//usr/bin/g++ $0 -lEGL -lGL `pkg-config --cflags gstreamer-1.0` `pkg-config --libs gstreamer-1.0` && ./a.out; exit
// This is a self-running .cpp file.  chmod +x this file.  Then you can run it like a shell script.
// Based on https://github.com/DaneLLL/gstreamer_eglstreamsrc and https://github.com/DaneLLL/simpleEGLStreams_producer

#include <cstdlib>
#include <gst/gst.h>
#include <gst/gstinfo.h>
#include <EGL/egl.h>
#include <EGL/eglext.h>
#include <GLES3/gl32.h>
#include <GLES2/gl2ext.h>
#include <iostream>
#include <sstream>
#include <unistd.h>

using namespace std;

int main(int argc, char** argv) {
    gst_init (&argc, &argv);
    GMainLoop *main_loop = g_main_loop_new(NULL, FALSE);

    int width = 960, height = 540;
    ostringstream launch_stream;
    launch_stream << "nveglstreamsrc name=egl_src ! ";
    launch_stream << "video/x-raw(memory:NVMM), format=RGBA, width="<< width <<", height="<< height <<", framerate=15/1 ! ";
    launch_stream << "nvvidconv ! video/x-raw(memory:NVMM),format=NV12 ! ";
    launch_stream << "fakesink ";

    string launch_string = launch_stream.str();
    g_print("Using launch string: %s\n", launch_string.c_str());

    // eglSetupExtensions() See bug 200161837 on EGL pointer functions should renamed. Not renaming egl pointer function causes 64 bit app to crash.
    PFNEGLCREATESTREAMKHRPROC EglCreateStreamKHR = (PFNEGLCREATESTREAMKHRPROC)eglGetProcAddress("eglCreateStreamKHR");
    PFNEGLDESTROYSTREAMKHRPROC EglDestroyStreamKHR = (PFNEGLDESTROYSTREAMKHRPROC)eglGetProcAddress("eglDestroyStreamKHR");
    PFNEGLQUERYSTREAMKHRPROC EglQueryStreamKHR = (PFNEGLQUERYSTREAMKHRPROC)eglGetProcAddress("eglQueryStreamKHR");
    PFNEGLQUERYSTREAMU64KHRPROC EglQueryStreamu64KHR = (PFNEGLQUERYSTREAMU64KHRPROC)eglGetProcAddress("eglQueryStreamu64KHR");
    PFNEGLQUERYSTREAMTIMEKHRPROC EglQueryStreamTimeKHR = (PFNEGLQUERYSTREAMTIMEKHRPROC)eglGetProcAddress("eglQueryStreamTimeKHR");
    PFNEGLSTREAMATTRIBKHRPROC EglStreamAttribKHR = (PFNEGLSTREAMATTRIBKHRPROC)eglGetProcAddress("eglStreamAttribKHR");
    PFNEGLSTREAMCONSUMERACQUIREKHRPROC EglStreamConsumerAcquireKHR = (PFNEGLSTREAMCONSUMERACQUIREKHRPROC)eglGetProcAddress("eglStreamConsumerAcquireKHR");
    PFNEGLSTREAMCONSUMERRELEASEKHRPROC EglStreamConsumerReleaseKHR = (PFNEGLSTREAMCONSUMERRELEASEKHRPROC)eglGetProcAddress("eglStreamConsumerReleaseKHR");
    PFNEGLSTREAMCONSUMERGLTEXTUREEXTERNALKHRPROC EglStreamConsumerGLTextureExternalKHR = (PFNEGLSTREAMCONSUMERGLTEXTUREEXTERNALKHRPROC)eglGetProcAddress("eglStreamConsumerGLTextureExternalKHR");
    PFNEGLGETSTREAMFILEDESCRIPTORKHRPROC EglGetStreamFileDescriptorKHR = (PFNEGLGETSTREAMFILEDESCRIPTORKHRPROC)eglGetProcAddress("eglGetStreamFileDescriptorKHR");
    PFNEGLCREATESTREAMFROMFILEDESCRIPTORKHRPROC EglCreateStreamFromFileDescriptorKHR = (PFNEGLCREATESTREAMFROMFILEDESCRIPTORKHRPROC)eglGetProcAddress("eglCreateStreamFromFileDescriptorKHR");
    PFNEGLCREATESTREAMPRODUCERSURFACEKHRPROC EglCreateStreamProducerSurfaceKHR = (PFNEGLCREATESTREAMPRODUCERSURFACEKHRPROC)eglGetProcAddress("eglCreateStreamProducerSurfaceKHR");
    EGLDisplay   eglDisplay;
    EGLSurface   eglSurface;
    EGLConfig    eglConfig;
    EGLContext   eglContext;
    EGLStreamKHR eglStream;

    GError *error;
    GstPipeline *gst_pipeline;

  for (int loopCnt=0; loopCnt < 10; loopCnt++)
  {
    printf("    **************************************\n");
    printf("    **************  LOOP %d  *************\n", loopCnt);
    printf("    **************************************\n");

      error = nullptr;
      gst_pipeline  = (GstPipeline*) gst_parse_launch(launch_string.c_str(), &error);
      if (gst_pipeline == nullptr) {
        g_print( "Failed to parse launch: %s\n", error->message);
        return -1;
      }
      if(error) g_error_free(error);

    {
        printf("EGLStreamInit() begin...\n");
        if ((eglDisplay = eglGetDisplay(EGL_DEFAULT_DISPLAY)) == EGL_NO_DISPLAY) return 1;
        if (!eglInitialize(eglDisplay, 0, 0)) return 1;
        EGLint streamAttrMailboxMode[] = { EGL_NONE };
        if ((eglStream = EglCreateStreamKHR(eglDisplay, streamAttrMailboxMode)) == EGL_NO_STREAM_KHR) return 1;
        if (!EglStreamAttribKHR(eglDisplay, eglStream, EGL_CONSUMER_LATENCY_USEC_KHR, 16000)) return 1;
        if (!EglStreamAttribKHR(eglDisplay, eglStream, EGL_CONSUMER_ACQUIRE_TIMEOUT_USEC_KHR, 16000)) return 1;
        printf("EGLStreamInit() success!\n");
    }
    {
        printf("GST_STATE_PLAYING begin\n");
        GstElement *videoSource = gst_bin_get_by_name(GST_BIN(gst_pipeline), "egl_src");
        if(!GST_IS_ELEMENT(videoSource)) return 1;
        g_object_set(G_OBJECT(videoSource), "display", eglDisplay, NULL);
        g_object_set(G_OBJECT(videoSource), "eglstream", eglStream, NULL);
        gst_element_set_state((GstElement*)gst_pipeline, GST_STATE_PLAYING);
        printf(" GST_STATE_PLAYING success!\n");
    }
    {
        printf("EGLStreamCreateProducer() begin...\n");
        EGLint cfg_attr[] = {
            EGL_SURFACE_TYPE, EGL_STREAM_BIT_KHR,
            EGL_RENDERABLE_TYPE, EGL_OPENGL_ES2_BIT,
            EGL_ALPHA_SIZE, 1,
            EGL_NONE
        };
        EGLint n = 0;
        if (!eglChooseConfig(eglDisplay, cfg_attr, &eglConfig, 1, &n) || !n) return 1;
        EGLint ctx_attr[] = { EGL_CONTEXT_CLIENT_VERSION, 2, EGL_NONE };
        eglBindAPI(EGL_OPENGL_ES_API);
        if ((eglContext = eglCreateContext(eglDisplay, eglConfig, EGL_NO_CONTEXT, ctx_attr)) == EGL_NO_CONTEXT) return 1;
        EGLint srf_attr[] = { EGL_WIDTH, width, EGL_HEIGHT, height, EGL_NONE };
        if ((eglSurface = EglCreateStreamProducerSurfaceKHR(eglDisplay, eglConfig, eglStream, srf_attr)) == EGL_NO_SURFACE) return 1;
        if (!eglMakeCurrent(eglDisplay, eglSurface, eglSurface, eglContext)) return 1;
        printf("EGLStreamCreateProducer() success!\n");
    }
    {
        printf("Render loop begin\n");
        float r = 0, g = 0.5, b = 1;
        glClearColor(r, g, b, 1); // blue-ish background
        glClear(GL_COLOR_BUFFER_BIT);
        eglSwapBuffers(eglDisplay, eglSurface);
        for (int frame = 0; frame < 20; frame++) {
            if (frame % 15 == 0) {
                r = (r > 0)?0:0.5;
                g = (g > 0)?0:0.5;
                b = (b > 0.5)?0.5:1;
            }
            glClearColor(r, g, b, 1); // blue-ish background
            glClear(GL_COLOR_BUFFER_BIT);
            eglSwapBuffers(eglDisplay, eglSurface);
            usleep(32000);
        }
        printf("Render loop success!\n");
    }
    {
        printf("GST_STATE_NULL begin\n");
        gst_element_set_state((GstElement*)gst_pipeline, GST_STATE_NULL);
        gst_object_unref(GST_OBJECT(gst_pipeline));
//        g_main_loop_unref(main_loop);
        printf("GST_STATE_NULL success!\n");
    }
    {
        printf("EGLStreamFini begin\n");
        EGLint streamState = 0;
        if(!EglQueryStreamKHR(eglDisplay, eglStream, EGL_STREAM_STATE_KHR, &streamState)) return 1;
        eglMakeCurrent(eglDisplay, EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT);
        eglDestroyContext(eglDisplay, eglContext);
        eglDestroySurface(eglDisplay, eglSurface);
        EglDestroyStreamKHR(eglDisplay, eglStream);
        printf("EGLStreamFini success!\n");
    }
    printf("    **************  LOOP %d DONE  *************\n", loopCnt);
  }
    g_main_loop_unref(main_loop);
    return 0;
}