wikimedia/wikimedia-fundraising-dash

define( [
    'knockout',
    'jquery',
    'text!components/filters/filters.html'
], function ( ko, $, template ) {

    function FiltersViewModel( params ) {
        var self = this;

        this.filters = ko.observableArray( [] );
        this.setChoices = function () {
            var qs = '',
                choices = {};

            $.each( self.filters(), function ( i, filter ) {
                var filterQs = filter.queryString();
                if ( !filterQs || filterQs === '' ) {
                    return;
                }
                if ( qs === '' ) {
                    qs += '$filter=(';
                } else {
                    qs += ' and (';
                }
                qs += filterQs;
                qs += ')';
                choices[ filter.name ] = filter.userChoices();
            } );
            params.queryString( qs );
            params.userChoices( choices );
            params.change();
        };

        params.metadataRequest.then( function ( metadata ) {
            var filters = [];
            $.each( metadata.filters, function ( name, filterMeta ) {
                if ( !filterMeta.display ) {
                    return;
                }
                var filter = {
                    name: name,
                    metadata: filterMeta,
                    queryString: ko.observable( '' )
                };
                switch ( filterMeta.type ) {
                    case 'dropdown':
                        filter.userChoices = ko.observableArray( params.userChoices()[ name ] || [] );
                        break;
                    case 'text':
                    case 'number':
                        filter.userChoices = ko.observable( params.userChoices()[ name ] || {} );
                        break;
                    default:
                        // not yet supported filter type
                        return;
                }
                filter.queryString.subscribe( self.setChoices );
                filters.push( filter );
            } );
            // sort filters by type then display name
            filters.sort( function ( a, b ) {
                var aMeta = a.metadata,
                    bMeta = b.metadata;

                if ( aMeta.type > bMeta.type ) {
                    return 1;
                }
                if ( aMeta.type < bMeta.type ) {
                    return -1;
                }
                if ( aMeta.display > bMeta.display ) {
                    return 1;
                }
                if ( aMeta.display < bMeta.display ) {
                    return -1;
                }
                return 0;
            } );
            self.filters( filters );
        } );
    }

    return { viewModel: FiltersViewModel, template: template };
} );