fix: change coupons to promo codes

lib/promo-codes.js

@@ -0,0 +1,29 @@
+const db = require('./db')
+const uuid = require('uuid')
+
+function getAvailablePromoCodes () {
+  const sql = `SELECT * FROM coupons WHERE soft_deleted=false`
+  return db.any(sql)
+}
+
+function getPromoCode (code) {
+  const sql = `SELECT * FROM coupons WHERE code=$1 AND soft_deleted=false`
+  return db.oneOrNone(sql, [code])
+}
+
+function createPromoCode (code, discount) {
+  const sql = `INSERT INTO coupons (id, code, discount) VALUES ($1, $2, $3) RETURNING *`
+  return db.one(sql, [uuid.v4(), code, discount])
+}
+
+function deletePromoCode (id) {
+  const sql = `UPDATE coupons SET soft_deleted=true WHERE id=$1`
+  return db.none(sql, [id])
+}
+
+function getNumberOfAvailablePromoCodes () {
+  const sql = `SELECT COUNT(id) FROM coupons WHERE soft_deleted=false`
+  return db.one(sql).then(res => res.count)
+}
+
+module.exports = { getAvailablePromoCodes, getPromoCode, createPromoCode, deletePromoCode, getNumberOfAvailablePromoCodes }