/*
 * Copyright 2003 John M Bell <jmb202@ecs.soton.ac.uk>
 * Copyright 2004 Richard Wilson <not_ginger_matt@users.sourceforge.net>
 * Copyright 2008 Sean Fox <dyntryx@gmail.com>
 *
 * This file is part of NetSurf, http://www.netsurf-browser.org/
 *
 * NetSurf is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; version 2 of the License.
 *
 * NetSurf 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include "utils/config.h"
#ifdef WITH_GIF

#include <assert.h>
#include <string.h>
#include <stdbool.h>
#include <stdlib.h>
#include <libnsgif.h>
#include "utils/config.h"
#include "content/content.h"
#include "desktop/browser.h"
#include "desktop/options.h"
#include "desktop/plotters.h"
#include "image/bitmap.h"
#include "image/gif.h"
#include "utils/log.h"
#include "utils/messages.h"
#include "utils/utils.h"


/*	GIF FUNCTIONALITY
	=================

	All GIFs are dynamically decompressed using the routines that gifread.c
	provides. Whilst this allows support for progressive decoding, it is
	not implemented here as NetSurf currently does not provide such support.

	[rjw] - Sun 4th April 2004
*/

static void nsgif_invalidate(void *bitmap, void *private_word);
static void nsgif_animate(void *p);
static gif_result nsgif_get_frame(struct content *c);

/*	The Bitmap callbacks function table;
	necessary for interaction with nsgiflib.
*/
gif_bitmap_callback_vt gif_bitmap_callbacks = {
	.bitmap_create = nsgif_bitmap_create,
	.bitmap_destroy = bitmap_destroy,
	.bitmap_get_buffer = bitmap_get_buffer,
	.bitmap_set_opaque = bitmap_set_opaque,
	.bitmap_test_opaque = bitmap_test_opaque,
	.bitmap_modified = bitmap_modified
};


bool nsgif_create(struct content *c, const char *params[]) {
	union content_msg_data msg_data;
	/*	Initialise our data structure
	*/
	c->data.gif.gif = calloc(sizeof(gif_animation), 1);
	if (!c->data.gif.gif) {
		msg_data.error = messages_get("NoMemory");
		content_broadcast(c, CONTENT_MSG_ERROR, msg_data);
		return false;
	}
	gif_create(c->data.gif.gif, &gif_bitmap_callbacks);
	return true;
}


bool nsgif_convert(struct content *c, int iwidth, int iheight) {
	int res;
	struct gif_animation *gif;
	union content_msg_data msg_data;

	/*	Get the animation
	*/
	gif = c->data.gif.gif;

	/*	Initialise the GIF
	*/
	do {
		res = gif_initialise(gif, c->source_size, (unsigned char *)c->source_data);
		if (res != GIF_OK && res != GIF_WORKING) {
			switch (res)
			{
				case GIF_INSUFFICIENT_FRAME_DATA:
				case GIF_FRAME_DATA_ERROR:
				case GIF_INSUFFICIENT_DATA:
				case GIF_DATA_ERROR:
					msg_data.error = messages_get("BadGIF");
					break;
				case GIF_INSUFFICIENT_MEMORY:
					msg_data.error = messages_get("NoMemory");
					break;
			}
			content_broadcast(c, CONTENT_MSG_ERROR, msg_data);
			return false;
		}
	} while (res != GIF_OK);

	/*	Abort on bad GIFs
	*/
	if ((gif->frame_count_partial == 0) || (gif->width == 0) ||
			(gif->height == 0)) {
		msg_data.error = messages_get("BadGIF");
		content_broadcast(c, CONTENT_MSG_ERROR, msg_data);
		return false;
	}

	/*	Store our content width and description
	*/
	c->width = gif->width;
	c->height = gif->height;
	c->title = malloc(100);
	if (c->title)
		snprintf(c->title, 100, messages_get("GIFTitle"), c->width, c->height, c->source_size);
	c->size += (gif->width * gif->height * 4) + 16 + 44 + 100;

	/*	Schedule the animation if we have one
	*/
	c->data.gif.current_frame = 0;
	if (gif->frame_count_partial > 1)
		schedule(gif->frames[0].frame_delay, nsgif_animate, c);
	else
		bitmap_set_suspendable(gif->frame_image, gif, nsgif_invalidate);

	/*	Exit as a success
	*/
	c->bitmap = gif->frame_image;
	c->status = CONTENT_STATUS_DONE;
	/* Done: update status bar */
	content_set_status(c, "");
	return true;
}

void nsgif_invalidate(void *bitmap, void *private_word) {
	struct gif_animation *gif = (struct gif_animation *)private_word;

	gif->decoded_frame = -1;
}

bool nsgif_redraw(struct content *c, int x, int y,
		int width, int height,
		int clip_x0, int clip_y0, int clip_x1, int clip_y1,
		float scale, unsigned long background_colour) {

	if (c->data.gif.current_frame != c->data.gif.gif->decoded_frame)
		if (nsgif_get_frame(c) != GIF_OK)
			return false;
	c->bitmap = c->data.gif.gif->frame_image;
	return plot.bitmap(x, y, width, height,	c->bitmap, background_colour, c);
}


bool nsgif_redraw_tiled(struct content *c, int x, int y,
		int width, int height,
		int clip_x0, int clip_y0, int clip_x1, int clip_y1,
		float scale, unsigned long background_colour,
		bool repeat_x, bool repeat_y) {

	gif_result res;

	if (c->data.gif.current_frame != c->data.gif.gif->decoded_frame)
		if (nsgif_get_frame(c) != GIF_OK)
			return false;
	c->bitmap = c->data.gif.gif->frame_image;
	return plot.bitmap_tile(x, y, width, height, c->bitmap, background_colour,
			repeat_x, repeat_y, c);
}


void nsgif_destroy(struct content *c)
{

	/*	Free all the associated memory buffers
	*/
	schedule_remove(nsgif_animate, c);
	gif_finalise(c->data.gif.gif);
	free(c->data.gif.gif);
	free(c->title);
}


/**
 * Updates the GIF bitmap to display the current frame
 *
 * \param c  the content to update
 */
gif_result nsgif_get_frame(struct content *c) {
	int previous_frame, current_frame, frame;

	current_frame = c->data.gif.current_frame;
	if (!option_animate_images)
		current_frame = 0;
	if (current_frame < c->data.gif.gif->decoded_frame)
		previous_frame = 0;
	else
		previous_frame = c->data.gif.gif->decoded_frame + 1;
	for (frame = previous_frame; frame <= current_frame; frame++)
		return gif_decode_frame(c->data.gif.gif, frame);
}


/**	Performs any necessary animation.

	@param	c		The content to animate
*/
void nsgif_animate(void *p)
{
	struct content *c = p;
	union content_msg_data data;
	struct gif_animation *gif;
	int delay;
	int f;

	/*	Advance by a frame, updating the loop count accordingly
	*/
	gif = c->data.gif.gif;
	c->data.gif.current_frame++;
	if (c->data.gif.current_frame == (int)gif->frame_count_partial) {
		c->data.gif.current_frame = 0;

		/*	A loop count of 0 has a special meaning of infinite
		*/
		if (gif->loop_count != 0) {
			gif->loop_count--;
			if (gif->loop_count == 0) {
				c->data.gif.current_frame = gif->frame_count_partial - 1;
				gif->loop_count = -1;
			}
		}
	}

	/*	Continue animating if we should
	*/
	if (gif->loop_count >= 0) {
		delay = gif->frames[c->data.gif.current_frame].frame_delay;
		if (delay < option_minimum_gif_delay)
			delay = option_minimum_gif_delay;
		schedule(delay, nsgif_animate, c);
	}

	if ((!option_animate_images) || (!gif->frames[c->data.gif.current_frame].display))
		return;

	/* area within gif to redraw */
	f = c->data.gif.current_frame;
	data.redraw.x = gif->frames[f].redraw_x;
	data.redraw.y = gif->frames[f].redraw_y;
	data.redraw.width = gif->frames[f].redraw_width;
	data.redraw.height = gif->frames[f].redraw_height;

	/* redraw background (true) or plot on top (false) */
	if (c->data.gif.current_frame > 0) {
		data.redraw.full_redraw = gif->frames[f - 1].redraw_required;
		/* previous frame needed clearing: expand the redraw area to cover it */
		if (data.redraw.full_redraw) {
			if (data.redraw.x > gif->frames[f - 1].redraw_x) {
				data.redraw.width += data.redraw.x - gif->frames[f - 1].redraw_x;
				data.redraw.x = gif->frames[f - 1].redraw_x;
			}
			if (data.redraw.y > gif->frames[f - 1].redraw_y) {
				data.redraw.height += (data.redraw.y - gif->frames[f - 1].redraw_y);
				data.redraw.y = gif->frames[f - 1].redraw_y;
			}
			if ((gif->frames[f - 1].redraw_x + gif->frames[f - 1].redraw_width) >
					(data.redraw.x + data.redraw.width))
				data.redraw.width = gif->frames[f - 1].redraw_x - data.redraw.x +
						gif->frames[f - 1].redraw_width;
			if ((gif->frames[f - 1].redraw_y + gif->frames[f - 1].redraw_height) >
					(data.redraw.y + data.redraw.height))
				data.redraw.height = gif->frames[f - 1].redraw_y - data.redraw.y +
						gif->frames[f - 1].redraw_height;
		}
	} else {
		/* do advanced check */
		if ((data.redraw.x == 0) && (data.redraw.y == 0) &&
				(data.redraw.width == gif->width) &&
				(data.redraw.height == gif->height)) {
			data.redraw.full_redraw = !gif->frames[f].opaque;
		} else {
			data.redraw.full_redraw = true;
			data.redraw.x = 0;
			data.redraw.y = 0;
			data.redraw.width = gif->width;
			data.redraw.height = gif->height;
		}
	}

	/* other data */
	data.redraw.object = c;
	data.redraw.object_x = 0;
	data.redraw.object_y = 0;
	data.redraw.object_width = c->width;
	data.redraw.object_height = c->height;

	content_broadcast(c, CONTENT_MSG_REDRAW, data);
}


/**
 * Callback for libnsgif; forwards the call to bitmap_create()
 *
 * \param  width   width of image in pixels
 * \param  height  width of image in pixels
 * \return an opaque struct bitmap, or NULL on memory exhaustion
 */
void *nsgif_bitmap_create(int width, int height) {
	return bitmap_create(width, height, BITMAP_NEW);
}

#endif