#include <stdio.h>
#include <wayland-client.h>
#include <wayland-egl.h>
#include <EGL/egl.h>
#include <GL/gl.h>
#include <string.h>
#include <stdlib.h>

struct wl_compositor *compositor = NULL;
struct wl_registry *registry = NULL;
struct wl_shell *shell = NULL;
struct wl_surface *surface = NULL;
struct wl_shm *shm = NULL;
EGLBoolean errcode = 0;

void registry_handle_global(void *data, struct wl_registry *registry,
		uint32_t name, const char *interface, uint32_t version)
{
    printf("Wayland interface: '%s', version: %d, name: %d\n",
               interface, version, name);
    if (!strcmp(interface, wl_compositor_interface.name))
    {
        fprintf(stdout, "Registering compositor...\n");
        compositor = wl_registry_bind(registry, name, &wl_compositor_interface, 1);
    }

    if (!strcmp(interface, wl_shell_interface.name))
    {
        fprintf(stdout, "Getting shell interface...\n");
        shell = wl_registry_bind(registry, name, &wl_shell_interface, 1);
    }
}


void registry_handle_global_remove(void *data, struct wl_registry *registry,
		uint32_t name)
{
	// This space deliberately left blank
}

static const struct wl_registry_listener
registry_listener = {
	.global = registry_handle_global,
	.global_remove = registry_handle_global_remove,
};

int main()
{
    fprintf(stdout, "Starting platform layer...\n");
    struct wl_display *display = wl_display_connect(NULL);
    if (!display)
    {
        fprintf(stdout, "Cannot retrieve wayland display!\n");
    }

    registry = wl_display_get_registry(display);
    if (!registry)
    {
        fprintf(stderr, "Cannot retrieve wayland registry!\n");
    }

    fprintf(stdout, "Linking registry listener...\n");
    wl_registry_add_listener(registry, &registry_listener, NULL);

    wl_display_dispatch(display);
    wl_display_roundtrip(display);

    surface = wl_compositor_create_surface(compositor);
    if (!surface)
    {
        fprintf(stderr, "Can't create surface!\n");
    }

    /* WL EGL initialization */
    struct wl_egl_window *window = wl_egl_window_create(surface, 480, 460);

    EGLDisplay egl_display = eglGetDisplay((EGLNativeDisplayType) display);
    if (egl_display == EGL_NO_DISPLAY)
    {
      fprintf(stderr, "Could not retrieve EGL display from wayland display\n");
    }
    errcode = eglInitialize(egl_display, NULL, NULL);
    switch (errcode)
    {
    case EGL_FALSE:
    case EGL_BAD_DISPLAY:
    case EGL_NOT_INITIALIZED:
      fprintf(stderr, "Could not initialize EGL display\n");
      break;
    case EGL_TRUE:
      ;
      break;
    }

    int config_count;
    errcode = eglGetConfigs(egl_display, NULL, 0, &config_count);
    switch (errcode)
    {
    case EGL_FALSE:
    case EGL_BAD_DISPLAY:
    case EGL_NOT_INITIALIZED:
    case EGL_BAD_PARAMETER:
      fprintf(stderr, "Could not retrieve EGL config number\n");
      break;
    case EGL_TRUE:
      ;
      break;
    }
    
    EGLConfig *configs = calloc(config_count, sizeof(EGLConfig));

    EGLint attr_list[] = {
	EGL_SURFACE_TYPE, EGL_WINDOW_BIT,
	EGL_RED_SIZE, 8,
	EGL_GREEN_SIZE, 8,
	EGL_BLUE_SIZE, 8,
	EGL_RENDERABLE_TYPE, EGL_OPENGL_ES2_BIT,
	EGL_NONE
    };
    int chosen_config_count;
    
    errcode = eglChooseConfig(egl_display, attr_list, configs, config_count * sizeof(EGLConfig), &chosen_config_count);
    switch (errcode)
    {
    case EGL_FALSE:
    case EGL_BAD_DISPLAY:
    case EGL_NOT_INITIALIZED:
    case EGL_BAD_PARAMETER:
      fprintf(stderr, "Could not choose EGL config parameters\n");
      break;
    case EGL_TRUE:
      ;
      break;
    }

    EGLSurface egl_surface = eglCreateWindowSurface(egl_display, configs[0], (EGLNativeWindowType)window, NULL);

    switch ((intptr_t)egl_surface)
    {
    case (intptr_t)EGL_NO_SURFACE:
    case EGL_BAD_DISPLAY:
    case EGL_NOT_INITIALIZED:
    case EGL_BAD_CONFIG:
    case EGL_BAD_NATIVE_WINDOW:
    case EGL_BAD_ATTRIBUTE:
    case EGL_BAD_ALLOC:
    case EGL_BAD_MATCH:
      fprintf(stderr, "Could not choose EGL config parameters\n");
      break;
    case EGL_TRUE:
      ;
      break;
    }

    static const EGLint context_attribs[] = {
      EGL_CONTEXT_MAJOR_VERSION, 3,
      EGL_CONTEXT_MINOR_VERSION, 2,
      EGL_CONTEXT_OPENGL_DEBUG, EGL_TRUE,
      EGL_NONE
    };

    /* Change from OpenGL ES to regular OpenGL */
    errcode = eglBindAPI(EGL_OPENGL_API);
    switch (errcode)
    {
    case EGL_FALSE:
    case EGL_BAD_PARAMETER:
      fprintf(stderr, "Could not bind OpenGL API to EGL\n");
      break;
    }

    EGLContext egl_context = eglCreateContext(egl_display, configs[0], EGL_NO_CONTEXT, context_attribs);

    errcode = eglMakeCurrent(egl_display, egl_surface, egl_surface, egl_context);
    switch (errcode)
    {
    case EGL_BAD_CONTEXT:
    case EGL_BAD_SURFACE:
    case EGL_BAD_MATCH:
    case EGL_BAD_NATIVE_WINDOW:
    case EGL_BAD_CURRENT_SURFACE:
    case EGL_BAD_ALLOC:
    case EGL_CONTEXT_LOST:
    case EGL_NOT_INITIALIZED:
    case EGL_BAD_DISPLAY:
      fprintf(stderr, "Could not make EGL context current\n");
      break;
    }
    
    struct wl_region *region = wl_compositor_create_region(compositor);
    wl_region_add(region, 0, 0, 480, 360);
    wl_surface_set_opaque_region(surface, region);

    // Main event loop
    while (1)
    {
        //wl_display_dispatch_pending(display);
        fprintf(stdout, "Dispatching event...\n");
        glClearColor(0.5, 0.3, 0.0, 1.0);
        glClear(GL_COLOR_BUFFER_BIT);
        glFlush();
        eglSwapBuffers(egl_display, egl_surface);
    }

    wl_display_disconnect(display);
    return 0;
}