getting suggested amount and getting charities

app/controllers/donor/index.js

@@ -0,0 +1,5 @@
+module.exports = {
+	donor: require('./donor.controller'),
+	grant: require('./grant.controller'),
+	organization: require('./organization.controller')
+};

app/controllers/donor/organization.controller.js

@@ -0,0 +1,53 @@
+const db = require('../../config/db.config.js'),
+	errorMaker = require('../../helpers/error.maker');
+
+const { Grant, Cause, Region, Organization } = db;
+
+const log10 = val => {
+	return Math.log(val) / Math.log(10);
+};
+
+// GET suggested organizations based on chosen causes + regions
+exports.findSuggested = (req, res, next) => {
+	const { amount, causes, regions } = req.body;
+
+	// formula for max amount of organizations to choose
+	const max_orgs = Math.floor(1.5 * log10(amount));
+
+	const QUERY =
+		'SELECT * from organizations ' +
+		'WHERE primary_cause IN (:causes) and primary_region IN (:regions) ' +
+		'LIMIT :max_orgs';
+	db.sequelize
+		.query(QUERY, {
+			replacements: { causes, regions, max_orgs },
+			type: db.Sequelize.QueryTypes.SELECT
+		})
+		.then(orgs => {
+			res.status(200).json({
+				orgs,
+				num_items: orgs.length,
+				max_orgs,
+				distribution: amount / orgs.length
+			});
+		})
+		.catch(error => next(error));
+};
+
+// GET min and optimal amounts for the chosen causes + regions
+exports.findAmounts = (req, res, next) => {
+	const { num_causes, num_regions } = req.body;
+
+	const feature_factor = parseInt(num_causes) + parseFloat(num_regions / 2);
+
+	// calculate min amount for chosen causes and regions
+	const min_amount = Math.ceil(feature_factor * 15);
+
+	// calculate optimal for chosen causes and regions
+	const optimal_amount = Math.ceil(Math.pow(5, feature_factor));
+
+	res.status(200).json({
+		min_amount,
+		optimal_amount
+	});
+};