/************************************************************//**
*
*	@file: egl_surface.cpp
*	@author: Martin Fouilleul
*	@date: 17/02/2023
*	@revision:
*
*****************************************************************/

#define EGL_EGLEXT_PROTOTYPES
#include<EGL/egl.h>
#include<EGL/eglext.h>
#include"mp_app_internal.h"
#include"graphics_internal.h"
#include"gl_loader.h"

#if PLATFORM_MACOS
	//NOTE: EGL_PLATFORM_ANGLE_TYPE_DEFAULT_ANGLE on osx defaults to CGL backend, which doesn't handle SwapInterval correctly
	#define MG_EGL_PLATFORM_ANGLE_TYPE EGL_PLATFORM_ANGLE_TYPE_METAL_ANGLE

	//NOTE: hardcode GLES versions for now
	//TODO: use version hints, once we have all api versions correctly categorized by glapi.py
	#define MG_GLES_VERSION_MAJOR 3
	#define MG_GLES_VERSION_MINOR 0
	#define mg_gl_load_gles mg_gl_load_gles30
#else
	#define MG_EGL_PLATFORM_ANGLE_TYPE EGL_PLATFORM_ANGLE_TYPE_DEFAULT_ANGLE
	#define MG_GLES_VERSION_MAJOR 3
	#define MG_GLES_VERSION_MINOR 1
	#define mg_gl_load_gles mg_gl_load_gles31
#endif


typedef struct mg_egl_surface
{
	mg_surface_data interface;

	EGLDisplay eglDisplay;
	EGLConfig eglConfig;
	EGLContext eglContext;
	EGLSurface eglSurface;

	mg_gl_api api;

} mg_egl_surface;

void mg_egl_surface_destroy(mg_surface_data* interface)
{
	mg_egl_surface* surface = (mg_egl_surface*)interface;

	if(&surface->api == mg_gl_get_api())
	{
		mg_gl_select_api(0);
	}
	if(eglGetCurrentContext() == surface->eglContext)
	{
		eglMakeCurrent(surface->eglDisplay, EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT);
	}
	eglDestroyContext(surface->eglDisplay, surface->eglContext);
	eglDestroySurface(surface->eglDisplay, surface->eglSurface);

	mg_surface_cleanup((mg_surface_data*)surface);
	free(surface);
}

void mg_egl_surface_prepare(mg_surface_data* interface)
{
	mg_egl_surface* surface = (mg_egl_surface*)interface;
	eglMakeCurrent(surface->eglDisplay, surface->eglSurface, surface->eglSurface, surface->eglContext);
	mg_gl_select_api(&surface->api);
}

void mg_egl_surface_present(mg_surface_data* interface)
{
	mg_egl_surface* surface = (mg_egl_surface*)interface;
	eglSwapBuffers(surface->eglDisplay, surface->eglSurface);
}

void mg_egl_surface_swap_interval(mg_surface_data* interface, int swap)
{
	mg_egl_surface* surface = (mg_egl_surface*)interface;
	eglSwapInterval(surface->eglDisplay, swap);
}

void mg_egl_surface_init(mg_egl_surface* surface)
{
	void* nativeLayer = surface->interface.nativeLayer((mg_surface_data*)surface);

	surface->interface.backend = MG_BACKEND_GLES;

	surface->interface.destroy = mg_egl_surface_destroy;
	surface->interface.prepare = mg_egl_surface_prepare;
	surface->interface.present = mg_egl_surface_present;
	surface->interface.swapInterval = mg_egl_surface_swap_interval;

	EGLAttrib displayAttribs[] = {
		EGL_PLATFORM_ANGLE_TYPE_ANGLE, MG_EGL_PLATFORM_ANGLE_TYPE,
	    EGL_PLATFORM_ANGLE_DEVICE_TYPE_ANGLE, EGL_PLATFORM_ANGLE_DEVICE_TYPE_HARDWARE_ANGLE,
	    EGL_NONE};

	surface->eglDisplay = eglGetPlatformDisplay(EGL_PLATFORM_ANGLE_ANGLE, (void*)EGL_DEFAULT_DISPLAY, displayAttribs);
	eglInitialize(surface->eglDisplay, NULL, NULL);

	EGLint const configAttributes[] = {
		EGL_SURFACE_TYPE, EGL_WINDOW_BIT,
		EGL_RED_SIZE, 8,
		EGL_GREEN_SIZE, 8,
		EGL_BLUE_SIZE, 8,
		EGL_ALPHA_SIZE, 8,
		EGL_DEPTH_SIZE, 24,
		EGL_STENCIL_SIZE, 8,
		EGL_SAMPLE_BUFFERS, 0,
		EGL_SAMPLES, EGL_DONT_CARE,
		EGL_COLOR_COMPONENT_TYPE_EXT, EGL_COLOR_COMPONENT_TYPE_FIXED_EXT,
		EGL_NONE };

	int numConfigs = 0;
	eglChooseConfig(surface->eglDisplay, configAttributes, &surface->eglConfig, 1, &numConfigs);

	EGLint const surfaceAttributes[] = {EGL_NONE};
	surface->eglSurface = eglCreateWindowSurface(surface->eglDisplay,
		                                            surface->eglConfig,
		                                            nativeLayer,
		                                            surfaceAttributes);

	eglBindAPI(EGL_OPENGL_ES_API);
	EGLint contextAttributes[] = {
		EGL_CONTEXT_MAJOR_VERSION_KHR, MG_GLES_VERSION_MAJOR,
		EGL_CONTEXT_MINOR_VERSION_KHR, MG_GLES_VERSION_MINOR,
		EGL_CONTEXT_BIND_GENERATES_RESOURCE_CHROMIUM, EGL_TRUE,
		EGL_CONTEXT_CLIENT_ARRAYS_ENABLED_ANGLE, EGL_TRUE,
		EGL_CONTEXT_OPENGL_BACKWARDS_COMPATIBLE_ANGLE, EGL_FALSE,
		EGL_NONE};

	surface->eglContext = eglCreateContext(surface->eglDisplay, surface->eglConfig, EGL_NO_CONTEXT, contextAttributes);
	eglMakeCurrent(surface->eglDisplay, surface->eglSurface, surface->eglSurface, surface->eglContext);

	mg_gl_load_gles(&surface->api, (mg_gl_load_proc)eglGetProcAddress);

	eglSwapInterval(surface->eglDisplay, 1);
}

mg_surface_data* mg_egl_surface_create_remote(u32 width, u32 height)
{
	mg_egl_surface* surface = 0;

	surface = malloc_type(mg_egl_surface);
	if(surface)
	{
		memset(surface, 0, sizeof(mg_egl_surface));

		mg_surface_init_remote((mg_surface_data*)surface, width, height);
		mg_egl_surface_init(surface);
	}

	return((mg_surface_data*)surface);
}

mg_surface_data* mg_egl_surface_create_for_window(mp_window window)
{
	mg_egl_surface* surface = 0;
	mp_window_data* windowData = mp_window_ptr_from_handle(window);
	if(windowData)
	{
		surface = malloc_type(mg_egl_surface);
		if(surface)
		{
			memset(surface, 0, sizeof(mg_egl_surface));

			mg_surface_init_for_window((mg_surface_data*)surface, windowData);
			mg_egl_surface_init(surface);
		}
	}
	return((mg_surface_data*)surface);
}