using System.Text.Json;

namespace LehrerApp.Core.Services;

public sealed class DashboardCardSetting
{
    public string Key { get; set; } = "";
    public bool IsVisible { get; set; } = true;
    public int Order { get; set; }
}

/// <summary>Speichert Sichtbarkeit und Reihenfolge der Dashboard-Kacheln lokal.</summary>
public sealed class DashboardSettingsService
{
    public static readonly string[] DefaultCardOrder =
    [
        "today", "tasks", "calendar", "excuses", "upcoming",
        "corrections", "unplanned", "alerts", "attendance", "support", "groups", "examload",
    ];

    private readonly string _configPath;

    public DashboardSettingsService(string appDataPath) =>
        _configPath = Path.Combine(appDataPath, "dashboardsettings.json");

    public List<DashboardCardSetting> Load()
    {
        try
        {
            if (File.Exists(_configPath))
            {
                var saved = JsonSerializer.Deserialize<List<DashboardCardSetting>>(
                    File.ReadAllText(_configPath)) ?? [];
                var byKey = saved
                    .Where(s => DefaultCardOrder.Contains(s.Key))
                    .GroupBy(s => s.Key).ToDictionary(g => g.Key, g => g.First());
                return DefaultCardOrder.Select((key, defaultOrder) => byKey.TryGetValue(key, out var item)
                        ? new DashboardCardSetting { Key = key, IsVisible = item.IsVisible, Order = item.Order }
                        : new DashboardCardSetting { Key = key, IsVisible = true, Order = defaultOrder })
                    .OrderBy(s => s.Order).ThenBy(s => Array.IndexOf(DefaultCardOrder, s.Key))
                    .Select((s, index) => new DashboardCardSetting
                        { Key = s.Key, IsVisible = s.IsVisible, Order = index })
                    .ToList();
            }
        }
        catch { /* beschädigte Konfiguration -> Standardreihenfolge */ }

        return DefaultCardOrder.Select((key, index) => new DashboardCardSetting
            { Key = key, IsVisible = true, Order = index }).ToList();
    }

    public void Save(IEnumerable<DashboardCardSetting> settings)
    {
        var normalized = settings.Select((s, index) => new DashboardCardSetting
        {
            Key = s.Key,
            IsVisible = s.IsVisible,
            Order = index,
        }).ToList();
        File.WriteAllText(_configPath, JsonSerializer.Serialize(normalized));
    }
}