#include <vhex/display/image.h>
#include <vhex/defs/utils.h>

#include <stdlib.h>
#include <string.h>

//---
// Image-object API
//---

/* image_alloc(): Create a new (uninitialized) image */
image_t *image_alloc(size_t width, size_t height, int format)
{
	image_t *img = image_create(width, height, format);
	if(img == NULL)
		return (NULL);

	if(IMAGE_IS_RGB16(format))
		img->stride = ((width + 1) >> 1) * 4;
	else if(IMAGE_IS_P8(format))
		img->stride = width;
	else if(IMAGE_IS_P4(format))
		img->stride = ((width + 1) >> 1);

	void *data = malloc(height * img->stride);
	if(data == NULL) {
		image_free(img);
		return (NULL);
	}

	img->data = data;
	img->flags |= IMAGE_FLAGS_DATA_ALLOC;
	return img;
}

/* image_create(): Create a bare image with no data/palette */
image_t *image_create(size_t width, size_t height, int format)
{
	if(!IMAGE_IS_RGB16(format)
			&& !IMAGE_IS_P8(format)
			&& !IMAGE_IS_P4(format)) {
		return (NULL);
	}
	if(width > 0xffff || height > 0xffff)
		return (NULL);

	image_t *img = calloc(1, sizeof(image_t));
	if(img == NULL)
		return (NULL);

	img->format = format;
	img->flags = 0;
	img->color_count = 0;
	img->width = width;
	img->height = height;
	img->stride = 0;
	img->data = NULL;
	img->palette = NULL;

	return (img);
}

/* image_free(): Free and image and the data it owns */
void image_free(image_t *img)
{
	if(img == NULL)
		return;

	if(img->flags & IMAGE_FLAGS_DATA_ALLOC)
		free(img->data);
	if(img->flags & IMAGE_FLAGS_PALETTE_ALLOC)
		free(img->palette);

	if (!(img->flags & IMAGE_FLAGS_RO))
		free(img);
}

//---
// Palette API
//---

/* image_set_palette(): Specify an external palette for an image */
void image_set_palette(image_t *img, uint16_t *palette, size_t size, bool owns)
{
	if(img == NULL || !IMAGE_IS_INDEXED(img->format))
		return;

	if(img->flags & IMAGE_FLAGS_PALETTE_ALLOC)
		free(img->palette);

	img->palette = palette;
	img->color_count = size;

	if(owns) {
		img->flags |= IMAGE_FLAGS_PALETTE_ALLOC;
	} else {
		img->flags &= ~IMAGE_FLAGS_PALETTE_ALLOC;
	}
}


/* image_alloc_palette(): Allocate a new palette for an image */
bool image_alloc_palette(image_t *img, int size)
{
	if(img == NULL || !IMAGE_IS_INDEXED(img->format))
		return (false);

	if(img->flags & IMAGE_FLAGS_PALETTE_ALLOC)
		free(img->palette);

	if(IMAGE_IS_P8(img->format)) {
		size = (size <= 0) ? 256 : min(size, 256);
	}
	if(IMAGE_IS_P4(img->format)) {
		size = 16;
	}

	img->palette = calloc(size, sizeof(uint16_t));
	img->color_count = 0;
	img->flags &= ~IMAGE_FLAGS_PALETTE_ALLOC;

	if(img->palette == NULL)
		return (false);

	memset(img->palette, 0, size * sizeof(uint16_t));
	img->color_count = size;
	img->flags |= IMAGE_FLAGS_PALETTE_ALLOC;
	return (true);
}

/* image_copy_palette(): Copy another image's palette */
bool image_copy_palette(image_t const *src, image_t *dst, int size)
{
	if(!image_valid(src) || dst == NULL)
		return (false);

	if(!IMAGE_IS_INDEXED(dst->format))
		return (true);

	if(size < 0)
		size = src->color_count;
	if(!image_alloc_palette(dst, size))
		return (false);

	int N = min(src->color_count, dst->color_count);
	memcpy(dst->palette, src->palette, N * sizeof(uint16_t));
	return (true);
}