SdlGamepadManager.cs

using Microsoft.Extensions.Logging;
using static SDL2.SDL;
 
namespace Gondwana.Input.Gamepad.SDL2;

public sealed class SdlGamepadManager : IGamepadManager<SdlGamepadAdapter>
{
    public static SdlGamepadManager? Instance { get; private set; }
 
    private readonly Dictionary<int, SdlGamepadAdapter> _connected = new();

    public IReadOnlyCollection<SdlGamepadAdapter> ConnectedAdapters => _connected.Values;
 
    private SdlGamepadManager()
    {
        if (SDL_Init(SDL_INIT_GAMECONTROLLER) < 0)
            throw new InvalidOperationException($"SDL gamepad initialization failed: {SDL_GetError()}");
 
        _ = SDL_GameControllerEventState(SDL_DISABLE); // Polling only
 
        Engine.Logger.LogInformation("SdlGamepadManager initialized. Polling enabled.");
    }

    public static SdlGamepadManager Start()
    {
        if (Instance == null)
            Instance = new SdlGamepadManager();
 
        return Instance;
    }

    public static void Stop()
    {
        if (Instance != null)
        {
            Engine.Logger.LogInformation("SdlGamepadManager stopped. Disposing gamepad adapters...");
 
            foreach (var adapter in Instance._connected.Values)
                adapter.Dispose();
 
            Instance._connected.Clear();
            Instance = null;
        }
    }

    public void UpdateConnections()
    {
        var stillConnected = new HashSet<int>();
 
        for (int i = 0; i < SDL_NumJoysticks(); i++)
        {
            if (SDL_IsGameController(i) == SDL_bool.SDL_FALSE)
                continue;
 
            stillConnected.Add(i);
 
            if (!_connected.ContainsKey(i))
            {
                _connected[i] = new SdlGamepadAdapter(i);
                Engine.Logger.LogInformation("Gamepad connected: SDL_CONTROLLER_{ControllerIndex}", i);
            }
        }
 
        foreach (var index in _connected.Keys.Except(stillConnected).ToList())
        {
            Engine.Logger.LogInformation("Gamepad disconnected: SDL_CONTROLLER_{ControllerIndex}", index);
            _connected[index].Dispose();
            _connected.Remove(index);
        }
    }

    public void Poll()
    {
        SDL_GameControllerUpdate();
 
        foreach (var adapter in _connected.Values)
            adapter.Poll();
    }

    [Obsolete("Use UpdateConnections() and Poll() separately.")]
    public void Update()
    {
        UpdateConnections();
        Poll();
    }
}