/**
 * Tabs aria support
 * @creator yiminghe@gmail.com
 */
KISSY.add('switchable/tabs/aria', function(S, DOM, Event, Switchable, Aria, Tabs) {

        var KEY_PAGEUP = 33;
        var KEY_PAGEDOWN = 34;
        var KEY_END = 35;
        var KEY_HOME = 36;

        var KEY_LEFT = 37;
        var KEY_UP = 38;
        var KEY_RIGHT = 39;
        var KEY_DOWN = 40;
        var KEY_TAB = 9;

//    var KEY_SPACE = 32;
//    var KEY_BACKSPACE = 8;
//    var KEY_DELETE = 46;
//    var KEY_ENTER = 13;
//    var KEY_INSERT = 45;
//    var KEY_ESCAPE = 27;

        S.mix(Tabs.Config, {
            aria:true
        });

        Tabs.Plugins.push({
            name:"aria",
            init:function(self) {
                if (!self.config.aria) return;
                var triggers = self.triggers,
                    activeIndex = self.activeIndex,
                    panels = self.panels;
                var container = self.container;
                if (self.nav) {
                    DOM.attr(self.nav, "role", "tablist");
                }
                var i = 0;
                S.each(triggers, function(trigger) {
                    trigger.setAttribute("role", "tab");
                    setTabIndex(trigger, activeIndex == i ? "0" : "-1");
                    if (!trigger.id) {
                        trigger.id = S.guid("ks-switchable");
                    }
                    i++;
                });
                i = 0;
                S.each(panels, function(panel) {
                    var t = triggers[i];
                    panel.setAttribute("role", "tabpanel");
                    panel.setAttribute("aria-hidden", activeIndex == i ? "false" : "true");
                    panel.setAttribute("aria-labelledby", t.id);
                    i++;
                });

                self.on("switch", _tabSwitch, self);


                Event.on(container, "keydown", _tabKeydown, self);
                /**
                 * prevent firefox native tab switch
                 */
                Event.on(container, "keypress", _tabKeypress, self);

            }
        });

        var setTabIndex = Aria.setTabIndex;


        function _currentTabFromEvent(t) {
            var triggers = this.triggers,
                trigger;
            S.each(triggers, function(ct) {
                if (ct == t || DOM.contains(ct, t)) {
                    trigger = ct;
                }
            });
            return trigger;
        }

        function _tabKeypress(e) {

            switch (e.keyCode) {

                case KEY_PAGEUP:
                case KEY_PAGEDOWN:
                    if (e.ctrlKey && !e.altKey && !e.shiftKey) {
                        e.halt();
                    } // endif
                    break;

                case KEY_TAB:
                    if (e.ctrlKey && !e.altKey) {
                        e.halt();
                    } // endif
                    break;

            }
        }

        var getDomEvent = Switchable.getDomEvent;

        /**
         * Keyboard commands for the Tab Panel
         * @param e
         */
        function _tabKeydown(e) {
            var t = e.target,self = this;
            var triggers = self.triggers;

            // Save information about a modifier key being pressed
            // May want to ignore keyboard events that include modifier keys
            var no_modifier_pressed_flag = !e.ctrlKey && !e.shiftKey && !e.altKey;
            var control_modifier_pressed_flag = e.ctrlKey && !e.shiftKey && !e.altKey;

            switch (e.keyCode) {

                case KEY_LEFT:
                case KEY_UP:
                    if (_currentTabFromEvent.call(self, t)
                    // 争渡读屏器阻止了上下左右键
                    //&& no_modifier_pressed_flag
                        ) {
                        self.prev(getDomEvent(e));
                        e.halt();
                    } // endif
                    break;

                case KEY_RIGHT:
                case KEY_DOWN:
                    if (_currentTabFromEvent.call(self, t)
                    //&& no_modifier_pressed_flag
                        ) {
                        self.next(getDomEvent(e));
                        e.halt();
                    } // endif
                    break;

                case KEY_PAGEDOWN:

                    if (control_modifier_pressed_flag) {
                        e.halt();
                        self.next(getDomEvent(e));
                    }
                    break;

                case KEY_PAGEUP:
                    if (control_modifier_pressed_flag) {
                        e.halt();
                        self.prev(getDomEvent(e));
                    }
                    break;

//            case KEY_HOME:
//                if (no_modifier_pressed_flag) {
//                    self.switchTo(0, undefined, getDomEvent(e));
//                    e.halt();
//                }
//                break;
//            case KEY_END:
//                if (no_modifier_pressed_flag) {
//                    self.switchTo(triggers.length - 1, undefined, getDomEvent(e));
//                    e.halt();
//                }
//
//                break;

                case KEY_TAB:
                    if (e.ctrlKey && !e.altKey) {
                        e.halt();
                        if (e.shiftKey)
                            self.prev(getDomEvent(e));
                        else
                            self.next(getDomEvent(e));
                    }
                    break;
            }
        }

        function _tabSwitch(ev) {
            var domEvent = !!(ev.originalEvent.target || ev.originalEvent.srcElement);

            var self = this;
            // 上一个激活 tab
            var lastActiveIndex = self.completedIndex;

            // 当前激活 tab
            var activeIndex = ev.currentIndex;

            if (lastActiveIndex == activeIndex) return;

            var lastTrigger = self.triggers[lastActiveIndex];
            var trigger = self.triggers[activeIndex];
            var lastPanel = self.panels[lastActiveIndex];
            var panel = self.panels[activeIndex];
            if (lastTrigger) {
                setTabIndex(lastTrigger, "-1");
            }
            setTabIndex(trigger, "0");

            // move focus to current trigger if invoked by dom event
            if (domEvent) {
                trigger.focus();
            }
            if (lastPanel) {
                lastPanel.setAttribute("aria-hidden", "true");
            }
            panel.setAttribute("aria-hidden", "false");
        }


    },
    {
        requires:["dom","event","../base","../aria","./base"]
    });

/**
 * 2011-05-08 承玉：add support for aria & keydown
 * <h2>键盘快捷键</h2>

 <ul class="list">
 <li>左/上键:当焦点在标签时转到上一个标签
 <li>右/下键:当焦点在标签时转到下一个标签
 <li>Home: 当焦点在标签时转到第一个标签 -- 去除
 输入框内 home 跳到输入框第一个字符前面 ，
 end 跳到输入框最后一个字符后面 ，
 不应该拦截
 <li>End: 当焦点在标签时转到最后一个标签 -- 去除
 <li>Control + PgUp and Control + Shift + Tab: 当然焦点在容器内时转到当前标签上一个标签
 <li>Control + PgDn and Control + Tab: 当然焦点在容器内时转到当前标签下一个标签
 </ul>
 */