/*
 * filter_charcoal.c -- charcoal filter
 * Copyright (C) 2003-2022 Meltytech, LLC
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 */

#include <framework/mlt_filter.h>
#include <framework/mlt_frame.h>
#include <framework/mlt_profile.h>
#include <framework/mlt_slices.h>

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

static inline int get_Y( uint8_t *pixels, int width, int height, int x, int y, int max_luma )
{
	if ( x < 0 || x >= width || y < 0 || y >= height )
	{
		return max_luma;
	}
	else
	{
		uint8_t *pixel = pixels + y * ( width << 1 ) + ( x << 1 );
		return *pixel;
	}
}

static inline int sqrti( int n )
{
	int p = 0;
	int q = 1;
	int r = n;
	int h = 0;

	while( q <= n )
		q = q << 2;

	while( q != 1 )
	{
		q = q >> 2;
		h = p + q;
		p = p >> 1;
		if ( r >= h )
		{
			p = p + q;
			r = r - h;
		}
	}

	return p;
}

typedef struct {
	uint8_t *image;
	uint8_t *dest;
	int width;
	int height;
	int x_scatter;
	int y_scatter;
	int min;
	int max_luma;
	int max_chroma;
	int invert;
	int invert_luma;
	float scale;
	float mix;
} slice_desc;

static int slice_proc(int id, int index, int jobs, void* data)
{
	(void) id; // unused
	slice_desc* d = (slice_desc*) data;
	int slice_line_start, slice_height = mlt_slices_size_slice(jobs, index, d->height, &slice_line_start);
	uint8_t *p = d->dest  + slice_line_start * d->width * 2;
	uint8_t *q = d->image + slice_line_start * d->width * 2;
	int matrix[3][3];
	int sum1;
	int sum2;
	float sum;
	int val;

	for (int y = slice_line_start; y < slice_line_start + slice_height; y++) {
		for (int x = 0; x < d->width; x++) {
			// Populate the matrix
			matrix[0][0] = get_Y(d->image, d->width, d->height, x - d->x_scatter, y - d->y_scatter, d->max_luma);
			matrix[0][1] = get_Y(d->image, d->width, d->height, x               , y - d->y_scatter, d->max_luma);
			matrix[0][2] = get_Y(d->image, d->width, d->height, x + d->x_scatter, y - d->y_scatter, d->max_luma);
			matrix[1][0] = get_Y(d->image, d->width, d->height, x - d->x_scatter, y               , d->max_luma);
			matrix[1][2] = get_Y(d->image, d->width, d->height, x + d->x_scatter, y               , d->max_luma);
			matrix[2][0] = get_Y(d->image, d->width, d->height, x - d->x_scatter, y + d->y_scatter, d->max_luma);
			matrix[2][1] = get_Y(d->image, d->width, d->height, x               , y + d->y_scatter, d->max_luma);
			matrix[2][2] = get_Y(d->image, d->width, d->height, x + d->x_scatter, y + d->y_scatter, d->max_luma);

			// Do calculations
			sum1 = (matrix[2][0] - matrix[0][0]) + ((matrix[2][1] - matrix[0][1]) << 1 ) + (matrix[2][2] - matrix[2][0]);
			sum2 = (matrix[0][2] - matrix[0][0]) + ((matrix[1][2] - matrix[1][0]) << 1 ) + (matrix[2][2] - matrix[2][0]);
			sum = d->scale * sqrti(sum1 * sum1 + sum2 * sum2);

			// Assign value
			*p++ = !d->invert ? (sum >= d->min && sum <= d->max_luma ? d->invert_luma - sum : sum < d->min ? d->max_luma : d->min) :
			                    (sum >= d->min && sum <= d->max_luma ? sum : sum < d->min ? d->min : d->max_luma);
			q++;
			val = 128 + d->mix * (*q++ - 128);
			val = CLAMP(val, d->min, d->max_chroma);
			*p++ = val;
		}
	}

	return 0;
}

static int filter_get_image( mlt_frame frame, uint8_t **image, mlt_image_format *format, int *width, int *height, int writable )
{
	// Get the filter
	mlt_filter filter = mlt_frame_pop_service( frame );
	mlt_properties properties = MLT_FILTER_PROPERTIES( filter );
	mlt_position position = mlt_filter_get_position( filter, frame );
	mlt_position length = mlt_filter_get_length2( filter, frame );

	// Get the image
	*format = mlt_image_yuv422;
	int error = mlt_frame_get_image(frame, image, format, width, height, 0);

	// Only process if we have no error and a valid colour space
	if ( error == 0 ) {
		int size = *width * *height * 2;
		int full_range = mlt_properties_get_int(MLT_FRAME_PROPERTIES(frame), "full_range");
		// Get the charcoal scatter value
		int x_scatter = mlt_properties_anim_get_double( properties, "x_scatter", position, length );
		int y_scatter = mlt_properties_anim_get_double( properties, "y_scatter", position, length );
		mlt_profile profile = mlt_service_profile(MLT_FILTER_SERVICE(filter));
		double scale_x = mlt_profile_scale_width(profile, *width);
		double scale_y = mlt_profile_scale_height(profile, *height);
		if (scale_x > 0.0 || scale_y > 0.0) {
			x_scatter = MAX(1, lrint(x_scatter * scale_x));
			y_scatter = MAX(1, lrint(y_scatter * scale_y));
		}

		slice_desc desc = {
		    // We need to create a new frame as this effect modifies the input
		    .image = *image,
		    .dest = mlt_pool_alloc(size),
		    .width = *width,
		    .height = *height,
		    .x_scatter = x_scatter,
		    .y_scatter = y_scatter,
		    .min = full_range? 0 : 16,
		    .max_luma = full_range? 255 : 235,
		    .max_chroma = full_range? 255 : 240,
		    .invert = mlt_properties_anim_get_int(properties, "invert", position, length),
		    .invert_luma = full_range? 255 : 251,
		    .scale = mlt_properties_anim_get_double(properties, "scale", position, length),
		    .mix = mlt_properties_anim_get_double(properties, "mix", position, length)
		};
		mlt_slices_run_normal(0, slice_proc, &desc);

		// Return the created image
		*image = desc.dest;

		// Store new and destroy old
		mlt_frame_set_image(frame, *image, size, mlt_pool_release);
	}

	return error;
}

/** Filter processing.
*/

static mlt_frame filter_process( mlt_filter filter, mlt_frame frame )
{
	// Push the frame filter
	mlt_frame_push_service( frame, filter );
	mlt_frame_push_get_image( frame, filter_get_image );

	return frame;
}

/** Constructor for the filter.
*/

mlt_filter filter_charcoal_init( mlt_profile profile, mlt_service_type type, const char *id, char *arg )
{
	mlt_filter filter = mlt_filter_new( );
	if ( filter != NULL )
	{
		filter->process = filter_process;
		mlt_properties_set_int( MLT_FILTER_PROPERTIES( filter ), "x_scatter", 1 );
		mlt_properties_set_int( MLT_FILTER_PROPERTIES( filter ), "y_scatter", 1 );
		mlt_properties_set_double( MLT_FILTER_PROPERTIES( filter ), "scale", 1.5 );
		mlt_properties_set_double( MLT_FILTER_PROPERTIES( filter ), "mix", 0.0 );
	}
	return filter;
}

