import WidgetKit
import SwiftUI
import AppIntents

// MARK: - Interactive intents

/// Tapping a checkbox toggles the task's completion directly in the App Group.
struct ToggleTaskIntent: AppIntent {
    static var title: LocalizedStringResource = "Toggle Task Complete"

    @Parameter(title: "Task ID")
    var taskId: String

    init() {}
    init(taskId: String) { self.taskId = taskId }

    func perform() async throws -> some IntentResult {
        toggleWidgetTaskComplete(id: taskId)
        return .result()
    }
}

/// The "+" button opens the app and asks it to present the add-task sheet.
struct AddTaskFromWidgetIntent: AppIntent {
    static var title: LocalizedStringResource = "Add Task"
    static var openAppWhenRun = true

    func perform() async throws -> some IntentResult {
        UserDefaults.kisani.set(true, forKey: "kisani.widget.openAddTask")
        return .result()
    }
}

// MARK: - Entry + Provider

struct TasksEntry: TimelineEntry {
    let date: Date
    let tasks: [WidgetTask]
    let openCount: Int
}

struct TasksProvider: TimelineProvider {
    func placeholder(in context: Context) -> TasksEntry {
        TasksEntry(date: .now, tasks: [
            WidgetTask(id: UUID(), title: "Pray for Uganda", dueDate: .now, isComplete: false,
                       quadrant: "Urgent + Important", category: "reminder"),
            WidgetTask(id: UUID(), title: "Masters of the Universe", dueDate: .now, isComplete: false,
                       quadrant: "Schedule It", category: "reminder")
        ], openCount: 2)
    }

    func getSnapshot(in context: Context, completion: @escaping (TasksEntry) -> Void) {
        completion(loadEntry())
    }

    func getTimeline(in context: Context, completion: @escaping (Timeline<TasksEntry>) -> Void) {
        let next = Calendar.current.startOfDay(for: Date().addingTimeInterval(86400))
        completion(Timeline(entries: [loadEntry()], policy: .after(next)))
    }

    private func loadEntry() -> TasksEntry {
        let tasks = todayWidgetTasks()
        return TasksEntry(date: .now, tasks: tasks, openCount: tasks.filter { !$0.isComplete }.count)
    }
}

// MARK: - Widget

struct MyTasksWidget: Widget {
    let kind = "KisaniMyTasks"

    var body: some WidgetConfiguration {
        StaticConfiguration(kind: kind, provider: TasksProvider()) { entry in
            MyTasksView(entry: entry)
        }
        .configurationDisplayName("My Tasks")
        .description("Today's tasks — check them off right from the widget.")
        .supportedFamilies([.systemSmall, .systemMedium, .systemLarge])
    }
}

struct MyTasksView: View {
    let entry: TasksEntry
    @Environment(\.widgetFamily) var family

    private var maxRows: Int {
        switch family {
        case .systemLarge:  return 9
        case .systemMedium: return 4
        default:            return 3
        }
    }

    var body: some View {
        VStack(alignment: .leading, spacing: 8) {
            HStack(spacing: 6) {
                Text("Today")
                    .font(.system(size: 18, weight: .bold))
                    .foregroundColor(Color(red: 0.42, green: 0.5, blue: 0.96))
                Text("\(entry.openCount)")
                    .font(.system(size: 15, weight: .semibold))
                    .foregroundColor(Color(white: 0.5))
                Spacer()
                Button(intent: AddTaskFromWidgetIntent()) {
                    Image(systemName: "plus")
                        .font(.system(size: 16, weight: .semibold))
                        .foregroundColor(Color(red: 0.42, green: 0.5, blue: 0.96))
                }
                .buttonStyle(.plain)
            }

            if entry.tasks.isEmpty {
                Spacer()
                Text("All clear for today 🎉")
                    .font(.system(size: 13))
                    .foregroundColor(Color(white: 0.5))
                    .frame(maxWidth: .infinity, alignment: .center)
                Spacer()
            } else {
                ForEach(entry.tasks.prefix(maxRows)) { task in
                    HStack(spacing: 10) {
                        Button(intent: ToggleTaskIntent(taskId: task.id.uuidString)) {
                            Image(systemName: task.isComplete ? "checkmark.circle.fill" : "circle")
                                .font(.system(size: 18))
                                .foregroundColor(task.isComplete ? task.accentColor : Color(white: 0.45))
                        }
                        .buttonStyle(.plain)

                        Text(task.title)
                            .font(.system(size: 14))
                            .foregroundColor(task.isComplete ? Color(white: 0.45) : .white)
                            .strikethrough(task.isComplete, color: Color(white: 0.45))
                            .lineLimit(1)
                        Spacer(minLength: 0)
                    }
                }
                if entry.tasks.count > maxRows {
                    Text("+\(entry.tasks.count - maxRows) more")
                        .font(.system(size: 11, weight: .medium))
                        .foregroundColor(Color(white: 0.4))
                        .padding(.leading, 28)
                }
                Spacer(minLength: 0)
            }
        }
        .containerBackground(.black, for: .widget)
    }
}