import SstData
import SstUI
import SwiftUI

/// The transport deck: VU meter, counter, LED bar and the REC/STOP keys. Always visible at the top.
struct DeckView: View {
    @EnvironmentObject private var model: AppModel

    var body: some View {
        HStack(alignment: .top, spacing: Layout.panelGap) {
            instruments
            Spacer(minLength: 0)
            controls
        }
        .padding(Layout.panelPadding)
        .background(PanelBackground())
    }

    private var instruments: some View {
        TimelineView(.animation(minimumInterval: 1 / Motion.needleUpdateHz, paused: !model.isRecording)) { context in
            let dbfs = Double(model.levelSource.dbfs)
            HStack(alignment: .top, spacing: Layout.panelGap) {
                VUMeterView(levelDbfs: dbfs, isActive: model.isRecording, brand: AppIdentity.brandCaption)
                    .frame(width: MeterTokens.vuWidth)
                VStack(alignment: .leading, spacing: Layout.panelGap) {
                    SilkLabel(Strings.time, style: Typography.labelSmall)
                    SegmentCounterView(StopwatchFormat.string(elapsed(at: context.date)))
                    SilkLabel(Strings.level, style: Typography.labelSmall)
                    LEDBarView(fraction: model.isRecording ? VUScale.fraction(forDbfs: dbfs) : 0)
                }
            }
        }
    }

    private func elapsed(at date: Date) -> TimeInterval {
        if let started = model.recordingStartedAt { return date.timeIntervalSince(started) }
        return model.lastDuration ?? 0
    }

    private var controls: some View {
        VStack(alignment: .trailing, spacing: Layout.panelGap) {
            HStack(spacing: Layout.panelGap) {
                Button { model.toggleWindowRecording() } label: {
                    HStack(spacing: Space.s3) {
                        LampView(isOn: model.isRecording)
                        Text(Strings.record)
                    }
                }
                .buttonStyle(KeyButtonStyle(kind: .record, latched: model.isRecording))
                .disabled(!model.isRecording && model.windowRecordingBlocker != nil)
                .help(model.windowRecordingBlocker ?? "")

                Button(Strings.stop) { model.stopWindowRecording() }
                    .buttonStyle(KeyButtonStyle())
                    .disabled(!model.isRecording)
            }
            if let error = model.lastError {
                HStack(spacing: Space.s3) {
                    LampView(isOn: true, tint: .amber)
                    Text(error)
                        .textStyle(Typography.meta)
                        .foregroundStyle(Palette.inkSecondary)
                        .multilineTextAlignment(.trailing)
                }
            } else {
                Text(model.statusLine)
                    .textStyle(Typography.meta)
                    .foregroundStyle(Palette.inkSecondary)
                    .multilineTextAlignment(.trailing)
            }
        }
        .frame(maxWidth: Layout.sidebarWidth, alignment: .trailing)
    }
}