import AppIntents
import SwiftUI
import WidgetKit

/// The home screen and lock screen widget (#428): All Subscriptions' unread count, and the episode
/// you were last on with a button to carry on or pause. It draws what the app last wrote to their
/// shared App Group (`Snapshot`); the app asks for a redraw when that changes.
@main
struct IPXWidgets: WidgetBundle {
    var body: some Widget {
        IPXWidget()
    }
}

struct IPXWidget: Widget {
    var body: some WidgetConfiguration {
        StaticConfiguration(kind: "net.sdf1.ipx.widget", provider: Provider()) { entry in
            WidgetView(snap: entry.snap)
                .containerBackground(.fill.tertiary, for: .widget)
        }
        .configurationDisplayName("iPX")
        .description("What is unread, and the episode you were listening to.")
        .supportedFamilies([.systemSmall, .systemMedium, .accessoryCircular, .accessoryRectangular])
    }
}

struct Entry: TimelineEntry {
    let date: Date
    let snap: Snapshot
}

struct Provider: TimelineProvider {
    private static let sample = Snapshot(unread: 12, title: "An episode", feedTitle: "A show",
                                         position: 600, duration: 1800)

    func placeholder(in context: Context) -> Entry { Entry(date: .now, snap: Self.sample) }

    func getSnapshot(in context: Context, completion: @escaping (Entry) -> Void) {
        completion(Entry(date: .now, snap: context.isPreview ? Self.sample : Snapshot.load()))
    }

    /// One entry, kept until the app says something changed: the widget has nothing of its own
    /// to look at.
    func getTimeline(in context: Context, completion: @escaping (Timeline<Entry>) -> Void) {
        completion(Timeline(entries: [Entry(date: .now, snap: Snapshot.load())], policy: .never))
    }
}

struct WidgetView: View {
    @Environment(\.widgetFamily) private var family
    let snap: Snapshot

    var body: some View {
        switch family {
        case .accessoryCircular:
            VStack(spacing: 0) {
                Text(count).font(.title3.weight(.semibold)).minimumScaleFactor(0.5)
                Text("unread").font(.caption2)
            }
        case .accessoryRectangular:
            VStack(alignment: .leading) {
                Text("\(count) unread").font(.headline)
                if let title = snap.title { Text(title).font(.caption).lineLimit(2) }
            }
        case .systemMedium:
            HStack(spacing: 16) {
                unread
                Divider()
                episode
            }
        default:
            VStack(alignment: .leading) {
                unread
                Spacer(minLength: 4)
                if let title = snap.title {
                    Text(title).font(.caption).lineLimit(2).foregroundStyle(.secondary)
                }
            }
            .frame(maxWidth: .infinity, alignment: .leading)
        }
    }

    private var count: String {
        guard let n = snap.unread else { return "–" }
        return n > 999 ? "999+" : "\(n)"
    }

    private var unread: some View {
        VStack(alignment: .leading, spacing: 0) {
            Text(count).font(.system(size: 40, weight: .semibold, design: .rounded))
                .minimumScaleFactor(0.5).lineLimit(1)
            Text("unread").font(.caption).foregroundStyle(.secondary)
        }
    }

    @ViewBuilder private var episode: some View {
        if let title = snap.title {
            VStack(alignment: .leading, spacing: 6) {
                Text(snap.feedTitle ?? "").font(.caption2).foregroundStyle(.secondary).lineLimit(1)
                Text(title).font(.subheadline.weight(.semibold)).lineLimit(2)
                if let p = snap.progress { ProgressView(value: p).tint(.orange) }
                Button(intent: PlayPauseIntent()) {
                    Label(snap.playing ? "Pause" : "Resume",
                          systemImage: snap.playing ? "pause.fill" : "play.fill")
                        .font(.caption.weight(.semibold))
                }
                .tint(.orange)
            }
            .frame(maxWidth: .infinity, alignment: .leading)
        } else {
            Text("Nothing playing").font(.subheadline).foregroundStyle(.secondary)
                .frame(maxWidth: .infinity, alignment: .leading)
        }
    }
}