/*
 *  _       _                     _   
 * | |     | |                   | |  
 * | | __ _| |__   ___ ___   __ _| |_               Labcoat (R)
 * | |/ _` | '_ \ / __/ _ \ / _` | __|              Powerful development environment for Quirrel.
 * | | (_| | |_) | (_| (_) | (_| | |_               Copyright (C) 2010 - 2013 SlamData, Inc.
 * |_|\__,_|_.__/ \___\___/ \__,_|\__|              All Rights Reserved.
 *
 *
 * This program is free software: you can redistribute it and/or modify it under the terms of the 
 * GNU Affero General Public License as published by the Free Software Foundation, either version 
 * 3 of the License, or (at your option) any later version.
 *
 * This program 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 Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License along with this 
 * program. If not, see <http://www.gnu.org/licenses/>.
 *
 */
/* ***** BEGIN LICENSE BLOCK *****
 * Distributed under the BSD license:
 *
 * Copyright (c) 2010, Ajax.org B.V.
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *     * Neither the name of Ajax.org B.V. nor the
 *       names of its contributors may be used to endorse or promote products
 *       derived from this software without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL AJAX.ORG B.V. BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * ***** END LICENSE BLOCK ***** */

define(function(require, exports, module) {
"use strict";

var oop = require("./lib/oop");
var dom = require("./lib/dom");
var event = require("./lib/event");
var EventEmitter = require("./lib/event_emitter").EventEmitter;

/**
 * 
 *
 * A set of methods for setting and retrieving the editor's scrollbar. 
 * @class ScrollBar
 **/

/**
 * Creates a new `ScrollBar`. `parent` is the owner of the scroll bar.
 * @param {DOMElement} parent A DOM element 
 *
 * 
 *
 * 
 * @constructor
 **/
var ScrollBar = function(parent) {
    this.element = dom.createElement("div");
    this.element.className = "ace_scrollbar";

    this.inner = dom.createElement("div");
    this.inner.className = "ace_scrollbar-inner";
    this.element.appendChild(this.inner);

    parent.appendChild(this.element);

    // in OSX lion the scrollbars appear to have no width. In this case resize
    // the to show the scrollbar but still pretend that the scrollbar has a width
    // of 0px
    // in Firefox 6+ scrollbar is hidden if element has the same width as scrollbar
    // make element a little bit wider to retain scrollbar when page is zoomed 
    this.width = dom.scrollbarWidth(parent.ownerDocument);
    this.element.style.width = (this.width || 15) + 5 + "px";

    event.addListener(this.element, "scroll", this.onScroll.bind(this));
};

(function() {
    oop.implement(this, EventEmitter);

    /**
     * Emitted when the scroll bar, well, scrolls.
     * @event scroll
     * @param {Object} e Contains one property, `"data"`, which indicates the current scroll top position
     *
     * 
     *
     **/
    this.onScroll = function() {
        if (!this.skipEvent) {
            this.scrollTop = this.element.scrollTop;
            this._emit("scroll", {data: this.scrollTop});
        }
        this.skipEvent = false;
    };

    /**
     * 
     * Returns the width of the scroll bar.
     * @returns {Number}
     **/
    this.getWidth = function() {
        return this.width;
    };

    /**
     * Sets the height of the scroll bar, in pixels.
     * @param {Number} height The new height
     *
     * 
     *
     **/
    this.setHeight = function(height) {
        this.element.style.height = height + "px";
    };

    /**
     * Sets the inner height of the scroll bar, in pixels.
     * @param {Number} height The new inner height
     *
     * 
     *
     **/
    this.setInnerHeight = function(height) {
        this.inner.style.height = height + "px";
    };


    // on chrome 17+ for small zoom levels after calling this function
    // this.element.scrollTop != scrollTop which makes page to scroll up.
    /**
     * Sets the scroll top of the scroll bar.
     * @param {Number} scrollTop The new scroll top
     *
     * 
     *
     **/
    this.setScrollTop = function(scrollTop) {
        if (this.scrollTop != scrollTop) {
            this.skipEvent = true;
            this.scrollTop = this.element.scrollTop = scrollTop;
        }
    };

}).call(ScrollBar.prototype);

exports.ScrollBar = ScrollBar;
});
