const ParameterizedSQL = require('loopback-connector').ParameterizedSQL;
const mergeFilters = require('vn-loopback/util/filter').mergeFilters;

module.exports = Self => {
    Self.remoteMethod('freeAgencies', {
        description: 'Returns a list of agencies without a supplier assigned',
        accepts: [{
            arg: 'filter',
            type: 'object',
            description: `Filter defining where, order, offset, and limit - must be a JSON-encoded string`
        }],
        returns: {
            type: ['object'],
            root: true
        },
        http: {
            path: `/freeAgencies`,
            verb: 'GET'
        }
    });

    Self.freeAgencies = async(filter, options) => {
        const conn = Self.dataSource.connector;
        const where = {'sat.supplierFk': null};
        const myOptions = {};

        if (typeof options == 'object')
            Object.assign(myOptions, options);

        filter = mergeFilters(filter, {where});

        let stmt = new ParameterizedSQL(
            `SELECT a.name, a.id
                FROM agency a 
                    LEFT JOIN supplierAgencyTerm sat ON sat.agencyFk = a.id`,
            null, myOptions);

        stmt.merge(conn.makeSuffix(filter));

        return conn.executeStmt(stmt);
    };
};