# src/tablefilter.js

    import Event from './event';
    import Dom from './dom';
    import Str from './string';
    import Types from './types';
    import DateHelper from './date';
    import Helpers from './helpers';
    import {Emitter} from './emitter';

    // Features
    import {Store} from './modules/store';
    import {GridLayout} from './modules/gridLayout';
    import {Loader} from './modules/loader';
    import {HighlightKeyword} from './modules/highlightKeywords';
    import {PopupFilter} from './modules/popupFilter';
    import {Dropdown} from './modules/dropdown';
    import {CheckList} from './modules/checkList';
    import {RowsCounter} from './modules/rowsCounter';
    import {StatusBar} from './modules/statusBar';
    import {Paging} from './modules/paging';
    import {ClearButton} from './modules/clearButton';
    import {Help} from './modules/help';
    import {AlternateRows} from './modules/alternateRows';
    import {NoResults} from './modules/noResults';

    let global = window,
        doc = global.document;

    export class TableFilter {

        /**
         * TableFilter object constructor
         * requires `table` or `id` arguments, `row` and `configuration` optional
         * @param {DOMElement} table Table DOM element
         * @param {String} id Table id
         * @param {Number} row index indicating the 1st row
         * @param {Object} configuration object
         */
        constructor(...args) {
            if(args.length === 0){ return; }

            this.id = null;
            this.version = '{VERSION}';
            this.year = new Date().getFullYear();
            this.tbl = null;
            this.startRow = null;
            this.refRow = null;
            this.headersRow = null;
            this.cfg = {};
            this.nbFilterableRows = null;
            this.nbRows = null;
            this.nbCells = null;
            this._hasGrid = false;

            // TODO: use for-of with babel plug-in
            args.forEach((arg)=> {
            // for (let arg of args) {
                let argtype = typeof arg;
                if(argtype === 'object' && arg && arg.nodeName === 'TABLE'){
                    this.tbl = arg;
                    this.id = arg.id || `tf_${new Date().getTime()}_`;
                } else if(argtype === 'string'){
                    this.id = arg;
                    this.tbl = Dom.id(arg);
                } else if(argtype === 'number'){
                    this.startRow = arg;
                } else if(argtype === 'object'){
                    this.cfg = arg;
                }
            // }
            });

            if(!this.tbl || this.tbl.nodeName != 'TABLE' || this.getRowsNb() === 0){
                throw new Error(
                    'Could not instantiate TableFilter: HTML table not found.');
            }

            // configuration object
            let f = this.cfg;

            this.emitter = new Emitter();

            //Start row et cols nb
            this.refRow = this.startRow === null ? 2 : (this.startRow+1);
            try{ this.nbCells = this.getCellsNb(this.refRow); }
            catch(e){ this.nbCells = this.getCellsNb(0); }

            //default script base path
            this.basePath = f.base_path || 'tablefilter/';

            /*** filter types ***/
            this.fltTypeInp = 'input';
            this.fltTypeSlc = 'select';
            this.fltTypeMulti = 'multiple';
            this.fltTypeCheckList = 'checklist';
            this.fltTypeNone = 'none';

            /*** filters' grid properties ***/

            //enables/disables filter grid
            this.fltGrid = f.grid === false ? false : true;

            //enables/disables grid layout (fixed headers)
            this.gridLayout = Boolean(f.grid_layout);

            this.filtersRowIndex = isNaN(f.filters_row_index) ?
                0 : f.filters_row_index;
            this.headersRow = isNaN(f.headers_row_index) ?
                (this.filtersRowIndex === 0 ? 1 : 0) : f.headers_row_index;

            //defines tag of the cells containing filters (td/th)
            this.fltCellTag = f.filters_cell_tag!=='th' ||
                f.filters_cell_tag!=='td' ? 'td' : f.filters_cell_tag;

            //stores filters ids
            this.fltIds = [];
            //stores filters DOM elements
            this.fltElms = [];
            //stores valid rows indexes (rows visible upon filtering)
            this.validRowsIndex = [];
            //stores filters row element
            this.fltGridEl = null;
            //container div for paging elements, reset btn etc.
            this.infDiv = null;
            //div for rows counter
            this.lDiv = null;
            //div for reset button and results per page select
            this.rDiv = null;
            //div for paging elements
            this.mDiv = null;

            //defines css class for div containing paging elements, rows counter etc
            this.infDivCssClass = f.inf_div_css_class || 'inf';
            //defines css class for left div
            this.lDivCssClass = f.left_div_css_class || 'ldiv';
            //defines css class for right div
            this.rDivCssClass = f.right_div_css_class || 'rdiv';
            //defines css class for mid div
            this.mDivCssClass = f.middle_div_css_class || 'mdiv';
            //table container div css class
            this.contDivCssClass = f.content_div_css_class || 'cont';

            /*** filters' grid appearance ***/
            //stylesheet file
            this.stylePath = f.style_path || this.basePath + 'style/';
            this.stylesheet = f.stylesheet || this.stylePath+'tablefilter.css';
            this.stylesheetId = this.id + '_style';
            //defines css class for filters row
            this.fltsRowCssClass = f.flts_row_css_class || 'fltrow';
             //enables/disables icons (paging, reset button)
            this.enableIcons = f.enable_icons===false ? false : true;
            //enables/disbles rows alternating bg colors
            this.alternateRows = Boolean(f.alternate_rows);
            //defines widths of columns
            this.hasColWidths = Types.isArray(f.col_widths);
            this.colWidths = this.hasColWidths ? f.col_widths : null;
            //defines css class for filters
            this.fltCssClass = f.flt_css_class || 'flt';
            //defines css class for multiple selects filters
            this.fltMultiCssClass = f.flt_multi_css_class || 'flt_multi';
            //defines css class for filters
            this.fltSmallCssClass = f.flt_small_css_class || 'flt_s';
            //defines css class for single-filter
            this.singleFltCssClass = f.single_flt_css_class || 'single_flt';

            /*** filters' grid behaviours ***/
            //enables/disables enter key
            this.enterKey = f.enter_key===false ? false : true;
            //calls function before filtering starts
            this.onBeforeFilter = Types.isFn(f.on_before_filter) ?
                f.on_before_filter : null;
            //calls function after filtering
            this.onAfterFilter = Types.isFn(f.on_after_filter) ?
                f.on_after_filter : null;
            //enables/disables case sensitivity
            this.caseSensitive = Boolean(f.case_sensitive);
            //has exact match per column
            this.hasExactMatchByCol = Types.isArray(f.columns_exact_match);
            this.exactMatchByCol = this.hasExactMatchByCol ?
                f.columns_exact_match : [];
            //enables/disbles exact match for search
            this.exactMatch = Boolean(f.exact_match);
            //refreshes drop-down lists upon validation
            this.linkedFilters = Boolean(f.linked_filters);
            //wheter excluded options are disabled
            this.disableExcludedOptions = Boolean(f.disable_excluded_options);
            //stores active filter element
            this.activeFlt = null;
            //id of active filter
            this.activeFilterId = null;
            //enables always visible rows
            this.hasVisibleRows = Boolean(f.rows_always_visible);
            //array containing always visible rows
            this.visibleRows = this.hasVisibleRows ? f.rows_always_visible : [];
            //enables/disables external filters generation
            this.isExternalFlt = Boolean(f.external_flt_grid);
            //array containing ids of external elements containing filters
            this.externalFltTgtIds = f.external_flt_grid_ids || [];
            //stores filters elements if isExternalFlt is true
            this.externalFltEls = [];
            //delays any filtering process if loader true
            this.execDelay = !isNaN(f.exec_delay) ? parseInt(f.exec_delay,10) : 100;
            //calls function when filters grid loaded
            this.onFiltersLoaded = Types.isFn(f.on_filters_loaded) ?
                f.on_filters_loaded : null;
            //enables/disables single filter search
            this.singleSearchFlt = Boolean(f.single_filter);
            //calls function after row is validated
            this.onRowValidated = Types.isFn(f.on_row_validated) ?
                f.on_row_validated : null;
            //array defining columns for customCellData event
            this.customCellDataCols = f.custom_cell_data_cols ?
                f.custom_cell_data_cols : [];
            //calls custom function for retrieving cell data
            this.customCellData = Types.isFn(f.custom_cell_data) ?
                f.custom_cell_data : null;
            //input watermark text array
            this.watermark = f.watermark || '';
            this.isWatermarkArray = Types.isArray(this.watermark);
            //id of toolbar container element
            this.toolBarTgtId = f.toolbar_target_id || null;
            //enables/disables help div
            this.help = Types.isUndef(f.help_instructions) ?
                undefined : Boolean(f.help_instructions);
            //popup filters
            this.popupFilters = Boolean(f.popup_filters);
            //active columns color
            this.markActiveColumns = Boolean(f.mark_active_columns);
            //defines css class for active column header
            this.activeColumnsCssClass = f.active_columns_css_class ||
                'activeHeader';
            //calls function before active column header is marked
            this.onBeforeActiveColumn = Types.isFn(f.on_before_active_column) ?
                f.on_before_active_column : null;
            //calls function after active column header is marked
            this.onAfterActiveColumn = Types.isFn(f.on_after_active_column) ?
                f.on_after_active_column : null;

            /*** select filter's customisation and behaviours ***/
            //defines 1st option text
            this.displayAllText = f.display_all_text || 'Clear';
            //enables/disables empty option in combo-box filters
            this.enableEmptyOption = Boolean(f.enable_empty_option);
            //defines empty option text
            this.emptyText = f.empty_text || '(Empty)';
            //enables/disables non empty option in combo-box filters
            this.enableNonEmptyOption = Boolean(f.enable_non_empty_option);
            //defines empty option text
            this.nonEmptyText = f.non_empty_text || '(Non empty)';
            //enables/disables onChange event on combo-box
            this.onSlcChange = f.on_change===false ? false : true;
            //enables/disables select options sorting
            this.sortSlc = f.sort_select===false ? false : true;
            //enables/disables ascending numeric options sorting
            this.isSortNumAsc = Boolean(f.sort_num_asc);
            this.sortNumAsc = this.isSortNumAsc ? f.sort_num_asc : [];
            //enables/disables descending numeric options sorting
            this.isSortNumDesc = Boolean(f.sort_num_desc);
            this.sortNumDesc = this.isSortNumDesc ? f.sort_num_desc : [];
            //Select filters are populated on demand
            this.loadFltOnDemand = Boolean(f.load_filters_on_demand);
            this.hasCustomOptions = Types.isObj(f.custom_options);
            this.customOptions = f.custom_options;

            /*** Filter operators ***/
            this.rgxOperator = f.regexp_operator || 'rgx:';
            this.emOperator = f.empty_operator || '[empty]';
            this.nmOperator = f.nonempty_operator || '[nonempty]';
            this.orOperator = f.or_operator || '||';
            this.anOperator = f.and_operator || '&&';
            this.grOperator = f.greater_operator || '>';
            this.lwOperator = f.lower_operator || '<';
            this.leOperator = f.lower_equal_operator || '<=';
            this.geOperator = f.greater_equal_operator || '>=';
            this.dfOperator = f.different_operator || '!';
            this.lkOperator = f.like_operator || '*';
            this.eqOperator = f.equal_operator || '=';
            this.stOperator = f.start_with_operator || '{';
            this.enOperator = f.end_with_operator || '}';
            this.curExp = f.cur_exp || '^[¥£€$]';
            this.separator = f.separator || ',';

            /*** rows counter ***/
            //show/hides rows counter
            this.rowsCounter = Boolean(f.rows_counter);

            /*** status bar ***/
            //show/hides status bar
            this.statusBar = Boolean(f.status_bar);

            /*** loader ***/
            //enables/disables loader/spinner indicator
            this.loader = Boolean(f.loader);

            /*** validation - reset buttons/links ***/
            //show/hides filter's validation button
            this.displayBtn = Boolean(f.btn);
            //defines validation button text
            this.btnText = f.btn_text || (!this.enableIcons ? 'Go' : '');
            //defines css class for validation button
            this.btnCssClass = f.btn_css_class ||
                (!this.enableIcons ? 'btnflt' : 'btnflt_icon');
            //show/hides reset link
            this.btnReset = Boolean(f.btn_reset);
            //defines css class for reset button
            this.btnResetCssClass = f.btn_reset_css_class || 'reset';
            //callback function before filters are cleared
            this.onBeforeReset = Types.isFn(f.on_before_reset) ?
                f.on_before_reset : null;
            //callback function after filters are cleared
            this.onAfterReset = Types.isFn(f.on_after_reset) ?
                f.on_after_reset : null;

            /*** paging ***/
            //enables/disables table paging
            this.paging = Boolean(f.paging);
            this.nbVisibleRows = 0; //nb visible rows
            this.nbHiddenRows = 0; //nb hidden rows

            /*** autofilter on typing ***/
            //enables/disables auto filtering, table is filtered when user stops
            //typing
            this.autoFilter = Boolean(f.auto_filter);
            //onkeyup delay timer (msecs)
            this.autoFilterDelay = !isNaN(f.auto_filter_delay) ?
                f.auto_filter_delay : 900;
            //typing indicator
            this.isUserTyping = null;
            this.autoFilterTimer = null;

            /*** keyword highlighting ***/
            //enables/disables keyword highlighting
            this.highlightKeywords = Boolean(f.highlight_keywords);

            /*** No results feature ***/
            this.noResults = Types.isObj(f.no_results_message) ||
                Boolean(f.no_results_message);

            /*** data types ***/
            //defines default date type (european DMY)
            this.defaultDateType = f.default_date_type || 'DMY';
            //defines default thousands separator
            //US = ',' EU = '.'
            this.thousandsSeparator = f.thousands_separator || ',';
            //defines default decimal separator
            //US & javascript = '.' EU = ','
            this.decimalSeparator = f.decimal_separator || '.';
            //enables number format per column
            this.hasColNbFormat = Types.isArray(f.col_number_format);
            //array containing columns nb formats
            this.colNbFormat = this.hasColNbFormat ? f.col_number_format : null;
            //enables date type per column
            this.hasColDateType = Types.isArray(f.col_date_type);
            //array containing columns date type
            this.colDateType = this.hasColDateType ? f.col_date_type : null;

            /*** ids prefixes ***/
            //css class name added to table
            this.prfxTf = 'TF';
            //filters (inputs - selects)
            this.prfxFlt = 'flt';
            //validation button
            this.prfxValButton = 'btn';
            //container div for paging elements, rows counter etc.
            this.prfxInfDiv = 'inf_';
            //left div
            this.prfxLDiv = 'ldiv_';
            //right div
            this.prfxRDiv = 'rdiv_';
            //middle div
            this.prfxMDiv = 'mdiv_';
            //filter values cookie
            this.prfxCookieFltsValues = 'tf_flts_';
            //page nb cookie
            this.prfxCookiePageNb = 'tf_pgnb_';
            //page length cookie
            this.prfxCookiePageLen = 'tf_pglen_';

            /*** cookies ***/
            //remembers filters values on page load
            this.rememberGridValues = Boolean(f.remember_grid_values);
            //remembers page nb on page load
            this.rememberPageNb = this.paging && f.remember_page_number;
            //remembers page length on page load
            this.rememberPageLen = this.paging && f.remember_page_length;
            this.hasPersistence = this.rememberGridValues || this.rememberPageNb ||
                this.rememberPageLen;

            /*** extensions ***/
            //imports external script
            this.extensions = f.extensions;
            this.hasExtensions = Types.isArray(this.extensions);

            /*** themes ***/
            this.enableDefaultTheme = Boolean(f.enable_default_theme);
            //imports themes
            this.hasThemes = (this.enableDefaultTheme || Types.isArray(f.themes));
            this.themes = f.themes || [];
            //themes path
            this.themesPath = f.themes_path || this.stylePath + 'themes/';

            // Features registry
            this.Mod = {};

            // Extensions registry
            this.ExtRegistry = {};

            /*** TF events ***/
            this.Evt = {
                // Detect <enter> key
                detectKey(e) {
                    if(!this.enterKey){ return; }
                    if(e){
                        let key = Event.keyCode(e);
                        if(key===13){
                            this.filter();
                            Event.cancel(e);
                            Event.stop(e);
                        } else {
                            this.isUserTyping = true;
                            global.clearInterval(this.autoFilterTimer);
                            this.autoFilterTimer = null;
                        }
                    }
                },
                // if auto-filter on, detect user is typing and filter columns
                onKeyUp(e) {
                    if(!this.autoFilter){
                        return;
                    }
                    let key = Event.keyCode(e);
                    this.isUserTyping = false;

                    function filter() {
                        global.clearInterval(this.autoFilterTimer);
                        this.autoFilterTimer = null;
                        if(!this.isUserTyping){
                            this.filter();
                            this.isUserTyping = null;
                        }
                    }

                    if(key!==13 && key!==9 && key!==27 && key!==38 && key!==40) {
                        if(this.autoFilterTimer === null){
                            this.autoFilterTimer = global.setInterval(
                                filter.bind(this), this.autoFilterDelay);
                        }
                    } else {
                        global.clearInterval(this.autoFilterTimer);
                        this.autoFilterTimer = null;
                    }
                },
                // if auto-filter on, detect user is typing
                onKeyDown() {
                    if(!this.autoFilter) { return; }
                    this.isUserTyping = true;
                },
                // if auto-filter on, clear interval on filter blur
                onInpBlur() {
                    if(this.autoFilter){
                        this.isUserTyping = false;
                        global.clearInterval(this.autoFilterTimer);
                    }
                    this.emitter.emit('filter-blur', this);
                },
                // set focused text-box filter as active
                onInpFocus(e) {
                    let elm = Event.target(e);
                    this.activeFilterId = elm.getAttribute('id');
                    this.activeFlt = Dom.id(this.activeFilterId);
                    this.emitter.emit('filter-focus', this);
                }
            };
        }

        /**
         * Initialise features and layout
         */
        init(){
            if(this._hasGrid){
                return;
            }

            let Mod = this.Mod;
            let n = this.singleSearchFlt ? 1 : this.nbCells,
                inpclass;

            //loads stylesheet if not imported
            this.import(this.stylesheetId, this.stylesheet, null, 'link');

            //loads theme
            if(this.hasThemes){ this.loadThemes(); }

            // Instantiate help feature and initialise only if set true
            if(!Mod.help){
                Mod.help = new Help(this);
            }
            if(this.help){
                Mod.help.init();
            }

            if(this.hasPersistence){
                if(!Mod.store){
                    Mod.store = new Store(this);
                }
                Mod.store.init();
            }

            if(this.gridLayout){
                if(!Mod.gridLayout){
                    Mod.gridLayout = new GridLayout(this);
                }
                Mod.gridLayout.init();
            }

            if(this.loader){
                if(!Mod.loader){
                    Mod.loader = new Loader(this);
                }
                Mod.loader.init();
            }

            if(this.highlightKeywords){
                Mod.highlightKeyword = new HighlightKeyword(this);
                Mod.highlightKeyword.init();
            }

            if(this.popupFilters){
                if(!Mod.popupFilter){
                    Mod.popupFilter = new PopupFilter(this);
                }
                Mod.popupFilter.init();
            }

            //filters grid is not generated
            if(!this.fltGrid){
                this._initNoFilters();
            } else {
                let fltrow = this._insertFiltersRow();

                this.nbFilterableRows = this.getRowsNb();
                this.nbVisibleRows = this.nbFilterableRows;
                this.nbRows = this.tbl.rows.length;

                // Generate filters
                for(let i=0; i<n; i++){
                    this.emitter.emit('before-filter-init', this, i);

                    let fltcell = Dom.create(this.fltCellTag),
                        col = this.getFilterType(i);

                    if(this.singleSearchFlt){
                        fltcell.colSpan = this.nbCells;
                    }
                    if(!this.gridLayout){
                        fltrow.appendChild(fltcell);
                    }
                    inpclass = (i==n-1 && this.displayBtn) ?
                        this.fltSmallCssClass : this.fltCssClass;

                    //only 1 input for single search
                    if(this.singleSearchFlt){
                        col = this.fltTypeInp;
                        inpclass = this.singleFltCssClass;
                    }

                    //drop-down filters
                    if(col===this.fltTypeSlc || col===this.fltTypeMulti){
                        if(!Mod.dropdown){
                            Mod.dropdown = new Dropdown(this);
                        }
                        Mod.dropdown.init(i, this.isExternalFlt, fltcell);
                    }
                    // checklist
                    else if(col===this.fltTypeCheckList){
                        if(!Mod.checkList){
                            Mod.checkList = new CheckList(this);
                        }
                        Mod.checkList.init(i, this.isExternalFlt, fltcell);
                    } else {
                        this._buildInputFilter(i, inpclass, fltcell);
                    }

                    // this adds submit button
                    if(i==n-1 && this.displayBtn){
                        this._buildSubmitButton(i, fltcell);
                    }

                    this.emitter.emit('after-filter-init', this, i);
                }

            }//if this.fltGrid

            /* Features */
            if(this.hasVisibleRows){
                this.emitter.on(['after-filtering'], ()=> this.enforceVisibility());
                this.enforceVisibility();
            }
            if(this.rowsCounter){
                Mod.rowsCounter = new RowsCounter(this);
                Mod.rowsCounter.init();
            }
            if(this.statusBar){
                Mod.statusBar = new StatusBar(this);
                Mod.statusBar.init();
            }
            if(this.paging){
                if(!Mod.paging){
                    Mod.paging = new Paging(this);
                    Mod.paging.init();
                } else{
                    Mod.paging.reset();
                }
            }
            if(this.btnReset){
                Mod.clearButton = new ClearButton(this);
                Mod.clearButton.init();
            }

            if(this.hasColWidths && !this.gridLayout){
                this.setColWidths();
            }
            if(this.alternateRows){
                Mod.alternateRows = new AlternateRows(this);
                Mod.alternateRows.init();
            }
            if(this.noResults){
                if(!Mod.noResults){
                    Mod.noResults = new NoResults(this);
                }
                Mod.noResults.init();
            }

            this._hasGrid = true;

            if(this.hasPersistence){
                this.resetFilterValues();
            }

            //TF css class is added to table
            if(!this.gridLayout){
                Dom.addClass(this.tbl, this.prfxTf);
            }

            /* Loads extensions */
            if(this.hasExtensions){
                this.initExtensions();
            }

            // Subscribe to events
            if(this.markActiveColumns){
                this.emitter.on(['before-filtering'],
                    ()=> this.clearActiveColumns());
                this.emitter.on(['cell-processed'],
                    (tf, colIndex)=> this.markActiveColumn(colIndex));
            }
            if(this.linkedFilters){
                this.emitter.on(['after-filtering'], ()=> this.linkFilters());
            }

            if(this.onFiltersLoaded){
                this.onFiltersLoaded.call(null, this);
            }

            this.initialized = true;
            this.emitter.emit('initialized', this);
        }

        /**
         * Insert filters row at initialization
         */
        _insertFiltersRow() {
            if(this.gridLayout){
                return;
            }
            let fltrow;

            let thead = Dom.tag(this.tbl, 'thead');
            if(thead.length > 0){
                fltrow = thead[0].insertRow(this.filtersRowIndex);
            } else {
                fltrow = this.tbl.insertRow(this.filtersRowIndex);
            }

            // if(this.headersRow > 1 && this.filtersRowIndex <= this.headersRow){
            //     this.headersRow++;
            // }

            fltrow.className = this.fltsRowCssClass;

            if(this.isExternalFlt){
                fltrow.style.display = 'none';
            }

            this.emitter.emit('filters-row-inserted', this, fltrow);
            return fltrow;
        }

        /**
         * Initialize filtersless table
         */
        _initNoFilters(){
            if(this.fltGrid){
                return;
            }
            this.refRow = this.refRow > 0 ? this.refRow-1 : 0;
            this.nbFilterableRows = this.getRowsNb();
            this.nbVisibleRows = this.nbFilterableRows;
            this.nbRows = this.nbFilterableRows + this.refRow;
        }

        /**
         * Build input filter type
         * @param  {Number} colIndex      Column index
         * @param  {String} cssClass      Css class applied to filter
         * @param  {DOMElement} container Container DOM element
         */
        _buildInputFilter(colIndex, cssClass, container){
            let col = this.getFilterType(colIndex);
            let externalFltTgtId = this.isExternalFlt ?
                this.externalFltTgtIds[colIndex] : null;
            let inptype = col===this.fltTypeInp ? 'text' : 'hidden';
            let inp = Dom.create(this.fltTypeInp,
                ['id', this.prfxFlt+colIndex+'_'+this.id],
                ['type', inptype], ['ct', colIndex]);

            if(inptype !== 'hidden' && this.watermark){
                inp.setAttribute('placeholder',
                    this.isWatermarkArray ? (this.watermark[colIndex] || '') :
                        this.watermark
                );
            }
            inp.className = cssClass || this.fltCssClass;
            Event.add(inp, 'focus', this.Evt.onInpFocus.bind(this));

            //filter is appended in custom element
            if(externalFltTgtId){
                Dom.id(externalFltTgtId).appendChild(inp);
                this.externalFltEls.push(inp);
            } else {
                container.appendChild(inp);
            }

            this.fltIds.push(inp.id);

            Event.add(inp, 'keypress', this.Evt.detectKey.bind(this));
            Event.add(inp, 'keydown', this.Evt.onKeyDown.bind(this));
            Event.add(inp, 'keyup', this.Evt.onKeyUp.bind(this));
            Event.add(inp, 'blur', this.Evt.onInpBlur.bind(this));
        }

        /**
         * Build submit button
         * @param  {Number} colIndex      Column index
         * @param  {DOMElement} container Container DOM element
         */
        _buildSubmitButton(colIndex, container){
            let externalFltTgtId = this.isExternalFlt ?
                this.externalFltTgtIds[colIndex] : null;
            let btn = Dom.create(this.fltTypeInp,
                ['id', this.prfxValButton+colIndex+'_'+this.id],
                ['type', 'button'], ['value', this.btnText]);
            btn.className = this.btnCssClass;

            //filter is appended in custom element
            if(externalFltTgtId){
                Dom.id(externalFltTgtId).appendChild(btn);
            } else{
                container.appendChild(btn);
            }

            Event.add(btn, 'click', ()=> this.filter());
        }

        /**
         * Return a feature instance for a given name
         * @param  {String} name Name of the feature
         * @return {Object}
         */
        feature(name){
            return this.Mod[name];
        }

        /**
         * Initialise all the extensions defined in the configuration object
         */
        initExtensions(){
            let exts = this.extensions;
            // Set config's publicPath dynamically for Webpack...
            __webpack_public_path__ = this.basePath;

            this.emitter.emit('before-loading-extensions', this);
            for(let i=0, len=exts.length; i<len; i++){
                let ext = exts[i];
                if(!this.ExtRegistry[ext.name]){
                    this.loadExtension(ext);
                }
            }
            this.emitter.emit('after-loading-extensions', this);
        }

        /**
         * Load an extension module
         * @param  {Object} ext Extension config object
         */
        loadExtension(ext){
            if(!ext || !ext.name){
                return;
            }

            let name = ext.name;
            let path = ext.path;
            let modulePath;

            if(name && path){
                modulePath = ext.path + name;
            } else {
                name = name.replace('.js', '');
                modulePath = 'extensions/{}/{}'.replace(/{}/g, name);
            }

            // Require pattern for Webpack
            require(['./' + modulePath], (mod)=> {
                /* eslint-disable */
                let inst = new mod.default(this, ext);
                /* eslint-enable */
                inst.init();
                this.ExtRegistry[name] = inst;
            });
        }

        /**
         * Get an extension instance
         * @param  {String} name Name of the extension
         * @return {Object}      Extension instance
         */
        extension(name){
            return this.ExtRegistry[name];
        }

        /**
         * Check passed extension name exists
         * @param  {String}  name Name of the extension
         * @return {Boolean}
         */
        hasExtension(name){
            return !Types.isEmpty(this.ExtRegistry[name]);
        }

        /**
         * Destroy all the extensions defined in the configuration object
         */
        destroyExtensions(){
            let exts = this.extensions;

            for(let i=0, len=exts.length; i<len; i++){
                let ext = exts[i];
                let extInstance = this.ExtRegistry[ext.name];
                if(extInstance){
                    extInstance.destroy();
                    this.ExtRegistry[ext.name] = null;
                }
            }
        }

        /**
         * Load themes defined in the configuration object
         */
        loadThemes(){
            let themes = this.themes;
            this.emitter.emit('before-loading-themes', this);

            //Default theme config
            if(this.enableDefaultTheme){
                let defaultTheme = { name: 'default' };
                this.themes.push(defaultTheme);
            }
            if(Types.isArray(themes)){
                for(let i=0, len=themes.length; i<len; i++){
                    let theme = themes[i];
                    let name = theme.name;
                    let path = theme.path;
                    let styleId = this.prfxTf + name;
                    if(name && !path){
                        path = this.themesPath + name + '/' + name + '.css';
                    }
                    else if(!name && theme.path){
                        name = 'theme{0}'.replace('{0}', i);
                    }

                    if(!this.isImported(path, 'link')){
                        this.import(styleId, path, null, 'link');
                    }
                }
            }

            //Some elements need to be overriden for default theme
            //Reset button
            this.btnResetText = null;
            this.btnResetHtml = '<input type="button" value="" class="' +
                this.btnResetCssClass+'" title="Clear filters" />';

            //Paging buttons
            this.btnPrevPageHtml = '<input type="button" value="" class="' +
                this.btnPageCssClass+' previousPage" title="Previous page" />';
            this.btnNextPageHtml = '<input type="button" value="" class="' +
                this.btnPageCssClass+' nextPage" title="Next page" />';
            this.btnFirstPageHtml = '<input type="button" value="" class="' +
                this.btnPageCssClass+' firstPage" title="First page" />';
            this.btnLastPageHtml = '<input type="button" value="" class="' +
                this.btnPageCssClass+' lastPage" title="Last page" />';

            //Loader
            this.loader = true;
            this.loaderHtml = '<div class="defaultLoader"></div>';
            this.loaderText = null;

            this.emitter.emit('after-loading-themes', this);
        }

        /**
         * Return stylesheet DOM element for a given theme name
         * @return {DOMElement} stylesheet element
         */
        getStylesheet(name='default'){
            return Dom.id(this.prfxTf + name);
        }

        /**
         * Destroy filter grid
         */
        destroy(){
            if(!this._hasGrid){
                return;
            }
            let rows = this.tbl.rows,
                Mod = this.Mod,
                emitter = this.emitter;

            if(this.isExternalFlt && !this.popupFilters){
                this.removeExternalFlts();
            }
            if(this.infDiv){
                this.removeToolbar();
            }
            if(this.markActiveColumns){
                this.clearActiveColumns();
                emitter.off(['before-filtering'], ()=> this.clearActiveColumns());
                emitter.off(['cell-processed'],
                    (tf, colIndex)=> this.markActiveColumn(colIndex));
            }
            if(this.hasExtensions){
                this.destroyExtensions();
            }

            this.validateAllRows();

            if(this.fltGrid && !this.gridLayout){
                this.fltGridEl = rows[this.filtersRowIndex];
                this.tbl.deleteRow(this.filtersRowIndex);
            }

            // broadcast destroy event
            emitter.emit('destroy', this);

            // Destroy modules
            // TODO: subcribe modules to destroy event instead
            Object.keys(Mod).forEach(function(key){
                var feature = Mod[key];
                if(feature && Types.isFn(feature.destroy)){
                    feature.destroy();
                }
            });

            // unsubscribe to events
            if(this.hasVisibleRows){
                emitter.off(['after-filtering'], ()=> this.enforceVisibility());
            }
            if(this.linkedFilters){
                emitter.off(['after-filtering'], ()=> this.linkFilters());
            }

            Dom.removeClass(this.tbl, this.prfxTf);
            this.nbHiddenRows = 0;
            this.validRowsIndex = [];
            this.fltIds = [];
            this.activeFlt = null;
            this._hasGrid = false;
            this.initialized = false;
        }

        /**
         * Generate container element for paging, reset button, rows counter etc.
         */
        setToolbar(){
            if(this.infDiv){
                return;
            }

            /*** container div ***/
            let infdiv = Dom.create('div', ['id', this.prfxInfDiv+this.id]);
            infdiv.className = this.infDivCssClass;

            //custom container
            if(this.toolBarTgtId){
                Dom.id(this.toolBarTgtId).appendChild(infdiv);
            }
            //grid-layout
            else if(this.gridLayout){
                let gridLayout = this.Mod.gridLayout;
                gridLayout.tblMainCont.appendChild(infdiv);
                infdiv.className = gridLayout.gridInfDivCssClass;
            }
            //default location: just above the table
            else{
                var cont = Dom.create('caption');
                cont.appendChild(infdiv);
                this.tbl.insertBefore(cont, this.tbl.firstChild);
            }
            this.infDiv = Dom.id(this.prfxInfDiv+this.id);

            /*** left div containing rows # displayer ***/
            let ldiv = Dom.create('div', ['id', this.prfxLDiv+this.id]);
            ldiv.className = this.lDivCssClass;
            infdiv.appendChild(ldiv);
            this.lDiv = Dom.id(this.prfxLDiv+this.id);

            /***    right div containing reset button
                    + nb results per page select    ***/
            let rdiv = Dom.create('div', ['id', this.prfxRDiv+this.id]);
            rdiv.className = this.rDivCssClass;
            infdiv.appendChild(rdiv);
            this.rDiv = Dom.id(this.prfxRDiv+this.id);

            /*** mid div containing paging elements ***/
            let mdiv = Dom.create('div', ['id', this.prfxMDiv+this.id]);
            mdiv.className = this.mDivCssClass;
            infdiv.appendChild(mdiv);
            this.mDiv = Dom.id(this.prfxMDiv+this.id);

            // emit help initialisation only if undefined
            if(Types.isUndef(this.help)){
                this.emitter.emit('init-help', this);
            }
        }

        /**
         * Remove toolbar container element
         */
        removeToolbar(){
            if(!this.infDiv){
                return;
            }
            Dom.remove(this.infDiv);
            this.infDiv = null;

            let tbl = this.tbl;
            let captions = Dom.tag(tbl, 'caption');
            if(captions.length > 0){
                [].forEach.call(captions, (elm)=> tbl.removeChild(elm));
            }
        }

        /**
         * Remove all the external column filters
         */
        removeExternalFlts(){
            if(!this.isExternalFlt){
                return;
            }
            let ids = this.externalFltTgtIds,
                len = ids.length;
            for(let ct=0; ct<len; ct++){
                let externalFltTgtId = ids[ct],
                    externalFlt = Dom.id(externalFltTgtId);
                if(externalFlt){
                    externalFlt.innerHTML = '';
                }
            }
        }

        /**
         * Check if given column implements a filter with custom options
         * @param  {Number}  colIndex Column's index
         * @return {Boolean}
         */
        isCustomOptions(colIndex) {
            return this.hasCustomOptions &&
                this.customOptions.cols.indexOf(colIndex) != -1;
        }

        /**
         * Returns an array [[value0, value1 ...],[text0, text1 ...]] with the
         * custom options values and texts
         * @param  {Number} colIndex Column's index
         * @return {Array}
         */
        getCustomOptions(colIndex){
            if(Types.isEmpty(colIndex) || !this.isCustomOptions(colIndex)){
                return;
            }

            let customOptions = this.customOptions;
            let cols = customOptions.cols;
            let optTxt = [], optArray = [];
            let index = cols.indexOf(colIndex);
            let slcValues = customOptions.values[index];
            let slcTexts = customOptions.texts[index];
            let slcSort = customOptions.sorts[index];

            for(let r=0, len=slcValues.length; r<len; r++){
                optArray.push(slcValues[r]);
                if(slcTexts[r]){
                    optTxt.push(slcTexts[r]);
                } else {
                    optTxt.push(slcValues[r]);
                }
            }
            if(slcSort){
                optArray.sort();
                optTxt.sort();
            }
            return [optArray, optTxt];
        }

        /**
         * Reset persisted filter values
         */
        resetFilterValues(){
            if(!this.rememberGridValues){
                return;
            }

            let storeValues = this.Mod.store.getFilterValues();
            storeValues.forEach((val, idx)=> {
                if(val !== ' '){
                    this.setFilterValue(idx, val);
                }
            });
            this.filter();
        }

        /**
         * Filter the table by retrieving the data from each cell in every single
         * row and comparing it to the search term for current column. A row is
         * hidden when all the search terms are not found in inspected row.
         */
        filter(){
            if(!this.fltGrid || !this._hasGrid){
                return;
            }
            //invoke onbefore callback
            if(this.onBeforeFilter){
                this.onBeforeFilter.call(null, this);
            }
            this.emitter.emit('before-filtering', this);

            let row = this.tbl.rows,
                hiddenrows = 0;

            this.validRowsIndex = [];
            // search args re-init
            let searchArgs = this.getFiltersValue();

            var numCellData, nbFormat;
            var re_le = new RegExp(this.leOperator),
                re_ge = new RegExp(this.geOperator),
                re_l = new RegExp(this.lwOperator),
                re_g = new RegExp(this.grOperator),
                re_d = new RegExp(this.dfOperator),
                re_lk = new RegExp(Str.rgxEsc(this.lkOperator)),
                re_eq = new RegExp(this.eqOperator),
                re_st = new RegExp(this.stOperator),
                re_en = new RegExp(this.enOperator),
                // re_an = new RegExp(this.anOperator),
                // re_cr = new RegExp(this.curExp),
                re_em = this.emOperator,
                re_nm = this.nmOperator,
                re_re = new RegExp(Str.rgxEsc(this.rgxOperator));

            //keyword highlighting
            function highlight(str, ok, cell){
                /*jshint validthis:true */
                if(this.highlightKeywords && ok){
                    str = str.replace(re_lk, '');
                    str = str.replace(re_eq, '');
                    str = str.replace(re_st, '');
                    str = str.replace(re_en, '');
                    let w = str;
                    if(re_le.test(str) || re_ge.test(str) || re_l.test(str) ||
                        re_g.test(str) || re_d.test(str)){
                        w = Dom.getText(cell);
                    }
                    if(w !== ''){
                        this.emitter.emit('highlight-keyword', this, cell, w);
                    }
                }
            }

            //looks for search argument in current row
            function hasArg(sA, cellData, j){
                /*jshint validthis:true */
                sA = Str.matchCase(sA, this.caseSensitive);

                let occurence,
                    removeNbFormat = Helpers.removeNbFormat;

                //Search arg operator tests
                let hasLO = re_l.test(sA),
                    hasLE = re_le.test(sA),
                    hasGR = re_g.test(sA),
                    hasGE = re_ge.test(sA),
                    hasDF = re_d.test(sA),
                    hasEQ = re_eq.test(sA),
                    hasLK = re_lk.test(sA),
                    // hasAN = re_an.test(sA),
                    hasST = re_st.test(sA),
                    hasEN = re_en.test(sA),
                    hasEM = (re_em === sA),
                    hasNM = (re_nm === sA),
                    hasRE = re_re.test(sA);

                //Search arg dates tests
                let isLDate = hasLO &&
                    DateHelper.isValid(sA.replace(re_l,''), dtType);
                let isLEDate = hasLE &&
                    DateHelper.isValid(sA.replace(re_le,''), dtType);
                let isGDate = hasGR &&
                    DateHelper.isValid(sA.replace(re_g,''), dtType);
                let isGEDate = hasGE &&
                    DateHelper.isValid(sA.replace(re_ge,''), dtType);
                let isDFDate = hasDF &&
                    DateHelper.isValid(sA.replace(re_d,''), dtType);
                let isEQDate = hasEQ &&
                    DateHelper.isValid(sA.replace(re_eq,''), dtType);

                let dte1, dte2;
                //dates
                if(DateHelper.isValid(cellData, dtType)){
                    dte1 = DateHelper.format(cellData, dtType);
                    // lower date
                    if(isLDate){
                        dte2 = DateHelper.format(sA.replace(re_l,''), dtType);
                        occurence = dte1 < dte2;
                    }
                    // lower equal date
                    else if(isLEDate){
                        dte2 = DateHelper.format(sA.replace(re_le,''), dtType);
                        occurence = dte1 <= dte2;
                    }
                    // greater equal date
                    else if(isGEDate){
                        dte2 = DateHelper.format(sA.replace(re_ge,''), dtType);
                        occurence = dte1 >= dte2;
                    }
                    // greater date
                    else if(isGDate){
                        dte2 = DateHelper.format(sA.replace(re_g,''), dtType);
                        occurence = dte1 > dte2;
                    }
                    // different date
                    else if(isDFDate){
                        dte2 = DateHelper.format(sA.replace(re_d,''), dtType);
                        occurence = dte1.toString() != dte2.toString();
                    }
                    // equal date
                    else if(isEQDate){
                        dte2 = DateHelper.format(sA.replace(re_eq,''), dtType);
                        occurence = dte1.toString() == dte2.toString();
                    }
                    // searched keyword with * operator doesn't have to be a date
                    else if(re_lk.test(sA)){// like date
                        occurence = Str.contains(sA.replace(re_lk,''), cellData,
                            false, this.caseSensitive);
                    }
                    else if(DateHelper.isValid(sA,dtType)){
                        dte2 = DateHelper.format(sA,dtType);
                        occurence = dte1.toString() === dte2.toString();
                    }
                    //empty
                    else if(hasEM){
                        occurence = Str.isEmpty(cellData);
                    }
                    //non-empty
                    else if(hasNM){
                        occurence = !Str.isEmpty(cellData);
                    } else {
                        occurence = Str.contains(sA, cellData, this.isExactMatch(j),
                            this.caseSensitive);
                    }
                }

                else{
                    //first numbers need to be formated
                    if(this.hasColNbFormat && this.colNbFormat[j]){
                        numCellData = removeNbFormat(
                            cellData, this.colNbFormat[j]);
                        nbFormat = this.colNbFormat[j];
                    } else {
                        if(this.thousandsSeparator === ',' &&
                            this.decimalSeparator === '.'){
                            numCellData = removeNbFormat(cellData, 'us');
                            nbFormat = 'us';
                        } else {
                            numCellData = removeNbFormat(cellData, 'eu');
                            nbFormat = 'eu';
                        }
                    }

                    // first checks if there is any operator (<,>,<=,>=,!,*,=,{,},
                    // rgx:)
                    // lower equal
                    if(hasLE){
                        occurence = numCellData <= removeNbFormat(
                            sA.replace(re_le, ''), nbFormat);
                    }
                    //greater equal
                    else if(hasGE){
                        occurence = numCellData >= removeNbFormat(
                            sA.replace(re_ge, ''), nbFormat);
                    }
                    //lower
                    else if(hasLO){
                        occurence = numCellData < removeNbFormat(
                            sA.replace(re_l, ''), nbFormat);
                    }
                    //greater
                    else if(hasGR){
                        occurence = numCellData > removeNbFormat(
                            sA.replace(re_g, ''), nbFormat);
                    }
                    //different
                    else if(hasDF){
                        occurence = Str.contains(sA.replace(re_d, ''), cellData,
                            false, this.caseSensitive) ? false : true;
                    }
                    //like
                    else if(hasLK){
                        occurence = Str.contains(sA.replace(re_lk, ''), cellData,
                            false, this.caseSensitive);
                    }
                    //equal
                    else if(hasEQ){
                        occurence = Str.contains(sA.replace(re_eq, ''), cellData,
                            true, this.caseSensitive);
                    }
                    //starts with
                    else if(hasST){
                        occurence = cellData.indexOf(sA.replace(re_st, '')) === 0 ?
                            true : false;
                    }
                    //ends with
                    else if(hasEN){
                        let searchArg = sA.replace(re_en, '');
                        occurence =
                            cellData.lastIndexOf(searchArg, cellData.length-1) ===
                            (cellData.length-1)-(searchArg.length-1) &&
                            cellData.lastIndexOf(
                                searchArg, cellData.length-1) > -1 ? true : false;
                    }
                    //empty
                    else if(hasEM){
                        occurence = Str.isEmpty(cellData);
                    }
                    //non-empty
                    else if(hasNM){
                        occurence = !Str.isEmpty(cellData);
                    }
                    //regexp
                    else if(hasRE){
                        //in case regexp fires an exception
                        try{
                            //operator is removed
                            let srchArg = sA.replace(re_re,'');
                            let rgx = new RegExp(srchArg);
                            occurence = rgx.test(cellData);
                        } catch(e) { occurence = false; }
                    } else {
                        occurence = Str.contains(sA, cellData, this.isExactMatch(j),
                            this.caseSensitive);
                    }

                }//else
                return occurence;
            }//fn

            for(let k=this.refRow; k<this.nbRows; k++){
                // already filtered rows display re-init
                row[k].style.display = '';

                let cell = row[k].cells,
                    nchilds = cell.length;

                // checks if row has exact cell #
                if(nchilds !== this.nbCells){
                    continue;
                }

                let occurence = [],
                    isRowValid = true,
                    //only for single filter search
                    singleFltRowValid = false;

                // this loop retrieves cell data
                for(let j=0; j<nchilds; j++){
                    //searched keyword
                    let sA = searchArgs[this.singleSearchFlt ? 0 : j];
                    var dtType = this.hasColDateType ?
                            this.colDateType[j] : this.defaultDateType;

                    if(sA === ''){
                        continue;
                    }

                    let cellData = Str.matchCase(this.getCellData(cell[j]),
                        this.caseSensitive);

                    //multiple search parameter operator ||
                    let sAOrSplit = sA.toString().split(this.orOperator),
                        //multiple search || parameter boolean
                        hasMultiOrSA = sAOrSplit.length > 1,
                        //multiple search parameter operator &&
                        sAAndSplit = sA.toString().split(this.anOperator),
                        //multiple search && parameter boolean
                        hasMultiAndSA = sAAndSplit.length > 1;

                    //detect operators or array query
                    if(Types.isArray(sA) || hasMultiOrSA || hasMultiAndSA){
                        let cS,
                            s,
                            occur = false;
                        if(Types.isArray(sA)){
                            s = sA;
                        } else {
                            s = hasMultiOrSA ? sAOrSplit : sAAndSplit;
                        }
                        // TODO: improve clarity/readability of this block
                        for(let w=0, len=s.length; w<len; w++){
                            cS = Str.trim(s[w]);
                            occur = hasArg.call(this, cS, cellData, j);
                            highlight.call(this, cS, occur, cell[j]);
                            if((hasMultiOrSA && occur) ||
                                (hasMultiAndSA && !occur)){
                                break;
                            }
                            if(Types.isArray(sA) && occur){
                                break;
                            }
                        }
                        occurence[j] = occur;

                    }
                    //single search parameter
                    else {
                        occurence[j] = hasArg.call(this, Str.trim(sA), cellData, j);
                        highlight.call(this, sA, occurence[j], cell[j]);
                    }//else single param

                    if(!occurence[j]){
                        isRowValid = false;
                    }
                    if(this.singleSearchFlt && occurence[j]){
                        singleFltRowValid = true;
                    }

                    this.emitter.emit('cell-processed', this, j, cell[j]);
                }//for j

                if(this.singleSearchFlt && singleFltRowValid){
                    isRowValid = true;
                }

                if(!isRowValid){
                    this.validateRow(k, false);
                    hiddenrows++;
                } else {
                    this.validateRow(k, true);
                }

                this.emitter.emit('row-processed', this, k,
                    this.validRowsIndex.length, isRowValid);
            }// for k

            this.nbVisibleRows = this.validRowsIndex.length;
            this.nbHiddenRows = hiddenrows;

            //invokes onafterfilter callback
            if(this.onAfterFilter){
                this.onAfterFilter.call(null, this);
            }

            this.emitter.emit('after-filtering', this);
        }

        /**
         * Return the data of a specified column
         * @param  {Number} colIndex Column index
         * @param  {Boolean} includeHeaders  Optional: include headers row
         * @param  {Boolean} num     Optional: return unformatted number
         * @param  {Array} exclude   Optional: list of row indexes to be excluded
         * @return {Array}           Flat list of data for a column
         */
        getColValues(colIndex, includeHeaders=false, num=false, exclude=[]){
            if(!this.fltGrid){
                return;
            }
            let row = this.tbl.rows,
                colValues = [];

            if(includeHeaders){
                colValues.push(this.getHeadersText()[colIndex]);
            }

            for(let i=this.refRow; i<this.nbRows; i++){
                let isExludedRow = false;
                // checks if current row index appears in exclude array
                if(exclude.length > 0){
                    isExludedRow = exclude.indexOf(i) != -1;
                }
                let cell = row[i].cells,
                    nchilds = cell.length;

                // checks if row has exact cell # and is not excluded
                if(nchilds === this.nbCells && !isExludedRow){
                    // this loop retrieves cell data
                    for(let j=0; j<nchilds; j++){
                        if(j != colIndex || row[i].style.display !== ''){
                            continue;
                        }
                        let cellData = this.getCellData(cell[j]),
                            nbFormat = this.colNbFormat ?
                                this.colNbFormat[colIndex] : null,
                            data = num ?
                                    Helpers.removeNbFormat(cellData, nbFormat) :
                                    cellData;
                        colValues.push(data);
                    }
                }
            }
            return colValues;
        }

        /**
         * Return the filter's value of a specified column
         * @param  {Number} index Column index
         * @return {String}       Filter value
         */
        getFilterValue(index){
            if(!this.fltGrid){
                return;
            }
            let fltValue = '',
                fltValues = [],
                flt = this.getFilterElement(index);
            if(!flt){
                return '';
            }

            let fltColType = this.getFilterType(index);
            if(fltColType !== this.fltTypeMulti &&
                fltColType !== this.fltTypeCheckList){
                fltValue = flt.value;
            }
            //mutiple select
            else if(fltColType === this.fltTypeMulti){
                // TODO: extract a method in dropdown module from below
                for(let j=0, len=flt.options.length; j<len; j++){
                    if(flt.options[j].selected){
                        fltValues.push(flt.options[j].value);
                    }
                }
                //return empty string if collection is empty
                fltValue = fltValues.length > 0 ? fltValues : '';
            }
            //checklist
            else if(fltColType === this.fltTypeCheckList){
                // TODO: extract a method in checklist module from below
                if(flt.getAttribute('value') !== null){
                    fltValues = flt.getAttribute('value');
                    //removes last operator ||
                    fltValues = fltValues.substr(0, fltValues.length-3);
                    //convert || separated values into array
                    fltValues = fltValues.split(' ' + this.orOperator + ' ');
                }
                //return empty string if collection is empty
                fltValue = fltValues.length > 0 ? fltValues : '';
            }
            //return an empty string if collection contains a single empty string
            if(Types.isArray(fltValue) && fltValue.length === 1 &&
                fltValue[0] === ''){
                fltValue = '';
            }
            return fltValue;
        }

        /**
         * Return the filters' values
         * @return {Array} List of filters' values
         */
        getFiltersValue(){
            if(!this.fltGrid){
                return;
            }
            let searchArgs = [];
            for(let i=0, len=this.fltIds.length; i<len; i++){
                let fltValue = this.getFilterValue(i);
                if(Types.isArray(fltValue)){
                    searchArgs.push(fltValue);
                } else {
                    searchArgs.push(Str.trim(fltValue));
                }
            }
            return searchArgs;
        }

        /**
         * Return the ID of the filter of a specified column
         * @param  {Number} index Column's index
         * @return {String}       ID of the filter element
         */
        getFilterId(index){
            if(!this.fltGrid){
                return;
            }
            return this.fltIds[index];
        }

        /**
         * Return the list of ids of filters matching a specified type.
         * Note: hidden filters are also returned
         *
         * @param  {String} type  Filter type string ('input', 'select', 'multiple',
         *                        'checklist')
         * @param  {Boolean} bool If true returns columns indexes instead of IDs
         * @return {[type]}       List of element IDs or column indexes
         */
        getFiltersByType(type, bool){
            if(!this.fltGrid){
                return;
            }
            let arr = [];
            for(let i=0, len=this.fltIds.length; i<len; i++){
                let fltType = this.getFilterType(i);
                if(fltType === Str.lower(type)){
                    let a = bool ? i : this.fltIds[i];
                    arr.push(a);
                }
            }
            return arr;
        }

        /**
         * Return the filter's DOM element for a given column
         * @param  {Number} index     Column's index
         * @return {DOMElement}
         */
        getFilterElement(index){
            let fltId = this.fltIds[index];
            return Dom.id(fltId);
        }

        /**
         * Return the number of cells for a given row index
         * @param  {Number} rowIndex Index of the row
         * @return {Number}          Number of cells
         */
        getCellsNb(rowIndex=0){
            let tr = this.tbl.rows[rowIndex];
            return tr.cells.length;
        }

        /**
         * Return the number of filterable rows starting from reference row if
         * defined
         * @param  {Boolean} includeHeaders Include the headers row
         * @return {Number}                 Number of filterable rows
         */
        getRowsNb(includeHeaders){
            let s = Types.isUndef(this.refRow) ? 0 : this.refRow,
                ntrs = this.tbl.rows.length;
            if(includeHeaders){ s = 0; }
            return parseInt(ntrs-s, 10);
        }

        /**
         * Return the data of a given cell
         * @param  {DOMElement} cell Cell's DOM object
         * @return {String}
         */
        getCellData(cell){
            let idx = cell.cellIndex;
            //Check for customCellData callback
            if(this.customCellData && this.customCellDataCols.indexOf(idx) != -1){
                return this.customCellData.call(null, this, cell, idx);
            } else {
                return Dom.getText(cell);
            }
        }

        /**
         * Return the table data with following format:
         * [
         *     [rowIndex, [value0, value1...]],
         *     [rowIndex, [value0, value1...]]
         * ]
         * @param  {Boolean} includeHeaders  Optional: include headers row
         * @param  {Boolean} excludeHiddenCols  Optional: exclude hidden columns
         * @return {Array}
         *
         * TODO: provide an API returning data in JSON format
         */
        getTableData(includeHeaders=false, excludeHiddenCols=false){
            let rows = this.tbl.rows;
            let tblData = [];
            if(includeHeaders){
                let headers = this.getHeadersText(excludeHiddenCols);
                tblData.push([this.getHeadersRowIndex(), headers]);
            }
            for(let k=this.refRow; k<this.nbRows; k++){
                let rowData = [k, []];
                let cells = rows[k].cells;
                for(let j=0, len=cells.length; j<len; j++){
                    if(excludeHiddenCols && this.hasExtension('colsVisibility')){
                        if(this.extension('colsVisibility').isColHidden(j)){
                            continue;
                        }
                    }
                    let cellData = this.getCellData(cells[j]);
                    rowData[1].push(cellData);
                }
                tblData.push(rowData);
            }
            return tblData;
        }

        /**
         * Return the filtered data with following format:
         * [
         *     [rowIndex, [value0, value1...]],
         *     [rowIndex, [value0, value1...]]
         * ]
         * @param  {Boolean} includeHeaders  Optional: include headers row
         * @param  {Boolean} excludeHiddenCols  Optional: exclude hidden columns
         * @return {Array}
         *
         * TODO: provide an API returning data in JSON format
         */
        getFilteredData(includeHeaders=false, excludeHiddenCols=false){
            if(!this.validRowsIndex){
                return [];
            }
            let rows = this.tbl.rows,
                filteredData = [];
            if(includeHeaders){
                let headers = this.getHeadersText(excludeHiddenCols);
                filteredData.push([this.getHeadersRowIndex(), headers]);
            }

            let validRows = this.getValidRows(true);
            for(let i=0; i<validRows.length; i++){
                let rData = [this.validRowsIndex[i], []],
                    cells = rows[this.validRowsIndex[i]].cells;
                for(let k=0; k<cells.length; k++){
                    if(excludeHiddenCols && this.hasExtension('colsVisibility')){
                        if(this.extension('colsVisibility').isColHidden(k)){
                            continue;
                        }
                    }
                    let cellData = this.getCellData(cells[k]);
                    rData[1].push(cellData);
                }
                filteredData.push(rData);
            }
            return filteredData;
        }

        /**
         * Return the filtered data for a given column index
         * @param  {Number} colIndex Colmun's index
         * @param  {Boolean} includeHeaders  Optional: include headers row
         * @return {Array}           Flat list of values ['val0','val1','val2'...]
         *
         * TODO: provide an API returning data in JSON format
         */
        getFilteredDataCol(colIndex, includeHeaders=false){
            if(Types.isUndef(colIndex)){
                return [];
            }
            let data = this.getFilteredData(),
                colData = [];
            if(includeHeaders){
                colData.push(this.getHeadersText()[colIndex]);
            }
            for(let i=0, len=data.length; i<len; i++){
                let r = data[i],
                    //cols values of current row
                    d = r[1],
                    //data of searched column
                    c = d[colIndex];
                colData.push(c);
            }
            return colData;
        }

        /**
         * Get the display value of a row
         * @param  {RowElement} row DOM element of the row
         * @return {String}     Usually 'none' or ''
         */
        getRowDisplay(row){
            if(!Types.isObj(row)){
                return null;
            }
            return row.style.display;
        }

        /**
         * Validate/invalidate row by setting the 'validRow' attribute on the row
         * @param  {Number}  rowIndex Index of the row
         * @param  {Boolean} isValid
         */
        validateRow(rowIndex, isValid){
            let row = this.tbl.rows[rowIndex];
            if(!row || typeof isValid !== 'boolean'){
                return;
            }

            // always visible rows are valid
            if(this.hasVisibleRows && this.visibleRows.indexOf(rowIndex) !== -1){
                isValid = true;
            }

            let displayFlag = isValid ? '' : 'none',
                validFlag = isValid ? 'true' : 'false';
            row.style.display = displayFlag;

            if(this.paging){
                row.setAttribute('validRow', validFlag);
            }

            if(isValid){
                if(this.validRowsIndex.indexOf(rowIndex) === -1){
                    this.validRowsIndex.push(rowIndex);
                }

                if(this.onRowValidated){
                    this.onRowValidated.call(null, this, rowIndex);
                }

                this.emitter.emit('row-validated', this, rowIndex);
            }
        }

        /**
         * Validate all filterable rows
         */
        validateAllRows(){
            if(!this._hasGrid){
                return;
            }
            this.validRowsIndex = [];
            for(let k=this.refRow; k<this.nbFilterableRows; k++){
                this.validateRow(k, true);
            }
        }

        /**
         * Set search value to a given filter
         * @param {Number} index     Column's index
         * @param {String or Array} query  searcharg Search term
         */
        setFilterValue(index, query=''){
            if(!this.fltGrid){
                return;
            }
            let slc = this.getFilterElement(index),
                fltColType = this.getFilterType(index);

            if(fltColType !== this.fltTypeMulti &&
                fltColType != this.fltTypeCheckList){
                if(this.loadFltOnDemand && !this.initialized){
                    this.emitter.emit('build-select-filter', this, index,
                        this.linkedFilters, this.isExternalFlt);
                }
                slc.value = query;
            }
            //multiple selects
            else if(fltColType === this.fltTypeMulti){
                let values = Types.isArray(query) ? query :
                    query.split(' '+this.orOperator+' ');

                if(this.loadFltOnDemand && !this.initialized){
                    this.emitter.emit('build-select-filter', this, index,
                        this.linkedFilters, this.isExternalFlt);
                }

                this.emitter.emit('select-options', this, index, values);
            }
            //checklist
            else if(fltColType === this.fltTypeCheckList){
                let values = [];
                if(this.loadFltOnDemand && !this.initialized){
                    this.emitter.emit('build-checklist-filter', this, index,
                        this.isExternalFlt);
                }
                if(Types.isArray(query)){
                    values = query;
                } else {
                    query = Str.matchCase(query, this.caseSensitive);
                    values = query.split(' '+this.orOperator+' ');
                }

                this.emitter.emit('select-checklist-options', this, index, values);
            }
        }

        /**
         * Set them columns' widths as per configuration
         * @param {Element} tbl DOM element
         */
        setColWidths(tbl){
            if(!this.hasColWidths){
                return;
            }
            tbl = tbl || this.tbl;

            setWidths.call(this);

            function setWidths(){
                let nbCols = this.nbCells;
                let colWidths = this.colWidths;
                let colTags = Dom.tag(tbl, 'col');
                let tblHasColTag = colTags.length > 0;
                let frag = !tblHasColTag ? doc.createDocumentFragment() : null;
                for(let k=0; k<nbCols; k++){
                    let col;
                    if(tblHasColTag){
                        col = colTags[k];
                    } else {
                        col = Dom.create('col', ['id', this.id+'_col_'+k]);
                        frag.appendChild(col);
                    }
                    col.style.width = colWidths[k];
                }
                if(!tblHasColTag){
                    tbl.insertBefore(frag, tbl.firstChild);
                }
            }
        }

        /**
         * Makes defined rows always visible
         */
        enforceVisibility(){
            if(!this.hasVisibleRows){
                return;
            }
            for(let i=0, len=this.visibleRows.length; i<len; i++){
                let row = this.visibleRows[i];
                //row index cannot be > nrows
                if(row <= this.nbRows){
                    this.validateRow(row, true);
                }
            }
        }

        /**
         * Clear all the filters' values
         */
        clearFilters(){
            if(!this.fltGrid){
                return;
            }

            this.emitter.emit('before-clearing-filters', this);

            if(this.onBeforeReset){
                this.onBeforeReset.call(null, this, this.getFiltersValue());
            }
            for(let i=0, len=this.fltIds.length; i<len; i++){
                this.setFilterValue(i, '');
            }

            this.filter();

            if(this.onAfterReset){ this.onAfterReset.call(null, this); }
            this.emitter.emit('after-clearing-filters', this);
        }

        /**
         * Clears filtered columns visual indicator (background color)
         */
        clearActiveColumns(){
            for(let i=0, len=this.getCellsNb(this.headersRow); i<len; i++){
                Dom.removeClass(
                    this.getHeaderElement(i), this.activeColumnsCssClass);
            }
        }

        /**
         * Mark currently filtered column
         * @param  {Number} colIndex Column index
         */
        markActiveColumn(colIndex){
            let header = this.getHeaderElement(colIndex);
            if(Dom.hasClass(header, this.activeColumnsCssClass)){
                return;
            }
            if(this.onBeforeActiveColumn){
                this.onBeforeActiveColumn.call(null, this, colIndex);
            }
            Dom.addClass(header, this.activeColumnsCssClass);
            if(this.onAfterActiveColumn){
                this.onAfterActiveColumn.call(null, this, colIndex);
            }
        }

        /**
         * Refresh the filters subject to linking ('select', 'multiple',
         * 'checklist' type)
         */
        linkFilters(){
            if(!this.linkedFilters || !this.activeFilterId){
                return;
            }
            let slcA1 = this.getFiltersByType(this.fltTypeSlc, true),
                slcA2 = this.getFiltersByType(this.fltTypeMulti, true),
                slcA3 = this.getFiltersByType(this.fltTypeCheckList, true),
                slcIndex = slcA1.concat(slcA2);
            slcIndex = slcIndex.concat(slcA3);

            let activeFlt = this.activeFilterId.split('_')[0];
            activeFlt = activeFlt.split(this.prfxFlt)[1];
            let slcSelectedValue;
            for(let i=0, len=slcIndex.length; i<len; i++){
                let curSlc = Dom.id(this.fltIds[slcIndex[i]]);
                slcSelectedValue = this.getFilterValue(slcIndex[i]);

                // Welcome to cyclomatic complexity hell :)
                // TODO: simplify/refactor if statement
                if(activeFlt!==slcIndex[i] ||
                    (this.paging && slcA1.indexOf(slcIndex[i]) != -1 &&
                        activeFlt === slcIndex[i] ) ||
                    (!this.paging && (slcA3.indexOf(slcIndex[i]) != -1 ||
                        slcA2.indexOf(slcIndex[i]) != -1)) ||
                    slcSelectedValue === this.displayAllText ){

                    // if(slcA3.indexOf(slcIndex[i]) != -1){
                    // this.Mod.checkList.checkListDiv[slcIndex[i]].innerHTML = '';
                    // } else {
                    //     curSlc.innerHTML = '';
                    // }

                    //1st option needs to be inserted
                    if(this.loadFltOnDemand) {
                        let opt0 = Dom.createOpt(this.displayAllText, '');
                        curSlc.innerHTML = '';
                        curSlc.appendChild(opt0);
                    }

                    if(slcA3.indexOf(slcIndex[i]) != -1){
                        this.emitter.emit('build-checklist-filter', this,
                            slcIndex[i], this.isExternalFlt);
                    } else {
                        this.emitter.emit('build-select-filter', this, slcIndex[i],
                            true, this.isExternalFlt);
                    }

                    this.setFilterValue(slcIndex[i], slcSelectedValue);
                }
            }// for i
        }

        /**
         * Determines if passed filter column implements exact query match
         * @param  {Number}  colIndex [description]
         * @return {Boolean}          [description]
         */
        isExactMatch(colIndex){
            let fltType = this.getFilterType(colIndex);
            return this.exactMatchByCol[colIndex] || this.exactMatch ||
                (fltType !== this.fltTypeInp);
        }

        /**
         * Check if passed script or stylesheet is already imported
         * @param  {String}  filePath Ressource path
         * @param  {String}  type     Possible values: 'script' or 'link'
         * @return {Boolean}
         */
        isImported(filePath, type){
            let imported = false,
                importType = !type ? 'script' : type,
                attr = importType == 'script' ? 'src' : 'href',
                files = Dom.tag(doc, importType);
            for (let i=0, len=files.length; i<len; i++){
                if(files[i][attr] === undefined){
                    continue;
                }
                if(files[i][attr].match(filePath)){
                    imported = true;
                    break;
                }
            }
            return imported;
        }

        /**
         * Import script or stylesheet
         * @param  {String}   fileId   Ressource ID
         * @param  {String}   filePath Ressource path
         * @param  {Function} callback Callback
         * @param  {String}   type     Possible values: 'script' or 'link'
         */
        import(fileId, filePath, callback, type){
            let ftype = !type ? 'script' : type,
                imported = this.isImported(filePath, ftype);
            if(imported){
                return;
            }
            let o = this,
                isLoaded = false,
                file,
                head = Dom.tag(doc, 'head')[0];

            if(Str.lower(ftype) === 'link'){
                file = Dom.create(
                    'link',
                    ['id', fileId], ['type', 'text/css'],
                    ['rel', 'stylesheet'], ['href', filePath]
                );
            } else {
                file = Dom.create(
                    'script', ['id', fileId],
                    ['type', 'text/javascript'], ['src', filePath]
                );
            }

            //Browser <> IE onload event works only for scripts, not for stylesheets
            file.onload = file.onreadystatechange = function(){
                if(!isLoaded &&
                    (!this.readyState || this.readyState === 'loaded' ||
                        this.readyState === 'complete')){
                    isLoaded = true;
                    if(typeof callback === 'function'){
                        callback.call(null, o);
                    }
                }
            };
            file.onerror = function(){
                throw new Error('TF script could not load: ' + filePath);
            };
            head.appendChild(file);
        }

        /**
         * Check if table has filters grid
         * @return {Boolean}
         */
        hasGrid(){
            return this._hasGrid;
        }

        /**
         * Get list of filter IDs
         * @return {[type]} [description]
         */
        getFiltersId(){
            return this.fltIds || [];
        }

        /**
         * Get filtered (valid) rows indexes
         * @param  {Boolean} reCalc Force calculation of filtered rows list
         * @return {Array}          List of row indexes
         */
        getValidRows(reCalc){
            if(!reCalc){
                return this.validRowsIndex;
            }

            this.validRowsIndex = [];
            for(let k=this.refRow; k<this.getRowsNb(true); k++){
                let r = this.tbl.rows[k];
                if(!this.paging){
                    if(this.getRowDisplay(r) !== 'none'){
                        this.validRowsIndex.push(r.rowIndex);
                    }
                } else {
                    if(r.getAttribute('validRow') === 'true' ||
                        r.getAttribute('validRow') === null){
                        this.validRowsIndex.push(r.rowIndex);
                    }
                }
            }
            return this.validRowsIndex;
        }

        /**
         * Get the index of the row containing the filters
         * @return {Number}
         */
        getFiltersRowIndex(){
            return this.filtersRowIndex;
        }

        /**
         * Get the index of the headers row
         * @return {Number}
         */
        getHeadersRowIndex(){
            return this.headersRow;
        }

        /**
         * Get the row index from where the filtering process start (1st filterable
         * row)
         * @return {Number}
         */
        getStartRowIndex(){
            return this.refRow;
        }

        /**
         * Get the index of the last row
         * @return {Number}
         */
        getLastRowIndex(){
            return (this.nbRows-1);
        }

        /**
         * Get the header DOM element for a given column index
         * @param  {Number} colIndex Column index
         * @return {Object}
         */
        getHeaderElement(colIndex){
            let table = this.gridLayout ? this.Mod.gridLayout.headTbl : this.tbl;
            let tHead = Dom.tag(table, 'thead');
            let headersRow = this.headersRow;
            let header;
            for(let i=0; i<this.nbCells; i++){
                if(i !== colIndex){
                    continue;
                }
                if(tHead.length === 0){
                    header = table.rows[headersRow].cells[i];
                }
                if(tHead.length === 1){
                    header = tHead[0].rows[headersRow].cells[i];
                }
                break;
            }
            return header;
        }

        /**
         * Return the list of headers' text
         * @param  {Boolean} excludeHiddenCols  Optional: exclude hidden columns
         * @return {Array} list of headers' text
         */
        getHeadersText(excludeHiddenCols=false){
            let headers = [];
            for(let j=0; j<this.nbCells; j++){
                if(excludeHiddenCols && this.hasExtension('colsVisibility')){
                    if(this.extension('colsVisibility').isColHidden(j)){
                        continue;
                    }
                }
                let header = this.getHeaderElement(j);
                let headerText = Dom.getFirstTextNode(header);
                headers.push(headerText);
            }
            return headers;
        }

        /**
         * Return the filter type for a specified column
         * @param  {Number} colIndex Column's index
         * @return {String}
         */
        getFilterType(colIndex){
            let colType = this.cfg['col_'+colIndex];
            return !colType ? this.fltTypeInp : Str.lower(colType);
        }

        /**
         * Get the total number of filterable rows
         * @return {Number}
         */
        getFilterableRowsNb(){
            return this.getRowsNb(false);
        }

        /**
         * Get the configuration object (literal object)
         * @return {Object}
         */
        config(){
            return this.cfg;
        }
    }