import SwiftUI

struct RankingsView: View {
    @StateObject private var viewModel = RankingsViewModel()
    
    var body: some View {
        NavigationStack {
            Group {
                if viewModel.isLoading {
                    ProgressView("加载排行榜...")
                } else if let error = viewModel.error {
                    VStack {
                        Text("加载失败: \(error.localizedDescription)")
                        Button("重试") {
                            viewModel.loadRankings()
                        }
                        .padding()
                        .background(Color.blue)
                        .foregroundColor(.white)
                        .cornerRadius(8)
                    }
                } else {
                    List {
                        ForEach(Array(viewModel.rankings.enumerated()), id: \.element.album_id) { index, item in
                            HStack(alignment: .center, spacing: 12) {
                                // 排名标签
                                Text("\(index + 1)")
                                    .font(.headline)
                                    .frame(width: 24, height: 24)
                                    .background(index < 3 ? Color.yellow : Color.gray)
                                    .foregroundColor(index < 3 ? Color.black : Color.white)
                                    .cornerRadius(4)
                                    .padding(.leading, 4)
                                
                                // 内容标题
                                NavigationLink(destination: PhotoView(albumId: item.album_id)) {
                                    VStack(alignment: .leading, spacing: 4) {
                                        Text(item.title)
                                            .font(.subheadline)
                                            .lineLimit(1)
                                        Text("ID: \(item.album_id)")
                                            .font(.caption)
                                            .foregroundColor(.gray)
                                    }
                                }
                                
                                Spacer()
                                
                                // 热度图标
                                Image(systemName: "flame.fill")
                                    .foregroundColor(.orange)
                            }
                        }
                    }
                    .refreshable {
                        viewModel.loadRankings()
                    }
                }
            }
            .navigationTitle("周热度排行")
        }
    }
}

// 排行榜视图模型
class RankingsViewModel: ObservableObject {
    @Published var rankings: [AlbumItem] = []
    @Published var isLoading = false
    @Published var error: Error?
    
    init() {
        loadRankings()
    }
    
    func loadRankings() {
        isLoading = true
        error = nil
        
        let urlString = Config.shared.apiURL(path: "rankings/week?page=1")
        
        guard let url = URL(string: urlString) else {
            error = NSError(domain: "RankingsError", code: 0, userInfo: [NSLocalizedDescriptionKey: "无效的URL"])
            isLoading = false
            return
        }
        
        URLSession.shared.dataTask(with: url) { [weak self] data, response, error in
            DispatchQueue.main.async {
                self?.isLoading = false
                
                if let error = error {
                    self?.error = error
                    return
                }
                
                guard let httpResponse = response as? HTTPURLResponse, httpResponse.statusCode == 200 else {
                    self?.error = NSError(domain: "RankingsError", code: 1, userInfo: [NSLocalizedDescriptionKey: "服务器返回错误"])
                    return
                }
                
                guard let data = data else {
                    self?.error = NSError(domain: "RankingsError", code: 2, userInfo: [NSLocalizedDescriptionKey: "没有接收到数据"])
                    return
                }
                
                do {
                    let decoder = JSONDecoder()
                    self?.rankings = try decoder.decode([AlbumItem].self, from: data)
                } catch {
                    self?.error = NSError(domain: "RankingsError", code: 3, userInfo: [NSLocalizedDescriptionKey: "解析数据失败: \(error.localizedDescription)"])
                    print("排行榜解码错误: \(error)")
                }
            }
        }.resume()
    }
}