/**
 * Sorts a column containing chapter numbers. This can be most useful when
 * using DataTables for a book or book reference style application. By
 * default, five sections are supported (a.b.c.d.e) with each being upto
 * four-digits long. Those defaults are controlled by constMaxSections and
 * constMaxSectionDigits respectively, and can be easily changed
 *
 *  @name chapter
 *  @summary Sort book chapters numerically
 *  @author Colin Marks
 *
 *  @example
 *    $('#example').dataTable( {
 *       columnDefs: [
 *         { type: 'chapter', targets: 0 }
 *       ]
 *    } );
 */

jQuery.extend(jQuery.fn.dataTableExt.oSort, {
	'chapter-pre': function(a) {
		function makeFiller(count) {
			return count === 0 ? '' : Array(count + 1).join('0');
		}

		var constMaxSections = 5;
		var constMaxSectionDigits = 4;

		var filler;
		var result = '';
		var sections = a.split('.');

		for (var i = 0; i < constMaxSections; i++) {
			filler = i < sections.length ? constMaxSectionDigits - sections[i].length : constMaxSectionDigits;

			result += filler === 0 ? '' : Array(filler + 1).join('0');
			result += i < sections.length ? sections[i] : '';
		}

		return result;
	},

	'chapter-asc': function(a, b) {
		return a < b ? -1 : a > b ? 1 : 0;
	},

	'chapter-desc': function(a, b) {
		return a < b ? 1 : a > b ? -1 : 0;
	}
});