import SwiftUI
import AVKit

// MARK: - API Response Models
struct MaterialResponse: Decodable {
    let code: Int
    let data: MaterialData
    
    struct MaterialData: Decodable {
        let items: [MemoryItem]
        let hasMore: Bool
        
        enum CodingKeys: String, CodingKey {
            case items
            case hasMore = "has_more"
        }
    }
}

struct MemoryItem: Identifiable, Decodable {
    let id: String
    let name: String?
    let description: String?
    let fileInfo: FileInfo
    let previewFileInfo: FileInfo
    
    var title: String { name ?? "Untitled" }
    var subtitle: String { description ?? "" }
    var mediaType: MemoryMediaType { 
        let url = fileInfo.url.lowercased()
        if url.hasSuffix(".mp4") || url.hasSuffix(".mov") {
            return .video(url: fileInfo.url, previewUrl: previewFileInfo.url)
        } else {
            return .image(fileInfo.url)
        }
    }
    var aspectRatio: CGFloat { 1.0 }
    
    enum CodingKeys: String, CodingKey {
        case id, name, description
        case fileInfo = "file_info"
        case previewFileInfo = "preview_file_info"
    }
}

struct FileInfo: Decodable {
    let id: String
    let fileName: String
    let url: String
    
    enum CodingKeys: String, CodingKey {
        case id
        case fileName = "file_name"
        case url
    }
}

enum MemoryMediaType: Equatable {
    case image(String)
    case video(url: String, previewUrl: String)
}

struct MemoriesView: View {
    @Environment(\.dismiss) private var dismiss
    @State private var memories: [MemoryItem] = []
    @State private var isLoading = false
    @State private var errorMessage: String?
    
    let columns = [
        GridItem(.flexible(), spacing: 1),
        GridItem(.flexible(), spacing: 1)
    ]
    
    var body: some View {
        NavigationView {
            VStack(spacing: 0) {
                // 顶部导航栏
                HStack {
                    Button(action: {
                        // 返回上一级
                        self.dismiss()
                    }) {
                        Image(systemName: "chevron.left")
                            .foregroundColor(.themeTextMessageMain)
                            .font(.system(size: 20))
                    }
                    Spacer()
                    Text("My Memories")
                        .foregroundColor(.themeTextMessageMain)
                        .font(Typography.font(for: .body, family: .quicksandBold))
                    Spacer()
                }
                .padding()
                .background(Color.themeTextWhiteSecondary)
                
                // 内容区域
                ZStack {
                    Color.themeTextWhiteSecondary.ignoresSafeArea()
                    
                    Group {
                        if isLoading {
                            ProgressView()
                                .scaleEffect(1.5)
                        } else if let error = errorMessage {
                            Text("Error: \(error)")
                                .foregroundColor(.red)
                        } else {
                            ScrollView {
                                LazyVGrid(columns: columns, spacing: 4) {
                                    ForEach(memories) { memory in
                                        MemoryCard(memory: memory)
                                            .padding(.horizontal, 2)
                                    }
                                }
                                .padding(.top, 4)
                                .padding(.horizontal, 4)
                            }
                        }
                    }
                }
            }
        }
        .navigationBarBackButtonHidden(true)
        .onAppear {
            fetchMemories()
        }
    }
    
    private func fetchMemories() {
        isLoading = true
        errorMessage = nil
        
        let parameters: [String: Any] = ["page": 0]
        
        NetworkService.shared.get(path: "/material/list", parameters: parameters) { [self] (result: Result<MaterialResponse, NetworkError>) in
            DispatchQueue.main.async { [self] in
                self.isLoading = false
                
                switch result {
                case .success(let response):
                    print("✅ Successfully fetched \(response.data.items) memory items")
                    response.data.items.forEach { item in
                        print("📝 Item ID: \(item.id), Title: \(item.name ?? "Untitled"), URL: \(item)")
                    }
                    self.memories = response.data.items
                case .failure(let error):
                    self.errorMessage = error.localizedDescription
                    print("❌ Failed to fetch memories: \(error.localizedDescription)")
                }
            }
        }
    }
}

struct MemoryCard: View {
    let memory: MemoryItem
    
    var body: some View {
        VStack(alignment: .leading, spacing: 12) {  
            ZStack {
                // Media content
                Group {
                    switch memory.mediaType {
                    case .image(let urlString):
                        if let url = URL(string: urlString) {
                            AsyncImage(url: url) { phase in
                                if let image = phase.image {
                                    image
                                        .resizable()
                                        .aspectRatio(contentMode: .fill)
                                } else if phase.error != nil {
                                    Color.gray.opacity(0.3)
                                } else {
                                    ProgressView()
                                }
                            }
                        }
                        
                    case .video(let url, let previewUrl):
                        // Use preview image for video
                        if let previewUrl = URL(string: previewUrl) {
                            AsyncImage(url: previewUrl) { phase in
                                if let image = phase.image {
                                    image
                                        .resizable()
                                        .aspectRatio(contentMode: .fill)
                                } else if phase.error != nil {
                                    Color.gray.opacity(0.3)
                                } else {
                                    ProgressView()
                                }
                            }
                        } else {
                            Color.gray.opacity(0.3)
                        }
                    }
                }
                .frame(width: (UIScreen.main.bounds.width / 2) - 24, 
                      height: (UIScreen.main.bounds.width / 2 - 24) * (1/memory.aspectRatio))
                .clipped()
                .cornerRadius(12)
                
                // Show play button for videos
                if case .video = memory.mediaType {
                    Image(systemName: "play.circle.fill")
                        .font(.system(size: 40))
                        .foregroundColor(.white.opacity(0.9))
                        .shadow(radius: 3)
                }
            }
            
            // Title and Subtitle
            VStack(alignment: .leading, spacing: 8) {  
                Text(memory.title)
                    .font(Typography.font(for: .body, family: .quicksandBold))
                    .foregroundColor(.themeTextMessageMain)
                    .lineLimit(1)
                
                Text(memory.subtitle)
                    .font(.system(size: 14))
                    .foregroundColor(.themeTextMessageMain)
            }
            .padding(.horizontal, 2)
            .padding(.bottom, 8)
        }
    }
}

// Helper extension to pause video
private extension AVPlayer {
    func pause() {
        self.pause()
    }
}

#Preview {
    MemoriesView()
}