import SwiftUI

struct Task: Identifiable {
    let id = UUID()
    var title: String
    var isCompleted: Bool = false
}

struct ContentView: View {
    @State private var tasks: [Task] = []
    @State private var newTaskTitle: String = ""

    var body: some View {
        NavigationView {
            VStack {
                HStack {
                    TextField("New Task", text: $newTaskTitle)
                        .textFieldStyle(RoundedBorderTextFieldStyle())

                    Button(action: addTask) {
                        Image(systemName: "plus")
                            .padding()
                            .background(Color.blue)
                            .foregroundColor(.white)
                            .clipShape(Circle())
                    }
                    .disabled(newTaskTitle.trimmingCharacters(in: .whitespaces).isEmpty)
                }
                .padding()

                List {
                    ForEach(tasks) { task in
                        HStack {
                            Image(systemName: task.isCompleted ? "checkmark.circle.fill" : "circle")
                                .onTapGesture {
                                    toggleTask(task)
                                }
                            Text(task.title)
                                .strikethrough(task.isCompleted)
                        }
                    }
                    .onDelete(perform: deleteTask)
                }
            }
            .navigationTitle("To-Do List")
        }
    }

    private func addTask() {
        let trimmedTitle = newTaskTitle.trimmingCharacters(in: .whitespaces)
        guard !trimmedTitle.isEmpty else { return }

        let newTask = Task(title: trimmedTitle)
        tasks.append(newTask)
        newTaskTitle = ""
    }

    private func toggleTask(_ task: Task) {
        if let index = tasks.firstIndex(where: { $0.id == task.id }) {
            tasks[index].isCompleted.toggle()
        }
    }

    private func deleteTask(at offsets: IndexSet) {
        tasks.remove(atOffsets: offsets)
    }
}

#Preview {
    ContentView()
}