/*
Copyright (c) 2009, http://seyfertdesign.com/jquery/ui-tabs-paging.html

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
*/

$.extend($.ui.tabs.prototype, {
        paging: function(options) {
                var opts = {
                        tabsPerPage: 0,
                        nextButton: '»',
                        prevButton: '«',
                        follow: false,
                        cycle: false,
                        selectOnAdd: false,
                        followOnSelect: false
                };

                opts = $.extend(opts, options);

                var self = this, initialized = false, currentPage,
                        buttonWidth, containerWidth, allTabsWidth, tabWidths,
                        maxPageWidth, pages, resizeTimer = null,
                        windowHeight = $(window).height(), windowWidth = $(window).width();

                function init() {
                        destroy();

                        allTabsWidth = 0, currentPage = 0, maxPageWidth = 0, buttonWidth = 0,
                                pages = new Array(), tabWidths = new Array(), selectedTabWidths = new Array();

                        containerWidth = self.element.width();

                        // loops through LIs, get width of each tab when selected and unselected.
                        var maxDiff = 0;  // the max difference between a selected and unselected tab
                        self.lis.each(function(i) {
                                if (i == self.options.selected) {
                                        selectedTabWidths[i] = $(this).outerWidth({ margin: true });
                                        tabWidths[i] = self.lis.eq(i).removeClass('ui-tabs-selected').outerWidth({ margin: true });
                                        self.lis.eq(i).addClass('ui-tabs-selected');
                                        maxDiff = Math.min(maxDiff, Math.abs(selectedTabWidths[i] - tabWidths[i]));
                                        allTabsWidth += tabWidths[i];
                                } else {
                                        tabWidths[i] = $(this).outerWidth({ margin: true });
                                        selectedTabWidths[i] = self.lis.eq(i).addClass('ui-tabs-selected').outerWidth({ margin: true });
                                        self.lis.eq(i).removeClass('ui-tabs-selected');
                                        maxDiff = Math.max(maxDiff, Math.abs(selectedTabWidths[i] - tabWidths[i]));
                                        allTabsWidth += tabWidths[i];
                                }
                        });
            // fix padding issues with buttons
                        allTabsWidth += maxDiff + ($.browser.msie?4:0) + 9;

                        // if the width of all tables is greater than the container's width, calculate the pages
                        if (allTabsWidth > containerWidth) {
                                // create next button
                                li = $('<li></li>')
                                        .addClass('ui-state-default ui-tabs-paging-next')
                                        .append($('<a href="#"></a>')
                                                        .click(function() { page('next'); return false; })
                                                        .html(opts.nextButton));

                                self.lis.eq(self.length()-1).after(li);
                                buttonWidth = li.outerWidth({ margin: true });

                                // create prev button
                                li = $('<li></li>')
                                        .addClass('ui-state-default ui-tabs-paging-prev')
                                        .append($('<a href="#"></a>')
                                                        .click(function() { page('prev'); return false; })
                                                        .html(opts.prevButton));
                                self.lis.eq(0).before(li);
                                buttonWidth += li.outerWidth({ margin: true });

                                buttonWidth += 19;

                                var pageIndex = 0, pageWidth = 0, maxTabPadding = 0;

                                // start calculating pageWidths
                                for (var i = 0; i < tabWidths.length; i++) {
                                        // if first tab of page or selected tab's padding larger than the current max, set the maxTabPadding
                                        if (pageWidth == 0 || selectedTabWidths[i] - tabWidths[i] > maxTabPadding)
                                                maxTabPadding = (selectedTabWidths[i] - tabWidths[i]);

                                        // if first tab of page, initialize pages variable for page
                                        if (pages[pageIndex] == null) {
                                                pages[pageIndex] = { start: i };

                                        } else if ((i > 0 && (i % opts.tabsPerPage) == 0) || (tabWidths[i] + pageWidth + buttonWidth + 12) > containerWidth) {
                                                if ((pageWidth + maxTabPadding) > maxPageWidth)
                                                        maxPageWidth = (pageWidth + maxTabPadding);
                                                pageIndex++;
                                                pages[pageIndex] = { start: i };
                                                pageWidth = 0;
                                        }
                                        pages[pageIndex].end = i+1;
                                        pageWidth += tabWidths[i];
                                        if (i == self.options.selected) currentPage = pageIndex;
                                }
                                if ((pageWidth + maxTabPadding) > maxPageWidth)
                                        maxPageWidth = (pageWidth + maxTabPadding);

                            // hide all tabs then show tabs for current page
                                self.lis.hide().slice(pages[currentPage].start, pages[currentPage].end).show();
                                if (currentPage == (pages.length - 1) && !opts.cycle)
                                        disableButton('next');
                                if (currentPage == 0 && !opts.cycle)
                                        disableButton('prev');

                                // calculate the right padding for the next button
                                buttonPadding = containerWidth - maxPageWidth - buttonWidth;
                                if (buttonPadding > 0)
                                        $('.ui-tabs-paging-next', self.element).css({ paddingRight: buttonPadding + 'px' });

                                initialized = true;
                        } else {
                                destroy();
                        }

                        $(window).bind('resize', handleResize);
                }

                function page(direction) {
                        currentPage = currentPage + (direction == 'prev'?-1:1);

                        if ((direction == 'prev' && currentPage < 0 && opts.cycle) ||
                                (direction == 'next' && currentPage >= pages.length && !opts.cycle))
                                currentPage = pages.length - 1;
                        else if ((direction == 'prev' && currentPage < 0) ||
                                         (direction == 'next' && currentPage >= pages.length && opts.cycle))
                                currentPage = 0;

                        var start = pages[currentPage].start;
                        var end = pages[currentPage].end;
                        self.lis.hide().slice(start, end).show();

                        if (direction == 'prev') {
                                enableButton('next');
                                if (opts.follow && (self.options.selected < start || self.options.selected > (end-1))) self.select(end-1);
                                if (!opts.cycle && start <= 0) disableButton('prev');
                        } else {
                                enableButton('prev');
                                if (opts.follow && (self.options.selected < start || self.options.selected > (end-1))) self.select(start);
                                if (!opts.cycle && end >= self.length()) disableButton('next');
                        }
                }

                function disableButton(direction) {
                        $('.ui-tabs-paging-'+direction, self.element).addClass('ui-tabs-paging-disabled');
                }

                function enableButton(direction) {
                        $('.ui-tabs-paging-'+direction, self.element).removeClass('ui-tabs-paging-disabled');
                }

                // special function defined to handle IE6 and IE7 resize issues
                function handleResize() {
                        if (resizeTimer) clearTimeout(resizeTimer);

                        if (windowHeight != $(window).height() || windowWidth != $(window).width())
                                resizeTimer = setTimeout(reinit, 100);
                }

                function reinit() {
                        windowHeight = $(window).height();
                        windowWidth = $(window).width();
                        init();
                }

                function destroy() {
                        // remove buttons
                        $('.ui-tabs-paging-next', self.element).remove();
                        $('.ui-tabs-paging-prev', self.element).remove();

                        // show all tabs
                        self.lis.show();

                        initialized = false;

                        $(window).unbind('resize', handleResize);
                }

                // reconfigure "ui.tabs" add/remove events to reinit paging
                var tabsAdd = self.add;
                self.add = function(url, label, index) {
                        // remove paging buttons before adding a tab
                        if (initialized)
                                destroy();

                        tabsAdd.apply(this, [url, label, index]);

                        if (opts.selectOnAdd) {
                                if (index == undefined) index = this.lis.length-1;
                                this.select(index);
                        }
                        // re-initialize paging buttons
                        init();
                };
                var tabsRemove = self.remove;
                self.remove = function(index) {
                        // remove paging buttons before removing a tab
                        if (initialized)
                                destroy();

                        tabsRemove.apply(this, [index]);

                        // re-initialize paging buttons
                        init();
                };
                // reconfigure "ui.tabs" select event to change pages if new tab is selected
                var tabsSelect = self.select;
                self.select = function(index) {
                        tabsSelect.apply(this, [index]);

                        // if paging is not initialized or it is not configured to
                        // change pages when a new tab is selected, then do nothing
                        if (!initialized || !opts.followOnSelect)
                                return;

                        // find the new page based on index of the tab selected
                        for (i in pages) {
                                var start = pages[i].start;
                                var end = pages[i].end;
                                if (index >= start && index < end) {
                                        // if the the tab selected is not within the currentPage of tabs, then change pages
                                        if (i != currentPage) {
                                                self.lis.hide().slice(start, end).show();

                                                currentPage = parseInt(i);
                                                if (currentPage == 0) {
                                                        enableButton('next');
                                                        if (!opts.cycle && start <= 0) disableButton('prev');
                                                } else {
                                                        enableButton('prev');
                                                        if (!opts.cycle && end >= self.length()) disableButton('next');
                                                }
                                        }
                                        break;
                                }
                        }
                };

                // add, remove, and destroy functions specific for paging
                $.extend($.ui.tabs.prototype, {
                        pagingDestroy: function() {
                                destroy();
                        }
                });

                init();
        }
});