/*************************************************************************************************
	 * Generates a valid CAML filter string based on the specified taxonomy filter
	 * @param filter : The taxonomy filter that needs to be formatted into a CAML filter string
	 *************************************************************************************************/
    private static generateTaxonomyFilter(filter:IQueryFilter): string
    {
        let filterOutput = '';
        let filterTerms = filter.value as ITag[];

        if(isEmpty(filter.value)) {
            return '';
        }
        else if (filter.operator == QueryFilterOperator.ContainsAny || filterTerms == null) {
            let values = filterTerms != null ? filterTerms.map(x => Text.format("<Value Type='Integer'>{0}</Value>", x.key)).join('') : '';
            filterOutput = Text.format("<In><FieldRef Name='{0}' LookupId='TRUE' /><Values>{1}</Values></In>", filter.field.internalName, values);
        }
        else if (filter.operator == QueryFilterOperator.ContainsAll) {
            let taxFilters: IQueryFilter[] = [];

            for(let term of filterTerms) {
                let termValue:ITag[] = [ term ];

                let taxFilter:IQueryFilter = {
                    index: null,
                    field: filter.field,
                    value: termValue,
                    join: QueryFilterJoin.And,
                    operator: QueryFilterOperator.ContainsAny
                };
                taxFilters.push(taxFilter);
            }

            filterOutput = this.generateFilters(taxFilters);
        }

        return filterOutput;
    }

					response.json().then((data:any) => {
						let fields:any[] = data.value;
						let fieldTermSetId = null;

						if(fields.length > 0) {
							let field = fields[0];

							if(field.IsTermSetValid && !isEmpty(field.TermSetId)) {
								fieldTermSetId = field.TermSetId;
							}
						}
						resolve(fieldTermSetId);
					})

    /*************************************************************************************************
     * Generates a full CAML query based on the provided IQuerySettings
     * @param querySettings : A IQuerySettings object required for generating the CAML query
     *************************************************************************************************/
    public static generateCamlQuery(querySettings:IQuerySettings): string {
        let query = '';

        // Generates the <Where /> part
        if(querySettings.filters && !isEmpty(querySettings.filters)) {
            let sortedFilters = querySettings.filters.sort((a, b) => { return a.index - b.index; });
            query += Text.format('<Where>{0}</Where>', this.generateFilters(sortedFilters));
        }

        // Generates the <OrderBy /> part
        if(querySettings.orderBy && !isEmpty(querySettings.orderBy)) {
            let isAscending = querySettings.orderByDirection == 'desc' ? 'FALSE' : 'TRUE';
            query += Text.format("<OrderBy><FieldRef Name='{0}' Ascending='{1}' /></OrderBy>", querySettings.orderBy, isAscending);
        }

        // Wraps the <Where /> and <OrderBy /> into a <Query /> tag
        query = Text.format('<Query>{0}</Query>', query);

        // Generates the <RowLimit /> part
        if(querySettings.limitEnabled) {
            query += Text.format('<RowLimit>{0}</RowLimit>', querySettings.itemLimit);
        }

        // Generates the <ViewFields /> part
        if(querySettings.viewFields && !isEmpty(querySettings.viewFields)) {
            query += Text.format('<ViewFields>{0}</ViewFields>', querySettings.viewFields.map(field => Text.format("<FieldRef Name='{0}' />", field)).join(''));
        }

        // Wraps the everything into a final <View /> tag
        if(querySettings.recursiveEnabled) {
            query = Text.format('<View Scope="RecursiveAll">{0}</View>', query);
        }
        else {
            query = Text.format('<View>{0}</View>', query);
        }

        return query;
    }

	/*************************************************************************************************
	 * Returns the value of the specified filter correctly formatted based on its type of value
	 * @param filter : The filter that needs its value to be formatted
	 *************************************************************************************************/
    private static formatFilterValue(filter:IQueryFilter): string
    {
        let filterValue = "";

        if(filter.field.type == QueryFilterFieldType.Datetime) {
            if(filter.expression != null && !isEmpty(filter.expression)) {
                filterValue = this.formatDateExpressionFilterValue(filter.expression);
            }
            else {
                filterValue = this.formatDateFilterValue(filter.value as string);
            }
        }
        else {
            filterValue = this.formatTextFilterValue(filter.value as string);
        }

        return filterValue;
    }

    /*************************************************************************************************
	 * Generates a valid CAML filter string based on the specified user filter
	 * @param filter : The user filter that needs to be formatted into a CAML filter string
	 *************************************************************************************************/
    private static generateUserFilter(filter:IQueryFilter): string
    {
        let filterOutput = '';
        let filterUsers = filter.value as IPersonaProps[];

        if(filter.me) {
            filterOutput = Text.format("<Eq><FieldRef Name='{0}' /><Value Type='Integer'><UserID /></Value></Eq>", filter.field.internalName);
        }
        else if(isEmpty(filter.value)) {
            return '';
        }
        else if (filter.operator == QueryFilterOperator.ContainsAny || filterUsers == null)
        {
            let values = filterUsers != null ? filterUsers.map(x => Text.format("<Value Type='Integer'>{0}</Value>", x.optionalText)).join('') : '';
            filterOutput = Text.format("<In><FieldRef Name='{0}' LookupId='TRUE' /><Values>{1}</Values></In>", filter.field.internalName, values);
        }
        else if (filter.operator == QueryFilterOperator.ContainsAll)
        {
            let userFilters: IQueryFilter[] = [];

            for(let user of filterUsers) {
                let userValue:IPersonaProps[] = [ user ];

                let userFilter:IQueryFilter = {
                    index: null,
                    field: filter.field,
                    value: userValue,
                    join: QueryFilterJoin.And,
                    operator: QueryFilterOperator.ContainsAny
                };
                userFilters.push(userFilter);
            }

            filterOutput = this.generateFilters(userFilters);
        }

        return filterOutput;
    }