#include <libimg.h>
#include "libimg-internal.h"

#include <gint/display.h>
#include <gint/std/stdlib.h>
#include <gint/std/string.h>

int img_target(img_t img, int w, int h)
{
	if(img.flags & FLAG_RO) return 0;
	if(img_null(img)) return 0;
	if(img.width < w || img.height < h) return 0;
	return 1;
}

img_t img_create(int w, int h)
{
	if(w <= 0 || h <= 0 || w >= 0x10000 || h >= 0x10000)
		return NULL_IMG;

	img_t s = {
		.width = w, .height = h, .stride = w,
		.flags = FLAG_OWN,
		.pixels = malloc(w * h * sizeof *s.pixels),
	};

	if(!s.pixels) return NULL_IMG;
	return s;
}

img_t img_copy(img_t img)
{
	int w = img.width, h = img.height;
	img_t s = img_create(w, h);
	if(img_null(s)) return s;

	img_pixel_t *src_px = img.pixels;
	img_pixel_t *dst_px = s.pixels;

	for(int y = 0; y < img.height; y++)
	{
		memcpy(dst_px, src_px, w * sizeof *src_px);
		src_px += img.stride;
		dst_px += s.stride;
	}
	return s;
}

int img_null(img_t img)
{
	return !img.width || !img.height || !img.pixels;
}

img_t img_sub(img_t img, int x, int y, int w, int h)
{
	if(img_null(img)) return img;

	/* If w or h is negative, use the full width and height (this formula
	   works even if x<0 or y<0) */
	if(w < 0) w = img.width - x;
	if(h < 0) h = img.height - y;

	/* Clip in bounds */
	if(x < 0) w += x, x = 0;
	if(y < 0) h += y, y = 0;
	if(x + w > img.width) w = img.width - x;
	if(y + h > img.height) h = img.height - y;
	if(w <= 0 || h <= 0) return NULL_IMG;

	img_t s = {
		.width = w, .height = h, .stride = img.stride,
		.flags = 0,
		.pixels = img.pixels + (y * img.stride) + x,
	};
	return s;
}

img_t img_at(img_t img, int x, int y)
{
	return img_sub(img, x, y, -1, -1);
}

#ifdef FXCG50
img_t img_vram(void)
{
	img_t vram = {
		.width = 396, .height = 224, .stride = 396,
		.flags = 0,
		.pixels = gint_vram,
	};
	return vram;
}
#endif

void img_destroy(img_t img)
{
	if(img.flags & FLAG_OWN && !(img.flags & FLAG_RO)) free(img.pixels);
}