/**************************************************************************
 *
 * Copyright 2011 Jose Fonseca
 * 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.
 *
 **************************************************************************/


/*
 * WGL bindings.
 */


#include <iostream>

#include "glproc.hpp"
#include "glws.hpp"
#include "ws_win32.hpp"

#include <GL/wglext.h>

namespace glws {


/*
 * Several WGL functions come in two flavors:
 * - GDI (ChoosePixelFormat, SetPixelFormat, SwapBuffers, etc)
 * - WGL (wglChoosePixelFormat, wglSetPixelFormat, wglSwapBuffers, etc)
 *
 * The GDI entrypoints will inevitably dispatch to the first module named
 * "OPENGL32", loading "C:\Windows\System32\opengl32.dll" if none was loaded so
 * far.
 *
 * In order to use a implementation other than the one installed in the system
 * (when specified via the TRACE_LIBGL environment variable), we need to use
 * WGL entrypoints.
 *
 * See also:
 * - http://www.opengl.org/archives/resources/faq/technical/mswindows.htm
 */
static PFN_WGLCHOOSEPIXELFORMAT pfnChoosePixelFormat = &ChoosePixelFormat;
static PFN_WGLDESCRIBEPIXELFORMAT pfnDescribePixelFormat = &DescribePixelFormat;
static PFN_WGLSETPIXELFORMAT pfnSetPixelFormat = &SetPixelFormat;
static PFN_WGLSWAPBUFFERS pfnSwapBuffers = &SwapBuffers;


#define WGL_PROC(type, func, name) \
    func = (type) wglGetProcAddress(name); \
    if (!func) { \
        std::cerr << "error: failed to get pointer to " << name << "\n"; \
        exit(1); \
    }


static bool has_WGL_ARB_pbuffer = false;
static PFNWGLGETEXTENSIONSSTRINGARBPROC pfnWglGetExtensionsStringARB;
static PFNWGLCREATEPBUFFERARBPROC pfnWglCreatePbufferARB;
static PFNWGLGETPBUFFERDCARBPROC pfnWglGetPbufferDCARB;
static PFNWGLCHOOSEPIXELFORMATARBPROC pfnWglChoosePixelFormatARB;
static PFNWGLDESTROYPBUFFERARBPROC pfnWglDestroyPbufferARB;
static PFNWGLRELEASEPBUFFERDCARBPROC pfnWglReleasePbufferDCARB;

static bool has_WGL_ARB_render_texture = false;
static PFNWGLBINDTEXIMAGEARBPROC pfnWglBindTexImageARB;
static PFNWGLRELEASETEXIMAGEARBPROC pfnWglReleaseTexImageARB;
static PFNWGLSETPBUFFERATTRIBARBPROC pfnWglSetPbufferAttribARB;

static bool has_WGL_ARB_make_current_read = false;
static PFNWGLMAKECONTEXTCURRENTARBPROC pfnWglMakeContextCurrentARB;
static PFNWGLGETCURRENTREADDCARBPROC pfnWglGetCurrentReadDCARB;


class WglDrawable : public Drawable
{
public:
    // Only one of hWnd and pbBuffer will be non-zero
    HWND hWnd;
    HPBUFFERARB hPBuffer;
    HDC hDC;

    WglDrawable(const Visual *vis, int width, int height,
                const glws::pbuffer_info *pbInfo) :
        Drawable(vis, width, height, pbInfo ? true : false)
    {

        if (pbInfo) {
            createPbuffer(vis, pbInfo, width, height);
            hWnd = 0;
        }
        else {
            hWnd = ws::createWindow("glretrace", width, height);

            hDC = GetDC(hWnd);

            PIXELFORMATDESCRIPTOR pfd;
            ZeroMemory(&pfd, sizeof pfd);
            pfd.nSize = sizeof pfd;
            pfd.nVersion = 1;
            pfd.iPixelType = PFD_TYPE_RGBA;
            pfd.dwFlags = PFD_DRAW_TO_WINDOW | PFD_SUPPORT_OPENGL;
            pfd.cColorBits = 3;
            // XXX: ChoosePixelFormat will return a software pixelformat if we
            // request alpha bits and the hardware driver doesn't advertise any
            // pixel format with alpha bits (e.g. NVIDIA OpenGL driver on 16bpp
            // screens.)
            pfd.cAlphaBits = 1;
            pfd.cDepthBits = 1;
            pfd.cStencilBits = 1;
            pfd.iLayerType = PFD_MAIN_PLANE;

            if (visual->doubleBuffer) {
               pfd.dwFlags |= PFD_DOUBLEBUFFER;
            }

            int iPixelFormat = pfnChoosePixelFormat(hDC, &pfd);
            if (iPixelFormat <= 0) {
                std::cerr << "error: ChoosePixelFormat failed\n";
                exit(1);
            }

            pfnDescribePixelFormat(hDC, iPixelFormat, sizeof pfd, &pfd);
            assert(pfd.dwFlags & PFD_SUPPORT_OPENGL);
            if (pfd.dwFlags & PFD_GENERIC_FORMAT) {
                std::cerr << "warning: ChoosePixelFormat returned a pixel format supported by the GDI software implementation\n";
            }

            BOOL bRet = pfnSetPixelFormat(hDC, iPixelFormat, &pfd);
            if (!bRet) {
                std::cerr << "error: SetPixelFormat failed\n";
                exit(1);
            }

            hPBuffer = 0;
        }
    }

    ~WglDrawable() {
        if (hPBuffer) {
            pfnWglReleasePbufferDCARB(hPBuffer, hDC);
            pfnWglDestroyPbufferARB(hPBuffer);
        }
        else {
            ReleaseDC(hWnd, hDC);
            DestroyWindow(hWnd);
        }
    }
    
    void
    resize(int w, int h) {
        if (w == width && h == height) {
            return;
        }

        Drawable::resize(w, h);

        ws::resizeWindow(hWnd, w, h);
    }

    void show(void) {
        if (visible) {
            return;
        }

        ws::showWindow(hWnd);

        Drawable::show();
    }

    void swapBuffers(void) {
        assert(!pbuffer);
        BOOL bRet;
        bRet = pfnSwapBuffers(hDC);
        if (!bRet) {
            std::cerr << "warning: SwapBuffers failed\n";
        }
    }

private:
    bool createPbuffer(const Visual *vis,
                       const glws::pbuffer_info *pbInfo, int width, int height);
};


class WglContext : public Context
{
public:
    HGLRC hglrc;
    WglContext *shareContext;
    bool debug;

    WglContext(const Visual *vis, WglContext *share, bool _debug) :
        Context(vis),
        hglrc(0),
        shareContext(share),
        debug(_debug)
    {}

    ~WglContext() {
        if (hglrc) {
            wglDeleteContext(hglrc);
        }
    }

    bool
    createARB(HDC hDC) {
        bool required = profile.api != glfeatures::API_GL ||
                        profile.versionGreaterOrEqual(3, 1);

        // We need to create context through WGL_ARB_create_context.  This
        // implies binding a temporary context to get the extensions strings
        // and function pointers.

        // This function is only called inside makeCurrent, so we don't need
        // to save and restore the previous current context/drawable.
        BOOL bRet = wglMakeCurrent(hDC, hglrc);
        if (!bRet) {
            std::cerr << "error: wglMakeCurrent failed\n";
            exit(1);
        }

        pfnWglGetExtensionsStringARB =
            (PFNWGLGETEXTENSIONSSTRINGARBPROC) wglGetProcAddress("wglGetExtensionsStringARB");
        if (!pfnWglGetExtensionsStringARB) {
            if (required) {
                std::cerr << "error: WGL_ARB_extensions_string not supported\n";
                exit(1);
            } else {
                return false;
            }
        }
        const char * extensionsString = pfnWglGetExtensionsStringARB(hDC);
        assert(extensionsString);

        if (checkExtension("WGL_ARB_pbuffer", extensionsString)) {
            has_WGL_ARB_pbuffer = true;
            WGL_PROC(PFNWGLCREATEPBUFFERARBPROC,
                     pfnWglCreatePbufferARB, "wglCreatePbufferARB");
            WGL_PROC(PFNWGLGETPBUFFERDCARBPROC,
                     pfnWglGetPbufferDCARB, "wglGetPbufferDCARB");
            WGL_PROC(PFNWGLCHOOSEPIXELFORMATARBPROC,
                     pfnWglChoosePixelFormatARB, "wglChoosePixelFormatARB");
            WGL_PROC(PFNWGLDESTROYPBUFFERARBPROC,
                     pfnWglDestroyPbufferARB, "wglDestroyPbufferARB");
            WGL_PROC(PFNWGLRELEASEPBUFFERDCARBPROC,
                     pfnWglReleasePbufferDCARB, "wglReleasePbufferDCARB");
        }
        if (checkExtension("WGL_ARB_render_texture", extensionsString)) {
            assert(has_WGL_ARB_pbuffer);
            has_WGL_ARB_render_texture = true;
            WGL_PROC(PFNWGLBINDTEXIMAGEARBPROC,
                     pfnWglBindTexImageARB, "wglBindTexImageARB");
            WGL_PROC(PFNWGLRELEASETEXIMAGEARBPROC,
                     pfnWglReleaseTexImageARB, "wglReleaseTexImageARB");
            WGL_PROC(PFNWGLSETPBUFFERATTRIBARBPROC,
                     pfnWglSetPbufferAttribARB, "wglSetPbufferAttribARB");
        }

        if (checkExtension("WGL_ARB_make_current_read", extensionsString)) {
            has_WGL_ARB_make_current_read = true;
            WGL_PROC(PFNWGLMAKECONTEXTCURRENTARBPROC,
                     pfnWglMakeContextCurrentARB, "wglMakeContextCurrentARB");
            WGL_PROC(PFNWGLGETCURRENTREADDCARBPROC,
                     pfnWglGetCurrentReadDCARB, "wglGetCurrentReadDCARB");
        }

        if (!checkExtension("WGL_ARB_create_context", extensionsString)) {
            if (required) {
                std::cerr << "error: WGL_ARB_create_context not supported\n";
                exit(1);
            } else {
                return false;
            }
        }

        PFNWGLCREATECONTEXTATTRIBSARBPROC pfnWglCreateContextAttribsARB =
            (PFNWGLCREATECONTEXTATTRIBSARBPROC) wglGetProcAddress("wglCreateContextAttribsARB");
        if (!pfnWglCreateContextAttribsARB) {
            if (required) {
                std::cerr << "error: failed to get pointer to wglCreateContextAttribsARB\n";
                exit(1);
            } else {
                return false;
            }
        }

        wglMakeCurrent(hDC, NULL);

        Attributes<int> attribs;
        int contextFlags = 0;
        if (profile.api == glfeatures::API_GL) {
            attribs.add(WGL_CONTEXT_MAJOR_VERSION_ARB, profile.major);
            attribs.add(WGL_CONTEXT_MINOR_VERSION_ARB, profile.minor);
            if (profile.versionGreaterOrEqual(3, 2)) {
                if (!checkExtension("WGL_ARB_create_context_profile", extensionsString)) {
                    assert(required);
                    std::cerr << "error: WGL_ARB_create_context_profile not supported\n";
                    exit(1);
                }
                int profileMask = profile.core ? WGL_CONTEXT_CORE_PROFILE_BIT_ARB : WGL_CONTEXT_COMPATIBILITY_PROFILE_BIT_ARB;
                attribs.add(WGL_CONTEXT_PROFILE_MASK_ARB, profileMask);
                if (profile.forwardCompatible) {
                    contextFlags |= WGL_CONTEXT_FORWARD_COMPATIBLE_BIT_ARB;
                }
            }
        } else if (profile.api == glfeatures::API_GLES) {
            if (checkExtension("WGL_EXT_create_context_es_profile", extensionsString)) {
                attribs.add(WGL_CONTEXT_PROFILE_MASK_ARB, WGL_CONTEXT_ES_PROFILE_BIT_EXT);
                attribs.add(WGL_CONTEXT_MAJOR_VERSION_ARB, profile.major);
                attribs.add(WGL_CONTEXT_MINOR_VERSION_ARB, profile.minor);
            } else if (profile.major != 2) {
                std::cerr << "warning: OpenGL ES " << profile.major << " requested but WGL_EXT_create_context_es_profile not supported\n";
            } else if (checkExtension("WGL_EXT_create_context_es2_profile", extensionsString)) {
                assert(profile.major == 2);
                attribs.add(WGL_CONTEXT_PROFILE_MASK_ARB, WGL_CONTEXT_ES2_PROFILE_BIT_EXT);
                attribs.add(WGL_CONTEXT_MAJOR_VERSION_ARB, profile.major);
                attribs.add(WGL_CONTEXT_MINOR_VERSION_ARB, profile.minor);
            } else {
                std::cerr << "warning: OpenGL ES " << profile.major << " requested but WGL_EXT_create_context_es_profile or WGL_EXT_create_context_es2_profile not supported\n";
            }
        } else {
            assert(0);
        }
        if (debug) {
            contextFlags |= WGL_CONTEXT_DEBUG_BIT_ARB;
        }
        if (contextFlags) {
            attribs.add(WGL_CONTEXT_FLAGS_ARB, contextFlags);
        }
        attribs.end();


        HGLRC new_hglrc;
        new_hglrc = pfnWglCreateContextAttribsARB(hDC,
                                                  shareContext ? shareContext->hglrc : 0,
                                                  attribs);
        if (!new_hglrc) {
            if (required) {
                std::cerr << "error: wglCreateContextAttribsARB failed\n";
                exit(1);
            } else {
                return false;
            }
        }

        wglDeleteContext(hglrc);
        hglrc = new_hglrc;

        return true;
    }

    bool
    create(WglDrawable *wglDrawable) {
        if (!hglrc) {
            HDC hDC = wglDrawable->hDC;

            hglrc = wglCreateContext(hDC);
            if (!hglrc) {
                std::cerr << "error: wglCreateContext failed\n";
                exit(1);
            }

            if (shareContext) {
                shareContext->create(wglDrawable);
            }

            if (!createARB(hDC)) {
                if (shareContext) {
                    BOOL bRet;
                    bRet = wglShareLists(shareContext->hglrc,
                                         hglrc);
                    if (!bRet) {
                        std::cerr
                            << "warning: wglShareLists failed: "
                            << std::hex << GetLastError() << std::dec
                            << "\n";
                    }
                }
            }
        }

        return true;
    }

};


void
init(void) {
    /*
     * OpenGL library must be loaded by the time we call GDI.
     */

    const char * libgl_filename = getenv("TRACE_LIBGL");

    if (libgl_filename) {
        _libGlHandle = LoadLibraryA(libgl_filename);
        if (_libGlHandle) {
            pfnChoosePixelFormat = (PFN_WGLCHOOSEPIXELFORMAT)GetProcAddress(_libGlHandle, "wglChoosePixelFormat");
            assert(pfnChoosePixelFormat);
            pfnDescribePixelFormat = (PFN_WGLDESCRIBEPIXELFORMAT)GetProcAddress(_libGlHandle, "wglDescribePixelFormat");
            assert(pfnDescribePixelFormat);
            pfnSetPixelFormat = (PFN_WGLSETPIXELFORMAT)GetProcAddress(_libGlHandle, "wglSetPixelFormat");
            assert(pfnSetPixelFormat);
            pfnSwapBuffers = (PFN_WGLSWAPBUFFERS)GetProcAddress(_libGlHandle, "wglSwapBuffers");
            assert(pfnSwapBuffers);
        }
    } else {
        libgl_filename = "OPENGL32";
        _libGlHandle = LoadLibraryA(libgl_filename);
    }

    if (!_libGlHandle) {
        std::cerr << "error: unable to open " << libgl_filename << "\n";
        exit(1);
    }
}

void
cleanup(void) {
}

Visual *
createVisual(bool doubleBuffer, unsigned samples, Profile profile) {
    Visual *visual = new Visual(profile);

    visual->doubleBuffer = doubleBuffer;

    return visual;
}

Drawable *
createDrawable(const Visual *visual, int width, int height,
               const glws::pbuffer_info *pbInfo)
{
    return new WglDrawable(visual, width, height, pbInfo);
}

Context *
createContext(const Visual *visual, Context *shareContext, bool debug)
{
    return new WglContext(visual, static_cast<WglContext *>(shareContext), debug);
}

bool
makeCurrentInternal(Drawable *drawable, Drawable *readable, Context *context)
{
    if (!drawable || !context) {
        return wglMakeCurrent(NULL, NULL);
    } else {
        WglDrawable *wglDrawable = static_cast<WglDrawable *>(drawable);
        WglDrawable *wglReadable = static_cast<WglDrawable *>(readable);
        WglContext *wglContext = static_cast<WglContext *>(context);

        wglContext->create(wglDrawable);
        wglContext->create(wglReadable);

        if (has_WGL_ARB_make_current_read &&
            wglDrawable->hDC != wglReadable->hDC) {
            return pfnWglMakeContextCurrentARB(wglDrawable->hDC,
                                               wglReadable->hDC,
                                               wglContext->hglrc);
        }
        else {
            return wglMakeCurrent(wglDrawable->hDC, wglContext->hglrc);
        }
    }
}

bool
processEvents(void)
{
    return ws::processEvents();
}


bool
glws::WglDrawable::createPbuffer(const Visual *vis,
                                 const glws::pbuffer_info *pbInfo,
                                 int width, int height)
{
    if (!has_WGL_ARB_pbuffer) {
        std::cerr << "error: WGL_ARB_pbuffer extension is unsupported\n";
        exit(1);
        return false;
    }

    // choose pixel format
    Attributes<int> attribs;
    attribs.add(WGL_DRAW_TO_PBUFFER_ARB, true);
    attribs.add(WGL_DEPTH_BITS_ARB, 24);
    attribs.add(WGL_STENCIL_BITS_ARB, 8);
    attribs.add(WGL_RED_BITS_ARB, 8);
    attribs.add(WGL_GREEN_BITS_ARB, 8);
    attribs.add(WGL_BLUE_BITS_ARB, 8);
    attribs.add(WGL_ALPHA_BITS_ARB, 8);
    attribs.add(WGL_COLOR_BITS_ARB, 32);
    if (pbInfo->texFormat) {
        if (pbInfo->texFormat == GL_RGBA)
            attribs.add(WGL_BIND_TO_TEXTURE_RGBA_ARB, true);
        else if (pbInfo->texFormat == GL_RGB)
            attribs.add(WGL_BIND_TO_TEXTURE_RGB_ARB, true);
        else {
            std::cerr << "error: unexpected texture format.\n";
            exit(1);
        }
    }
    attribs.end();

    int pixelFormats[20];
    UINT numPixelFormats;
    WglDrawable *wgl_draw = static_cast<WglDrawable *>(pbInfo->hdc_drawable);
    HDC hdc = wgl_draw->hDC;
    assert(hdc);

    if (!pfnWglChoosePixelFormatARB(hdc, attribs, NULL,
                                    20, pixelFormats,
                                    &numPixelFormats)) {
        std::cerr << "error: wglChoosePixelFormatARB failed.\n";
        exit(1);
    }

    // create pbuffer
    Attributes<int> pbAttribs;
    if (pbInfo->texFormat) {
        if (pbInfo->texFormat == GL_RGBA) {
            pbAttribs.add(WGL_TEXTURE_FORMAT_ARB, WGL_TEXTURE_RGBA_ARB);
        } else if (pbInfo->texFormat == GL_RGB) {
            pbAttribs.add(WGL_TEXTURE_FORMAT_ARB, WGL_TEXTURE_RGB_ARB);
        } else {
            std::cerr << "error: unexpected texture format.\n";
            exit(1);
        }
    }
    if (pbInfo->texTarget) {
        if (pbInfo->texTarget == GL_TEXTURE_1D) {
            pbAttribs.add(WGL_TEXTURE_TARGET_ARB, WGL_TEXTURE_1D_ARB);
        } else if (pbInfo->texTarget == GL_TEXTURE_2D) {
            pbAttribs.add(WGL_TEXTURE_TARGET_ARB, WGL_TEXTURE_2D_ARB);
        } else if (pbInfo->texTarget == GL_TEXTURE_CUBE_MAP) {
            pbAttribs.add(WGL_TEXTURE_TARGET_ARB, WGL_TEXTURE_CUBE_MAP_ARB);
        } else {
            std::cerr << "error: unexpected texture targett.\n";
            exit(1);
        }
    }
    if (pbInfo->texMipmap) {
        pbAttribs.add(WGL_MIPMAP_TEXTURE_ARB, pbInfo->texMipmap);
    }
    pbAttribs.end();

    hPBuffer = pfnWglCreatePbufferARB(hdc, pixelFormats[0],
                                      width, height, pbAttribs);
    if (!hPBuffer) {
        std::cerr << "error: wglCreatePbufferARB failed (format "
                  << pixelFormats[0] << ")\n";
        DWORD er = GetLastError();
        std::cerr << "error code " << er << "\n";
        exit(1);
    }
    hDC = pfnWglGetPbufferDCARB(hPBuffer);
    if (!hDC) {
        std::cerr << "error: wglGetPbufferDCARB failed\n";
        exit(1);
    }

    return true;
}


static int
enum_buffer_to_wgl_buffer(GLenum buffer)
{
    switch (buffer) {
    case GL_FRONT_LEFT:
        return WGL_FRONT_LEFT_ARB;
    case GL_BACK_LEFT:
        return WGL_BACK_LEFT_ARB;
    case GL_FRONT_RIGHT:
        return WGL_FRONT_RIGHT_ARB;
    case GL_BACK_RIGHT:
        return WGL_BACK_RIGHT_ARB;
    case GL_AUX0:
        return WGL_AUX0_ARB;
    default:
        std::cerr << "error: invalid buffer in enum_buffer_to_wgl_buffer()\n";
        return WGL_FRONT_LEFT_ARB;
    }
}

bool
bindTexImage(Drawable *pBuffer, int buf) {
    if (!has_WGL_ARB_render_texture) {
        return false;
    }
    WglDrawable *wglDrawable = static_cast<WglDrawable *>(pBuffer);
    return pfnWglBindTexImageARB(wglDrawable->hPBuffer,
                                 enum_buffer_to_wgl_buffer(buf));
}

bool
releaseTexImage(Drawable *pBuffer, int buf) {
    if (!has_WGL_ARB_render_texture) {
        return false;
    }
    WglDrawable *wglDrawable = static_cast<WglDrawable *>(pBuffer);
    return pfnWglReleaseTexImageARB(wglDrawable->hPBuffer,
                                    enum_buffer_to_wgl_buffer(buf));
}

bool
setPbufferAttrib(Drawable *pBuffer, const int *attribList) {
    if (!has_WGL_ARB_render_texture) {
        return false;
    }
    WglDrawable *wglDrawable = static_cast<WglDrawable *>(pBuffer);
    return pfnWglSetPbufferAttribARB(wglDrawable->hPBuffer, attribList);
}


} /* namespace glws */