using System;
using System.Collections.ObjectModel;
using System.Linq;
using System.Threading.Tasks;
using Avalonia.Media;
using CommunityToolkit.Mvvm.ComponentModel;
using Elfisa.Core;

namespace Elfisa.Avalonia.ViewModels;

public partial class SettingsViewModel : ViewModelBase
{
    private readonly ApiClient _api = new();

    /// <summary>Пункт «По умолчанию» в списке шрифтов.</summary>
    public const string DefaultFontLabel = "По умолчанию";

    [ObservableProperty] private string _apiBaseUrl = "";
    public string[] Themes { get; } = { "Светлая", "Тёмная" };
    [ObservableProperty] private int _themeIndex;

    /// <summary>Размер шрифта/текста — масштаб интерфейса.</summary>
    public string[] FontSizes { get; } = { "Мелкий (90%)", "Обычный (100%)", "Крупный (115%)", "Очень крупный (130%)", "Огромный (150%)" };
    private static readonly double[] ScaleValues = { 0.9, 1.0, 1.15, 1.3, 1.5 };
    [ObservableProperty] private int _fontSizeIndex = 1;
    public double SelectedScale => ScaleValues[Math.Clamp(FontSizeIndex, 0, ScaleValues.Length - 1)];

    /// <summary>Все системные шрифты + «По умолчанию» первым.</summary>
    public ObservableCollection<string> Fonts { get; } = new();
    [ObservableProperty] private string _selectedFont = DefaultFontLabel;

    public ObservableCollection<BuyerLocationDto> Locations { get; } = new();
    [ObservableProperty] private BuyerLocationDto? _selectedLocation;

    public SettingsViewModel()
    {
        _api.SetToken(Session.Current.Token);
        ApiBaseUrl = SettingsStore.Current.ApiBaseUrl ?? AppConfig.DefaultApiBaseUrl;
        ThemeIndex = SettingsStore.Current.Theme == "Dark" ? 1 : 0;

        var scale = SettingsStore.Current.UiScale;
        var best = 1;
        for (int i = 0; i < ScaleValues.Length; i++)
            if (Math.Abs(ScaleValues[i] - scale) < Math.Abs(ScaleValues[best] - scale)) best = i;
        FontSizeIndex = best;

        Fonts.Add(DefaultFontLabel);
        foreach (var f in FontManager.Current.SystemFonts
                     .Select(x => x.Name)
                     .Where(n => !string.IsNullOrWhiteSpace(n))
                     .Distinct()
                     .OrderBy(n => n, StringComparer.CurrentCultureIgnoreCase))
            Fonts.Add(f);

        var saved = SettingsStore.Current.FontFamily;
        SelectedFont = !string.IsNullOrWhiteSpace(saved) && Fonts.Contains(saved!)
            ? saved!
            : DefaultFontLabel;

        if (Session.Current.IsAuthenticated) _ = LoadLocationsAsync();
    }

    private async Task LoadLocationsAsync()
    {
        try
        {
            var locs = await _api.GetBuyerLocationsAsync();
            Locations.Clear();
            foreach (var l in locs) Locations.Add(l);
            var savedId = SettingsStore.Current.DefaultLocationId;
            SelectedLocation = Locations.FirstOrDefault(l => l.BuyerLocationId == savedId)
                               ?? Locations.FirstOrDefault(l => l.IsDefault)
                               ?? Locations.FirstOrDefault();
        }
        catch { /* локации не критичны для настроек */ }
    }
}