/*
* Dropdown.js
*
* Copyright (c) 2012, Stefan Jänicke. All rights reserved.
*
* 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 3 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
*/

/**
 * @class Dropdown
 * Implementation for Dropdown box
 * @author Stefan Jänicke (stjaenicke@informatik.uni-leipzig.de)
 * @release 1.0
 * @release date: 2012-07-27
 * @version date: 2012-07-27
 *
 * @param {HTML object} parent parent div for the dropdown box
 * @param {Array} elements list of dropdown entries
 * @param {String} title dropdown button title
 */
function Dropdown(parent, elements, title, maxListHeight) {

	var dropdown = this;
	this.visibility = false;
	this.div = document.createElement("div");
	this.div.setAttribute('class', 'dropdown');

	this.selection = document.createElement("div");
	this.selection.setAttribute('class', 'dropdownSelection');
	parent.appendChild(this.div);

	var leftBorder = document.createElement("div");
	leftBorder.setAttribute('class', 'dropdownLeft');
	this.div.appendChild(leftBorder);

	this.div.appendChild(this.selection);

	var dropdownButton = document.createElement("div");
	this.div.appendChild(dropdownButton);
	if (elements.length > 1) {
		dropdownButton.setAttribute('class', 'dropdownButtonEnabled');
	} else {
		dropdownButton.setAttribute('class', 'dropdownButtonDisabled');
	}
	dropdownButton.onclick = function() {
		if (elements.length > 1) {
			dropdown.changeVisibility();
		}
	}
	dropdownButton.title = title;

	this.getValue = function() {
		return this.selectedEntry.innerHTML;
	};

	var entryMenu = document.createElement("div");
	entryMenu.setAttribute('class', 'dropdownMenu');
	this.div.appendChild(entryMenu);
	if (typeof maxListHeight !== "undefined")
		$(entryMenu).height(maxListHeight);

	var entries = document.createElement("dl");
	var addEntry = function(e) {
		var entry = document.createElement("dt");
		entry.setAttribute('class', 'dropdownUnselectedEntry');
		entry.innerHTML = e.name;
		entry.onclick = function() {
			e.onclick();
			dropdown.changeVisibility();
			dropdown.changeEntries(e);
		}
		entries.appendChild(entry);
		e.entry = entry;
	}
	for (var i = 0; i < elements.length; i++) {
		addEntry(elements[i]);
	}
	entryMenu.appendChild(entries);
	this.selection.style.width = entryMenu.offsetWidth + "px";
	entryMenu.style.width = (entryMenu.offsetWidth + leftBorder.offsetWidth + dropdownButton.offsetWidth - 2) + "px";
	this.div.style.maxHeight = this.div.offsetHeight + "px";

	entryMenu.style.display = 'none';

	this.setEntry = function(index) {
		if ( typeof (index) == "undefined") {
			if ((elements) && elements.length > 0) {
				this.changeEntries(elements[0]);
			}
		} else {
			this.changeEntries(elements[index]);
		}
	}

	this.changeEntries = function(element) {
		if (this.selectedEntry) {
			this.selectedEntry.setAttribute('class', 'dropdownUnselectedEntry');
		}
		this.selectedEntry = element.entry;
		this.selectedEntry.setAttribute('class', 'dropdownSelectedEntry');
		this.selection.innerHTML = "<div style='display:inline-block;vertical-align:middle;'>" + element.name + "</div>";
	}

	this.changeVisibility = function() {
		this.visibility = !this.visibility;
		if (this.visibility) {
			entryMenu.style.display = "block";
		} else {
			entryMenu.style.display = "none";
		}
	}
}