/**************************************************************************
 *
 * Copyright 2011 Jose Fonseca
 * Copyright 2008-2009 VMware, Inc.
 * All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 *
 **************************************************************************/


#include <stdio.h>

#include "d3dshader.hpp"
#include "os.hpp"


struct ID3DXBuffer : public IUnknown {
    virtual LPVOID STDMETHODCALLTYPE GetBufferPointer(void) = 0;
    virtual DWORD  STDMETHODCALLTYPE GetBufferSize(void) = 0;
};

typedef HRESULT
(WINAPI *PD3DXDISASSEMBLESHADER)(
    CONST DWORD *pShader,
    BOOL EnableColorCode,
    LPCSTR pComments,
    ID3DXBuffer **ppDisassembly
);


HRESULT
DisassembleShader(const DWORD *tokens, IDisassemblyBuffer **ppDisassembly)
{
    static BOOL firsttime = TRUE;

    /*
     * TODO: Consider using d3dcompile_xx.dll per
     * http://msdn.microsoft.com/en-us/library/windows/desktop/ee663275.aspx
     */

    static HMODULE hD3DXModule = NULL;
    static PD3DXDISASSEMBLESHADER pfnD3DXDisassembleShader = NULL;

    if (firsttime) {
        if (!hD3DXModule) {
            unsigned release;
            int version;
            for (release = 0; release <= 1; ++release) {
                /* Version 41 corresponds to Mar 2009 version of DirectX Runtime / SDK */
                for (version = 41; version >= 0; --version) {
                    char filename[256];
                    _snprintf(filename, sizeof(filename),
                              "d3dx9%s%s%u.dll", release ? "" : "d", version ? "_" : "", version);
                    hD3DXModule = LoadLibraryA(filename);
                    if (hD3DXModule)
                        goto found;
                }
            }
found:
            ;
        }

        if (hD3DXModule) {
            if (!pfnD3DXDisassembleShader) {
                pfnD3DXDisassembleShader = (PD3DXDISASSEMBLESHADER)GetProcAddress(hD3DXModule, "D3DXDisassembleShader");
            }
        }

        firsttime = FALSE;
    }

    HRESULT hr = E_FAIL;
    if (pfnD3DXDisassembleShader) {
        hr = pfnD3DXDisassembleShader(tokens, FALSE, NULL,
                                      reinterpret_cast<ID3DXBuffer **>(ppDisassembly));
    }
    return hr;
}


struct ID3D10Blob : public IUnknown {
    virtual LPVOID STDMETHODCALLTYPE GetBufferPointer(void) = 0;
    virtual SIZE_T STDMETHODCALLTYPE GetBufferSize(void) = 0;
};

typedef ID3D10Blob ID3DBlob;

#define D3D_DISASM_ENABLE_COLOR_CODE            0x00000001
#define D3D_DISASM_ENABLE_DEFAULT_VALUE_PRINTS  0x00000002
#define D3D_DISASM_ENABLE_INSTRUCTION_NUMBERING 0x00000004
#define D3D_DISASM_ENABLE_INSTRUCTION_CYCLE     0x00000008
#define D3D_DISASM_DISABLE_DEBUG_INFO           0x00000010
#define D3D_DISASM_ENABLE_INSTRUCTION_OFFSET    0x00000020
#define D3D_DISASM_INSTRUCTION_ONLY             0x00000040

typedef HRESULT
(WINAPI *PFND3DDISASSEMBLE)(
    LPCVOID pSrcData,
    SIZE_T SrcDataSize,
    UINT Flags,
    LPCSTR szComments,
    ID3DBlob **ppDisassembly
);

static PFND3DDISASSEMBLE pfnD3DDisassemble = NULL;

typedef HRESULT
(WINAPI *PFND3D10DISASSEMBLESHADER)(
    const void *pShader,
    SIZE_T BytecodeLength,
    BOOL EnableColorCode,
    LPCSTR pComments,
    ID3D10Blob **ppDisassembly
);

static PFND3D10DISASSEMBLESHADER pfnD3D10DisassembleShader = NULL;


HRESULT
DisassembleShader(const void *pShaderBytecode, SIZE_T BytecodeLength, IDisassemblyBuffer **ppDisassembly)
{
    static bool firsttime = true;

    if (firsttime) {
        char szFilename[MAX_PATH];
        HMODULE hModule = NULL;
        int version;
        for (version = 44; version >= 33; --version) {
            _snprintf(szFilename, sizeof(szFilename), "d3dcompiler_%i.dll", version);
            hModule = LoadLibraryA(szFilename);
            if (hModule) {
                pfnD3DDisassemble = (PFND3DDISASSEMBLE)
                    GetProcAddress(hModule, "D3DDisassemble");
                if (pfnD3DDisassemble) {
                    break;
                }
            }
        }
        if (!pfnD3DDisassemble) {
            /*
             * Fallback to D3D10DisassembleShader, which should be always present.
             */
            if (GetSystemDirectoryA(szFilename, MAX_PATH)) {
                strcat(szFilename, "\\d3d10.dll");
                hModule = LoadLibraryA(szFilename);
                if (hModule) {
                    pfnD3D10DisassembleShader = (PFND3D10DISASSEMBLESHADER)
                        GetProcAddress(hModule, "D3D10DisassembleShader");
                }
            }
        }

        firsttime = false;
    }

    HRESULT hr = E_FAIL;

    if (pfnD3DDisassemble) {
        hr = pfnD3DDisassemble(pShaderBytecode, BytecodeLength, 0, NULL,
                               reinterpret_cast<ID3DBlob **>(ppDisassembly));
    } else if (pfnD3D10DisassembleShader) {
        hr = pfnD3D10DisassembleShader(pShaderBytecode, BytecodeLength, 0, NULL,
                                       reinterpret_cast<ID3D10Blob **>(ppDisassembly));
    }

    return hr;
}