import SwiftUI
import WidgetKit

@main
struct StemifyWidgets: WidgetBundle {
    var body: some Widget {
        MixerWidget()
        MixWidget()
        if #available(iOS 18.0, *) { MixControl() }
    }
}

/// Audio intents run in the app's process, so the extension's copy never does anything.
@MainActor
enum MixRemote {
    static func run(_ a: MixAction) {}
}

// ---- timeline -----------------------------------------------------------------------------

struct MixerEntry: TimelineEntry {
    var date = Date()
    var snap: WidgetSnapshot
    var art: UIImage?

    /// The app reloads the widgets whenever the song or mix changes, so one entry is enough.
    static func now() -> MixerEntry {
        let s = WidgetStore.load()
        let art = s.art == nil ? nil : WidgetStore.artURL.flatMap { UIImage(contentsOfFile: $0.path) }
        return MixerEntry(snap: s, art: art)
    }

    static let sample = MixerEntry(snap: WidgetSnapshot(
        title: "Midnight City", artist: "M83", mix: "Karaoke", next: "A Cappella", playing: true,
        stems: [
            WidgetStem(name: "vocals", label: "Vocals", color: 0xFF7AB6, level: 0.8, percent: 100, muted: true),
            WidgetStem(name: "drums", label: "Drums", color: 0xFFB547, level: 0.8, percent: 100),
            WidgetStem(name: "bass", label: "Bass", color: 0x7C8CFF, level: 0.9, percent: 127),
            WidgetStem(name: "other", label: "Other", color: 0x4CD07D, level: 0.7, percent: 77),
        ]))
}

struct MixerProvider: TimelineProvider {
    func placeholder(in context: Context) -> MixerEntry { .sample }

    func getSnapshot(in context: Context, completion: @escaping (MixerEntry) -> Void) {
        let e = MixerEntry.now()
        completion(context.isPreview && !e.snap.hasStems ? .sample : e)
    }

    func getTimeline(in context: Context, completion: @escaping (Timeline<MixerEntry>) -> Void) {
        completion(Timeline(entries: [.now()], policy: .never))
    }
}

// ---- widgets ------------------------------------------------------------------------------

struct MixerWidget: Widget {
    var body: some WidgetConfiguration {
        StaticConfiguration(kind: WidgetStore.mixerKind, provider: MixerProvider()) { e in
            MixerView(entry: e).containerBackground(for: .widget) { Look.bg }
        }
        .configurationDisplayName("Stem Mixer")
        .description("A knob for each stem. Tap the arrows to turn it, tap the knob to mute it.")
        .supportedFamilies([.systemMedium, .systemLarge])
    }
}

struct MixWidget: Widget {
    var body: some WidgetConfiguration {
        StaticConfiguration(kind: WidgetStore.mixKind, provider: MixerProvider()) { e in
            MixView(entry: e)
        }
        .configurationDisplayName("Mix")
        .description("The mix that's playing, and a button for the next one.")
        .supportedFamilies([.systemSmall, .accessoryRectangular, .accessoryCircular])
    }
}

/// Swaps the Lock Screen's flashlight or camera for a Mix button. Also works in Control Center and on the Action button.
@available(iOS 18.0, *)
struct MixControl: ControlWidget {
    var body: some ControlWidgetConfiguration {
        StaticControlConfiguration(kind: WidgetStore.controlKind, provider: Provider()) { mix in
            ControlWidgetButton(action: CycleMixIntent()) {
                Label(mix, systemImage: "slider.vertical.3")
            }
        }
        .displayName("Change Mix")
        .description("Moves to the next stem mix while stems play.")
    }

    struct Provider: ControlValueProvider {
        var previewValue: String { "Karaoke" }
        func currentValue() async throws -> String {
            let s = WidgetStore.load()
            return s.hasStems ? s.mix : "Mix"
        }
    }
}