#include "unigi.ext/main.h"

void unigi_ext_texture_draw(unigi_ext_type_texture *sprite, unigi_ext_type_texture *fb, unigi_ext_type_rect texrect, unigi_ext_type_rect outrect) {
	// Precalc the step, as it's always the same even if we clip the rect
	unigi_ext_type_2d_coord tex_width, tex_height, out_width, out_height;
	unigi_ext_rect_dimensions(texrect,&tex_width,&tex_height);
	unigi_ext_rect_dimensions(outrect,&out_width,&out_height);
	int32_t stepx = (1 << unigi_ext_texture_fixedpointdepth) * (float)tex_width / out_width;
	int32_t stepy = (1 << unigi_ext_texture_fixedpointdepth) * (float)tex_height / out_height;
	int32_t texx_init = (1 << unigi_ext_texture_fixedpointdepth) * texrect.x1;
	int32_t texy = (1 << unigi_ext_texture_fixedpointdepth) * texrect.y1;
	// Clip the rect
	if (outrect.x1 < 0) {
		texx_init += stepx * -outrect.x1;
		outrect.x1 = 0;
	}
	if (outrect.y1 < 0) {
		texy += stepy * -outrect.y1;
		outrect.y1 = 0;
	}
	if (outrect.x2 >= fb->width) {
		outrect.x2 = fb->width - 1;
	}
	if (outrect.y2 >= fb->height) {
		outrect.y2 = fb->height - 1;
	}
	
	for (int y = outrect.y1; y < outrect.y2; y++) {
		int32_t texx = texx_init;
		int yiter = y * fb->width;
		for (int x = outrect.x1; x < outrect.x2; x++) {
			uint16_t pix = sprite->pixels[((texy >> unigi_ext_texture_fixedpointdepth) * sprite->width) + (texx >> unigi_ext_texture_fixedpointdepth)];
			
			if (pix & 0xF000) {
		fb->pixels[yiter + x] = pix;
			}
			texx += stepx;
		}
		texy += stepy;
	}
}

unigi_ext_type_texture * unigi_ext_texture_create(unigi_ext_type_2d_coord width, unigi_ext_type_2d_coord height) {
	unigi_ext_type_texture * texture = malloc(sizeof(unigi_ext_type_texture));
	if (texture == NULL) { return NULL; }
	texture->width = width;
	texture->height = height;
	texture->pixels = malloc(sizeof(unigi_type_color) * width * height);
	if (texture->pixels == NULL) {
		free(texture);
		return NULL;
	}
	return texture;
}

void unigi_ext_texture_destroy(unigi_ext_type_texture * texture) {
	free(texture->pixels);
	free(texture);
}

#include <unistd.h>
#include <fcntl.h>
unigi_ext_type_texture * unigi_ext_texture_open(char * path) {
	int fd = open(path,O_RDONLY);
	if (fd == -1) { goto fail; }
	uint16_t width;
	uint16_t height;
	if (read(fd,&width,sizeof(uint16_t)) != sizeof(uint16_t)) { goto fail_file; }
	if (read(fd,&height,sizeof(uint16_t)) != sizeof(uint16_t)) { goto fail_file; }
	unigi_ext_type_texture * texture = unigi_ext_texture_create(width,height);
	if (texture == NULL) { goto fail_file; }
	
	if (read(fd,texture->pixels,sizeof(uint16_t) * width * height) != sizeof(uint16_t) * width * height) {
		goto fail_texture;
	}
	
	close(fd);
	return texture;
	
	fail_texture:;
	unigi_ext_texture_destroy(texture);
	fail_file:;
	close(fd);
	fail:;
	return NULL;
}

void unigi_ext_rect_dimensions(
	unigi_ext_type_rect bounds,
	unigi_ext_type_2d_coord * width,
	unigi_ext_type_2d_coord * height
) {
	*width = abs(bounds.x2 - bounds.x1);
	*height = abs(bounds.y2 - bounds.y1);
}