import { API_CONFIG } from '../constants/Config';

const API_URL = API_CONFIG.BASE_URL;

export interface ProductResponse {
  productId: number;
  productName: string;
  description: string;
  price: number;
  stockQuantity: number;
  imageUrl: string;
  categoryId: number;
  categoryName: string;
  createdAt: string;
  updatedAt: string;
}

export interface ProductListResponse {
  products: ProductResponse[];
  currentPage: number;
  totalItems: number;
  totalPages: number;
  hasNext: boolean;
  hasPrevious: boolean;
}

class ProductService {
  /**
   * Lấy danh sách tất cả sản phẩm
   */
  async getAllProducts(
    page: number = 0,
    size: number = 10,
    sortBy: string = 'productId',
    sortDir: 'asc' | 'desc' = 'asc'
  ): Promise<ProductListResponse> {
    try {
      const params = new URLSearchParams({
        page: page.toString(),
        size: size.toString(),
        sortBy,
        sortDir,
      });

      const url = `${API_URL}/products?${params}`;
      console.log('Fetching products from:', url);

      const response = await fetch(url, {
        method: 'GET',
        headers: {
          'Content-Type': 'application/json',
          'Accept': 'application/json',
        },
      });
      
      if (!response.ok) {
        let errorMessage = `Failed to fetch products: ${response.status} ${response.statusText}`;
        try {
          const errorData = await response.json();
          errorMessage = errorData.message || errorData.error || errorMessage;
        } catch {
          // If response is not JSON, use the status text
          const text = await response.text().catch(() => '');
          errorMessage = text || errorMessage;
        }
        console.error('API Error:', {
          status: response.status,
          statusText: response.statusText,
          url,
        });
        throw new Error(errorMessage);
      }

      const data = await response.json();
      return data;
    } catch (error) {
      if (error instanceof TypeError && error.message.includes('fetch')) {
        console.error('Network error - API may be unreachable:', error);
        throw new Error('Không thể kết nối đến server. Vui lòng kiểm tra kết nối mạng.');
      }
      console.error('Error fetching products:', error);
      throw error;
    }
  }

  /**
   * Lấy chi tiết sản phẩm theo ID
   */
  async getProductById(id: number): Promise<ProductResponse> {
    try {
      const response = await fetch(`${API_URL}/products/${id}`);
      
      if (!response.ok) {
        throw new Error('Product not found');
      }

      return await response.json();
    } catch (error) {
      console.error('Error fetching product:', error);
      throw error;
    }
  }

  /**
   * Lấy sản phẩm theo category
   */
  async getProductsByCategory(
    categoryId: number,
    page: number = 0,
    size: number = 10,
    sortBy: string = 'productId',
    sortDir: 'asc' | 'desc' = 'asc'
  ): Promise<ProductListResponse> {
    try {
      const params = new URLSearchParams({
        page: page.toString(),
        size: size.toString(),
        sortBy,
        sortDir,
      });

      const response = await fetch(`${API_URL}/products/category/${categoryId}?${params}`);
      
      if (!response.ok) {
        throw new Error('Failed to fetch products by category');
      }

      return await response.json();
    } catch (error) {
      console.error('Error fetching products by category:', error);
      throw error;
    }
  }

  /**
   * Tìm kiếm sản phẩm
   */
  async searchProducts(
    keyword: string,
    page: number = 0,
    size: number = 10,
    sortBy: string = 'productId',
    sortDir: 'asc' | 'desc' = 'asc'
  ): Promise<ProductListResponse> {
    try {
      const params = new URLSearchParams({
        keyword,
        page: page.toString(),
        size: size.toString(),
        sortBy,
        sortDir,
      });

      const response = await fetch(`${API_URL}/products/search?${params}`);
      
      if (!response.ok) {
        throw new Error('Failed to search products');
      }

      return await response.json();
    } catch (error) {
      console.error('Error searching products:', error);
      throw error;
    }
  }

  /**
   * Lấy sản phẩm còn hàng
   */
  async getAvailableProducts(
    page: number = 0,
    size: number = 10,
    sortBy: string = 'productId',
    sortDir: 'asc' | 'desc' = 'asc'
  ): Promise<ProductListResponse> {
    try {
      const params = new URLSearchParams({
        page: page.toString(),
        size: size.toString(),
        sortBy,
        sortDir,
      });

      const response = await fetch(`${API_URL}/products/available?${params}`);
      
      if (!response.ok) {
        throw new Error('Failed to fetch available products');
      }

      return await response.json();
    } catch (error) {
      console.error('Error fetching available products:', error);
      throw error;
    }
  }
}

export default new ProductService();