import SwiftUI
import UniformTypeIdentifiers

enum Tab: String, CaseIterable, Identifiable {
    case overview = "Übersicht", history = "Verlauf", persons = "Personen", tasks = "Aufgaben"
    var id: String { rawValue }
}

/// Zustand der Oberfläche (welcher Bereich, welcher Eintrag wird gerade bearbeitet).
@MainActor
final class UIState: ObservableObject {
    @Published var tab: Tab = .overview
    @Published var draft: Entry?
    @Published var toast: String?

    func newEntry(task: String = "", person: String = "", partner: String = "") {
        draft = Entry(id: "", date: Day.today, task: task, person: person, partner: partner)
    }
    func show(_ message: String) {
        toast = message
        Task { try? await Task.sleep(for: .seconds(3)); if toast == message { toast = nil } }
    }
}

@main
struct MawariApp: App {
    @StateObject private var store = Store()
    @StateObject private var ui = UIState()
    @StateObject private var updates = UpdateController()

    var body: some Scene {
        Window("Mawari", id: "main") {
            ContentView()
                .environmentObject(store)
                .environmentObject(ui)
                .frame(minWidth: 960, minHeight: 600)
        }
        .defaultSize(width: 1280, height: 820)
        .commands {
            CommandGroup(after: .appInfo) {
                Button("Nach Updates suchen …") { updates.checkForUpdates() }
                    .disabled(!updates.canCheck)
            }
            CommandGroup(replacing: .newItem) {
                Button("Neuer Eintrag") { ui.newEntry() }.keyboardShortcut("n")
            }
            CommandGroup(replacing: .importExport) {
                Button("Export für Numbers …") { Exporter.exportXlsx(store: store, ui: ui) }.keyboardShortcut("e")
                Divider()
                Button("Sicherung speichern …") { Exporter.saveBackup(store: store, ui: ui) }
                Button("Sicherung / HTML-Daten laden …") { Exporter.importBackup(store: store, ui: ui) }
                Button("Datenordner im Finder zeigen") { NSWorkspace.shared.activateFileViewerSelecting([store.folder]) }
            }
            CommandMenu("Ansicht") {
                ForEach(Array(Tab.allCases.enumerated()), id: \.element) { i, tab in
                    Button(tab.rawValue) { ui.tab = tab }.keyboardShortcut(KeyEquivalent(Character("\(i + 1)")))
                }
            }
        }
    }
}

struct ContentView: View {
    @EnvironmentObject var store: Store
    @EnvironmentObject var ui: UIState

    var body: some View {
        Group {
            switch ui.tab {
            case .overview: OverviewView()
            case .history: HistoryView()
            case .persons: PersonsView()
            case .tasks: TasksView()
            }
        }
        .frame(maxWidth: .infinity, maxHeight: .infinity, alignment: .topLeading)
        .background(Color(nsColor: .textBackgroundColor))
        .toolbar {
            ToolbarItem(placement: .principal) {
                Picker("Bereich", selection: $ui.tab) {
                    ForEach(Tab.allCases) { Text($0.rawValue).tag($0) }
                }
                .pickerStyle(.segmented)
                .frame(width: 380)
            }
            ToolbarItemGroup(placement: .primaryAction) {
                Button { Exporter.exportXlsx(store: store, ui: ui) } label: {
                    Label("Export für Numbers", systemImage: "tablecells")
                }
                .help("Aktuellen Stand als Tabelle für Numbers speichern (⌘E)")
                Button { ui.newEntry() } label: { Label("Neuer Eintrag", systemImage: "plus") }
                    .help("Neuer Eintrag (⌘N)")
            }
        }
        .sheet(item: $ui.draft) { draft in
            EntrySheet(entry: draft)
        }
        .overlay(alignment: .bottom) {
            if let t = ui.toast ?? store.lastError {
                Text(t)
                    .font(.callout)
                    .padding(.horizontal, 14).padding(.vertical, 8)
                    .background(.regularMaterial, in: RoundedRectangle(cornerRadius: 8))
                    .padding(.bottom, 18)
                    .transition(.opacity)
            }
        }
        .animation(.easeInOut(duration: 0.2), value: ui.toast)
        .tint(Theme.tokiwa)
    }
}

extension Entry {
    var isNew: Bool { id.isEmpty }
}