import SwiftUI

struct ThreadsView: View {
    let board: Board
    @EnvironmentObject var settings: Settings
    @EnvironmentObject var apiClient: APIClient
    @EnvironmentObject var notificationManager: NotificationManager
    @EnvironmentObject var networkMonitor: NetworkMonitor
    @State private var threads: [Thread] = []
    @State private var isLoading = false
    @State private var errorMessage: String?
    @State private var currentPage = 0
    @State private var showingCreateThread = false
    
    private var pageSize: Int { settings.pageSize }
    private var totalPages: Int { (threads.count + pageSize - 1) / pageSize }
    private var currentThreads: [Thread] {
        let start = currentPage * pageSize
        let end = min(start + pageSize, threads.count)
        return Array(threads[start..<end])
    }
    
    var body: some View {
        VStack {
            if networkMonitor.offlineEffective {
                HStack(spacing: 8) {
                    Image(systemName: "wifi.slash")
                        .foregroundColor(.orange)
                    Text("Оффлайн режим. Показаны сохранённые данные")
                        .foregroundColor(.secondary)
                        .font(.caption)
                }
            }
            if isLoading {
                VStack {
                    ProgressView()
                        .progressViewStyle(CircularProgressViewStyle())
                    Text("Загрузка тредов...")
                        .foregroundColor(.secondary)
                }
                .frame(maxWidth: .infinity, maxHeight: .infinity)
            } else if let error = errorMessage {
                VStack(alignment: .leading, spacing: 8) {
                    Text("Ошибка загрузки")
                        .font(.headline)
                        .foregroundColor(.red)
                    Text(error)
                        .font(.body)
                        .foregroundColor(.secondary)
                    Button("Повторить") {
                        loadThreads()
                    }
                    .buttonStyle(.bordered)
                }
                .padding()
                            } else {
                    List {
                        ForEach(settings.enablePagination ? currentThreads : threads) { thread in
                            NavigationLink(destination: ThreadDetailView(board: board, thread: thread)
                                .environmentObject(settings)
                                .environmentObject(apiClient)) {
                                ThreadRow(thread: thread, board: board, showFiles: settings.showFiles)
                            }
                        }
                    }
                    .refreshable {
                        loadThreads()
                    }
                    
                    if settings.enablePagination && totalPages > 1 {
                        HStack {
                            Button("<-") {
                                if currentPage > 0 {
                                    currentPage -= 1
                                }
                            }
                            .disabled(currentPage == 0)
                            
                            Spacer()
                            
                            Text("Страница \(currentPage + 1) из \(totalPages)")
                                .font(.caption)
                                .foregroundColor(.secondary)
                            
                            Spacer()
                            
                            Button("->") {
                                if currentPage < totalPages - 1 {
                                    currentPage += 1
                                }
                            }
                            .disabled(currentPage >= totalPages - 1)
                        }
                        .padding(.horizontal)
                        .padding(.vertical, 8)
                    }
                }
        }
        .navigationTitle("/\(board.code)/")
        .navigationBarTitleDisplayMode(.inline)
        .toolbar {
            ToolbarItem(placement: .navigationBarTrailing) {
                Button("Создать") {
                    showingCreateThread = true
                }
            }
        }
        .sheet(isPresented: $showingCreateThread) {
            CreateThreadView(boardCode: board.code)
                .environmentObject(settings)
                .environmentObject(apiClient)
        }
        .onAppear {
            settings.lastBoard = board.code
            settings.saveSettings()
            
            if threads.isEmpty {
                loadThreads()
            }
        }
    }
    
    private func loadThreads() {
        isLoading = true
        errorMessage = nil
        
        apiClient.getThreads(forBoard: board.code) { result in
            DispatchQueue.main.async {
                self.isLoading = false
                
                switch result {
                case .success(let loadedThreads):
                    self.threads = loadedThreads
                    self.currentPage = 0
                case .failure(let error):
                    self.errorMessage = error.localizedDescription
                }
            }
        }
    }
}

struct ThreadRow: View {
    let thread: Thread
    let board: Board
    let showFiles: Bool
    @EnvironmentObject var settings: Settings
    
    var body: some View {
        if settings.compactMode {
            HStack {
                VStack(alignment: .leading, spacing: 2) {
                    HStack {
                        Text("#\(thread.id)")
                            .font(.caption)
                            .foregroundColor(.secondary)
                        
                        Text(thread.title)
                            .font(.body)
                            .lineLimit(1)
                        
                        Spacer()
                    }
                    
                    HStack {
                        Text(thread.creationDate, style: .date)
                            .font(.caption2)
                            .foregroundColor(.secondary)
                        
                        if thread.ratingValue > 0 {
                            HStack(spacing: 2) {
                                Image(systemName: "star.fill")
                                    .foregroundColor(.yellow)
                                    .font(.caption2)
                                Text("\(thread.ratingValue)")
                                    .font(.caption2)
                            }
                        }
                        
                        if showFiles && !thread.files.isEmpty {
                            HStack(spacing: 2) {
                                Image(systemName: "paperclip")
                                    .foregroundColor(.blue)
                                    .font(.caption2)
                                Text("\(thread.files.count)")
                                    .font(.caption2)
                            }
                        }
                        
                        if thread.isPinned {
                            Image(systemName: "pin.fill")
                                .foregroundColor(.orange)
                                .font(.caption2)
                        }
                        
                        Spacer()
                    }
                }
                
                Button(action: {
                    if settings.isFavorite(thread.id, boardCode: board.code) {
                        settings.removeFromFavorites(thread.id, boardCode: board.code)
                    } else {
                        settings.addToFavorites(thread, board: board)
                    }
                }) {
                    Image(systemName: settings.isFavorite(thread.id, boardCode: board.code) ? "heart.fill" : "heart")
                        .foregroundColor(settings.isFavorite(thread.id, boardCode: board.code) ? .red : .gray)
                        .font(.caption)
                }
                .buttonStyle(PlainButtonStyle())
            }
            .padding(.vertical, 2)
        } else {
            VStack(alignment: .leading, spacing: 6) {
                HStack {
                    Text("#\(thread.id): \(thread.title)")
                        .font(.headline)
                        .lineLimit(2)
                    
                    Spacer()
                    
                    Button(action: {
                        if settings.isFavorite(thread.id, boardCode: board.code) {
                            settings.removeFromFavorites(thread.id, boardCode: board.code)
                        } else {
                            settings.addToFavorites(thread, board: board)
                        }
                    }) {
                        Image(systemName: settings.isFavorite(thread.id, boardCode: board.code) ? "heart.fill" : "heart")
                            .foregroundColor(settings.isFavorite(thread.id, boardCode: board.code) ? .red : .gray)
                    }
                    .buttonStyle(PlainButtonStyle())
                    
                    if thread.isPinned {
                        Image(systemName: "pin.fill")
                            .foregroundColor(.orange)
                    }
                }
                
                HStack {
                    Text(thread.creationDate, style: .date)
                        .font(.caption)
                        .foregroundColor(.secondary)
                    
                    if thread.ratingValue > 0 {
                        HStack(spacing: 2) {
                            Image(systemName: "star.fill")
                                .foregroundColor(.yellow)
                            Text("\(thread.ratingValue)")
                                .font(.caption)
                        }
                    }
                    
                    if showFiles && !thread.files.isEmpty {
                        HStack(spacing: 2) {
                            Image(systemName: "paperclip")
                                .foregroundColor(.blue)
                            Text("\(thread.files.count)")
                                .font(.caption)
                        }
                    }
                    
                    Spacer()
                }
                
                if !thread.text.isEmpty {
                    Text(thread.text)
                        .font(.body)
                        .foregroundColor(.secondary)
                        .lineLimit(3)
                }
            }
            .padding(.vertical, 4)
        }
    }
}

#Preview {
    NavigationView {
        ThreadsView(board: Board(code: "test", description: "Test board"))
            .environmentObject(Settings())
            .environmentObject(APIClient())
    }
}