//
//  AppearanceSettingsTab.swift
//  Zyquo Agent
//
//  Author: Simon-Pierre Boucher
//  Mail: contact@spboucher.ai
//
//  Settings › Appearance — theme mode (Light/Dark/System), the five accent
//  choices with swatches (violet flagship + graphite, sky, emerald, amber),
//  and the chat font size slider (12–18pt) with live preview.
//

import SwiftUI

struct AppearanceSettingsTab: View {
    @EnvironmentObject private var appearance: AppearanceStore

    var body: some View {
        Form {
            Picker("Theme", selection: $appearance.themeMode) {
                ForEach(ThemeMode.allCases) { mode in
                    Text(mode.displayName).tag(mode)
                }
            }
            .pickerStyle(.segmented)

            VStack(alignment: .leading, spacing: ZyquoSpacing.xs) {
                Text("Accent")
                HStack(spacing: ZyquoSpacing.sm) {
                    ForEach(AccentChoice.allCases) { choice in
                        accentSwatch(choice)
                    }
                    Spacer(minLength: 0)
                }
            }

            VStack(alignment: .leading, spacing: ZyquoSpacing.xs) {
                HStack {
                    Text("Chat font size")
                    Spacer()
                    Text(String(format: "%.1f pt", appearance.chatFontSize))
                        .font(ZyquoFont.caption)
                        .foregroundStyle(ZyquoColor.textSecondary)
                        .monospacedDigit()
                }
                Slider(value: $appearance.chatFontSize, in: 12...18, step: 0.5)
                VStack(alignment: .leading, spacing: ZyquoSpacing.xxs) {
                    Text("Preview")
                        .font(ZyquoFont.caption)
                        .foregroundStyle(ZyquoColor.textTertiary)
                    Text("The quick brown fox jumps over the lazy dog — Zyquo Agent renders task text at this size, with generous 1.45 line height for readability.")
                        .font(ZyquoFont.body(size: appearance.chatFontSize))
                        .lineSpacing(appearance.chatFontSize * ZyquoFont.bodyLineSpacingFactor)
                        .foregroundStyle(ZyquoColor.textPrimary)
                        .padding(ZyquoSpacing.sm)
                        .frame(maxWidth: .infinity, alignment: .leading)
                        .background(
                            RoundedRectangle(cornerRadius: ZyquoRadius.medium, style: .continuous)
                                .fill(ZyquoColor.surface)
                                .overlay(
                                    RoundedRectangle(cornerRadius: ZyquoRadius.medium, style: .continuous)
                                        .strokeBorder(ZyquoColor.border, lineWidth: ZyquoMetrics.hairline)
                                )
                        )
                }
            }
        }
        .formStyle(.grouped)
    }

    private func accentSwatch(_ choice: AccentChoice) -> some View {
        let isSelected = appearance.accent == choice
        return Button {
            withAnimation(ZyquoMotion.appear) { appearance.accent = choice }
        } label: {
            VStack(spacing: ZyquoSpacing.xxs) {
                Circle()
                    .fill(swatchColor(choice))
                    .frame(width: 26, height: 26)
                    .overlay(
                        Circle().strokeBorder(
                            isSelected ? ZyquoColor.textPrimary : ZyquoColor.border,
                            lineWidth: isSelected ? 2 : ZyquoMetrics.hairline
                        )
                    )
                    .overlay {
                        if isSelected {
                            Image(systemName: "checkmark")
                                .font(.system(size: 10, weight: .bold))
                                .foregroundStyle(.white)
                        }
                    }
                Text(choice.displayName)
                    .font(ZyquoFont.caption)
                    .foregroundStyle(isSelected ? ZyquoColor.textPrimary : ZyquoColor.textSecondary)
            }
        }
        .buttonStyle(PressableButtonStyle())
        .help("\(choice.displayName) accent")
    }

    /// Appearance-resolved swatch color for one accent choice.
    private func swatchColor(_ choice: AccentChoice) -> Color {
        let (light, dark) = choice.accentHex
        return Color(nsColor: NSColor(name: nil) { appearance in
            let hex = appearance.bestMatch(from: [.darkAqua, .aqua]) == .darkAqua ? dark : light
            return NSColor(hex: hex)
        })
    }
}