hapipal / tandy / 102

'use strict';

const Boom = require('@hapi/boom');

const Ref = require('objection').ref;

const Actions = require('../action-util');

/**

 * Populate an association

 *

 * get /model/:parentid/:relation

 * get /model/:parentid/:relation/count

 * get /model/:parentid/:relation/:id

 *

 * @param {Object} where       - the find criteria (passed directly to the ORM)

 * @param {Integer} limit      - the maximum number of records to send back (useful for pagination)

 * @param {Integer} skip       - the number of records to skip (useful for pagination)

 * @param {String} sort        - the order of returned records, e.g. `name ASC` or `age DESC`

 *

 */

module.exports = function expand(route, options) {

    return async (request, h) => {

        const actionUtil = Actions(request, options, h);

        const Model = actionUtil.modelFromParam(options.model);

        const relation  = options.associationAttr;

        const RelationModel = actionUtil.modelFromParam(options.associationAttr);

        if (!RelationModel) {

            return Boom.badImplementation('Invalid relation for populate');

        }

        const keys = actionUtil.getKeys();

        const limit = actionUtil.parseLimit();

        const sort = actionUtil.parseSort(Model);

        const rangeStart = actionUtil.parseSkip();

        const rangeEnd = rangeStart + limit;

        let total;

        const modelFullQuery = Model.query().findById(keys.parent.value)

            .withGraphFetched(relation)

            .modifyGraph(relation, (builder) => {

                if (keys.child?.value) {

                    builder.where(Ref(RelationModel.tableName + '.' + keys.child.key), '=', keys.child.value);

                }

                    // we need to wrap this in an async iffe to trigger the query,

                    // as otherwise the main query gets borked

                }

                builder.range(rangeStart, rangeEnd).limit(limit);

                if (sort) {

                    builder.orderByRaw(sort);

                }

            });

        const modelFull = await modelFullQuery;

        if (!modelFull) {

            return Boom.notFound('No record found with the specified id.');

        }

        if (keys.child?.value) {

            if (modelFull[options.associationAttr].length) {

                return h.response().code(204);

            }

            return Boom.notFound();

        }

        }

        if (options._private.count) {

            return modelFull[options.associationAttr].length;

        }

        return modelFull[options.associationAttr];

    };

};