onyx/Packages/OnyxKit/Sources/MetricsProvider/MetricMenuBarModule.swift

import AppKit
import SwiftUI
import OnyxDesign
import OnyxMenuBar

/// Ein Menüleisten-Modul je Hardwaregröße.
///
/// Teilt sich das Modell — und damit die Messschleife — mit dem Panel-Widget
/// derselben Größe. Wer CPU im Panel **und** in der Menüleiste zeigt, bekommt
/// trotzdem nur eine Messung.
@MainActor
public final class MetricMenuBarModule: MenuBarModule {

    public let id: String
    public var displayName: String {
        String(localized: .init(metric.localizationKey), bundle: .module)
    }

    private let metric: MetricKind
    private let model: MetricsModel
    private var token: UUID?
    private var view: MetricStatusView?
    private var observation: (any NSObjectProtocol)?

    public init(metric: MetricKind, model: MetricsModel) {
        self.metric = metric
        self.model = model
        self.id = "metric.\(metric.rawValue)"
    }

    public func makeStatusView(presentation: MenuBarPresentation) -> NSView {
        let view = MetricStatusView(metric: metric, presentation: presentation)
        view.update(snapshot: model.snapshot, history: model.series(metric))
        self.view = view
        return view
    }

    public func makePopoverView() -> AnyView {
        AnyView(MetricPopover(model: model, metric: metric))
    }

    public func activate() {
        guard token == nil else { return }
        token = model.addConsumer(interval: 2)
        startObserving()
    }

    public func deactivate() {
        if let token { model.removeConsumer(token) }
        token = nil
        observation = nil
        view = nil
    }

    /// `withObservationTracking` meldet sich **einmal** und muss danach neu
    /// eingerichtet werden — sonst friert die Anzeige nach der ersten Messung ein.
    private func startObserving() {
        withObservationTracking {
            _ = model.snapshot
        } onChange: {
            Task { @MainActor [weak self] in
                guard let self, token != nil else { return }
                view?.update(snapshot: model.snapshot, history: model.series(metric))
                startObserving()
            }
        }
    }
}

/// Zeichnet den Messwert in die Menüleiste.
///
/// Eigene `NSView` statt SwiftUI: die Menüleiste verlangt eine feste Breite je
/// Darstellungsart, sonst springt bei jeder Messung die ganze Leiste. Mit
/// SwiftUI müsste man diese Breite doppelt führen — einmal für das Layout und
/// einmal für `NSStatusItem.length`.
final class MetricStatusView: NSView {

    private let metric: MetricKind
    private let presentation: MenuBarPresentation
    private var snapshot = MetricsSnapshot()
    private var history: [Double] = []

    init(metric: MetricKind, presentation: MenuBarPresentation) {
        self.metric = metric
        self.presentation = presentation
        super.init(frame: NSRect(x: 0, y: 0, width: presentation.width, height: 22))
    }

    @available(*, unavailable)
    required init?(coder: NSCoder) { fatalError() }

    override var intrinsicContentSize: NSSize {
        NSSize(width: presentation.width, height: 22)
    }

    func update(snapshot: MetricsSnapshot, history: [Double]) {
        self.snapshot = snapshot
        self.history = history
        needsDisplay = true
    }

    override func draw(_ dirtyRect: NSRect) {
        // `labelColor` statt der Onyx-Farben: die Menüleiste ist mal hell, mal
        // dunkel, und nur die Systemfarbe passt sich beidem an.
        let color = NSColor.labelColor

        switch presentation {
        case .value:
            drawText(MetricSummary.value(metric, snapshot), color: color)
        case .symbol:
            drawSymbol(color: color)
        case .graph:
            drawGraph(color: color, in: bounds.insetBy(dx: 2, dy: 5))
        case .bars:
            drawBars(color: color)
        case .valueAndGraph:
            let split = bounds.width * 0.55
            drawText(MetricSummary.value(metric, snapshot), color: color,
                     in: NSRect(x: 0, y: 0, width: split, height: bounds.height))
            drawGraph(color: color,
                      in: NSRect(x: split + 2, y: 5,
                                 width: bounds.width - split - 4, height: bounds.height - 10))
        }
    }

    private func drawText(_ text: String, color: NSColor, in rect: NSRect? = nil) {
        let attributes: [NSAttributedString.Key: Any] = [
            // Feste Ziffernbreite: ohne sie wackelt der Text bei jeder Messung.
            .font: NSFont.monospacedDigitSystemFont(ofSize: 11, weight: .regular),
            .foregroundColor: color,
        ]
        let string = NSAttributedString(string: text, attributes: attributes)
        let area = rect ?? bounds
        let size = string.size()
        string.draw(at: NSPoint(x: area.midX - size.width / 2,
                                y: area.midY - size.height / 2))
    }

    private func drawSymbol(color: NSColor) {
        guard let image = NSImage(systemSymbolName: metric.symbolName,
                                  accessibilityDescription: nil) else { return }
        image.isTemplate = true
        let side: CGFloat = 15
        let rect = NSRect(x: bounds.midX - side / 2, y: bounds.midY - side / 2,
                          width: side, height: side)
        color.set()
        image.draw(in: rect)
    }

    private func drawGraph(color: NSColor, in rect: NSRect) {
        guard history.count > 1, let context = NSGraphicsContext.current?.cgContext else { return }
        let step = rect.width / CGFloat(history.count - 1)

        context.setStrokeColor(color.withAlphaComponent(0.85).cgColor)
        context.setLineWidth(1)
        context.setLineJoin(.round)
        for (index, value) in history.enumerated() {
            let point = CGPoint(x: rect.minX + CGFloat(index) * step,
                                y: rect.minY + rect.height * CGFloat(min(max(value, 0), 1)))
            index == 0 ? context.move(to: point) : context.addLine(to: point)
        }
        context.strokePath()
    }

    /// Ein Balken je Kern. Bei fünfzehn Kernen ist das kein Diagramm mehr,
    /// sondern ein Muster — aber genau daran erkennt man auf einen Blick, ob
    /// eine einzelne Last läuft oder alles ausgelastet ist.
    private func drawBars(color: NSColor) {
        let values = metric == .cpu ? snapshot.cpu.perCore
                                    : [MetricSummary.fraction(metric, snapshot)]
        guard !values.isEmpty, let context = NSGraphicsContext.current?.cgContext else { return }

        let area = bounds.insetBy(dx: 2, dy: 5)
        let gap: CGFloat = values.count > 4 ? 1 : 2
        let width = (area.width - gap * CGFloat(values.count - 1)) / CGFloat(values.count)

        for (index, value) in values.enumerated() {
            let height = max(area.height * CGFloat(min(max(value, 0), 1)), 1)
            let rect = NSRect(x: area.minX + CGFloat(index) * (width + gap),
                              y: area.minY, width: width, height: height)
            context.setFillColor(color.withAlphaComponent(0.85).cgColor)
            context.fill(rect)
        }
    }
}

extension MenuBarPresentation {
    /// Feste Breite je Darstellungsart.
    ///
    /// Ohne sie ändert das Element bei jedem Messwert seine Größe und schiebt
    /// alle Symbole rechts davon hin und her — das fällt in der Menüleiste
    /// sofort unangenehm auf.
    var width: CGFloat {
        switch self {
        case .value: 42
        case .symbol: 22
        case .graph: 34
        case .bars: 30
        case .valueAndGraph: 74
        }
    }
}

public extension MetricSummary {
    /// Der Messwert als Anteil von 0 bis 1 — für Balken und Graphen.
    static func fraction(_ metric: MetricKind, _ snapshot: MetricsSnapshot) -> Double {
        switch metric {
        case .cpu: snapshot.cpu.total
        case .gpu: snapshot.gpu ?? 0
        case .memory: snapshot.memory.usedFraction
        case .battery: snapshot.battery?.charge ?? 0
        case .temperature: (snapshot.sensors.map(\.celsius).max() ?? 0) / 100
        }
    }
}

// MARK: - Popover

private struct MetricPopover: View {
    let model: MetricsModel
    let metric: MetricKind

    var body: some View {
        VStack(alignment: .leading, spacing: 8) {
            Text(String(localized: .init(metric.localizationKey), bundle: .module))
                .font(.headline)

            HStack(alignment: .firstTextBaseline, spacing: 6) {
                Text(MetricSummary.value(metric, model.snapshot))
                    .font(.system(size: 26, weight: .medium).monospacedDigit())
                if let detail = MetricSummary.detail(metric, model.snapshot) {
                    Text(detail).font(.callout).foregroundStyle(.secondary)
                }
            }

            Sparkline(values: model.series(metric), tint: .accentColor)
                .frame(width: 220, height: 44)

            if metric == .cpu, !model.snapshot.cpu.perCore.isEmpty {
                Text("metric.cpu.perCore", bundle: .module)
                    .font(.caption).foregroundStyle(.secondary)
                CoreBars(values: model.snapshot.cpu.perCore)
                    .frame(height: 26)
            }

            if metric == .temperature {
                ForEach(model.snapshot.sensors) { sensor in
                    HStack {
                        Text(sensor.name).font(.callout)
                        Spacer()
                        Text(MetricFormat.temperature(sensor.celsius))
                            .font(.callout.monospacedDigit())
                            .foregroundStyle(.secondary)
                    }
                }
            }
        }
        .padding(14)
        .frame(width: 250)
    }
}

private struct CoreBars: View {
    let values: [Double]

    var body: some View {
        GeometryReader { geometry in
            let gap: CGFloat = 2
            let width = (geometry.size.width - gap * CGFloat(values.count - 1))
                      / CGFloat(values.count)
            HStack(alignment: .bottom, spacing: gap) {
                ForEach(Array(values.enumerated()), id: \.offset) { _, value in
                    RoundedRectangle(cornerRadius: 1, style: .continuous)
                        .fill(Color.accentColor)
                        .frame(width: width,
                               height: max(geometry.size.height * value, 1))
                }
            }
            .frame(height: geometry.size.height, alignment: .bottom)
        }
    }
}