/**
 * @summary     ColumnSearch
 * @description Feature to provide column searching by text input or select
 * @version     1.0.0
 * @file        columnsearch.js
 * @author      datahandler (www.datahandler.uk)
 * @copyright   Copyright datahandler (www.datahandler.uk)
 * 
 * License      MIT - http://datatables.net/license/mit
 */

/**
 * Example usage 1
 * @example
 * zero configuration - displays a select in the footer of each column
 * var table = $('#table_id').DataTable();
 * $.fn.dataTable.ColumnSearch(table);
 */
/**
 * Example usage 2
 * @example
 * select search targetting specific columns
 * var table = $('#table_id').DataTable();
 * $.fn.dataTable.ColumnSearch(table, {
 *      selectAllText: 'Any',
 *      cols: [0,3,5]
 * }); 
 */
/**
 * Example usage 3
 * @example
 * text search with headings as placeholder
 * var table = $('#table_id').DataTable();
 * $.fn.dataTable.ColumnSearch(table, {
 *      searchElementType: 'text',
 *      displayHeadingAsPlaceholder: true
 * }); 
 */
/**
 * Example usage 4
 * @example
 * text search targetting the header or 
 * footer row specified by rowId, and
 * targetting specific columns
 * var table = $('#table_id').DataTable();
 * $.fn.dataTable.ColumnSearch(table, {
 *      searchElementType: 'Any',
 *      rowId: 'rowSearch',
 *      cols: [0,3,5]
 * }); 
 */
(function ($) {
    var ColumnSearch = function (dt, options) {
        var opts = $.extend({}, ColumnSearch.defaults, options);

        if (opts.searchElementType === 'select') initSelectSearch();
        else initTextSearch();

        function initSelectSearch() {
            if (opts.rowId !== null) {
                $('tr#' + opts.rowId + ' th', dt.table().node()).each(function(i) {
                    if (opts.cols.indexOf(i) !== -1) {
                        var column = dt.column(i);
                        appendSelectTo($(this), column);
                    }
                });
            }
            else {
                dt.columns().every( function (i) {
                    if (opts.cols.indexOf(i) !== -1) {
                        var column = this;
                        appendSelectTo($(column.footer()).empty(), column);
                    }
                } );
            }            
        }

        function appendSelectTo($elem, col) {
            var select = $('<select class="col-filter"><option value="">' + opts.selectAllText + '</option></select>')
                .appendTo( $elem )
                .on( 'change', function () {
                    var val = $.fn.dataTable.util.escapeRegex(
                        $(this).val()
                    );

                    col
                        .search( val ? '^'+val+'$' : '', true, false )
                        .draw();
                } );

                col.data().unique().sort().each( function ( d, j ) {
                    select.append( '<option value="'+d+'">'+d+'</option>' )
            } );
        }

        function initTextSearch() {
             if (opts.rowId !== null) {
                $('tr#' + opts.rowId + ' th', dt.table().node()).each(function(i) {
                    if (opts.cols.indexOf(i) !== -1) {
                        var column = dt.column(i);                    
                        var header = $(column.header());
                        var headerText = header.text();
                        appendTextInputTo($(this), column, opts.displayHeadingAsPlaceholder ? headerText : '');
                    }
                });
            }
            else {
                dt.columns().every( function (i) {
                    if (opts.cols.indexOf(i) !== -1) {
                        var column = this;
                        var footer = $(column.footer());
                        var footerText = footer.text();
                        appendTextInputTo(footer.empty(), column, opts.displayHeadingAsPlaceholder ? footerText : '');
                    }
                } );
            }            
        }

        function appendTextInputTo($elem, col, placeholder) {
            var textInput = $('<input type="text" placeholder="Search '+placeholder+'" />')
            .appendTo( $elem )                
            .on( 'keyup change', function () {
                if ( col.search() !== this.value ) {
                    col
                        .search( this.value )
                        .draw();
                }
            } );
        }
    };

    ColumnSearch.defaults = {
        searchElementType: 'select',
        selectAllText: 'All',
        displayHeadingAsPlaceholder: false,
        rowId: null,
        cols: []
    };

    $.fn.dataTable.ColumnSearch = ColumnSearch;
    $.fn.DataTable.ColumnSearch = ColumnSearch;    
}(jQuery));