//
//  VanAligneiOSWidgetLiveActivity.swift
//  VanAligneiOSWidget
//
//  Created by Christopher Helberg on 02.09.26.
//

import ActivityKit
import WidgetKit
import SwiftUI

/// Formatiert Neigungswerte wie in der App – °, eine Nachkommastelle, "–"
/// wenn kein Messwert da ist. Eigene Kopie, da die Extension nicht von
/// `Shared/Models/Metric.swift` abhängt.
private func degreesText(_ value: Double?) -> String {
    guard let value else { return "–" }
    return String(format: "%.1f°", value)
}

private struct LevelIcon: View {
    let isLevel: Bool
    let hasReading: Bool

    var body: some View {
        Image(systemName: hasReading ? (isLevel ? "checkmark.circle.fill" : "level") : "level")
            .foregroundStyle(hasReading ? (isLevel ? .green : .orange) : .secondary)
    }
}

/// Verkleinerte Libelle für Sperrbildschirm/CarPlay und die erweiterte
/// Dynamic Island – dieselbe Optik wie `LevelBubble` in der App, aber ohne
/// deren Abhängigkeit auf `Shared/Models/LevelState.swift`, das in der
/// Extension nicht mitkompiliert wird.
private struct LevelBubbleGlyph: View {
    let pitch: Double?
    let roll: Double?
    let isLevel: Bool
    var diameter: CGFloat = 54

    /// Bis zu welcher Neigung die Blase ausschlägt, wie in der App-Libelle.
    private let range: Double = 6
    /// Muss mit `LevelState.levelTolerance` übereinstimmen.
    private let tolerance: Double = 0.5

    private var hasReading: Bool { pitch != nil || roll != nil }

    private var bubbleColor: Color {
        guard let pitch, let roll else { return .white.opacity(0.4) }
        let deviation = max(abs(pitch), abs(roll))
        if deviation <= tolerance { return .green }
        if deviation <= 2 { return .orange }
        return .red
    }

    var body: some View {
        let radius = diameter / 2
        let bubble = diameter * 0.22
        let travel = radius - bubble / 2 - 3
        let offsetX = clamped(roll) / range * travel
        let offsetY = clamped(pitch) / range * travel
        let toleranceRadius = max(tolerance / range * travel, bubble * 0.55)

        ZStack {
            Circle()
                .fill(Color.white.opacity(0.1))
            Circle()
                .strokeBorder(Color.white.opacity(0.3), lineWidth: 1)
            Circle()
                .strokeBorder(isLevel ? Color.green : Color.white.opacity(0.25),
                              lineWidth: isLevel ? 2 : 1)
                .frame(width: toleranceRadius * 2, height: toleranceRadius * 2)
            Circle()
                .fill(bubbleColor)
                .frame(width: bubble, height: bubble)
                // Positiver Pitch heisst: Heck steht höher, die Blase wandert
                // also nach oben – wie bei der echten Wasserwaage in der App.
                .offset(x: offsetX, y: -offsetY)
                .opacity(hasReading ? 1 : 0.3)
        }
        .frame(width: diameter, height: diameter)
    }

    private func clamped(_ value: Double?) -> Double {
        guard let value else { return 0 }
        return min(max(value, -range), range)
    }
}

struct VanAligneiOSWidgetLiveActivity: Widget {
    var body: some WidgetConfiguration {
        ActivityConfiguration(for: LevelActivityAttributes.self) { context in
            LockScreenLevelView(attributes: context.attributes, state: context.state)
                .activityBackgroundTint(Color(white: 0.08))
                .activitySystemActionForegroundColor(.white)

        } dynamicIsland: { context in
            DynamicIsland {
                DynamicIslandExpandedRegion(.leading) {
                    LevelBubbleGlyph(pitch: context.state.pitch, roll: context.state.roll,
                                     isLevel: context.state.isLevel, diameter: 44)
                }
                DynamicIslandExpandedRegion(.trailing) {
                    VStack(alignment: .trailing, spacing: 2) {
                        Text(degreesText(context.state.pitch)).monospacedDigit()
                        Text(degreesText(context.state.roll)).monospacedDigit()
                    }
                    .font(.headline)
                }
                DynamicIslandExpandedRegion(.bottom) {
                    Text(context.state.instruction ?? context.attributes.deviceName)
                        .font(.subheadline)
                        .foregroundStyle(context.state.isLevel ? .green : .primary)
                }
            } compactLeading: {
                LevelIcon(isLevel: context.state.isLevel, hasReading: context.state.pitch != nil)
            } compactTrailing: {
                Text(degreesText(context.state.pitch)).monospacedDigit()
            } minimal: {
                LevelIcon(isLevel: context.state.isLevel, hasReading: context.state.pitch != nil)
            }
            .keylineTint(context.state.isLevel ? .green : .orange)
        }
    }
}

/// Sperrbildschirm- und Banner-Ansicht. Dieselbe Ansicht landet automatisch
/// auch im CarPlay-Dashboard, sobald das iPhone verbunden ist – ein eigenes
/// CarPlay-App-Target ist dafür nicht nötig.
private struct LockScreenLevelView: View {
    let attributes: LevelActivityAttributes
    let state: LevelActivityAttributes.ContentState

    var body: some View {
        HStack(spacing: 16) {
            LevelBubbleGlyph(pitch: state.pitch, roll: state.roll, isLevel: state.isLevel)

            VStack(alignment: .leading, spacing: 4) {
                Text(attributes.deviceName)
                    .font(.caption)
                    .foregroundStyle(.secondary)
                Text(state.instruction ?? "Keine Messwerte")
                    .font(.headline)
                    .foregroundStyle(state.isLevel ? .green : .white)
                    .lineLimit(2)
            }

            Spacer()

            VStack(alignment: .trailing, spacing: 2) {
                reading("Längs", state.pitch)
                reading("Quer", state.roll)
            }
        }
        .padding(16)
        .foregroundStyle(.white)
    }

    private func reading(_ title: String, _ value: Double?) -> some View {
        HStack(spacing: 6) {
            Text(title)
                .font(.caption2)
                .foregroundStyle(.secondary)
            Text(degreesText(value))
                .font(.subheadline.monospacedDigit())
        }
    }
}

extension LevelActivityAttributes {
    fileprivate static var preview: LevelActivityAttributes {
        LevelActivityAttributes(deviceName: "Nivellierung")
    }
}

extension LevelActivityAttributes.ContentState {
    fileprivate static var level: LevelActivityAttributes.ContentState {
        LevelActivityAttributes.ContentState(pitch: 0.1, roll: -0.2, isLevel: true,
                                              instruction: "Steht eben", isCalibrated: true,
                                              updatedAt: .now)
    }

    fileprivate static var tilted: LevelActivityAttributes.ContentState {
        LevelActivityAttributes.ContentState(pitch: 2.4, roll: -1.1, isLevel: false,
                                              instruction: "Heck steht höher, links steht höher",
                                              isCalibrated: true, updatedAt: .now)
    }
}

#Preview("Notification", as: .content, using: LevelActivityAttributes.preview) {
   VanAligneiOSWidgetLiveActivity()
} contentStates: {
    LevelActivityAttributes.ContentState.level
    LevelActivityAttributes.ContentState.tilted
}