/*
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)
*/
/**
 * The FocusManager is responsible for globally:
 *
 * 1. Managing component focus
 * 2. Providing basic keyboard navigation
 * 3. (optional) Provide a visual cue for focused components, in the form of a focus ring/frame.
 *
 * To activate the FocusManager, simply call `Ext.FocusManager.enable();`. In turn, you may
 * deactivate the FocusManager by subsequently calling `Ext.FocusManager.disable();`.  The
 * FocusManager is disabled by default.
 *
 * To enable the optional focus frame, pass `true` or `{focusFrame: true}` to {@link #method-enable}.
 *
 * Another feature of the FocusManager is to provide basic keyboard focus navigation scoped to any {@link Ext.container.Container}
 * that would like to have navigation between its child {@link Ext.Component}'s.
 *
 * @author Jarred Nicholls <jarred@sencha.com>
 * @docauthor Jarred Nicholls <jarred@sencha.com>
 */
Ext.define('Ext.FocusManager', {
    singleton: true,
    alternateClassName: ['Ext.FocusMgr' ],

    mixins: {
        observable: 'Ext.util.Observable'
    },

    requires: [
        'Ext.AbstractComponent',
        'Ext.Component',
        'Ext.ComponentManager',
        'Ext.ComponentQuery',
        'Ext.util.HashMap',
        'Ext.util.KeyNav'
    ],

    /**
     * @property {Boolean} enabled
     * Whether or not the FocusManager is currently enabled
     */
    enabled: false,

    /**
     * @property {Ext.Component} focusedCmp
     * The currently focused component.
     */

    focusElementCls: Ext.baseCSSPrefix + 'focus-element',

    focusFrameCls: Ext.baseCSSPrefix + 'focus-frame',

    /**
     * @property {String[]} whitelist
     * A list of xtypes that should ignore certain navigation input keys and
     * allow for the default browser event/behavior. These input keys include:
     *
     * 1. Backspace
     * 2. Delete
     * 3. Left
     * 4. Right
     * 5. Up
     * 6. Down
     *
     * The FocusManager will not attempt to navigate when a component is an xtype (or descendents thereof)
     * that belongs to this whitelist. E.g., an {@link Ext.form.field.Text} should allow
     * the user to move the input cursor left and right, and to delete characters, etc.
     */
    whitelist: [
        'textfield'
    ],

    constructor: function(config) {
        var me = this,
            CQ = Ext.ComponentQuery;

        me.mixins.observable.constructor.call(me, config);

        me.addEvents(
            /**
             * @event beforecomponentfocus
             * Fires before a component becomes focused. Return `false` to prevent
             * the component from gaining focus.
             * @param {Ext.FocusManager} fm A reference to the FocusManager singleton
             * @param {Ext.Component} cmp The component that is being focused
             * @param {Ext.Component} previousCmp The component that was previously focused,
             * or `undefined` if there was no previously focused component.
             */
            'beforecomponentfocus',

            /**
             * @event componentfocus
             * Fires after a component becomes focused.
             * @param {Ext.FocusManager} fm A reference to the FocusManager singleton
             * @param {Ext.Component} cmp The component that has been focused
             * @param {Ext.Component} previousCmp The component that was previously focused,
             * or `undefined` if there was no previously focused component.
             */
            'componentfocus',

            /**
             * @event disable
             * Fires when the FocusManager is disabled
             * @param {Ext.FocusManager} fm A reference to the FocusManager singleton
             */
            'disable',

            /**
             * @event enable
             * Fires when the FocusManager is enabled
             * @param {Ext.FocusManager} fm A reference to the FocusManager singleton
             */
            'enable'
        );

        me.focusTask = new Ext.util.DelayedTask(me.handleComponentFocus, me);

        // Gain control on Component focus, blur, hide and destroy
        Ext.override(Ext.AbstractComponent, {
            onFocus: function() {
                this.callParent(arguments);
                if (me.enabled && this.hasFocus) {
                    Array.prototype.unshift.call(arguments, this);
                    me.onComponentFocus.apply(me, arguments);
                }
            },
            onBlur: function() {
                this.callParent(arguments);
                if (me.enabled && !this.hasFocus) {
                    Array.prototype.unshift.call(arguments, this);
                    me.onComponentBlur.apply(me, arguments);
                }
            },
            onDestroy: function() {
                this.callParent(arguments);
                if (me.enabled) {
                    Array.prototype.unshift.call(arguments, this);
                    me.onComponentDestroy.apply(me, arguments);
                }
            }
        });
        Ext.override(Ext.Component, {
            afterHide: function() {
                this.callParent(arguments);
                if (me.enabled) {
                    Array.prototype.unshift.call(arguments, this);
                    me.onComponentHide.apply(me, arguments);
                }
            }
        });
        // Setup KeyNav that's bound to document to catch all
        // unhandled/bubbled key events for navigation
        me.keyNav = new Ext.util.KeyNav(Ext.getDoc(), {
            disabled: true,
            scope: me,

            backspace: me.focusLast,
            enter: me.navigateIn,
            esc: me.navigateOut,
            tab: me.navigateSiblings,
            space: me.navigateIn,
            del: me.focusLast,
            left: me.navigateSiblings,
            right: me.navigateSiblings,
            down: me.navigateSiblings,
            up: me.navigateSiblings
        });

        me.focusData = {};
        me.subscribers = new Ext.util.HashMap();
        me.focusChain = {};

        // Setup some ComponentQuery pseudos
        Ext.apply(CQ.pseudos, {
            // Return the single next focusable sibling from the current idx in either direction (step -1 or 1)
            nextFocus: function(cmps, idx, step) {
                step = step || 1;
                idx = parseInt(idx, 10);

                var len = cmps.length,
                    i = idx, c;

                for (;;) {
                    // Increment index, and loop round if off either end
                    if ((i += step) >= len) {
                        i = 0;
                    } else if (i < 0) {
                        i = len - 1;
                    }

                    // As soon as we loop back to the starting index, give up, there are no focusable siblings.
                    if (i === idx) {
                        return [];
                    }

                    // If we have found a focusable sibling, return it
                    if ((c = cmps[i]).isFocusable()) {
                        return [c];
                    }
                }

                return [];
            },

            prevFocus: function(cmps, idx) {
                return this.nextFocus(cmps, idx, -1);
            },

            root: function(cmps) {
                var len = cmps.length,
                    results = [],
                    i = 0,
                    c;

                for (; i < len; i++) {
                    c = cmps[i];
                    if (!c.ownerCt) {
                        results.push(c);
                    }
                }

                return results;
            }
        });
    },

    /**
     * Adds the specified xtype to the {@link #whitelist}.
     * @param {String/String[]} xtype Adds the xtype(s) to the {@link #whitelist}.
     */
    addXTypeToWhitelist: function(xtype) {
        var me = this;

        if (Ext.isArray(xtype)) {
            Ext.Array.forEach(xtype, me.addXTypeToWhitelist, me);
            return;
        }

        if (!Ext.Array.contains(me.whitelist, xtype)) {
            me.whitelist.push(xtype);
        }
    },

    clearComponent: function(cmp) {
        clearTimeout(this.cmpFocusDelay);
        if (!cmp.isDestroyed) {
            cmp.blur();
        }
    },

    /**
     * Disables the FocusManager by turning of all automatic focus management and keyboard navigation
     */
    disable: function() {
        var me = this;

        if (!me.enabled) {
            return;
        }

        delete me.options;
        me.enabled = false;

        me.removeDOM();

        // Stop handling key navigation
        me.keyNav.disable();

        me.fireEvent('disable', me);
    },

    /**
     * Enables the FocusManager by turning on all automatic focus management and keyboard navigation
     * @param {Boolean/Object} options Either `true`/`false` to turn on the focus frame, or an object
     * with the following options:
     * @param {Boolean} [options.focusFrame=false] `true` to show the focus frame around a component when it is focused.
     */
    enable: function(options) {
        var me = this;

        if (options === true) {
            options = { focusFrame: true };
        }
        me.options = options = options || {};

        if (me.enabled) {
            return;
        }

        // When calling addFocusListener on Containers, the FocusManager must be enabled, otherwise it won't do it.
        me.enabled = true;
        me.initDOM(options);

        // Start handling key navigation
        me.keyNav.enable();

        // Finally, let's focus our global focus el so we start fresh
        me.focusEl.focus();
        delete me.focusedCmp;

        me.fireEvent('enable', me);
    },

    focusLast: function(e) {
        var me = this;

        if (me.isWhitelisted(me.focusedCmp)) {
            return true;
        }

        // Go back to last focused item
        if (me.previousFocusedCmp) {
            me.previousFocusedCmp.focus();
        }
    },

    getRootComponents: function() {
        var CQ = Ext.ComponentQuery,
            inline = CQ.query(':focusable:root:not([floating])'),
            floating = CQ.query(':focusable:root[floating]');

        // Floating items should go to the top of our root stack, and be ordered
        // by their z-index (highest first)
        floating.sort(function(a, b) {
            return a.el.getZIndex() > b.el.getZIndex();
        });

        return floating.concat(inline);
    },

    initDOM: function(options) {
        var me = this,
            cls = me.focusFrameCls,
            needListeners = Ext.ComponentQuery.query('{getFocusEl()}:not([focusListenerAdded])'),
            i = 0, len = needListeners.length;

        if (!Ext.isReady) {
            return Ext.onReady(me.initDOM, me);
        }

        // When we are enabled, we must ensure that all Components which return a focusEl that is *not naturally focusable*
        // have focus/blur listeners enabled to then trigger onFocus/onBlur handling so that we get to know about their focus action.
        // These listeners are not added at initialization unless the FocusManager is enabled at that time.
        for (; i < len; i++) {
            needListeners[i].addFocusListener();
        }

        // Make the document body the global focus element
        if (!me.focusEl) {
            me.focusEl = Ext.getBody();
            me.focusEl.dom.tabIndex = -1;
        }

        // Create global focus frame
        if (!me.focusFrame && options.focusFrame) {
            me.focusFrame = Ext.getBody().createChild({
                cls: cls,
                children: [
                    { cls: cls + '-top' },
                    { cls: cls + '-bottom' },
                    { cls: cls + '-left' },
                    { cls: cls + '-right' }
                ],
                style: 'top: -100px; left: -100px;'
            });
            me.focusFrame.setVisibilityMode(Ext.Element.DISPLAY);
            me.focusFrame.hide().setLocalXY(0, 0);
        }
    },

    isWhitelisted: function(cmp) {
        return cmp && Ext.Array.some(this.whitelist, function(x) {
            return cmp.isXType(x);
        });
    },

    navigateIn: function(e) {
        var me = this,
            focusedCmp = me.focusedCmp,
            defaultRoot,
            firstChild;

        if (me.isWhitelisted(focusedCmp)) {
            return true;
        }

        if (!focusedCmp) {
            // No focus yet, so focus the first root cmp on the page
            defaultRoot = me.getRootComponents()[0];
            if (defaultRoot) {
                // If the default root is based upon the body, then it will already be focused, and will not fire a focus event to
                // trigger its own onFocus processing, so we have to programatically blur it first.
                if (defaultRoot.getFocusEl() === me.focusEl) {
                    me.focusEl.blur();
                }
                defaultRoot.focus();
            }
        } else {
            // Drill into child ref items of the focused cmp, if applicable.
            // This works for any Component with a getRefItems implementation.
            firstChild = focusedCmp.hasFocus ? Ext.ComponentQuery.query('>:focusable', focusedCmp)[0] : focusedCmp;
            if (firstChild) {
                firstChild.focus();
            } else {
                // Let's try to fire a click event, as if it came from the mouse
                if (Ext.isFunction(focusedCmp.onClick)) {
                    e.button = 0;
                    focusedCmp.onClick(e);
                    if (focusedCmp.isVisible(true)) {
                        focusedCmp.focus();
                    } else {
                        me.navigateOut();
                    }
                }
            }
        }
    },

    navigateOut: function(e) {
        var me = this,
            parent;

        if (!me.focusedCmp || !(parent = me.focusedCmp.up(':focusable'))) {
            me.focusEl.focus();
        } else {
            parent.focus();
        }

        // In some browsers (Chrome) FocusManager can handle this before other
        // handlers. Ext Windows have their own Esc key handling, so we need to
        // return true here to allow the event to bubble.
        return true;
    },

    navigateSiblings: function(e, source, parent) {
        var me = this,
            src = source || me,
            key = e.getKey(),
            EO = Ext.EventObject,
            goBack = e.shiftKey || key == EO.LEFT || key == EO.UP,
            checkWhitelist = key == EO.LEFT || key == EO.RIGHT || key == EO.UP || key == EO.DOWN,
            nextSelector = goBack ? 'prev' : 'next',
            idx, next, focusedCmp, siblings;

        focusedCmp = (src.focusedCmp && src.focusedCmp.comp) || src.focusedCmp;
        if (!focusedCmp && !parent) {
            return true;
        }

        if (checkWhitelist && me.isWhitelisted(focusedCmp)) {
            return true;
        }

        // If no focused Component, or a root level one was focused, then siblings are root components.
        if (!focusedCmp || focusedCmp.is(':root')) {
            siblings = me.getRootComponents();
        } else {
            // Else if the focused component has a parent, get siblings from there
            parent = parent || focusedCmp.up();
            if (parent) {
                siblings = parent.getRefItems();
            }
        }


        // Navigate if we have found siblings.
        if (siblings) {
            idx = focusedCmp ? Ext.Array.indexOf(siblings, focusedCmp) : -1;
            next = Ext.ComponentQuery.query(':' + nextSelector + 'Focus(' + idx + ')', siblings)[0];
            if (next && focusedCmp !== next) {
                next.focus();
                return next;
            }
        }
    },

    onComponentBlur: function(cmp, e) {
        var me = this;

        if (me.focusedCmp === cmp) {
            me.previousFocusedCmp = cmp;
            delete me.focusedCmp;
        }

        if (me.focusFrame) {
            me.focusFrame.hide();
        }
    },

    onComponentFocus: function(cmp, e) {
        var me = this,
            chain = me.focusChain,
            parent;

        if (!cmp.isFocusable()) {
            me.clearComponent(cmp);

            // Check our focus chain, so we don't run into a never ending recursion
            // If we've attempted (unsuccessfully) to focus this component before,
            // then we're caught in a loop of child->parent->...->child and we
            // need to cut the loop off rather than feed into it.
            if (chain[cmp.id]) {
                return;
            }

            // Try to focus the parent instead
            parent = cmp.up();
            if (parent) {
                // Add component to our focus chain to detect infinite focus loop
                // before we fire off an attempt to focus our parent.
                // See the comments above.
                chain[cmp.id] = true;
                parent.focus();
            }

            return;
        }
        // Clear our focus chain when we have a focusable component
        me.focusChain = {};

        // Capture the focusEl to frame now.
        // Button returns its encapsulating element during the focus phase
        // So that element gets styled and framed.
        me.focusTask.delay(10, null, null, [cmp, cmp.getFocusEl()]);
    },

    handleComponentFocus: function(cmp, focusEl) {
        var me = this,
            cls,
            ff,
            box,
            bt,
            bl,
            bw,
            bh,
            ft,
            fb,
            fl,
            fr;

        if (me.fireEvent('beforecomponentfocus', me, cmp, me.previousFocusedCmp) === false) {
            me.clearComponent(cmp);
            return;
        }

        me.focusedCmp = cmp;

        // If we have a focus frame, show it around the focused component
        if (me.shouldShowFocusFrame(cmp)) {
            cls = '.' + me.focusFrameCls + '-';
            ff = me.focusFrame;
            
            // focusEl may in fact be a descendant component to which to delegate focus
            box = (focusEl.dom ? focusEl : focusEl.el).getBox();

            // Size the focus frame's t/b/l/r according to the box
            // This leaves a hole in the middle of the frame so user
            // interaction w/ the mouse can continue
            bt = box.top;
            bl = box.left;
            bw = box.width;
            bh = box.height;
            ft = ff.child(cls + 'top');
            fb = ff.child(cls + 'bottom');
            fl = ff.child(cls + 'left');
            fr = ff.child(cls + 'right');

            ft.setWidth(bw).setLocalXY(bl, bt);
            fb.setWidth(bw).setLocalXY(bl, bt + bh - 2);
            fl.setHeight(bh - 2).setLocalXY(bl, bt + 2);
            fr.setHeight(bh - 2).setLocalXY(bl + bw - 2, bt + 2);

            ff.show();
        }

        me.fireEvent('componentfocus', me, cmp, me.previousFocusedCmp);
    },

    onComponentHide: function(cmp) {
        var me = this,
            cmpHadFocus = false,
            focusedCmp = me.focusedCmp,
            parent;

        if (focusedCmp) {
            // See if the Component being hidden was the focused Component, or owns the focused Component
            // In these cases, focus needs to be removed from the focused Component to the nearest focusable ancestor
            cmpHadFocus = cmp.hasFocus || (cmp.isContainer && cmp.isAncestor(me.focusedCmp));
        }

        me.clearComponent(cmp);

        // Move focus onto the nearest focusable ancestor, or this is there is none
        if (cmpHadFocus && (parent = cmp.up(':focusable'))) {
            parent.focus();
        } else {
            me.focusEl.focus();
        }
    },

    onComponentDestroy: function() {

    },

    removeDOM: function() {
        var me = this;

        // If we are still enabled globally, or there are still subscribers
        // then we will halt here, since our DOM stuff is still being used
        if (me.enabled || me.subscribers.length) {
            return;
        }

        Ext.destroy(
            me.focusFrame
        );
        delete me.focusEl;
        delete me.focusFrame;
    },

    /**
     * Removes the specified xtype from the {@link #whitelist}.
     * @param {String/String[]} xtype Removes the xtype(s) from the {@link #whitelist}.
     */
    removeXTypeFromWhitelist: function(xtype) {
        var me = this;

        if (Ext.isArray(xtype)) {
            Ext.Array.forEach(xtype, me.removeXTypeFromWhitelist, me);
            return;
        }

        Ext.Array.remove(me.whitelist, xtype);
    },

    setupSubscriberKeys: function(container, keys) {
        var me = this,
            el = container.getFocusEl(),
            scope = keys.scope,
            handlers = {
                backspace: me.focusLast,
                enter: me.navigateIn,
                esc: me.navigateOut,
                scope: me
            },

            navSiblings = function(e) {
                if (me.focusedCmp === container) {
                    // Root the sibling navigation to this container, so that we
                    // can automatically dive into the container, rather than forcing
                    // the user to hit the enter key to dive in.
                    return me.navigateSiblings(e, me, container);
                } else {
                    return me.navigateSiblings(e);
                }
            };

        Ext.iterate(keys, function(key, cb) {
            handlers[key] = function(e) {
                var ret = navSiblings(e);

                if (Ext.isFunction(cb) && cb.call(scope || container, e, ret) === true) {
                    return true;
                }

                return ret;
            };
        }, me);

        return new Ext.util.KeyNav(el, handlers);
    },

    shouldShowFocusFrame: function(cmp) {
        var me = this,
            opts = me.options || {};

        // Do not show a focus frame if
        // 1. We are configured not to.
        // 2. No Component was passed
        if (!me.focusFrame || !cmp) {
            return false;
        }

        // Global trumps
        if (opts.focusFrame) {
            return true;
        }

        if (me.focusData[cmp.id].focusFrame) {
            return true;
        }

        return false;
    }
});