/**
 * Leaderboard: an object representing one leaderboard on the page. More than
 * one can be instantiated (i.e. a category's weekly and monthly leaderboards).
 * 
 * @param {String} parentId: The ID of the parent DIV
 * @param {String} url: The 'base' URL of the web service providing the data
 *  (e.g. http://cms.everestgaming.com:6644/leaderboard/ec/)
 * @param {Integer} maxRows: The maximum number of rows to load. Should be
 *  equal to or greater than the number of displayed rows.
 * @param {Boolean} paginate: If true (default), a paginated leaderboard is
 *  displayed showing every rank. If false, only a single page is displayed,
 *  limited to the number of rows in the table.
 * @param {Boolean} sortable: If true (default), clicking a column header
 *  will sort the table by that column.
 * @param {Boolean} filterable: If true, a 'filter' field appears in the 
 *  table.
 * @param {URI} language: The URL to a language file to use in the display.
 * @param {String} period: The initial period to display. Defaults to latest.
 */
function Leaderboard(parentId, url, maxRows, paginate, sortable, filterable, 
                    language, period, plainData) {	

    this.parent = $(parentId);
    
    // Bail if there's no such ID
    if (this.parent.length === 0)
       return;

    paginate = !(paginate === false);
    this.sortable = !(sortable === false);
    this.plainData = plainData === true;
    
    // Add 'sort by img alt' functions to DataTables
    if (this.sortable) {
		var getAlt = function(a){
			var x = a.match(/alt=["|'](.*?)["|']/);
			return x == null ? '' : x[1].toLowerCase();
		};
		
		jQuery.fn.dataTableExt.oSort['alt-string-asc'] = function(a, b){
			var x = getAlt(a), y = getAlt(b);
			return ((x < y) ? -1 : ((x > y) ? 1 : 0));
		};
		
		jQuery.fn.dataTableExt.oSort['alt-string-desc'] = function(a, b){
            var x = getAlt(a), y = getAlt(b);
			return ((x < y) ? 1 : ((x > y) ? -1 : 0));
		};
	}

	this.url = url;
	if (this.url[this.url.length-1] != '/')
	   this.url += '/';
	  
	this.maxRows = maxRows === null ? 0 : maxRows;
	
	this.parent = this.parent.first();
	this.thead = this.parent.find("thead").first();
	if (this.thead.length === 0) { 
      this.parent.find("th").parent().wrap("<thead />");
      this.thead = this.parent.find("thead").first().detach();
      this.thead.prependTo(this.parent.find("table").first());    
    }
    this.table = this.parent.find("table").first();
	this.tbody = this.table.find("tbody");
    this.numRows = this.tbody.find("tr").length;
	this.numRows = this.numRows > 1 ? this.numRows : 20;

    if (!paginate)
       this.maxRows = this.numRows;
    
	// Get actual column order from the table in the template.
	// Also generate blank 'filler' for rounding out last page.
	var _this = this;
    this.colnames = [];
	this.filler = "";
    this.parent.find("th").each(function(x) {
        _this.colnames.push($(this).attr('class'));
        _this.filler+="<td class='"+_this.colnames[x]+"'>&nbsp;</td>";
	});
	
	// Language data. See http://datatables.net/usage/i18n
    if (language == null) 
		language = {
            "sZeroRecords": "No leaderboard data available, try again later",
			"oPaginate": {
				"sFirst": "&lt;&lt;",
				"sPrevious": "&lt;",
				"sNext": "&gt;",
				"sLast": "&gt;&gt;"
			}
		};
	else
	     language = { "sUrl": language };
	
    this.table = this.table.dataTable({
		"bProcessing": false,
        "bPaginate": paginate,
        "sPaginationType": "full_numbers",
        "bFilter": filterable === true,
        "bLengthChange": false,
        "iDisplayLength": this.numRows,
        "bSort": this.sortable,
        "bInfo": false,
        "oLanguage": language,
        "aoColumnDefs": _this._getCols(),
		"fnDrawCallback": function(x) {
            for (var i = _this.tbody.find('tr').length; i < _this.numRows; i++) {
				var eo = i % 2 ? 'even' : 'odd';
				_this.tbody.append("<tr class='filler "+eo+"'>" + _this.filler + "</tr>");
			}
		}
    });
	
	$.fn.dataTableExt.oPagination.iFullNumbersShowPages = 20;
	
    this.table.fnClearTable();
	
    this.period = this.parent.find("span.period").first();
    this.lastUpdated = this.parent.find("span.lastUpdated").first();
	
	this.historyList = this.parent.find(".history select.historyList").first();
    this.next = this.parent.find(".history div.next").first();
	this.prev = this.parent.find(".history div.previous").first();
	
    this.history = [];
    this.updateHistory();
	this.historyIdx = 0;
    this.lastPeriod = '';
    this.updateBoard(period);
	
    this.next.click(function() {
        _this.nextPeriod();
    });
    
    this.prev.click(function() {
        _this.previousPeriod();
    });
    
    this.historyList.change(function() {
        _this.updateBoard(this.options[this.selectedIndex].value);
    });
   
}


/**
 * "Private" method for generating the column renderers. The first row of the 
 * table is used as a template; each cell's class attribute is duplicated, and 
 * if the cell contains an image, the URL/path and extension are applied to the 
 * cell's value (for flags based on country, etc.).
 */
Leaderboard.prototype._getCols = function() {
	var renderers = [];
	var _this = this;
    var firstrow = this.table.find("td").first().parent();
	firstrow.find("td").each(function(x) {
		var renderer = {
			'sClass': _this.colnames[x],
			'aTargets': [x]
		};
		var img = $(this).find("img").first();
		if (img.length > 0) {
			var src = img.attr('src');
            var urlEnd = src.substr(0,src.lastIndexOf("/")+1);
            var extStart = src.substr(src.lastIndexOf("."));
			renderer["fnRender"] = function(obj) {
				if (obj.aData[x] == null)
				    return "";
				var d = obj.aData[x].replace(/^\s\s*/, '').replace(/\s\s*$/, '');
    			if (d.length == 2)
                    return "<img src='" + urlEnd + d + extStart + 
					   "' alt='" + d + "'/>";
				return "";
            };
            if (_this.sortable)
                renderer["sType"] = "alt-string";
		}
		renderers.push(renderer);
		$(this).html("");
	});
	return renderers;
};


/**
 * Populate a leaderboard display
 * 
 * @param {Object} data The leaderboard JSON data
 */
Leaderboard.prototype.fillTable = function(data) {
    this.table.fnClearTable();
    var ents = [];
	if (this.plainData) 
		ents = data['entries'];
	else {
		for (var i = 0; i < data['entries'].length; i++) {
			var entry = data['entries'][i];
			var entAr = [];
			for (var j = 0; j < this.colnames.length; j++) 
				entAr.push(entry[this.colnames[j]]);
			ents.push(entAr);
		}
	}
	
    this.table.fnAddData(ents);
	
    this.lastUpdated.html(data['lastUpdate']);
    this.period.html(data['start'] + " - " + data['end']);
};


/**
 * Construct the history dropdown list.
 * 
 * @param {Array} data: The history as an array of two-item arrays. data[x][0]
 *  is the display name, data[x][1] is the dropdown option's value.
 */
Leaderboard.prototype.makeHistoryDropdown = function (data) {
//	if (this.historyList.length === 0)
    if (data.length === 0)
	   return;
	data.reverse();
	this.history = []; //data[0];
    this.historyList.html("");
    for (var i = 0; i < data.length; i++) {
		this.history.push(data[i][1]);
		this.historyList.append("<option value='" + data[i][1] + "'>" + 
		                          data[i][0]+" - " + data[i][1]+ "</option>");
    }
};


/**
 * Change the month displayed in the history dropdown, which will cause
 * the leaderboard to update.
 * 
 * @param {int} idx - The index into the history list of the date to display.
 */
Leaderboard.prototype.setHistorySelection = function (idx) {
	if (this.historyList.length === 0)
	   return;
    if (idx >= 0 && idx < this.history.length) {
        this.historyList.val(this.history[idx]);
		this.historyIdx = idx;
		this.updateBoard(this.history[idx]);
    }
};


/**
 * Refresh leaderboard content. 
 * 
 * @param {String} period: The ending date of a leaderboard period. If none
 *  is provided the latest is retrieved.
 */
Leaderboard.prototype.updateBoard = function(period){
	if (period == this.lastPeriod) 
		return;
	
	var _this = this;
	var thisUrl = this.url + (period == null ? 'current' : period);
	
    thisUrl += "?callback=?";
	
	if (this.plainData)
	   thisUrl += "&columns=" + this.colnames.join('+');
	
    if (this.maxRows)
        thisUrl += "&last=" + this.maxRows;
		
    $.getJSON(thisUrl, function(data){
      _this.fillTable(data);
    });
	
	try {
		// IE fix
		this.historyIdx = this.history.indexOf(period);
	} 
	catch (e) {
		if (!(typeof this.historyIdx) == 'number')
    		this.historyIdx = 0;
	}
	
    if (this.historyIdx <= 0) 
       this.historyIdx = 0;
    else if (this.historyIdx >= this.history.length)
       this.historyIdx = this.history.length - 1;

    if (this.history.length < 2) {
		this.next.hide();
		this.prev.hide();
	}
	else {
		if (this.historyIdx === 0) 
			this.next.hide();
		else 
			this.next.show();
		
		if (this.historyIdx == this.history.length - 1) 
			this.prev.hide();
		else 
			this.prev.show();
	}     
	      
    this.lastPeriod = period;
};


/**
 * The external call to build the history dropdown list.
 */
Leaderboard.prototype.updateHistory = function () {
	var _this = this;
    $.getJSON(this.url + "periods/?callback=?", function(data){
        _this.makeHistoryDropdown(data);
    });
};


/**
 * Load the next period (if one exists).
 * 
 */
Leaderboard.prototype.nextPeriod = function() {
    this.setHistorySelection(this.historyIdx-1);
};


/**
 * Load the previous period (if one exists).
 */
Leaderboard.prototype.previousPeriod = function () {
    this.setHistorySelection(this.historyIdx+1);
};