import SwiftUI

struct TasksView: View {
    @EnvironmentObject var authManager: AuthManager
    @State private var tasks: [PulseTask] = []
    @State private var isLoading = true
    @State private var showAddTask = false
    @State private var filter: TaskFilter = .pending

    enum TaskFilter: String, CaseIterable {
        case pending = "Активные"
        case completed = "Выполненные"
        case all = "Все"
    }

    var filteredTasks: [PulseTask] {
        switch filter {
        case .pending: return tasks.filter { !$0.completed }
        case .completed: return tasks.filter { $0.completed }
        case .all: return tasks
        }
    }

    var body: some View {
        ZStack {
            Color(hex: "0a0a1a").ignoresSafeArea()
            VStack(spacing: 0) {
                // Header
                HStack {
                    Text("Задачи").font(.title.bold()).foregroundColor(.white)
                    Spacer()
                    Button(action: { showAddTask = true }) {
                        Image(systemName: "plus.circle.fill").font(.title2).foregroundColor(Color(hex: "00d4aa"))
                    }
                }.padding()

                // Filter
                Picker("", selection: $filter) {
                    ForEach(TaskFilter.allCases, id: \.self) { f in Text(f.rawValue).tag(f) }
                }
                .pickerStyle(.segmented)
                .padding(.horizontal)
                .padding(.bottom, 8)

                if isLoading {
                    ProgressView().tint(Color(hex: "00d4aa")).padding(.top, 40)
                    Spacer()
                } else if filteredTasks.isEmpty {
                    VStack(spacing: 12) {
                        Text("✅").font(.system(size: 50))
                        Text(filter == .pending ? "Нет активных задач" : "Нет задач")
                            .foregroundColor(Color(hex: "8888aa"))
                    }.padding(.top, 60)
                    Spacer()
                } else {
                    List {
                        ForEach(filteredTasks) { task in
                            TaskRowView(task: task) { await completeTask(task) }
                                .listRowBackground(Color.clear)
                                .listRowSeparator(.hidden)
                        }
                        .onDelete { indices in
                            let tasksToDelete = indices.map { filteredTasks[$0] }
                            Task {
                                for task in tasksToDelete {
                                    try? await APIService.shared.deleteTask(token: authManager.token, id: task.id)
                                }
                                await loadTasks()
                            }
                        }
                    }
                    .listStyle(.plain)
                    .scrollContentBackground(.hidden)
                }
            }
        }
        .sheet(isPresented: $showAddTask) {
            AddTaskView(isPresented: $showAddTask) { await loadTasks() }
        }
        .task { await loadTasks() }
        .refreshable { await loadTasks() }
    }

    func loadTasks() async {
        isLoading = true
        tasks = (try? await APIService.shared.getTasks(token: authManager.token)) ?? []
        isLoading = false
    }

    func completeTask(_ task: PulseTask) async {
        try? await APIService.shared.completeTask(token: authManager.token, id: task.id)
        await loadTasks()
        UIImpactFeedbackGenerator(style: .light).impactOccurred()
    }
}