var repoindex = (function(repoindex) {

    /*!
     * \brief Adds bootstrap tabs to the HTML element with the specified id.
     */
    repoindex.Tabbing = function(containerId) {
        // assemble required element structure
        this.containerElement = document.createElement("div");
        this.tabbingElement = document.createElement("ul");
        this.tabbingElement.className = "nav nav-tabs";
        this.contentElement = document.createElement("div");
        this.contentElement.className = "tab-content";
        this.containerElement.appendChild(this.tabbingElement);
        this.containerElement.appendChild(this.contentElement);
        repoindex.getElement(containerId).appendChild(this.containerElement);

        this.tabs = [];

        // returns a tab by ID
        this.tabById = function(id) {
            for(var i = 0, len = this.tabs.length; i < len; ++i) {
                if(this.tabs[i].paneElement.id === id) {
                    return this.tabs[i];
                }
            }
        };

        // finds the currently shown tab
        this.findActiveTab = function() {
            for(var i = 0, len = this.tabs.length; i < len; ++i) {
                if(this.tabs[i].classList.contains("active")) {
                    return this.tabs[i];
                }
            }
        };

        // adds a new tab
        this.addTab = function(id, title, closeable, replaceActive) {
            // check whether a tab with the specified ID already exists
            var tabElement = this.tabById(id);
            if(tabElement) {
                // ID already used -> just return currenlty present tab
                return tabElement;
            }

            // create new tab
            tabElement = document.createElement("li");

            // replace active tab
            if(replaceActive) {
                var activeTabElement = this.findActiveTab();
                if(activeTabElement) {
                    this.tabbingElement.removeChild(activeTabElement);
                    this.contentElement.removeChild(activeTabElement.paneElement);
                    tabElement.tabbingIndex = activeTabElement.tabbingIndex;
                }
            }

            // initiate new tab
            if(tabElement.tabbingIndex === undefined) {
                tabElement.tabbingIndex = this.tabs.length;
            }
            var paneElement = document.createElement("div");
            var linkElement = document.createElement("a");
            linkElement.setAttribute("data-toggle", "tab");
            linkElement.href = "#" + id;
            linkElement.appendChild(document.createTextNode(title));
            tabElement.paneElement = paneElement;
            tabElement.linkElement = linkElement;
            tabElement.tabbing = this;
            tabElement.appendChild(linkElement);
            this.tabbingElement.appendChild(tabElement);
            paneElement.tabElement = tabElement;
            paneElement.setAttribute("id", id);
            if(this.tabs.length === 0) {
                tabElement.className = "active";
                paneElement.className = "tab-pane fade in active";
            } else {
                paneElement.className = "tab-pane fade";
            }

            this.contentElement.appendChild(paneElement);

            // method to active tab
            tabElement.activate = function() {
                this.linkElement.click();
            };

            if(closeable) {
                var closeButton = repoindex.makeCloseButton();
                closeButton.style.marginLeft = "4px";
                closeButton.onclick = function() {
                    tabElement.tabbing.removeTab(tabElement);
                };
                linkElement.appendChild(closeButton);
            };

            this.tabs[tabElement.tabbingIndex] = tabElement;
            return tabElement;
        };

        // removes a tab
        this.removeTab = function(tabElement) {
            this.tabbingElement.removeChild(tabElement);
            this.contentElement.removeChild(tabElement.paneElement);
            this.tabs.splice(tabElement.tabbingIndex, 1);
            if(this.tabs.length !== 0) {
                if(tabElement.tabbingIndex === 0) {
                    this.tabs[0].activate();
                } else if(tabElement.tabbingIndex - 1 < this.tabs.length) {
                    this.tabs[tabElement.tabbingIndex - 1].activate();
                } else {
                    this.tabs[this.tabs.length - 1].activate();
                }
                for(var i = tabElement.tabbingIndex, len = this.tabs.length; i < len; ++i) {
                    this.tabs[i].tabbingIndex = i;
                }
            }
            this.tabRemoved(tabElement);
        };

        // disassembles element strucutre
        this.remove = function() {
            this.containerElement.parentNode.removeChild(this.containerElement);
        };

        this.tabRemoved = function(tab) {};
    };

    return repoindex;

})(repoindex || {});