//
//  ContentView.swift
//  MultiChrono
//
//  Created by Beatrice Dellacà on 26/01/26.
//

import SwiftUI
import Combine

class ContentViewModel: ObservableObject {
    @Published var stopwatches: [Stopwatch] = []
    
    private let saveKey = "SavedStopwatches"
    
    init() {
        load()
    }
    
    func addStopwatch(name: String) {
        let newStopwatch = Stopwatch(name: name)
        stopwatches.append(newStopwatch)
        save()
    }
    
    func deleteStopwatch(at index: Int) {
        stopwatches[index].pause() // Ensure timer is stopped
        stopwatches.remove(at: index)
        save()
    }
    
    func deleteStopwatch(id: UUID) {
        if let index = stopwatches.firstIndex(where: { $0.id == id }) {
            deleteStopwatch(at: index)
        }
    }
    
    func save() {
        if let encoded = try? JSONEncoder().encode(stopwatches) {
            UserDefaults.standard.set(encoded, forKey: saveKey)
        }
    }
    
    func load() {
        if let data = UserDefaults.standard.data(forKey: saveKey) {
            if let decoded = try? JSONDecoder().decode([Stopwatch].self, from: data) {
                stopwatches = decoded
            }
        }
    }
}

struct ContentView: View {
    @StateObject private var viewModel = ContentViewModel()
    @State private var isShowingAddSheet = false
    @Environment(\.scenePhase) private var scenePhase
    
    var body: some View {
        NavigationStack {
            List {
                ForEach(viewModel.stopwatches) { stopwatch in
                    StopwatchRow(stopwatch: stopwatch, onDelete: {
                        viewModel.deleteStopwatch(id: stopwatch.id)
                    })
                }
                .onDelete { indexSet in
                    for index in indexSet {
                        viewModel.deleteStopwatch(at: index)
                    }
                }
            }
            .listStyle(.plain)
            .navigationTitle("MultiChrono")
            .toolbar {
                ToolbarItem(placement: .primaryAction) {
                    Button(action: {
                        isShowingAddSheet = true
                    }) {
                        Image(systemName: "plus")
                    }
                }
            }
            .sheet(isPresented: $isShowingAddSheet) {
                AddStopwatchView { name in
                    viewModel.addStopwatch(name: name)
                    isShowingAddSheet = false
                }
            }
            .overlay {
                if viewModel.stopwatches.isEmpty {
                    ContentUnavailableView(
                        "No Stopwatches",
                        systemImage: "timer",
                        description: Text("Tap the + button to create a stopwatch.")
                    )
                }
            }
        }
        .onChange(of: scenePhase) { newPhase in
            if newPhase == .background || newPhase == .inactive {
                viewModel.save()
            }
        }
    }
}

#Preview {
    ContentView()
}