Merge "Prepare for REL1_33 cut, labelling master as 1.34-alpha"

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

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 no-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|undefined} Conflicted item or undefined when not found
 */
FiltersViewModel.prototype.getFirstConflictedItem = function () {
        var i, filterItem, items = this.getItems();
        for ( i = 0; i < items.length; i++ ) {
                filterItem = items[ i ];
                if ( filterItem.isSelected() && filterItem.isConflicted() ) {
                        return filterItem;
                }
        }
};

/**
 * 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 no-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 no-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 no-jquery/no-each-util
        $.each( groupConflictResult, function ( group, conflicts ) {
                model.groups[ group ].setConflicts( conflicts );
        } );

        // Set conflicts for items
        // eslint-disable-next-line no-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 no-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 no-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 no-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 no-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 no-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 no-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 no-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 no-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 no-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 no-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 no-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 no-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 no-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 no-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;