/*
This file is part of Ext JS 4.2

Copyright (c) 2011-2013 Sencha Inc

Contact:  http://www.sencha.com/contact

GNU General Public License Usage
This file may be used under the terms of the GNU General Public License version 3.0 as
published by the Free Software Foundation and appearing in the file LICENSE included in the
packaging of this file.

Please review the following information to ensure the GNU General Public License version 3.0
requirements will be met: http://www.gnu.org/copyleft/gpl.html.

If you are unsure which license is appropriate for your use, please contact the sales department
at http://www.sencha.com/contact.

Build date: 2013-05-16 14:36:50 (f9be68accb407158ba2b1be2c226a6ce1f649314)
*/
/**
 * A mixin to add floating capability to a Component.
 */
Ext.define('Ext.util.Floating', {

    uses: ['Ext.Layer', 'Ext.window.Window'],

    /**
     * @cfg {Boolean} focusOnToFront
     * Specifies whether the floated component should be automatically {@link Ext.Component#method-focus focused} when
     * it is {@link #toFront brought to the front}.
     */
    focusOnToFront: true,

    /**
     * @cfg {String/Boolean} shadow
     * Specifies whether the floating component should be given a shadow. Set to true to automatically create an
     * {@link Ext.Shadow}, or a string indicating the shadow's display {@link Ext.Shadow#mode}. Set to false to
     * disable the shadow.
     */
    shadow: 'sides',

    /**
     * @cfg {Boolean} constrain
     * True to constrain this Components within its containing element, false to allow it to fall outside of its containing
     * element. By default this Component will be rendered to `document.body`. To render and constrain this Component within
     * another element specify {@link Ext.AbstractComponent#renderTo renderTo}.
     */
    constrain: false,

    /**
     * @cfg {Boolean} [fixed=false]
     * Configure as `true` to have this Component fixed at its `X, Y` coordinates in the browser viewport, immune
     * to scrolling the document.
     * 
     * *Only in browsers that support `position:fixed`*
     * 
     * *IE6 and IE7, 8 and 9 quirks do not support `position: fixed`*
     */

    /**
     * @cfg {Number} shadowOffset
     * Number of pixels to offset the shadow.
     */

    constructor: function (dom) {
        var me = this;

        // We do not support fixed on legacy browsers.
        me.fixed = me.fixed && !(Ext.isIE6 || Ext.isIEQuirks);

        me.el = new Ext.dom.Layer(Ext.apply({
            preventSync  : true,
            hideMode     : me.hideMode,
            hidden       : me.hidden,
            shadow       : (typeof me.shadow != 'undefined') ? me.shadow : 'sides',
            shadowOffset : me.shadowOffset,
            constrain    : false,
            fixed        : me.fixed,
            shim         : (me.shim === false) ? false : undefined
        }, me.floating), dom);

        // If modal, and focus navigation not being handled by the FocusManager,
        // catch tab navigation, and loop back in on tab off first or last item.
        if (me.modal && !(Ext.FocusManager && Ext.FocusManager.enabled)) {
            me.mon(me.el, {
                keydown: me.onKeyDown,
                scope: me
            });
        }

        // clickToRaise
        me.mon(me.el, {
            mousedown: me.onMouseDown,
            scope: me
        });

        // release config object (if it was one)
        me.floating = true;

        // Register with the configured ownerCt.
        // With this we acquire a floatParent for relative positioning, and a zIndexParent which is an
        // ancestor floater which provides zIndex management.
        me.registerWithOwnerCt();

        me.initHierarchyEvents();
    },

    initHierarchyEvents: function() {
        var me = this,
            syncHidden = this.syncHidden;

        if (!me.hasHierarchyEventListeners) {
            me.mon(me.hierarchyEventSource, {
                hide: syncHidden,
                collapse: syncHidden,
                show: syncHidden,
                expand: syncHidden,
                added: syncHidden,
                scope: me
            });
            me.hasHierarchyEventListeners = true;
        }
    },

    registerWithOwnerCt: function() {
        var me = this,
            ownerCt = me.ownerCt,
            zip = me.zIndexParent;

        if (zip) {
            zip.unregisterFloatingItem(me);
        }

        // Acquire a zIndexParent by traversing the ownerCt axis for the nearest floating ancestor.
        // This is to find a base which can allocate relative z-index values
        zip = me.zIndexParent = me.up('[floating]');

        // Set the floatParent to the ownertCt if one has been provided.
        // Otherwise use the zIndexParent.
        // Developers must only use ownerCt if there is really a containing relationship.
        me.setFloatParent(ownerCt || zip);
        delete me.ownerCt;

        if (zip) {
            zip.registerFloatingItem(me);
        } else {
            Ext.WindowManager.register(me);
        }
    },

    // Listen for TAB events and wrap round if tabbing of either end of the Floater
    onKeyDown: function(e) {
        var me = this,
            shift,
            focusables,
            first,
            last;

        // If tabbing off either end, wrap round.
        // See Ext.dom.Element.isFocusable
        // Certain browsers always report tabIndex zero in the absence of the tabIndex attribute.
        // Testing the specified property (Standards: http://www.w3.org/TR/DOM-Level-2-Core/core.html#ID-862529273)
        // Should filter out these cases.
        // The exceptions are IE6 to IE8. In these browsers all elements will yield a tabIndex
        // and therefore all elements will appear to be focusable.
        // This adversely affects modal Floating components.
        // These listen for the TAB key, and then test whether the event target === last focusable
        // or first focusable element, and forcibly to a circular navigation.
        // We cannot know the true first or last focusable element, so this problem still exists for IE6,7,8
        if (e.getKey() == Ext.EventObject.TAB) {
            shift = e.shiftKey;
            focusables = me.el.query(':focusable');
            first = focusables[0];
            last = focusables[focusables.length - 1];
            if (first && last && e.target === (shift ? first : last)) {
                e.stopEvent();
                (shift ? last : first).focus(false, true);
            }
        }
    },

    // @private
    // Mousedown brings to front, and programatically grabs focus *unless the mousedown was on a focusable element*
    onMouseDown: function (e) {
        var focusTask = this.focusTask;
        
        if (this.floating &&
            // get out of here if there is already a pending focus.  This usually means
            // that the handler for a mousedown on a child element set the focus on some
            // other component, and we so not want to steal it back. See EXTJSIV-9458
            (!focusTask || !focusTask.id)) {
            // If what was mousedowned upon is going to claim focus anyway, pass preventFocus as true.
            this.toFront(!!e.getTarget(':focusable'));
        }
    },

    setFloatParent: function(floatParent) {
        var me = this;

        me.floatParent = floatParent;

        // If a floating Component is configured to be constrained, but has no configured
        // constrainTo setting, set its constrainTo to be it's ownerCt before rendering.
        if ((me.constrain || me.constrainHeader) && !me.constrainTo) {
            me.constrainTo = floatParent ? floatParent.getTargetEl() : me.container;
        }
    },
    
    // @private
    syncShadow : function() {
        if (this.floating) {
            this.el.sync(true);
        }
    },
    
    onBeforeFloatLayout: function(){
        this.el.preventSync = true;
    },
    
    onAfterFloatLayout: function(){
        delete this.el.preventSync;
        this.syncShadow();   
    },

    /**
     * synchronizes the hidden state of this component with the state of its hierarchy
     * @private
     */
    syncHidden: function() {
        var me = this,
            hidden = me.hidden || !me.rendered,
            hierarchicallyHidden = me.hierarchicallyHidden = me.isHierarchicallyHidden(),
            pendingShow = me.pendingShow;

        if (hidden !== hierarchicallyHidden) {
            if (hierarchicallyHidden) {
                me.hide();
                me.pendingShow = true;
            } else if (pendingShow) {
                delete me.pendingShow;
                if (pendingShow.length) {
                    me.show.apply(me, pendingShow);
                } else {
                    me.show();
                }
            }
        }
    },

    // @private
    // z-index is managed by the zIndexManager and may be overwritten at any time.
    // Returns the next z-index to be used.
    // If this is a Container, then it will have rebased any managed floating Components,
    // and so the next available z-index will be approximately 10000 above that.
    setZIndex: function(index) {
        var me = this;

        me.el.setZIndex(index);

        // Next item goes 10 above;
        index += 10;

        // When a Container with floating descendants has its z-index set, it rebases any floating descendants it is managing.
        // The returned value is a round number approximately 10000 above the last z-index used.
        if (me.floatingDescendants) {
            index = Math.floor(me.floatingDescendants.setBase(index) / 100) * 100 + 10000;
        }
        return index;
    },

    /**
     * Moves this floating Component into a constrain region.
     *
     * By default, this Component is constrained to be within the container it was added to, or the element it was
     * rendered to.
     *
     * An alternative constraint may be passed.
     * @param {String/HTMLElement/Ext.Element/Ext.util.Region} [constrainTo] The Element or {@link Ext.util.Region Region}
     * into which this Component is to be constrained. Defaults to the element into which this floating Component
     * was rendered.
     */
    doConstrain: function(constrainTo) {
        var me = this,
            // Calculate the constrained poition.
            // calculateConstrainedPosition will provide a default constraint
            // region if there is no explicit constrainTo, *and* there is no floatParent owner Component.
            xy = me.calculateConstrainedPosition(constrainTo, null, true);

        // false is returned if no movement is needed
        if (xy) {
            me.setPosition(xy);
        }
    },

    /**
     * Brings this floating Component to the front of any other visible, floating Components managed by the same
     * {@link Ext.ZIndexManager ZIndexManager}
     *
     * If this Component is modal, inserts the modal mask just below this Component in the z-index stack.
     *
     * @param {Boolean} [preventFocus=false] Specify `true` to prevent the Component from being focused.
     * @return {Ext.Component} this
     */
    toFront: function(preventFocus) {
        var me = this,
            zip = me.zIndexParent,
            preventFocusSetting = me.preventFocusOnActivate;

        // Find the floating Component which provides the base for this Component's zIndexing.
        // That must move to front to then be able to rebase its zIndex stack and move this to the front
        if (zip && me.bringParentToFront !== false) {
            zip.toFront(true);
        }

        if (!Ext.isDefined(preventFocus)) {
            preventFocus = !me.focusOnToFront;
        }

        if (preventFocus) {
            me.preventFocusOnActivate = true;
        }
        if (me.zIndexManager.bringToFront(me, preventFocus)) {    
            if (!preventFocus) {
                // Kick off a delayed focus request.
                // If another floating Component is toFronted before the delay expires
                // this will not receive focus.
                me.focus(false, true);
            }
        }
        
        // Restore to original setting
        me.preventFocusOnActivate = preventFocusSetting;
        return me;
    },

    /**
     * This method is called internally by {@link Ext.ZIndexManager} to signal that a floating Component has either been
     * moved to the top of its zIndex stack, or pushed from the top of its zIndex stack.
     *
     * If a _Window_ is superceded by another Window, deactivating it hides its shadow.
     *
     * This method also fires the {@link Ext.Component#activate activate} or
     * {@link Ext.Component#deactivate deactivate} event depending on which action occurred.
     *
     * @param {Boolean} [active=false] True to activate the Component, false to deactivate it.
     * @param {Ext.Component} [newActive] The newly active Component which is taking over topmost zIndex position.
     */
    setActive: function(active, newActive) {
        var me = this;
        
        if (active) {
            if (me.el.shadow && !me.maximized) {
                me.el.enableShadow(true);
            }
            if (!me.preventFocusOnActivate) {
                me.focus(false, true);
            }
            me.fireEvent('activate', me);
        } else {
            // Only the *Windows* in a zIndex stack share a shadow. All other types of floaters
            // can keep their shadows all the time
            if (me.isWindow && (newActive && newActive.isWindow) && me.hideShadowOnDeactivate) {
                me.el.disableShadow();
            }
            me.fireEvent('deactivate', me);
        }
    },

    /**
     * Sends this Component to the back of (lower z-index than) any other visible windows
     * @return {Ext.Component} this
     */
    toBack: function() {
        this.zIndexManager.sendToBack(this);
        return this;
    },

    /**
     * Center this Component in its container.
     * @return {Ext.Component} this
     */
    center: function() {
        var me = this,
            xy;
            
        if (me.isVisible()) {
            xy = me.getAlignToXY(me.container, 'c-c');
            me.setPagePosition(xy);
        } else {
            me.needsCenter = true;
        }
        return me;
    },
    
    onFloatShow: function() {
        if (this.needsCenter) {
            this.center();    
        }
        delete this.needsCenter;
    },

    // @private
    fitContainer: function(animate) {
        var me = this,
            parent = me.floatParent,
            container = parent ? parent.getTargetEl() : me.container,
            newBox = container.getViewSize(false),
            newPosition = parent || (container.dom !== document.body) ?
                // If we are a contained floater, or rendered to a div, maximized position is (0,0)
                [0, 0] :
                // If no parent and rendered to body, align with origin of container el.
                container.getXY();

        newBox.x = newPosition[0];
        newBox.y = newPosition[1];
        me.setBox(newBox, animate);
    }
});
