using Dalamud.Hooking;
using Dalamud.Utility.Signatures;

namespace OrangeGuidanceTomestone.MiniPenumbra;

internal unsafe class VfxReplacer : IDisposable {
    private delegate byte ReadSqPackDelegate(void* resourceManager, SeFileDescriptor* pFileDesc, int priority, bool isSync);

    [Signature("E8 ?? ?? ?? ?? EB 05 E8 ?? ?? ?? ?? 84 C0 0F 84 ?? 00 00 00 4C 8B C3", DetourName = nameof(ReadSqPackDetour))]
    private Hook<ReadSqPackDelegate> _readSqPackHook;

    [Signature("E8 ?? ?? ?? ?? 84 C0 0F 84 ?? 00 00 00 4C 8B C3 BA 05")]
    private delegate* unmanaged<void*, SeFileDescriptor*, int, bool, byte> _readFile;

    private Plugin Plugin { get; }

    internal VfxReplacer(Plugin plugin) {
        this.Plugin = plugin;
        this.Plugin.GameInteropProvider.InitializeFromAttributes(this);

        this._readSqPackHook!.Enable();
    }

    public void Dispose() {
        this._readSqPackHook.Dispose();
    }

    private byte ReadSqPackDetour(void* resourceManager, SeFileDescriptor* fileDescriptor, int priority, bool isSync) {
        if (!this.Plugin.Config.RemoveGlow) {
            goto Original;
        }

        if (fileDescriptor == null || fileDescriptor->ResourceHandle == null) {
            goto Original;
        }

        var path = fileDescriptor->ResourceHandle->FileName.ToString();
        var index = Array.IndexOf(Messages.VfxPaths, path);
        if (index == -1) {
            goto Original;
        }

        var letter = (char) ('a' + index);
        var newPath = Path.Join(this.Plugin.AvfxFilePath, $"sign_{letter}.avfx");
        return this.DefaultRootedResourceLoad(newPath, resourceManager, fileDescriptor, priority, isSync);

        Original:
        return this._readSqPackHook.Original(resourceManager, fileDescriptor, priority, isSync);
    }

    // Load the resource from a path on the users hard drives.
    private byte DefaultRootedResourceLoad(string gamePath, void* resourceManager, SeFileDescriptor* fileDescriptor, int priority, bool isSync) {
        // Specify that we are loading unpacked files from the drive.
        // We need to copy the actual file path in UTF16 (Windows-Unicode) on two locations,
        // but since we only allow ASCII in the game paths, this is just a matter of upcasting.
        fileDescriptor->FileMode = SeFileMode.LoadUnpackedResource;

        var fd = stackalloc byte[0x20 + 2 * gamePath.Length + 0x16];
        fileDescriptor->FileDescriptor = fd;
        var fdPtr = (char*) (fd + 0x21);
        for (var i = 0; i < gamePath.Length; ++i) {
            (&fileDescriptor->Utf16FileName)[i] = gamePath[i];
            fdPtr[i] = gamePath[i];
        }

        (&fileDescriptor->Utf16FileName)[gamePath.Length] = '\0';
        fdPtr[gamePath.Length] = '\0';

        // Use the SE ReadFile function.
        var ret = this._readFile(resourceManager, fileDescriptor, priority, isSync);
        return ret;
    }
}