using System.IO;
using System.Text.Json;

namespace TeamsISO.App.Services;

/// <summary>
/// Persistent UI-side toggles that don't belong in <see cref="TeamsISO.Engine.Persistence.ConfigStore"/>
/// (which is the engine's domain model — framerate, NDI groups, ISO assignments).
///
/// Each toggle is a property on a single record persisted as JSON at
/// <c>%LOCALAPPDATA%\TeamsISO\ui-prefs.json</c>. Defaults match the original
/// in-memory behavior: HideLocalSelf=true (filter the operator's own preview
/// out of the participants list) and AutoDisableOnDeparture=false (a participant
/// going offline doesn't tear down their pipeline by default — operators
/// usually want to keep the routing in case they reconnect).
///
/// Centralizing these here means the settings VM doesn't have to plumb
/// individual Set methods to dedicated services for every new bool.
/// </summary>
public static class UIPreferences
{
    private static readonly object _gate = new();

    private static string PrefsPath =>
        Path.Combine(
            Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData),
            "TeamsISO", "ui-prefs.json");

    /// <summary>
    /// Sort modes for the participants DataGrid. <see cref="JoinOrder"/> is the default
    /// and matches the engine's discovery order (operators with custom Stream Deck
    /// layouts sometimes prefer Alphabetical for stability across meetings).
    /// </summary>
    public enum SortMode { JoinOrder, Alphabetical, OnlineFirst }

    /// <summary>The on-disk shape. New fields added here become opt-in for older files via default values.</summary>
    public sealed record Prefs(
        bool HideLocalSelf = true,
        bool AutoDisableOnDeparture = false,
        SortMode ParticipantSort = SortMode.JoinOrder,
        bool MinimizeToTray = false);

    public static Prefs Load()
    {
        try
        {
            if (!File.Exists(PrefsPath)) return new Prefs();
            var json = File.ReadAllText(PrefsPath);
            return JsonSerializer.Deserialize<Prefs>(json) ?? new Prefs();
        }
        catch
        {
            return new Prefs();
        }
    }

    public static void Save(Prefs prefs)
    {
        try
        {
            lock (_gate)
            {
                var dir = Path.GetDirectoryName(PrefsPath);
                if (!string.IsNullOrEmpty(dir)) Directory.CreateDirectory(dir);
                var json = JsonSerializer.Serialize(prefs, new JsonSerializerOptions { WriteIndented = true });
                File.WriteAllText(PrefsPath, json);
            }
        }
        catch
        {
            // Disk full / permission denied — in-memory state still holds for this session.
        }
    }
}