/*
 * Copyright 2016 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#include "GLWindowContext_unix.h"

#include <GL/gl.h>

#include "Window_unix.h"

namespace sk_app {

// platform-dependent create
GLWindowContext* GLWindowContext::Create(void* platformData, const DisplayParams& params) {
    GLWindowContext_unix* ctx = new GLWindowContext_unix(platformData, params);
    if (!ctx->isValid()) {
        delete ctx;
        return nullptr;
    }
    return ctx;
}

GLWindowContext_unix::GLWindowContext_unix(void* platformData, const DisplayParams& params)
    : GLWindowContext(platformData, params)
    , fDisplay(nullptr)
    , fWindow(0)
    , fGLContext(0) {

    // any config code here (particularly for msaa)?

    this->initializeContext(platformData, params);
}

GLWindowContext_unix::~GLWindowContext_unix() {
    this->destroyContext();
}

void GLWindowContext_unix::onInitializeContext(void* platformData, const DisplayParams& params) {
    ContextPlatformData_unix* unixPlatformData =
        reinterpret_cast<ContextPlatformData_unix*>(platformData);

    if (unixPlatformData) {
        fDisplay = unixPlatformData->fDisplay;
        fWindow = unixPlatformData->fWindow;
        fVisualInfo = unixPlatformData->fVisualInfo;
    }
    SkASSERT(fDisplay);

    fGLContext = glXCreateContext(fDisplay, fVisualInfo, nullptr, GL_TRUE);
    if (!fGLContext) {
        return;
    }

    if (glXMakeCurrent(fDisplay, fWindow, fGLContext)) {
        glClearStencil(0);
        glClearColor(0, 0, 0, 0);
        glStencilMask(0xffffffff);
        glClear(GL_STENCIL_BUFFER_BIT | GL_COLOR_BUFFER_BIT);

        int redBits, greenBits, blueBits;
        glXGetConfig(fDisplay, fVisualInfo, GLX_RED_SIZE, &redBits);
        glXGetConfig(fDisplay, fVisualInfo, GLX_GREEN_SIZE, &greenBits);
        glXGetConfig(fDisplay, fVisualInfo, GLX_BLUE_SIZE, &blueBits);
        fColorBits = redBits + greenBits + blueBits;
        glXGetConfig(fDisplay, fVisualInfo, GLX_STENCIL_SIZE, &fStencilBits);
        glXGetConfig(fDisplay, fVisualInfo, GLX_SAMPLES_ARB, &fSampleCount);

        XWindow root;
        int x, y;
        unsigned int border_width, depth;
        XGetGeometry(fDisplay, fWindow, &root, &x, &y,
                     (unsigned int*)&fWidth, (unsigned int*)&fHeight, &border_width, &depth); 
        glViewport(0, 0, fWidth, fHeight);
    }
}

void GLWindowContext_unix::onDestroyContext() {
    if (!fDisplay || !fGLContext) {
        return;
    }
    glXMakeCurrent(fDisplay, None, nullptr);
    glXDestroyContext(fDisplay, fGLContext);
    fGLContext = nullptr;
}


void GLWindowContext_unix::onSwapBuffers() {
    if (fDisplay && fGLContext) {
        glXSwapBuffers(fDisplay, fWindow);
    }
}


}   //namespace sk_app