const UserError = require('vn-loopback/util/user-error');

module.exports = Self => {
    /**
     * Returns a set of allowed values defined on table scheme
     * @param {String} column - Model or Table column name
     * @return {Array} - Array of set values
     */
    Self.getEnumValues = async function(column) {
        let model = this.app.models[this.modelName].definition;
        let properties = model.properties;
        let tableName = this.modelName;
        let schema = null;

        if (model.settings && model.settings.mysql) {
            let tableSplit = model.settings.mysql.table.split('.');
            tableName = tableSplit.pop();
            schema = tableSplit.pop() || null;
        }

        let property = properties[column];

        if (!property)
            throw new UserError(`Column does not exist`);

        let columnName = property.mysql
            ? property.mysql.columnName
            : column;

        let columnInfo = await this.rawSql(
            `SELECT column_type columnType
                FROM information_schema.columns
                WHERE table_name = ? 
                    AND table_schema = IFNULL(?, DATABASE())
                    AND column_name = ?`,
            [tableName, schema, columnName]
        );

        if (!columnInfo || !columnInfo[0])
            throw new UserError(`Cannot fetch column values`);

        let setValues;
        setValues = columnInfo[0].columnType
            .replace(/^enum\((.*)\)$/i, '$1')
            .replace(/'/g, '')
            .match(new RegExp(/(\w+)+/, 'ig'));

        let values = [];
        setValues.forEach(setValue => {
            values.push({value: setValue});
        });

        return values;
    };
};