/*
 * 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/dom/event.c
 * DOM mutation handling
 */

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

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

static const char *nsl__dom_node_type_to_string(dom_node_type type)
{
	const char *str[] = {
		"ELEMENT_NODE",
		"ATTRIBUTE_NODE",
		"TEXT_NODE",
		"CDATA_SECTION_NODE",
		"ENTITY_REFERENCE_NODE",
		"ENTITY_NODE",
		"PROCESSING_INSTRUCTION_NODE",
		"COMMENT_NODE",
		"DOCUMENT_NODE",
		"DOCUMENT_TYPE_NODE",
		"DOCUMENT_FRAGMENT_NODE",
		"NOTATION_NODE"
	};
	assert(DOM_NODE_TYPE_COUNT == 12);

	return str[type - 1];
}

static void nsl__dom_event_handler(struct dom_event *evt, void *pw)
{
	dom_event_target *node = NULL;
	dom_node_type node_type;
	dom_string *name = NULL;
	dom_string *type = NULL;
	dom_exception exc;

	UNUSED(pw);

	printf("  DOM Event: ");

	/* Ugly test to see what events come out */
	exc = dom_event_get_target(evt, &node);
	if ((exc != DOM_NO_ERR) || (node == NULL)) {
		printf("FAILED to get target node!\n");
		goto fail;
	}

	exc = dom_node_get_node_type(node, &node_type);
	if (exc != DOM_NO_ERR) {
		printf("FAILED to get target node type!\n");
		goto fail;
	}

	if (node_type == DOM_ELEMENT_NODE) {
		exc = dom_node_get_node_name(node, &name);
		if ((exc != DOM_NO_ERR) || (name == NULL)) {
			printf("FAILED to get target node name!\n");
			goto fail;
		}
	}

	exc = dom_event_get_type(evt, &type);
	if ((exc != DOM_NO_ERR) || (type == NULL)) {
		printf("FAILED to get event type!\n");
		goto fail;
	}

	if (node_type == DOM_ELEMENT_NODE) {
		printf("<%s> %s",
				dom_string_data(name),
				dom_string_data(type));
	} else {
		printf("%s %s",
				nsl__dom_node_type_to_string(node_type),
				dom_string_data(type));
	}

fail:
	if (type != NULL) dom_string_unref(type);
	if (name != NULL) dom_string_unref(name);
	if (node != NULL) dom_node_unref(node);

	printf("\n");
}

/* Exported function, documented in src/dom/event.h */
nslayout_error nsl_dom_event_layout_init(nslayout_layout *layout)
{
	dom_exception exc;

	/* TODO: LibDOM even listeners are really slow.  Need to find a better
	 *       way to get DOM change notifications.
	 */

	exc = dom_event_listener_create(layout->doc, nsl__dom_event_handler,
			layout, &layout->listener);
	if (exc != DOM_NO_ERR) {
		/* TODO: free stuff, return value */
		printf("Failed to register event handler!\n");
		return NSLAYOUT_NO_MEM;
	}
	exc = dom_event_target_add_event_listener(
			layout->doc, nsl_dom_str_node_inserted, 
			layout->listener, false);
	if (exc != DOM_NO_ERR) {
		/* TODO: free stuff, return value */
		printf("Failed to register event handler!\n");
		return NSLAYOUT_NO_MEM;
	}
	exc = dom_event_target_add_event_listener(
			layout->doc, nsl_dom_str_subtree_modified, 
			layout->listener, false);
	if (exc != DOM_NO_ERR) {
		/* TODO: free stuff, return value */
		printf("Failed to register event handler!\n");
		return NSLAYOUT_NO_MEM;
	}

	return NSLAYOUT_OK;
}

/* Exported function, documented in src/dom/event.h */
nslayout_error nsl_dom_event_layout_fini(nslayout_layout *layout)
{
	dom_exception exc;

	exc = dom_event_target_remove_event_listener(
			layout->doc, nsl_dom_str_node_inserted, 
			layout->listener, false);
	if (exc != DOM_NO_ERR) {
		/* TODO: free stuff, return value */
		printf("Failed to remove event handler!\n");
		return NSLAYOUT_NO_MEM;
	}
	exc = dom_event_target_remove_event_listener(
			layout->doc, nsl_dom_str_subtree_modified, 
			layout->listener, false);
	if (exc != DOM_NO_ERR) {
		/* TODO: free stuff, return value */
		printf("Failed to remove event handler!\n");
		return NSLAYOUT_NO_MEM;
	}
	dom_event_listener_unref(layout->listener);

	return NSLAYOUT_OK;
}