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 *
 * Copyright (c) 2010, Ajax.org B.V.
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 *       names of its contributors may be used to endorse or promote products
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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 ScrollBarV = function(parent, renderer) {
    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
    // element 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 
    renderer.$scrollbarWidth = 
    this.width = dom.scrollbarWidth(parent.ownerDocument);
    renderer.$scrollbarWidth = 
    this.width = dom.scrollbarWidth(parent.ownerDocument);
    this.fullWidth = this.width;
    this.inner.style.width =
    this.element.style.width = (this.width || 15) + 5 + "px";
    this.setVisible(false);
    this.element.style.overflowY = "scroll";
    
    event.addListener(this.element, "scroll", this.onScrollV.bind(this));
};

var ScrollBarH = function(parent, renderer) {
    this.element = dom.createElement("div");
    this.element.className = "ace_scrollbar-h";

    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
    // element 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.height = renderer.$scrollbarWidth;
    this.fullHeight = this.height;
    this.inner.style.height =
    this.element.style.height = (this.height || 15) + 5 + "px";
    this.setVisible(false);
    this.element.style.overflowX = "scroll";

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

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

    this.setVisible = function(show) {
        if (show) {
            this.element.style.display = "";
            if (this.fullWidth)
                this.width = this.fullWidth;
            if (this.fullHeight)
                this.height = this.fullHeight;
        } else {
            this.element.style.display = "none";
            this.height = this.width = 0;
        }
    };
    
    /**
     * Emitted when the scroll bar, well, scrolls.
     * @event scroll
     * @param {Object} e Contains one property, `"data"`, which indicates the current scroll top position
     **/
    this.onScrollV = function() {
        if (!this.skipEvent) {
            this.scrollTop = this.element.scrollTop;
            this._emit("scroll", {data: this.scrollTop});
        }
        this.skipEvent = false;
    };
    this.onScrollH = function() {
        if (!this.skipEvent) {
            this.scrollLeft = this.element.scrollLeft;
            this._emit("scroll", {data: this.scrollLeft});
        }
        this.skipEvent = false;
    };

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

    this.getHeight = function() {
        return this.height;
    };

    /**
     * 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";
    };
    
    this.setWidth = function(width) {
        this.element.style.width = width + "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";
    };
    
    this.setInnerWidth = function(width) {
        this.inner.style.width = width + "px";
    };

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

}).call(ScrollBarV.prototype);
ScrollBarH.prototype = ScrollBarV.prototype;



exports.ScrollBar = ScrollBarV; // backward compatibility
exports.ScrollBarV = ScrollBarV;
exports.ScrollBarH = ScrollBarH;
});
