Merge "resourceloader: Reduce 'implement' overhead for modules without scripts"

[lhc/web/wiklou.git] / resources / src / mediawiki.rcfilters / dm / FiltersViewModel.js

( function () {
        var FilterGroup = require( './FilterGroup.js' ),
                FilterItem = require( './FilterItem.js' ),
                FiltersViewModel;

        /**
         * View model for the filters selection and display
         *
         * @class mw.rcfilters.dm.FiltersViewModel
         * @mixins OO.EventEmitter
         * @mixins OO.EmitterList
         *
         * @constructor
         */
        FiltersViewModel = function MwRcfiltersDmFiltersViewModel() {
                // Mixin constructor
                OO.EventEmitter.call( this );
                OO.EmitterList.call( this );

                this.groups = {};
                this.defaultParams = {};
                this.highlightEnabled = false;
                this.parameterMap = {};
                this.emptyParameterState = null;

                this.views = {};
                this.currentView = 'default';
                this.searchQuery = null;

                // Events
                this.aggregate( { update: 'filterItemUpdate' } );
                this.connect( this, { filterItemUpdate: [ 'emit', 'itemUpdate' ] } );
        };

        /* Initialization */
        OO.initClass( FiltersViewModel );
        OO.mixinClass( FiltersViewModel, OO.EventEmitter );
        OO.mixinClass( FiltersViewModel, OO.EmitterList );

        /* Events */

        /**
         * @event initialize
         *
         * Filter list is initialized
         */

        /**
         * @event update
         *
         * Model has been updated
         */

        /**
         * @event itemUpdate
         * @param {mw.rcfilters.dm.FilterItem} item Filter item updated
         *
         * Filter item has changed
         */

        /**
         * @event highlightChange
         * @param {boolean} Highlight feature is enabled
         *
         * Highlight feature has been toggled enabled or disabled
         */

        /* Methods */

        /**
         * Re-assess the states of filter items based on the interactions between them
         *
         * @param {mw.rcfilters.dm.FilterItem} [item] Changed item. If not given, the
         *  method will go over the state of all items
         */
        FiltersViewModel.prototype.reassessFilterInteractions = function ( item ) {
                var allSelected,
                        model = this,
                        iterationItems = item !== undefined ? [ item ] : this.getItems();

                iterationItems.forEach( function ( checkedItem ) {
                        var allCheckedItems = checkedItem.getSubset().concat( [ checkedItem.getName() ] ),
                                groupModel = checkedItem.getGroupModel();

                        // Check for subsets (included filters) plus the item itself:
                        allCheckedItems.forEach( function ( filterItemName ) {
                                var itemInSubset = model.getItemByName( filterItemName );

                                itemInSubset.toggleIncluded(
                                        // If any of itemInSubset's supersets are selected, this item
                                        // is included
                                        itemInSubset.getSuperset().some( function ( supersetName ) {
                                                return ( model.getItemByName( supersetName ).isSelected() );
                                        } )
                                );
                        } );

                        // Update coverage for the changed group
                        if ( groupModel.isFullCoverage() ) {
                                allSelected = groupModel.areAllSelected();
                                groupModel.getItems().forEach( function ( filterItem ) {
                                        filterItem.toggleFullyCovered( allSelected );
                                } );
                        }
                } );

                // Check for conflicts
                // In this case, we must go over all items, since
                // conflicts are bidirectional and depend not only on
                // individual items, but also on the selected states of
                // the groups they're in.
                this.getItems().forEach( function ( filterItem ) {
                        var inConflict = false,
                                filterItemGroup = filterItem.getGroupModel();

                        // For each item, see if that item is still conflicting
                        // eslint-disable-next-line jquery/no-each-util
                        $.each( model.groups, function ( groupName, groupModel ) {
                                if ( filterItem.getGroupName() === groupName ) {
                                        // Check inside the group
                                        inConflict = groupModel.areAnySelectedInConflictWith( filterItem );
                                } else {
                                        // According to the spec, if two items conflict from two different
                                        // groups, the conflict only lasts if the groups **only have selected
                                        // items that are conflicting**. If a group has selected items that
                                        // are conflicting and non-conflicting, the scope of the result has
                                        // expanded enough to completely remove the conflict.

                                        // For example, see two groups with conflicts:
                                        // userExpLevel: [
                                        //   {
                                        //     name: 'experienced',
                                        //     conflicts: [ 'unregistered' ]
                                        //   }
                                        // ],
                                        // registration: [
                                        //   {
                                        //     name: 'registered',
                                        //   },
                                        //   {
                                        //     name: 'unregistered',
                                        //   }
                                        // ]
                                        // If we select 'experienced', then 'unregistered' is in conflict (and vice versa),
                                        // because, inherently, 'experienced' filter only includes registered users, and so
                                        // both filters are in conflict with one another.
                                        // However, the minute we select 'registered', the scope of our results
                                        // has expanded to no longer have a conflict with 'experienced' filter, and
                                        // so the conflict is removed.

                                        // In our case, we need to check if the entire group conflicts with
                                        // the entire item's group, so we follow the above spec
                                        inConflict = (
                                                // The foreign group is in conflict with this item
                                                groupModel.areAllSelectedInConflictWith( filterItem ) &&
                                                // Every selected member of the item's own group is also
                                                // in conflict with the other group
                                                filterItemGroup.findSelectedItems().every( function ( otherGroupItem ) {
                                                        return groupModel.areAllSelectedInConflictWith( otherGroupItem );
                                                } )
                                        );
                                }

                                // If we're in conflict, this will return 'false' which
                                // will break the loop. Otherwise, we're not in conflict
                                // and the loop continues
                                return !inConflict;
                        } );

                        // Toggle the item state
                        filterItem.toggleConflicted( inConflict );
                } );
        };

        /**
         * Get whether the model has any conflict in its items
         *
         * @return {boolean} There is a conflict
         */
        FiltersViewModel.prototype.hasConflict = function () {
                return this.getItems().some( function ( filterItem ) {
                        return filterItem.isSelected() && filterItem.isConflicted();
                } );
        };

        /**
         * Get the first item with a current conflict
         *
         * @return {mw.rcfilters.dm.FilterItem} Conflicted item
         */
        FiltersViewModel.prototype.getFirstConflictedItem = function () {
                var conflictedItem;

                this.getItems().forEach( function ( filterItem ) {
                        if ( filterItem.isSelected() && filterItem.isConflicted() ) {
                                conflictedItem = filterItem;
                                return false;
                        }
                } );

                return conflictedItem;
        };

        /**
         * Set filters and preserve a group relationship based on
         * the definition given by an object
         *
         * @param {Array} filterGroups Filters definition
         * @param {Object} [views] Extra views definition
         *  Expected in the following format:
         *  {
         *     namespaces: {
         *       label: 'namespaces', // Message key
         *       trigger: ':',
         *       groups: [
         *         {
         *            // Group info
         *            name: 'namespaces' // Parameter name
         *            title: 'namespaces' // Message key
         *            type: 'string_options',
         *            separator: ';',
         *            labelPrefixKey: { 'default': 'rcfilters-tag-prefix-namespace', inverted: 'rcfilters-tag-prefix-namespace-inverted' },
         *            fullCoverage: true
         *            items: []
         *         }
         *       ]
         *     }
         *  }
         */
        FiltersViewModel.prototype.initializeFilters = function ( filterGroups, views ) {
                var filterConflictResult, groupConflictResult,
                        allViews = {},
                        model = this,
                        items = [],
                        groupConflictMap = {},
                        filterConflictMap = {},
                        /*!
                         * Expand a conflict definition from group name to
                         * the list of all included filters in that group.
                         * We do this so that the direct relationship in the
                         * models are consistently item->items rather than
                         * mixing item->group with item->item.
                         *
                         * @param {Object} obj Conflict definition
                         * @return {Object} Expanded conflict definition
                         */
                        expandConflictDefinitions = function ( obj ) {
                                var result = {};

                                // eslint-disable-next-line jquery/no-each-util
                                $.each( obj, function ( key, conflicts ) {
                                        var filterName,
                                                adjustedConflicts = {};

                                        conflicts.forEach( function ( conflict ) {
                                                var filter;

                                                if ( conflict.filter ) {
                                                        filterName = model.groups[ conflict.group ].getPrefixedName( conflict.filter );
                                                        filter = model.getItemByName( filterName );

                                                        // Rename
                                                        adjustedConflicts[ filterName ] = $.extend(
                                                                {},
                                                                conflict,
                                                                {
                                                                        filter: filterName,
                                                                        item: filter
                                                                }
                                                        );
                                                } else {
                                                        // This conflict is for an entire group. Split it up to
                                                        // represent each filter

                                                        // Get the relevant group items
                                                        model.groups[ conflict.group ].getItems().forEach( function ( groupItem ) {
                                                                // Rebuild the conflict
                                                                adjustedConflicts[ groupItem.getName() ] = $.extend(
                                                                        {},
                                                                        conflict,
                                                                        {
                                                                                filter: groupItem.getName(),
                                                                                item: groupItem
                                                                        }
                                                                );
                                                        } );
                                                }
                                        } );

                                        result[ key ] = adjustedConflicts;
                                } );

                                return result;
                        };

                // Reset
                this.clearItems();
                this.groups = {};
                this.views = {};

                // Clone
                filterGroups = OO.copy( filterGroups );

                // Normalize definition from the server
                filterGroups.forEach( function ( data ) {
                        var i;
                        // What's this information needs to be normalized
                        data.whatsThis = {
                                body: data.whatsThisBody,
                                header: data.whatsThisHeader,
                                linkText: data.whatsThisLinkText,
                                url: data.whatsThisUrl
                        };

                        // Title is a msg-key
                        data.title = data.title ? mw.msg( data.title ) : data.name;

                        // Filters are given to us with msg-keys, we need
                        // to translate those before we hand them off
                        for ( i = 0; i < data.filters.length; i++ ) {
                                data.filters[ i ].label = data.filters[ i ].label ? mw.msg( data.filters[ i ].label ) : data.filters[ i ].name;
                                data.filters[ i ].description = data.filters[ i ].description ? mw.msg( data.filters[ i ].description ) : '';
                        }
                } );

                // Collect views
                allViews = $.extend( true, {
                        default: {
                                title: mw.msg( 'rcfilters-filterlist-title' ),
                                groups: filterGroups
                        }
                }, views );

                // Go over all views
                // eslint-disable-next-line jquery/no-each-util
                $.each( allViews, function ( viewName, viewData ) {
                        // Define the view
                        model.views[ viewName ] = {
                                name: viewData.name,
                                title: viewData.title,
                                trigger: viewData.trigger
                        };

                        // Go over groups
                        viewData.groups.forEach( function ( groupData ) {
                                var group = groupData.name;

                                if ( !model.groups[ group ] ) {
                                        model.groups[ group ] = new FilterGroup(
                                                group,
                                                $.extend( true, {}, groupData, { view: viewName } )
                                        );
                                }

                                model.groups[ group ].initializeFilters( groupData.filters, groupData.default );
                                items = items.concat( model.groups[ group ].getItems() );

                                // Prepare conflicts
                                if ( groupData.conflicts ) {
                                        // Group conflicts
                                        groupConflictMap[ group ] = groupData.conflicts;
                                }

                                groupData.filters.forEach( function ( itemData ) {
                                        var filterItem = model.groups[ group ].getItemByParamName( itemData.name );
                                        // Filter conflicts
                                        if ( itemData.conflicts ) {
                                                filterConflictMap[ filterItem.getName() ] = itemData.conflicts;
                                        }
                                } );
                        } );
                } );

                // Add item references to the model, for lookup
                this.addItems( items );

                // Expand conflicts
                groupConflictResult = expandConflictDefinitions( groupConflictMap );
                filterConflictResult = expandConflictDefinitions( filterConflictMap );

                // Set conflicts for groups
                // eslint-disable-next-line jquery/no-each-util
                $.each( groupConflictResult, function ( group, conflicts ) {
                        model.groups[ group ].setConflicts( conflicts );
                } );

                // Set conflicts for items
                // eslint-disable-next-line jquery/no-each-util
                $.each( filterConflictResult, function ( filterName, conflicts ) {
                        var filterItem = model.getItemByName( filterName );
                        // set conflicts for items in the group
                        filterItem.setConflicts( conflicts );
                } );

                // Create a map between known parameters and their models
                // eslint-disable-next-line jquery/no-each-util
                $.each( this.groups, function ( group, groupModel ) {
                        if (
                                groupModel.getType() === 'send_unselected_if_any' ||
                                groupModel.getType() === 'boolean' ||
                                groupModel.getType() === 'any_value'
                        ) {
                                // Individual filters
                                groupModel.getItems().forEach( function ( filterItem ) {
                                        model.parameterMap[ filterItem.getParamName() ] = filterItem;
                                } );
                        } else if (
                                groupModel.getType() === 'string_options' ||
                                groupModel.getType() === 'single_option'
                        ) {
                                // Group
                                model.parameterMap[ groupModel.getName() ] = groupModel;
                        }
                } );

                this.setSearch( '' );

                this.updateHighlightedState();

                // Finish initialization
                this.emit( 'initialize' );
        };

        /**
         * Update filter view model state based on a parameter object
         *
         * @param {Object} params Parameters object
         */
        FiltersViewModel.prototype.updateStateFromParams = function ( params ) {
                var filtersValue;
                // For arbitrary numeric single_option values make sure the values
                // are normalized to fit within the limits
                // eslint-disable-next-line jquery/no-each-util
                $.each( this.getFilterGroups(), function ( groupName, groupModel ) {
                        params[ groupName ] = groupModel.normalizeArbitraryValue( params[ groupName ] );
                } );

                // Update filter values
                filtersValue = this.getFiltersFromParameters( params );
                Object.keys( filtersValue ).forEach( function ( filterName ) {
                        this.getItemByName( filterName ).setValue( filtersValue[ filterName ] );
                }.bind( this ) );

                // Update highlight state
                this.getItemsSupportingHighlights().forEach( function ( filterItem ) {
                        var color = params[ filterItem.getName() + '_color' ];
                        if ( color ) {
                                filterItem.setHighlightColor( color );
                        } else {
                                filterItem.clearHighlightColor();
                        }
                } );
                this.updateHighlightedState();

                // Check all filter interactions
                this.reassessFilterInteractions();
        };

        /**
         * Get a representation of an empty (falsey) parameter state
         *
         * @return {Object} Empty parameter state
         */
        FiltersViewModel.prototype.getEmptyParameterState = function () {
                if ( !this.emptyParameterState ) {
                        this.emptyParameterState = $.extend(
                                true,
                                {},
                                this.getParametersFromFilters( {} ),
                                this.getEmptyHighlightParameters()
                        );
                }
                return this.emptyParameterState;
        };

        /**
         * Get a representation of only the non-falsey parameters
         *
         * @param {Object} [parameters] A given parameter state to minimize. If not given the current
         *  state of the system will be used.
         * @return {Object} Empty parameter state
         */
        FiltersViewModel.prototype.getMinimizedParamRepresentation = function ( parameters ) {
                var result = {};

                parameters = parameters ? $.extend( true, {}, parameters ) : this.getCurrentParameterState();

                // Params
                // eslint-disable-next-line jquery/no-each-util
                $.each( this.getEmptyParameterState(), function ( param, value ) {
                        if ( parameters[ param ] !== undefined && parameters[ param ] !== value ) {
                                result[ param ] = parameters[ param ];
                        }
                } );

                // Highlights
                Object.keys( this.getEmptyHighlightParameters() ).forEach( function ( param ) {
                        if ( parameters[ param ] ) {
                                // If a highlight parameter is not undefined and not null
                                // add it to the result
                                result[ param ] = parameters[ param ];
                        }
                } );

                return result;
        };

        /**
         * Get a representation of the full parameter list, including all base values
         *
         * @return {Object} Full parameter representation
         */
        FiltersViewModel.prototype.getExpandedParamRepresentation = function () {
                return $.extend(
                        true,
                        {},
                        this.getEmptyParameterState(),
                        this.getCurrentParameterState()
                );
        };

        /**
         * Get a parameter representation of the current state of the model
         *
         * @param {boolean} [removeStickyParams] Remove sticky filters from final result
         * @return {Object} Parameter representation of the current state of the model
         */
        FiltersViewModel.prototype.getCurrentParameterState = function ( removeStickyParams ) {
                var state = this.getMinimizedParamRepresentation( $.extend(
                        true,
                        {},
                        this.getParametersFromFilters( this.getSelectedState() ),
                        this.getHighlightParameters()
                ) );

                if ( removeStickyParams ) {
                        state = this.removeStickyParams( state );
                }

                return state;
        };

        /**
         * Delete sticky parameters from given object.
         *
         * @param {Object} paramState Parameter state
         * @return {Object} Parameter state without sticky parameters
         */
        FiltersViewModel.prototype.removeStickyParams = function ( paramState ) {
                this.getStickyParams().forEach( function ( paramName ) {
                        delete paramState[ paramName ];
                } );

                return paramState;
        };

        /**
         * Turn the highlight feature on or off
         */
        FiltersViewModel.prototype.updateHighlightedState = function () {
                this.toggleHighlight( this.getHighlightedItems().length > 0 );
        };

        /**
         * Get the object that defines groups by their name.
         *
         * @return {Object} Filter groups
         */
        FiltersViewModel.prototype.getFilterGroups = function () {
                return this.groups;
        };

        /**
         * Get the object that defines groups that match a certain view by their name.
         *
         * @param {string} [view] Requested view. If not given, uses current view
         * @return {Object} Filter groups matching a display group
         */
        FiltersViewModel.prototype.getFilterGroupsByView = function ( view ) {
                var result = {};

                view = view || this.getCurrentView();

                // eslint-disable-next-line jquery/no-each-util
                $.each( this.groups, function ( groupName, groupModel ) {
                        if ( groupModel.getView() === view ) {
                                result[ groupName ] = groupModel;
                        }
                } );

                return result;
        };

        /**
         * Get an array of filters matching the given display group.
         *
         * @param {string} [view] Requested view. If not given, uses current view
         * @return {mw.rcfilters.dm.FilterItem} Filter items matching the group
         */
        FiltersViewModel.prototype.getFiltersByView = function ( view ) {
                var groups,
                        result = [];

                view = view || this.getCurrentView();

                groups = this.getFilterGroupsByView( view );

                // eslint-disable-next-line jquery/no-each-util
                $.each( groups, function ( groupName, groupModel ) {
                        result = result.concat( groupModel.getItems() );
                } );

                return result;
        };

        /**
         * Get the trigger for the requested view.
         *
         * @param {string} view View name
         * @return {string} View trigger, if exists
         */
        FiltersViewModel.prototype.getViewTrigger = function ( view ) {
                return ( this.views[ view ] && this.views[ view ].trigger ) || '';
        };

        /**
         * Get the value of a specific parameter
         *
         * @param {string} name Parameter name
         * @return {number|string} Parameter value
         */
        FiltersViewModel.prototype.getParamValue = function ( name ) {
                return this.parameters[ name ];
        };

        /**
         * Get the current selected state of the filters
         *
         * @param {boolean} [onlySelected] return an object containing only the filters with a value
         * @return {Object} Filters selected state
         */
        FiltersViewModel.prototype.getSelectedState = function ( onlySelected ) {
                var i,
                        items = this.getItems(),
                        result = {};

                for ( i = 0; i < items.length; i++ ) {
                        if ( !onlySelected || items[ i ].getValue() ) {
                                result[ items[ i ].getName() ] = items[ i ].getValue();
                        }
                }

                return result;
        };

        /**
         * Get the current full state of the filters
         *
         * @return {Object} Filters full state
         */
        FiltersViewModel.prototype.getFullState = function () {
                var i,
                        items = this.getItems(),
                        result = {};

                for ( i = 0; i < items.length; i++ ) {
                        result[ items[ i ].getName() ] = {
                                selected: items[ i ].isSelected(),
                                conflicted: items[ i ].isConflicted(),
                                included: items[ i ].isIncluded()
                        };
                }

                return result;
        };

        /**
         * Get an object representing default parameters state
         *
         * @return {Object} Default parameter values
         */
        FiltersViewModel.prototype.getDefaultParams = function () {
                var result = {};

                // Get default filter state
                // eslint-disable-next-line jquery/no-each-util
                $.each( this.groups, function ( name, model ) {
                        if ( !model.isSticky() ) {
                                $.extend( true, result, model.getDefaultParams() );
                        }
                } );

                return result;
        };

        /**
         * Get a parameter representation of all sticky parameters
         *
         * @return {Object} Sticky parameter values
         */
        FiltersViewModel.prototype.getStickyParams = function () {
                var result = [];

                // eslint-disable-next-line jquery/no-each-util
                $.each( this.groups, function ( name, model ) {
                        if ( model.isSticky() ) {
                                if ( model.isPerGroupRequestParameter() ) {
                                        result.push( name );
                                } else {
                                        // Each filter is its own param
                                        result = result.concat( model.getItems().map( function ( filterItem ) {
                                                return filterItem.getParamName();
                                        } ) );
                                }
                        }
                } );

                return result;
        };

        /**
         * Get a parameter representation of all sticky parameters
         *
         * @return {Object} Sticky parameter values
         */
        FiltersViewModel.prototype.getStickyParamsValues = function () {
                var result = {};

                // eslint-disable-next-line jquery/no-each-util
                $.each( this.groups, function ( name, model ) {
                        if ( model.isSticky() ) {
                                $.extend( true, result, model.getParamRepresentation() );
                        }
                } );

                return result;
        };

        /**
         * Analyze the groups and their filters and output an object representing
         * the state of the parameters they represent.
         *
         * @param {Object} [filterDefinition] An object defining the filter values,
         *  keyed by filter names.
         * @return {Object} Parameter state object
         */
        FiltersViewModel.prototype.getParametersFromFilters = function ( filterDefinition ) {
                var groupItemDefinition,
                        result = {},
                        groupItems = this.getFilterGroups();

                if ( filterDefinition ) {
                        groupItemDefinition = {};
                        // Filter definition is "flat", but in effect
                        // each group needs to tell us its result based
                        // on the values in it. We need to split this list
                        // back into groupings so we can "feed" it to the
                        // loop below, and we need to expand it so it includes
                        // all filters (set to false)
                        this.getItems().forEach( function ( filterItem ) {
                                groupItemDefinition[ filterItem.getGroupName() ] = groupItemDefinition[ filterItem.getGroupName() ] || {};
                                groupItemDefinition[ filterItem.getGroupName() ][ filterItem.getName() ] = filterItem.coerceValue( filterDefinition[ filterItem.getName() ] );
                        } );
                }

                // eslint-disable-next-line jquery/no-each-util
                $.each( groupItems, function ( group, model ) {
                        $.extend(
                                result,
                                model.getParamRepresentation(
                                        groupItemDefinition ?
                                                groupItemDefinition[ group ] : null
                                )
                        );
                } );

                return result;
        };

        /**
         * This is the opposite of the #getParametersFromFilters method; this goes over
         * the given parameters and translates into a selected/unselected value in the filters.
         *
         * @param {Object} params Parameters query object
         * @return {Object} Filter state object
         */
        FiltersViewModel.prototype.getFiltersFromParameters = function ( params ) {
                var groupMap = {},
                        model = this,
                        result = {};

                // Go over the given parameters, break apart to groupings
                // The resulting object represents the group with its parameter
                // values. For example:
                // {
                //    group1: {
                //       param1: "1",
                //       param2: "0",
                //       param3: "1"
                //    },
                //    group2: "param4|param5"
                // }
                // eslint-disable-next-line jquery/no-each-util
                $.each( params, function ( paramName, paramValue ) {
                        var groupName,
                                itemOrGroup = model.parameterMap[ paramName ];

                        if ( itemOrGroup ) {
                                groupName = itemOrGroup instanceof FilterItem ?
                                        itemOrGroup.getGroupName() : itemOrGroup.getName();

                                groupMap[ groupName ] = groupMap[ groupName ] || {};
                                groupMap[ groupName ][ paramName ] = paramValue;
                        }
                } );

                // Go over all groups, so we make sure we get the complete output
                // even if the parameters don't include a certain group
                // eslint-disable-next-line jquery/no-each-util
                $.each( this.groups, function ( groupName, groupModel ) {
                        result = $.extend( true, {}, result, groupModel.getFilterRepresentation( groupMap[ groupName ] ) );
                } );

                return result;
        };

        /**
         * Get the highlight parameters based on current filter configuration
         *
         * @return {Object} Object where keys are `<filter name>_color` and values
         *                  are the selected highlight colors.
         */
        FiltersViewModel.prototype.getHighlightParameters = function () {
                var highlightEnabled = this.isHighlightEnabled(),
                        result = {};

                this.getItems().forEach( function ( filterItem ) {
                        if ( filterItem.isHighlightSupported() ) {
                                result[ filterItem.getName() + '_color' ] = highlightEnabled && filterItem.isHighlighted() ?
                                        filterItem.getHighlightColor() :
                                        null;
                        }
                } );

                return result;
        };

        /**
         * Get an object representing the complete empty state of highlights
         *
         * @return {Object} Object containing all the highlight parameters set to their negative value
         */
        FiltersViewModel.prototype.getEmptyHighlightParameters = function () {
                var result = {};

                this.getItems().forEach( function ( filterItem ) {
                        if ( filterItem.isHighlightSupported() ) {
                                result[ filterItem.getName() + '_color' ] = null;
                        }
                } );

                return result;
        };

        /**
         * Get an array of currently applied highlight colors
         *
         * @return {string[]} Currently applied highlight colors
         */
        FiltersViewModel.prototype.getCurrentlyUsedHighlightColors = function () {
                var result = [];

                if ( this.isHighlightEnabled() ) {
                        this.getHighlightedItems().forEach( function ( filterItem ) {
                                var color = filterItem.getHighlightColor();

                                if ( result.indexOf( color ) === -1 ) {
                                        result.push( color );
                                }
                        } );
                }

                return result;
        };

        /**
         * Sanitize value group of a string_option groups type
         * Remove duplicates and make sure to only use valid
         * values.
         *
         * @private
         * @param {string} groupName Group name
         * @param {string[]} valueArray Array of values
         * @return {string[]} Array of valid values
         */
        FiltersViewModel.prototype.sanitizeStringOptionGroup = function ( groupName, valueArray ) {
                var validNames = this.getGroupFilters( groupName ).map( function ( filterItem ) {
                        return filterItem.getParamName();
                } );

                return mw.rcfilters.utils.normalizeParamOptions( valueArray, validNames );
        };

        /**
         * Check whether no visible filter is selected.
         *
         * Filter groups that are hidden or sticky are not shown in the
         * active filters area and therefore not included in this check.
         *
         * @return {boolean} No visible filter is selected
         */
        FiltersViewModel.prototype.areVisibleFiltersEmpty = function () {
                // Check if there are either any selected items or any items
                // that have highlight enabled
                return !this.getItems().some( function ( filterItem ) {
                        var visible = !filterItem.getGroupModel().isSticky() && !filterItem.getGroupModel().isHidden(),
                                active = ( filterItem.isSelected() || filterItem.isHighlighted() );
                        return visible && active;
                } );
        };

        /**
         * Check whether the invert state is a valid one. A valid invert state is one where
         * there are actual namespaces selected.
         *
         * This is done to compare states to previous ones that may have had the invert model
         * selected but effectively had no namespaces, so are not effectively different than
         * ones where invert is not selected.
         *
         * @return {boolean} Invert is effectively selected
         */
        FiltersViewModel.prototype.areNamespacesEffectivelyInverted = function () {
                return this.getInvertModel().isSelected() &&
                        this.findSelectedItems().some( function ( itemModel ) {
                                return itemModel.getGroupModel().getName() === 'namespace';
                        } );
        };

        /**
         * Get the item that matches the given name
         *
         * @param {string} name Filter name
         * @return {mw.rcfilters.dm.FilterItem} Filter item
         */
        FiltersViewModel.prototype.getItemByName = function ( name ) {
                return this.getItems().filter( function ( item ) {
                        return name === item.getName();
                } )[ 0 ];
        };

        /**
         * Set all filters to false or empty/all
         * This is equivalent to display all.
         */
        FiltersViewModel.prototype.emptyAllFilters = function () {
                this.getItems().forEach( function ( filterItem ) {
                        if ( !filterItem.getGroupModel().isSticky() ) {
                                this.toggleFilterSelected( filterItem.getName(), false );
                        }
                }.bind( this ) );
        };

        /**
         * Toggle selected state of one item
         *
         * @param {string} name Name of the filter item
         * @param {boolean} [isSelected] Filter selected state
         */
        FiltersViewModel.prototype.toggleFilterSelected = function ( name, isSelected ) {
                var item = this.getItemByName( name );

                if ( item ) {
                        item.toggleSelected( isSelected );
                }
        };

        /**
         * Toggle selected state of items by their names
         *
         * @param {Object} filterDef Filter definitions
         */
        FiltersViewModel.prototype.toggleFiltersSelected = function ( filterDef ) {
                Object.keys( filterDef ).forEach( function ( name ) {
                        this.toggleFilterSelected( name, filterDef[ name ] );
                }.bind( this ) );
        };

        /**
         * Get a group model from its name
         *
         * @param {string} groupName Group name
         * @return {mw.rcfilters.dm.FilterGroup} Group model
         */
        FiltersViewModel.prototype.getGroup = function ( groupName ) {
                return this.groups[ groupName ];
        };

        /**
         * Get all filters within a specified group by its name
         *
         * @param {string} groupName Group name
         * @return {mw.rcfilters.dm.FilterItem[]} Filters belonging to this group
         */
        FiltersViewModel.prototype.getGroupFilters = function ( groupName ) {
                return ( this.getGroup( groupName ) && this.getGroup( groupName ).getItems() ) || [];
        };

        /**
         * Find items whose labels match the given string
         *
         * @param {string} query Search string
         * @param {boolean} [returnFlat] Return a flat array. If false, the result
         *  is an object whose keys are the group names and values are an array of
         *  filters per group. If set to true, returns an array of filters regardless
         *  of their groups.
         * @return {Object} An object of items to show
         *  arranged by their group names
         */
        FiltersViewModel.prototype.findMatches = function ( query, returnFlat ) {
                var i, searchIsEmpty,
                        groupTitle,
                        result = {},
                        flatResult = [],
                        view = this.getViewByTrigger( query.substr( 0, 1 ) ),
                        items = this.getFiltersByView( view );

                // Normalize so we can search strings regardless of case and view
                query = query.trim().toLowerCase();
                if ( view !== 'default' ) {
                        query = query.substr( 1 );
                }
                // Trim again to also intercept cases where the spaces were after the trigger
                // eg: '#   str'
                query = query.trim();

                // Check if the search if actually empty; this can be a problem when
                // we use prefixes to denote different views
                searchIsEmpty = query.length === 0;

                // item label starting with the query string
                for ( i = 0; i < items.length; i++ ) {
                        if (
                                searchIsEmpty ||
                                items[ i ].getLabel().toLowerCase().indexOf( query ) === 0 ||
                                (
                                        // For tags, we want the parameter name to be included in the search
                                        view === 'tags' &&
                                        items[ i ].getParamName().toLowerCase().indexOf( query ) > -1
                                )
                        ) {
                                result[ items[ i ].getGroupName() ] = result[ items[ i ].getGroupName() ] || [];
                                result[ items[ i ].getGroupName() ].push( items[ i ] );
                                flatResult.push( items[ i ] );
                        }
                }

                if ( $.isEmptyObject( result ) ) {
                        // item containing the query string in their label, description, or group title
                        for ( i = 0; i < items.length; i++ ) {
                                groupTitle = items[ i ].getGroupModel().getTitle();
                                if (
                                        searchIsEmpty ||
                                        items[ i ].getLabel().toLowerCase().indexOf( query ) > -1 ||
                                        items[ i ].getDescription().toLowerCase().indexOf( query ) > -1 ||
                                        groupTitle.toLowerCase().indexOf( query ) > -1 ||
                                        (
                                                // For tags, we want the parameter name to be included in the search
                                                view === 'tags' &&
                                                items[ i ].getParamName().toLowerCase().indexOf( query ) > -1
                                        )
                                ) {
                                        result[ items[ i ].getGroupName() ] = result[ items[ i ].getGroupName() ] || [];
                                        result[ items[ i ].getGroupName() ].push( items[ i ] );
                                        flatResult.push( items[ i ] );
                                }
                        }
                }

                return returnFlat ? flatResult : result;
        };

        /**
         * Get items that are highlighted
         *
         * @return {mw.rcfilters.dm.FilterItem[]} Highlighted items
         */
        FiltersViewModel.prototype.getHighlightedItems = function () {
                return this.getItems().filter( function ( filterItem ) {
                        return filterItem.isHighlightSupported() &&
                                filterItem.getHighlightColor();
                } );
        };

        /**
         * Get items that allow highlights even if they're not currently highlighted
         *
         * @return {mw.rcfilters.dm.FilterItem[]} Items supporting highlights
         */
        FiltersViewModel.prototype.getItemsSupportingHighlights = function () {
                return this.getItems().filter( function ( filterItem ) {
                        return filterItem.isHighlightSupported();
                } );
        };

        /**
         * Get all selected items
         *
         * @return {mw.rcfilters.dm.FilterItem[]} Selected items
         */
        FiltersViewModel.prototype.findSelectedItems = function () {
                var allSelected = [];

                // eslint-disable-next-line jquery/no-each-util
                $.each( this.getFilterGroups(), function ( groupName, groupModel ) {
                        allSelected = allSelected.concat( groupModel.findSelectedItems() );
                } );

                return allSelected;
        };

        /**
         * Get the current view
         *
         * @return {string} Current view
         */
        FiltersViewModel.prototype.getCurrentView = function () {
                return this.currentView;
        };

        /**
         * Get the label for the current view
         *
         * @param {string} viewName View name
         * @return {string} Label for the current view
         */
        FiltersViewModel.prototype.getViewTitle = function ( viewName ) {
                viewName = viewName || this.getCurrentView();

                return this.views[ viewName ] && this.views[ viewName ].title;
        };

        /**
         * Get the view that fits the given trigger
         *
         * @param {string} trigger Trigger
         * @return {string} Name of view
         */
        FiltersViewModel.prototype.getViewByTrigger = function ( trigger ) {
                var result = 'default';

                // eslint-disable-next-line jquery/no-each-util
                $.each( this.views, function ( name, data ) {
                        if ( data.trigger === trigger ) {
                                result = name;
                        }
                } );

                return result;
        };

        /**
         * Return a version of the given string that is without any
         * view triggers.
         *
         * @param {string} str Given string
         * @return {string} Result
         */
        FiltersViewModel.prototype.removeViewTriggers = function ( str ) {
                if ( this.getViewFromString( str ) !== 'default' ) {
                        str = str.substr( 1 );
                }

                return str;
        };

        /**
         * Get the view from the given string by a trigger, if it exists
         *
         * @param {string} str Given string
         * @return {string} View name
         */
        FiltersViewModel.prototype.getViewFromString = function ( str ) {
                return this.getViewByTrigger( str.substr( 0, 1 ) );
        };

        /**
         * Set the current search for the system.
         * This also dictates what items and groups are visible according
         * to the search in #findMatches
         *
         * @param {string} searchQuery Search query, including triggers
         * @fires searchChange
         */
        FiltersViewModel.prototype.setSearch = function ( searchQuery ) {
                var visibleGroups, visibleGroupNames;

                if ( this.searchQuery !== searchQuery ) {
                        // Check if the view changed
                        this.switchView( this.getViewFromString( searchQuery ) );

                        visibleGroups = this.findMatches( searchQuery );
                        visibleGroupNames = Object.keys( visibleGroups );

                        // Update visibility of items and groups
                        // eslint-disable-next-line jquery/no-each-util
                        $.each( this.getFilterGroups(), function ( groupName, groupModel ) {
                                // Check if the group is visible at all
                                groupModel.toggleVisible( visibleGroupNames.indexOf( groupName ) !== -1 );
                                groupModel.setVisibleItems( visibleGroups[ groupName ] || [] );
                        } );

                        this.searchQuery = searchQuery;
                        this.emit( 'searchChange', this.searchQuery );
                }
        };

        /**
         * Get the current search
         *
         * @return {string} Current search query
         */
        FiltersViewModel.prototype.getSearch = function () {
                return this.searchQuery;
        };

        /**
         * Switch the current view
         *
         * @private
         * @param {string} view View name
         */
        FiltersViewModel.prototype.switchView = function ( view ) {
                if ( this.views[ view ] && this.currentView !== view ) {
                        this.currentView = view;
                }
        };

        /**
         * Toggle the highlight feature on and off.
         * Propagate the change to filter items.
         *
         * @param {boolean} enable Highlight should be enabled
         * @fires highlightChange
         */
        FiltersViewModel.prototype.toggleHighlight = function ( enable ) {
                enable = enable === undefined ? !this.highlightEnabled : enable;

                if ( this.highlightEnabled !== enable ) {
                        this.highlightEnabled = enable;
                        this.emit( 'highlightChange', this.highlightEnabled );
                }
        };

        /**
         * Check if the highlight feature is enabled
         * @return {boolean}
         */
        FiltersViewModel.prototype.isHighlightEnabled = function () {
                return !!this.highlightEnabled;
        };

        /**
         * Toggle the inverted namespaces property on and off.
         * Propagate the change to namespace filter items.
         *
         * @param {boolean} enable Inverted property is enabled
         */
        FiltersViewModel.prototype.toggleInvertedNamespaces = function ( enable ) {
                this.toggleFilterSelected( this.getInvertModel().getName(), enable );
        };

        /**
         * Get the model object that represents the 'invert' filter
         *
         * @return {mw.rcfilters.dm.FilterItem}
         */
        FiltersViewModel.prototype.getInvertModel = function () {
                return this.getGroup( 'invertGroup' ).getItemByParamName( 'invert' );
        };

        /**
         * Set highlight color for a specific filter item
         *
         * @param {string} filterName Name of the filter item
         * @param {string} color Selected color
         */
        FiltersViewModel.prototype.setHighlightColor = function ( filterName, color ) {
                this.getItemByName( filterName ).setHighlightColor( color );
        };

        /**
         * Clear highlight for a specific filter item
         *
         * @param {string} filterName Name of the filter item
         */
        FiltersViewModel.prototype.clearHighlightColor = function ( filterName ) {
                this.getItemByName( filterName ).clearHighlightColor();
        };

        module.exports = FiltersViewModel;

}() );