import WidgetKit
import SwiftUI

struct TaskEntry: TimelineEntry {
    let date: Date
    let tasks: [TaskItem]
}

struct TaskProvider: TimelineProvider {
    func placeholder(in context: Context) -> TaskEntry {
        TaskEntry(date: .now, tasks: [TaskItem(title: "Plan the next task")])
    }

    func getSnapshot(in context: Context, completion: @escaping (TaskEntry) -> Void) {
        completion(TaskEntry(date: .now, tasks: openTasks()))
    }

    func getTimeline(in context: Context, completion: @escaping (Timeline<TaskEntry>) -> Void) {
        let entry = TaskEntry(date: .now, tasks: openTasks())
        let refresh = Calendar.current.date(byAdding: .minute, value: 15, to: .now)!
        completion(Timeline(entries: [entry], policy: .after(refresh)))
    }

    private func openTasks() -> [TaskItem] {
        TaskStore.loadTasks().filter { $0.list != .done }
    }
}

struct UTrelloTasksWidget: Widget {
    let kind = "UTrelloTasksWidget"

    var body: some WidgetConfiguration {
        StaticConfiguration(kind: kind, provider: TaskProvider()) { entry in
            TaskWidgetView(entry: entry)
        }
        .configurationDisplayName("UTrello Tasks")
        .description("Your unfinished tasks at a glance.")
        .supportedFamilies([.systemSmall, .systemMedium, .systemLarge])
    }
}

private struct TaskWidgetView: View {
    let entry: TaskEntry

    var body: some View {
        VStack(alignment: .leading, spacing: 8) {
            Text("My tasks")
                .font(.headline)
            if entry.tasks.isEmpty {
                Spacer()
                Text("All caught up")
                    .foregroundStyle(.secondary)
                Spacer()
            } else {
                ForEach(entry.tasks.prefix(4)) { task in
                    Label(task.title, systemImage: task.list == .doing ? "play.circle" : "circle")
                        .lineLimit(1)
                }
            }
            Spacer(minLength: 0)
            Text("\(entry.tasks.count) open")
                .font(.caption)
                .foregroundStyle(.secondary)
        }
        .containerBackground(for: .widget) { Color.clear }
    }
}