//
//  MAThemeManager.swift
//  Mobile Music Assistant
//
//  Created by Sven Hanold on 26.03.26.
//

import SwiftUI

@Observable
class MAThemeManager {
    var colorScheme: AppColorScheme {
        didSet {
            UserDefaults.standard.set(colorScheme.rawValue, forKey: "appColorScheme")
        }
    }
    
    init() {
        let savedValue = UserDefaults.standard.string(forKey: "appColorScheme") ?? "dark"
        colorScheme = AppColorScheme(rawValue: savedValue) ?? .dark
    }
    
    var preferredColorScheme: ColorScheme? {
        switch colorScheme {
        case .system:
            return nil
        case .light:
            return .light
        case .dark:
            return .dark
        }
    }
}

enum AppColorScheme: String, CaseIterable, Identifiable {
    case system = "system"
    case light = "light"
    case dark = "dark"
    
    var id: String { rawValue }
    
    var displayName: String {
        switch self {
        case .system:
            return "System"
        case .light:
            return "Light"
        case .dark:
            return "Dark"
        }
    }
    
    var description: String {
        switch self {
        case .system:
            return "Follows your device's appearance"
        case .light:
            return "Always use light mode"
        case .dark:
            return "Always use dark mode"
        }
    }
    
    var icon: String {
        switch self {
        case .system:
            return "circle.lefthalf.filled"
        case .light:
            return "sun.max.fill"
        case .dark:
            return "moon.fill"
        }
    }
}

// MARK: - Environment Key

private struct ThemeManagerKey: EnvironmentKey {
    static let defaultValue = MAThemeManager()
}

extension EnvironmentValues {
    var themeManager: MAThemeManager {
        get { self[ThemeManagerKey.self] }
        set { self[ThemeManagerKey.self] = newValue }
    }
}
// MARK: - Theme Applied Modifier

struct ThemeAppliedModifier: ViewModifier {
    @Environment(\.themeManager) var themeManager
    
    func body(content: Content) -> some View {
        content
            .preferredColorScheme(themeManager.preferredColorScheme)
            .id(themeManager.colorScheme) // Force refresh when theme changes
    }
}

extension View {
    func applyTheme() -> some View {
        modifier(ThemeAppliedModifier())
    }
}