#include <stdlib.h>
#include <string.h>
#include "png_load.h"
#include "base/logging.h"
#include "ext/stb_image/stb_image.h"


// #define PNG_AVAILABLE
#ifndef PNG_AVAILABLE

// *image_data_ptr should be deleted with free()
// return value of 1 == success.
int pngLoad(const char *file, int *pwidth, int *pheight, unsigned char **image_data_ptr,
	bool flip) {
	if (flip)
	{
		ELOG("pngLoad: flip flag not supported, image will be loaded upside down");
	}

	int x,y,n;
	unsigned char *data = stbi_load(file, &x, &y, &n, 4);	// 4 = force RGBA
	if (!data)
		return 0;

	*pwidth = x;
	*pheight = y;
	// ... process data if not NULL ...
	// ... x = width, y = height, n = # 8-bit components per pixel ...
	// ... replace '0' with '1'..'4' to force that many components per pixel
	// ... but 'n' will always be the number that it would have been if you said 0

	// TODO: Get rid of this silly copy which is only to make the buffer free-able with free()
	*image_data_ptr = (unsigned char *)malloc(x * y * 4);
	memcpy(*image_data_ptr, data, x * y * 4);
	stbi_image_free(data);
	return 1;
}

int pngLoadPtr(const unsigned char *input_ptr, size_t input_len, int *pwidth, int *pheight, unsigned char **image_data_ptr,
	bool flip) {
	if (flip)
	{
		ELOG("pngLoad: flip flag not supported, image will be loaded upside down");
	}

	int x,y,n;
	unsigned char *data = stbi_load_from_memory(input_ptr,(int)input_len, &x, &y, &n, 4);	// 4 = force RGBA
	if (!data)
		return 0;

	*pwidth = x;
	*pheight = y;
	// ... process data if not NULL ...
	// ... x = width, y = height, n = # 8-bit components per pixel ...
	// ... replace '0' with '1'..'4' to force that many components per pixel
	// ... but 'n' will always be the number that it would have been if you said 0

	// TODO: Get rid of this silly copy which is only to make the buffer free-able with free()
	*image_data_ptr = (unsigned char *)malloc(x * y * 4);
	memcpy(*image_data_ptr, data, x * y * 4);
	stbi_image_free(data);
	return 1;
}

#else

#include <png.h>
#include <stdlib.h>
#include <stdio.h>

// *image_data_ptr should be deleted with free()
// return value of 1 == success.
int pngLoad(const char *file, int *pwidth, 
						int *pheight, unsigned char **image_data_ptr,
						bool flip) {
	FILE *infile = fopen(file, "rb");
	if (!infile) {
		printf("No such file: %s\n", file);
		return 0;
	}
	/* Check for the 8-byte signature */
	char			sig[8];				/* PNG signature array */
	int len = fread(sig, 1, 8, infile);
	if (len != 8 || !png_check_sig((unsigned char *) sig, 8)) {
		fclose(infile);
		return 0;
	}
	png_structp png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
	if (!png_ptr) {
		fclose(infile);
		return 4;	 /* out of memory */
	}
	png_infop info_ptr = png_create_info_struct(png_ptr);
	if (!info_ptr) {
		png_destroy_read_struct(&png_ptr, (png_infopp) NULL, (png_infopp) NULL);
		fclose(infile);
		return 4;	 /* out of memory */
	}
	if (setjmp(png_jmpbuf(png_ptr))) {
		png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
		fclose(infile);
		return 0;
	}

	png_init_io(png_ptr, infile);
	png_set_sig_bytes(png_ptr, 8);	// we already checked the sig bytes
	png_read_info(png_ptr, info_ptr);
	int				bit_depth=0;
	int				color_type=0;
	png_uint_32 width=0, height=0;
	png_get_IHDR(png_ptr, info_ptr, &width, &height, &bit_depth, &color_type, NULL, NULL, NULL);
	*pwidth = (int)width;
	*pheight = (int)height;
	// Set up some transforms. Always load RGBA.
	if (color_type & PNG_COLOR_MASK_ALPHA) {
		// png_set_strip_alpha(png_ptr);
	}
	if (bit_depth > 8) {
		png_set_strip_16(png_ptr);
	}
	if (color_type == PNG_COLOR_TYPE_GRAY || color_type == PNG_COLOR_TYPE_GRAY_ALPHA) {
		png_set_gray_to_rgb(png_ptr);
	}
	if (color_type == PNG_COLOR_TYPE_PALETTE) {
		png_set_palette_to_rgb(png_ptr);
	}
	if (color_type == PNG_COLOR_TYPE_RGB) {
		png_set_filler(png_ptr, 255, PNG_FILLER_AFTER);
	}

	// Update the png info struct.
	png_read_update_info(png_ptr, info_ptr);
	unsigned long rowbytes = png_get_rowbytes(png_ptr, info_ptr);
	unsigned char *image_data = NULL;		/* raw png image data */
	if ((image_data = (unsigned char *) malloc(rowbytes * height))==NULL) {
		png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
		return 4;
	}
	png_bytepp row_pointers = NULL;
	if ((row_pointers = (png_bytepp)malloc(height*sizeof(png_bytep))) == NULL) {
		png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
		free(image_data);
		image_data = NULL;
		return 4;
	}
	if (flip) {
		for (unsigned long i = 0; i < height; ++i)
			row_pointers[height - 1 - i] = (png_byte *)(image_data + i*rowbytes);
	} else {
		for (unsigned long i = 0; i < height; ++i)
			row_pointers[i] = (png_byte *)(image_data + i*rowbytes);
	}
	png_read_image(png_ptr, row_pointers);
	free(row_pointers);
	png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
	fclose(infile);
	*image_data_ptr = image_data;
	return 1;
}

#endif