/*
 * 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/>.
 */

/** \file
 * Content for image/gif (implementation)
 *
 * 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
 */

#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_protected.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"

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 struct http_parameter *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 res;
	struct gif_animation *gif;
	union content_msg_data msg_data;
	const char *data;
	unsigned long size;
	char title[100];

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

	data = content__get_source_data(c, &size);

	/* Initialise the GIF */
	do {
		res = gif_initialise(gif, size, (unsigned char *) data);
		if (res != GIF_OK && res != GIF_WORKING && 
				res != GIF_INSUFFICIENT_FRAME_DATA) {
			switch (res) {
			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 && res != GIF_INSUFFICIENT_FRAME_DATA);

	/* 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;
	snprintf(title, sizeof(title), messages_get("GIFTitle"),
			c->width, c->height, size);
	content__set_title(c, title);
	c->size += (gif->width * gif->height * 4) + 16 + 44;

	/* 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;
	content_set_ready(c);
	content_set_done(c);
	/* 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, const struct rect *clip,
		float scale, colour 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;
	if ((width == -1) && (height == -1))
		return true;
	return plot.bitmap(x, y, width, height,	c->bitmap,
			background_colour, BITMAPF_NONE);
}


bool nsgif_redraw_tiled(struct content *c, int x, int y,
		int width, int height, const struct rect *clip,
		float scale, colour background_colour,
		bool repeat_x, bool repeat_y)
{
	bitmap_flags_t flags = BITMAPF_NONE;

	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;
            
	if (repeat_x)
		flags |= BITMAPF_REPEAT_X;
	if (repeat_y)
		flags |= BITMAPF_REPEAT_Y;

	return plot.bitmap(x, y, width, height, c->bitmap, background_colour, flags);
}


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);
}


bool nsgif_clone(const struct content *old, struct content *new_content)
{
	/* Simply replay creation and conversion of content */
	if (nsgif_create(new_content, NULL) == false)
		return false;

	if (old->status == CONTENT_STATUS_READY ||
			old->status == CONTENT_STATUS_DONE) {
		if (nsgif_convert(new_content) == false)
			return false;
	}

	return true;
}


/**
 * 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;
	gif_result res = GIF_OK;

	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++)
		res = gif_decode_frame(c->data.gif.gif, frame);

	return res;
}


/**
 * Performs any necessary animation.
 *
 * \param p  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