//
//  AppearanceStore.swift
//  Zyquo Agent
//
//  Author: Simon-Pierre Boucher
//  Mail: contact@spboucher.ai
//
//  User appearance preferences: theme mode, accent choice, chat font size.
//  Persisted to settings.json via PersistenceService.
//

import SwiftUI

/// Accent color choices offered in Settings → Appearance. Violet is the
/// Agent flagship default; alternates keep the same subtle-tint relationship
/// (graphite, sky, emerald, amber per the Phase 4 spec).
enum AccentChoice: String, Codable, CaseIterable, Identifiable {
    case violet
    case graphite
    case sky
    case emerald
    case amber

    var id: String { rawValue }

    var displayName: String {
        switch self {
        case .violet: return "Violet"
        case .graphite: return "Graphite"
        case .sky: return "Sky"
        case .emerald: return "Emerald"
        case .amber: return "Amber"
        }
    }

    /// (light, dark) accent hex pair.
    var accentHex: (UInt32, UInt32) {
        switch self {
        case .violet: return (0x7A5AF0, 0x9B82F6)
        case .graphite: return (0x5B6270, 0x8A93A6)
        case .sky: return (0x4E6AF0, 0x6D84F5)
        case .emerald: return (0x1D9A6B, 0x3BB58A)
        case .amber: return (0xC77D1D, 0xDD9B45)
        }
    }

    /// (light, dark) subtle-tint hex pair (selected rows, user bubbles).
    var subtleHex: (UInt32, UInt32) {
        switch self {
        case .violet: return (0xEFEBFD, 0x2E2749)
        case .graphite: return (0xEEF0F4, 0x2A2E3A)
        case .sky: return (0xEBEFFD, 0x28304C)
        case .emerald: return (0xE6F6EF, 0x1F3A2F)
        case .amber: return (0xFBF1E3, 0x3D3222)
        }
    }
}

enum ThemeMode: String, Codable, CaseIterable, Identifiable {
    case system, light, dark
    var id: String { rawValue }

    var displayName: String {
        switch self {
        case .system: return "System"
        case .light: return "Light"
        case .dark: return "Dark"
        }
    }

    var colorScheme: ColorScheme? {
        switch self {
        case .system: return nil
        case .light: return .light
        case .dark: return .dark
        }
    }
}

/// Observable appearance preferences, persisted as part of app settings.
@MainActor
final class AppearanceStore: ObservableObject {
    struct Stored: Codable {
        var themeMode: ThemeMode = .system
        var accent: AccentChoice = .violet
        var chatFontSize: Double = 13.5
    }

    static let fileName = "appearance.json"

    @Published var themeMode: ThemeMode { didSet { save() } }
    @Published var accent: AccentChoice {
        didSet {
            // Feed the design-system resolver so the static ZyquoColor.accent
            // token picks up the new choice on the next draw.
            ZyquoAccentResolver.current = accent
            save()
        }
    }
    /// Chat body font size, clamped to the spec's 12–18pt range.
    @Published var chatFontSize: Double {
        didSet {
            let clamped = min(18, max(12, chatFontSize))
            if clamped != chatFontSize { chatFontSize = clamped }
            save()
        }
    }

    private let persistence: PersistenceService

    init(persistence: PersistenceService = .shared) {
        self.persistence = persistence
        let stored = persistence.load(Stored.self, from: Self.fileName) ?? Stored()
        themeMode = stored.themeMode
        accent = stored.accent
        chatFontSize = stored.chatFontSize
        ZyquoAccentResolver.current = stored.accent
    }

    /// Current accent color resolved for the active appearance.
    var accentColor: Color {
        let (light, dark) = accent.accentHex
        return Color(nsColor: NSColor(name: nil) { appearance in
            let hex = appearance.bestMatch(from: [.darkAqua, .aqua]) == .darkAqua ? dark : light
            return NSColor(hex: hex)
        })
    }

    /// Current subtle accent tint resolved for the active appearance.
    var accentSubtleColor: Color {
        let (light, dark) = accent.subtleHex
        return Color(nsColor: NSColor(name: nil) { appearance in
            let hex = appearance.bestMatch(from: [.darkAqua, .aqua]) == .darkAqua ? dark : light
            return NSColor(hex: hex)
        })
    }

    private func save() {
        persistence.save(
            Stored(themeMode: themeMode, accent: accent, chatFontSize: chatFontSize),
            to: Self.fileName
        )
    }
}