#include "Texture.h"
#include <png.h>
#include "utils.h"
#include "Global.h"

Texture::Texture()
{

}


Texture::~Texture()
{
}

bool Texture::load(char * filePath)
{

	FILE *f;
	int is_png, bit_depth, color_type, row_bytes, i;

	png_infop info_ptr;
	png_uint_32 t_width, t_height;
	png_byte header[8], *image_data;

	png_bytepp row_pointers;
	png_structp png_ptr;
	int alpha;


	if (!(f = fopen(filePath, "rb")))
		return false;

	fread(header, 1, 8, f);
	is_png = !png_sig_cmp((png_const_bytep)header, 0, 8);
	if (!is_png) {
		printf("%s is not a png!\n", filePath);
		fclose(f);
		return false;
	}

	png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);

	if (!png_ptr) {
		fclose(f);
		return false;
	}

	info_ptr = png_create_info_struct(png_ptr);

	if (!info_ptr) {
		png_destroy_read_struct(&png_ptr, (png_infopp)NULL, (png_infopp)NULL);
		fclose(f);
		return false;
	}


	if (setjmp(png_jmpbuf(png_ptr))) {
		png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
		fclose(f);
		return false;
	}

	png_init_io(png_ptr, f);
	png_set_sig_bytes(png_ptr, 8);
	png_read_info(png_ptr, info_ptr);
	png_get_IHDR(png_ptr, info_ptr, &t_width, &t_height, &bit_depth, &color_type, NULL, NULL, NULL);

	this->width = t_width;
	this->height = t_height;

	png_read_update_info(png_ptr, info_ptr);

	row_bytes = png_get_rowbytes(png_ptr, info_ptr);
	image_data = (png_bytep)malloc(row_bytes * t_height * sizeof(png_byte));

	if (!image_data) {
		png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
		fclose(f);
		return false;
	}

	row_pointers = (png_bytepp)malloc(t_height * sizeof(png_bytep));

	if (!row_pointers) {
		png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
		free(image_data);
		fclose(f);
		return false;
	}

	for (i = 0; i < t_height; i++) {
		row_pointers[t_height - 1 - i] = image_data + i * row_bytes;
	}
	png_read_image(png_ptr, row_pointers);
	png_read_end(png_ptr, info_ptr);

	switch (png_get_color_type(png_ptr, info_ptr)) {
	case PNG_COLOR_TYPE_RGBA:
		alpha = GL_RGBA;
		break;
	case PNG_COLOR_TYPE_RGB:
		alpha = GL_RGB;
		break;
	default:
		printf("Color type %d not supported!\n", png_get_color_type(png_ptr, info_ptr));
		png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
		return false;
	}
	glEnable(GL_TEXTURE_2D);
	glGenTextures(1, &this->texID);
	glBindTexture(GL_TEXTURE_2D, this->texID);
	glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, this->width, this->height, 0, alpha, GL_UNSIGNED_BYTE, image_data);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);

	png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
	free(image_data);
	free(row_pointers);
	fclose(f);
	return true;
}

unsigned int Texture::getID() {
	return this->texID;
}

int Texture::getWidth() {
	return this->width;
}

int Texture::getHeight() {
	return this->height;
}