/**
 * @author Ed Spencer
 * @class Ext.tab.Bar
 * @extends Ext.panel.Header
 * <p>TabBar is used internally by a {@link Ext.tab.Panel TabPanel} and wouldn't usually need to be created manually.</p>
 */
Ext.define('Ext.tab.Bar', {
    extend: 'Ext.panel.Header',
    alias: 'widget.tabbar',
    baseCls: Ext.baseCSSPrefix + 'tab-bar',

    requires: [
        'Ext.tab.Tab',
        'Ext.FocusManager'
    ],

    // @private
    defaultType: 'tab',

    /**
     * @cfg Boolean plain
     * True to not show the full background on the tabbar
     */
    plain: false,

    // @private
    renderTpl: [
        '<div class="{baseCls}-body<tpl if="ui"> {baseCls}-body-{ui}<tpl for="uiCls"> {parent.baseCls}-body-{parent.ui}-{.}</tpl></tpl>"<tpl if="bodyStyle"> style="{bodyStyle}"</tpl>></div>',
        '<div class="{baseCls}-strip<tpl if="ui"> {baseCls}-strip-{ui}<tpl for="uiCls"> {parent.baseCls}-strip-{parent.ui}-{.}</tpl></tpl>"></div>'
    ],

    /**
     * @cfg {Number} minTabWidth The minimum width for each tab. Defaults to <tt>30</tt>.
     */
    minTabWidth: 30,

    /**
     * @cfg {Number} maxTabWidth The maximum width for each tab. Defaults to <tt>undefined</tt>.
     */
    maxTabWidth: undefined,

    // @private
    initComponent: function() {
        var me = this,
            keys;

        if (me.plain) {
            me.setUI(me.ui + '-plain');
        }
        
        me.addClsWithUI(me.dock);

        me.addEvents(
            /**
             * @event change
             * Fired when the currently-active tab has changed
             * @param {Ext.tab.Bar} tabBar The TabBar
             * @param {Ext.Tab} tab The new Tab
             * @param {Ext.Component} card The card that was just shown in the TabPanel
             */
            'change'
        );

        Ext.applyIf(me.renderSelectors, {
            body : '.' + me.baseCls + '-body',
            strip: '.' + me.baseCls + '-strip'
        });
        me.callParent(arguments);

        // TabBar must override the Header's align setting.
        me.layout.align = (me.orientation == 'vertical') ? 'left' : 'top';
        me.layout.overflowHandler = Ext.create('Ext.layout.container.boxOverflow.Scroller', me.layout);
        me.items.removeAt(me.items.getCount() - 1);
        me.items.removeAt(me.items.getCount() - 1);
        
        // Subscribe to Ext.FocusManager for key navigation
        keys = me.orientation == 'vertical' ? ['up', 'down'] : ['left', 'right'];
        Ext.FocusManager.subscribe(me, {
            keys: keys
        });
    },

    // @private
    onAdd: function(tab) {
        var me = this,
            tabPanel = me.tabPanel,
            hasOwner = !!tabPanel;

        me.callParent(arguments);
        tab.position = me.dock;
        if (hasOwner) {
            tab.minWidth = tabPanel.minTabWidth;
        }
        else {
            tab.minWidth = me.minTabWidth + (tab.iconCls ? 25 : 0);
        }
        tab.maxWidth = me.maxTabWidth || (hasOwner ? tabPanel.maxTabWidth : undefined);
    },

    // @private
    afterRender: function() {
        var me = this;

        me.mon(me.el, {
            scope: me,
            click: me.onClick,
            delegate: '.' + Ext.baseCSSPrefix + 'tab'
        });
        me.callParent(arguments);
        
    },

    afterComponentLayout : function() {
        var me = this;
        
        me.callParent(arguments);
        me.strip.setWidth(me.el.getWidth());
    },

    // @private
    onClick: function(e, target) {
        // The target might not be a valid tab el.
        var tab = Ext.getCmp(target.id),
            tabPanel = this.tabPanel,
            allowActive = true;

        target = e.getTarget();

        if (tab && tab.isDisabled && !tab.isDisabled()) {
            if (tab.closable && target === tab.closeEl.dom) {
                tab.onCloseClick();
            } else {
                if (tabPanel) {
                    // TabPanel will card setActiveTab of the TabBar
                    tabPanel.setActiveTab(tab.card);
                } else {
                    this.setActiveTab(tab);
                }
                tab.focus();
            }
        }
    },

    /**
     * @private
     * Closes the given tab by removing it from the TabBar and removing the corresponding card from the TabPanel
     * @param {Ext.Tab} tab The tab to close
     */
    closeTab: function(tab) {
        var me = this,
            card = tab.card,
            tabPanel = me.tabPanel,
            nextTab;
            
        if (card && card.fireEvent('beforeclose', card) === false) {
            return false;
        }

        if (tab.active && me.items.getCount() > 1) {
            nextTab = tab.next('tab') || me.items.items[0];
            me.setActiveTab(nextTab);
            if (tabPanel) {
                tabPanel.setActiveTab(nextTab.card);
            }
        }
        /*
         * force the close event to fire. By the time this function returns,
         * the tab is already destroyed and all listeners have been purged
         * so the tab can't fire itself.
         */
        tab.fireClose();
        me.remove(tab);

        if (tabPanel && card) {
            card.fireEvent('close', card);
            tabPanel.remove(card);
        }
        
        if (nextTab) {
            nextTab.focus();
        }
    },

    /**
     * @private
     * Marks the given tab as active
     * @param {Ext.Tab} tab The tab to mark active
     */
    setActiveTab: function(tab) {
        if (tab.disabled) {
            return;
        }
        var me = this;
        if (me.activeTab) {
            me.activeTab.deactivate();
        }
        tab.activate();
        
        if (me.rendered) {
            me.layout.layout();
            tab.el.scrollIntoView(me.layout.getRenderTarget());
        }
        me.activeTab = tab;
        me.fireEvent('change', me, tab, tab.card);
    }
});