using System;
using System.IO;
using System.Runtime.InteropServices;
using S3.Core;

namespace S3.Modules.Popout;

/// <summary>
/// Preloads the native S3Native.dll from the mod folder before any P/Invoke.
///
/// S³ is a pure-UMM install: there is no winhttp proxy and Unity never calls
/// UnityPluginLoad for our plugin. By loading the DLL ourselves via its full path,
/// every [DllImport("S3Native")] in <see cref="Native"/> then binds to it by name.
/// The native renderer lazily initializes its D3D device from the supplied texture,
/// so the missing UnityPluginLoad is fine — that lazy path becomes the normal one.
/// </summary>
internal static class NativeLoader
{
    [DllImport("kernel32", SetLastError = true, CharSet = CharSet.Unicode)]
    private static extern IntPtr LoadLibrary(string lpFileName);

    private static bool _loaded;

    public static bool EnsureLoaded()
    {
        if (_loaded) return true;

        string dll = Path.Combine(Main.ModEntry.Path, "S3Native.dll");
        if (!File.Exists(dll))
        {
            Log.Error($"[popout] native DLL not found: {dll}");
            return false;
        }

        IntPtr handle = LoadLibrary(dll);
        if (handle == IntPtr.Zero)
        {
            Log.Error($"[popout] LoadLibrary failed (Win32 error {Marshal.GetLastWin32Error()}): {dll}");
            return false;
        }

        _loaded = true;
        Log.Info($"[popout] native S3Native.dll loaded from {dll}");
        return true;
    }
}