      <Text style={styles.emptySubtext}>Try using different keywords or check your spelling</Text>
    </View>
  ), [searchText]);

  // 渲染产品项
  const renderProductItem = useCallback(({ item }: { item: Product }) => (
    <ProductItem product={item} onPress={handleProductPress} />
  ), [handleProductPress]);

  return (
    <SafeAreaView style={styles.safeArea}>
      <StatusBar barStyle="dark-content" backgroundColor="#fff" />
      <View style={styles.container}>
        {/* 搜索栏 */}
        <View style={styles.searchHeader}>
          <TouchableOpacity style={styles.backButton} onPress={goBack}>
            <IconComponent name="arrow-back" size={24} color="#333" />
          </TouchableOpacity>
          <View style={styles.searchBar}>
            <IconComponent name="search-outline" size={20} color="#999" />
            <TextInput
              style={styles.searchInput}
              placeholder="搜索商品"
              placeholderTextColor="#999"
              value={searchText}
              onChangeText={setSearchText}
              returnKeyType="search"
              onSubmitEditing={handleSearch}
            />
            {searchText.length > 0 && (
              <TouchableOpacity onPress={() => setSearchText('')}>
                <IconComponent name="close-circle" size={20} color="#999" />
              </TouchableOpacity>
            )}
          </View>
        </View>

        {/* 搜索结果 */}
        <View style={styles.resultsContainer}>
          {/* 搜索结果标题栏 */}
          <View style={styles.resultsHeader}>
            <Text style={styles.resultsTitle}>
              {loading ? 'Searching...' : `Results for "${searchText}"`}
            </Text>
            <Text style={styles.resultsCount}>
              {loading ? '' : `${products.length} items found`}
            </Text>
          </View>

          {/* 加载指示器 */}
          {loading ? (
            <View style={styles.loadingContainer}>
              <ActivityIndicator size="large" color="#0066FF" />
            </View>
          ) : (
            <FlatList
              data={products}
              renderItem={renderProductItem}
              keyExtractor={(item) => String(item.offer_id)}
              numColumns={2}
              contentContainerStyle={styles.productGrid}
              ListEmptyComponent={renderEmptyList}
              showsVerticalScrollIndicator={false}
              initialNumToRender={8}
              maxToRenderPerBatch={10}
              windowSize={5}
              removeClippedSubviews={true}
            />
          )}
        </View>
      </View>
    </SafeAreaView>
  );
};

const styles = StyleSheet.create({
  safeArea: {
    flex: 1,
    backgroundColor: '#ffffff',
  },
  container: {
    flex: 1,
    backgroundColor: '#f5f5f5',
  },
  searchHeader: {
    flexDirection: 'row',
    alignItems: 'center',
    paddingHorizontal: 15,
    paddingVertical: 10,
    backgroundColor: '#fff',
    borderBottomWidth: 1,
    borderBottomColor: '#f0f0f0',
  },
  backButton: {
    marginRight: 10,
    padding: 5,
  },
  searchBar: {
    flex: 1,
    flexDirection: 'row',
    alignItems: 'center',
    backgroundColor: '#f5f5f5',
    borderRadius: 20,
    paddingHorizontal: 15,
    height: 40,
  },
  searchInput: {
    flex: 1,
    marginLeft: 8,
    fontSize: 16,
    color: '#333',
    height: 40,
  },
  resultsContainer: {
    flex: 1,
  },
  resultsHeader: {
    flexDirection: 'row',
    justifyContent: 'space-between',
    alignItems: 'center',
    padding: 15,
    backgroundColor: '#fff',
    borderBottomWidth: 1,
    borderBottomColor: '#f0f0f0',
  },
  resultsTitle: {
    fontSize: 16,
    fontWeight: 'bold',
    color: '#333',
  },
  resultsCount: {
    fontSize: 14,
    color: '#999',
  },
  loadingContainer: {
    flex: 1,
    justifyContent: 'center',
    alignItems: 'center',
  },
  productGrid: {
    padding: 8,
  },
  productCard: {
    flex: 1,
    margin: 8,
    backgroundColor: '#fff',
    borderRadius: 8,
    overflow: 'hidden',
    elevation: 2, // Android shadow
    shadowColor: '#000', // iOS shadow
    shadowOffset: { width: 0, height: 1 },
    shadowOpacity: 0.1,
    shadowRadius: 2,
  },
  productImageContainer: {
    height: 150,
    backgroundColor: '#f9f9f9',
    alignItems: 'center',
    justifyContent: 'center',
  },
  productImage: {
    width: '100%',
    height: '100%',
  },
  placeholderText: {
    color: '#999',
    fontSize: 16,
  },
  productInfo: {
    padding: 10,
  },
  productPrice: {
    fontSize: 18,
    fontWeight: 'bold',
    color: '#ff6600',
    marginBottom: 5,
  },
  productTitle: {
    fontSize: 14,
    color: '#333',
    marginBottom: 5,
  },
  productSales: {
    fontSize: 12,
    color: '#999',
  },
  emptyContainer: {
    flex: 1,
    minHeight: 300,
    justifyContent: 'center',
    alignItems: 'center',
    padding: 20,
  },
  emptyText: {
    fontSize: 16,
    fontWeight: 'bold',
    color: '#333',
    marginTop: 15,
    marginBottom: 8,
  },
  emptySubtext: {
    fontSize: 14,
    color: '#999',
    textAlign: 'center',
  },
});