/*
 * This file is part of LibNSLayout
 * Licensed under the ISC License, http://opensource.org/licenses/ISC
 * Copyright 2015 Michael Drake <tlsa@netsurf-browser.org>
 */

/** \file src/layout.c
 * Layout object handling
 */

#include <assert.h>
#include <stdlib.h>

#include "libnslayout/nslayout.h"

#include "layout.h"
#include "util/util.h"
#include "dom/watcher.h"
#include "util/dom-str.h"


/**
 * The layout object for a DOM document
 */
struct nslayout_layout {
	dom_document *document;
	css_select_ctx *css_ctx;
	css_media_type *media;
	nslayout_callback cb;
	void *pw;

	struct nsl_dom_watcher *watcher;
};


/* Publically exported function, documented in include/libnslayout/nslayout.h */
nslayout_error nslayout_init(void)
{
	return nsl_dom_str_init();
}


/* Publically exported function, documented in include/libnslayout/nslayout.h */
nslayout_error nslayout_fini(void)
{
	return nsl_dom_str_fini();
}


/**
 * Callback function for dom modifications.
 *
 * \param[in]  type       The mutation type.
 * \param[in]  node       The target node.  (Caller yields ownership.)
 * \param[in]  node_type  The type of node.
 * \param[in]  pw         The layout object.
 * \return NSLAYOUT_OK on success, appropriate error otherwise.
 */
static nslayout_error nsl_layout_dom_watcher_cb(
		enum nsl_dom_watcher_type type,
		dom_event_target *node,
		dom_node_type node_type,
		void *pw)
{
	nslayout_layout *layout = pw;

	UNUSED(type);
	UNUSED(layout);
	UNUSED(node_type);

	/* TODO: Based on event type:
	 *         1. call to do (re)selection:
	 *              a. all nodes?
	 *              b. just this node?
	 *         2. call to update layout, if needed.
	 */

	dom_node_unref(node);

	return NSLAYOUT_OK;
}


/* Publically exported function, documented in include/libnslayout/nslayout.h */
nslayout_error nslayout_layout_create(
		dom_document *doc,
		css_select_ctx *css_ctx,
		css_media_type *media,
		nslayout_callback cb,
		void *pw,
		nslayout_layout **layout)
{
	nslayout_layout *l = NULL;
	nslayout_error err;

	assert(doc != NULL);
	assert(css_ctx != NULL);
	assert(media != NULL);
	assert(cb != NULL);

	l = calloc(1, sizeof(nslayout_layout));
	if (l == NULL) {
		return NSLAYOUT_NO_MEM;
	}

	/* TODO: Decide: ownership will probably be passed to libnslayout */
	l->document = doc;
	l->css_ctx = css_ctx;
	l->media = media;
	l->cb = cb;
	l->pw = pw;

	err = nsl_dom_watcher_create(&l->watcher, l->document,
			nsl_layout_dom_watcher_cb, l);
	if (err != NSLAYOUT_OK) {
		return err;
	}

	*layout = l;
	return NSLAYOUT_OK;
}


/* Publically exported function, documented in include/libnslayout/nslayout.h */
nslayout_error nslayout_layout_destroy(
		nslayout_layout *layout)
{
	nslayout_error err;

	assert(layout != NULL);

	/* TODO: free/unref the stuff we own in the layout */
	err = nsl_dom_watcher_destroy(layout->watcher);
	if (err != NSLAYOUT_OK) {
		return err;
	}

	free(layout);
	return NSLAYOUT_OK;
}