Updates tax after address / coupon change

db/index.js

@@ -7,5 +7,6 @@ module.exports = {
   cart: require('./models/cart'),
   order: require('./models/order'),
   address: require('./models/address'),
-  coupon: require('./models/coupon')
+  coupon: require('./models/coupon'),
+  config: require('./models/config')
 }

db/mappings/config.js

@@ -0,0 +1,11 @@
+module.exports = [{
+  mapId: 'configMap',
+  idProperty: 'uuid',
+  properties: [
+    'date_updated',
+    'default_tax_percent'
+  ],
+  associations: [
+    {name: 'modified_by', mapId: 'userMap', columnPrefix: 'user_'},
+  ]
+}]

db/mappings/index.js

@@ -1,4 +1,5 @@
 module.exports = [
+  ...require('./config'),
   ...require('./user'),
   ...require('./item'),
   ...require('./order')

db/mappings/item.js

@@ -21,8 +21,7 @@ module.exports = [{
     'urlslug',
     'price_cents',
     'published',
-    'number_in_stock',
-    'tax_rate'
+    'number_in_stock'
   ],
   collections: [
     {name: 'images', mapId: 'imageMap', columnPrefix: 'image_'}

db/models/config.js

@@ -0,0 +1,18 @@
+const pg = require('../pg')
+const joinjs = require('join-js').default;
+const debug = require('debug')('sos:db:config')
+const mappings = require('../mappings')
+
+const config = module.exports = {}
+
+config.getLatestConfig = async () => {
+  const {rows} = await pg.query('select * from sos.v_config')
+
+  return joinjs.mapOne(rows, mappings, 'configMap', 'config_')
+}
+
+config.getTaxRate = async () => {
+  const current = await config.getLatestConfig()
+  console.log(parseFloat(current.default_tax_percent))
+  return parseFloat(current.default_tax_percent)
+}

db/models/order.js

@@ -4,6 +4,8 @@ const debug = require('debug')('sos:db:order')
 const mappings = require('../mappings')
 const dbUtil = require('../util')
 
+const config = require('./config')
+
 const {DateTime} = require('luxon')
 const easypost = new (require('@easypost/api'))(process.env.EASYPOST_API_KEY);
 
@@ -45,6 +47,16 @@ order.findAllForSession = async function(session_uuid) {
   return joinjs.map(rows, mappings, 'orderMap', 'order_');
 }
 
+order.findForTransaction = transaction_uuid =>
+  dbUtil.executeFunction({
+    name: 'find_order_for_transaction',
+    params: [
+      transaction_uuid
+    ],
+    returnType: 'order',
+    single: true
+  })
+
 order.addAddress = async function (transaction, address){
   // Get parcel size
   const parcel = {
@@ -75,24 +87,59 @@ order.addAddress = async function (transaction, address){
   if(!price)
     throw new Error("Unable to estimate price");
 
-  // TODO: Update with real tax rate
-  const tax = epShipment.to_address.state === 'UT'
-    ? 200
-    : null
+  // Add up tax for all the items
+  const tax = epShipment.to_address.state !== 'UT'
+    ? null
+    : transaction.cart.items
+        // For each item type, create an array of length n (number of items of that type in cart)
+        // where each index is initialized to the item tax amount
+        .map(({item, count}) => new Array(count).fill(item.tax_rate * item.price_cents / 100))
+        // Flatten to just be all tax amounts
+        .flat()
+        // Sum all the numbers
+        .reduce((a,c) => (a+c))
 
   // Update database
   const query = {
-    text: 'select * from sos.add_address_to_order($1, $2, $3, $4)',
-    values: [transaction.uuid, address.uuid, price, tax]
+    text: 'select * from sos.add_address_to_order($1, $2, $3)',
+    values: [transaction.uuid, address.uuid, price]
   }
 
   debug(query)
-  const {rows} = await pg.query(query)
+  await pg.query(query)
 
-  return joinjs.map(rows, mappings, 'orderMap', 'order_')[0];
+  // Update tax
+  return await order.updateTax(transaction.uuid)
 }
 
-order.addCoupon = function(transaction, coupon) {
+order.updateTax = async function(transaction_uuid){
+  const _order = await order.findForTransaction(transaction_uuid)
+
+  if(!_order.address)
+    throw new Error("Order has no address");
+
+  if(_order.address.state !== 'UT'){
+    debug("Skipping tax for state: " + _order.address.state);
+    return
+  }
+
+  const {item_total_price, coupon_effective_discount} = _order.transactions.find(t => t.uuid === transaction_uuid)
+  const itemPriceWithDiscount = item_total_price - (coupon_effective_discount || 0)
+  const taxRate = await config.getTaxRate()
+
+  const computedTax = Math.round(itemPriceWithDiscount * taxRate / 100)
+  return await dbUtil.executeFunction({
+    name: 'add_tax_to_transaction',
+    params: [
+      transaction_uuid,
+      computedTax
+    ],
+    returnType: 'order',
+    single: true
+  })
+}
+
+order.addCoupon = async function(transaction, coupon) {
   // Check coupon validity
   const couponExpireTime = DateTime.fromJSDate(coupon.valid_until)
   if(couponExpireTime.diffNow().as('seconds') < 0)
@@ -133,7 +180,7 @@ order.addCoupon = function(transaction, coupon) {
       // Sum the item costs for total discount
       .reduce((a,c) => (a+c))
 
-  return dbUtil.executeFunction({
+  await dbUtil.executeFunction({
     name: 'add_coupon_to_transaction',
     params: [
       transaction.uuid,
@@ -143,6 +190,9 @@ order.addCoupon = function(transaction, coupon) {
     returnType: 'order',
     single: true
   })
+
+  // Update tax
+  return await order.updateTax(transaction.uuid)
 }
 
 order.addPayment = async function(transaction, paymentIntent){

db/sql/1-tables.sql

@@ -46,8 +46,7 @@ create table sos."item" (
   item_description text not null,
   item_urlslug citext unique not null,
   item_price_cents integer not null,
-  item_published  boolean not null default true,
-  item_tax_percent_override numeric(8,6) null
+  item_published  boolean not null default true
 );
 
 create table sos."cart_item" (
@@ -264,5 +263,10 @@ create table sos."item_stockchange_admin" (
 );
 
 create table sos."config" (
-  config_default_tax_percent      numeric(8,6)         not null default 7.250
+  config_uuid                     uuid                primary key default uuid_generate_v4(),
+  config_date_updated             timestamptz         not null default now(),
+  config_updated_by               uuid                references sos."user" (user_uuid),
+  config_default_tax_percent      numeric(8,6)        not null default 7.250
 );
+
+insert into sos."config" default values;

db/sql/2-views.sql

@@ -6,7 +6,6 @@ create or replace view sos.v_item as
     "item".item_urlslug,
     "item".item_price_cents,
     "item".item_published,
-    coalesce("item".item_tax_percent_override, "config".config_default_tax_percent) as item_tax_rate,
     "image".image_uuid,
     "image".image_featured,
     "image".image_mime_type,
@@ -14,7 +13,6 @@ create or replace view sos.v_item as
     "user".user_email as uploader_email,
     coalesce(num_added - num_removed, 0) as item_number_in_stock
   from sos."item"
-    left join sos."config" on true
     left join sos."image" on item.item_uuid = image.image_item_uuid
     left join sos."user"  on image.image_uploader_uuid = "user".user_uuid
     left join
@@ -125,3 +123,8 @@ create or replace view sos.v_order as
     left join sos.v_transaction_paid on "transaction".transaction_uuid = v_transaction_paid.transaction_uuid
     left join sos.v_payment on "transaction".transaction_uuid = payment_transaction_uuid
     left join sos.v_cart on cart_uuid = transaction_cart_uuid;
+
+create or replace view sos.v_config as
+  select * from sos."config"
+    left join sos."user" on config_updated_by = user_uuid
+    where config_date_updated = (select max(config_date_updated) from sos."config")

db/sql/3-functions.sql

@@ -555,7 +555,7 @@ begin
   return query select * from sos."address" where address_uuid = _address_uuid;
 end; $function$;
 
-create or replace function sos.add_address_to_order(_transaction_uuid uuid, _address_uuid uuid, _shipping_price integer, _tax_price integer)
+create or replace function sos.add_address_to_order(_transaction_uuid uuid, _address_uuid uuid, _shipping_price integer)
   returns setof sos.v_order
   language plpgsql
 as $function$
@@ -589,13 +589,9 @@ begin
     where order_uuid = _order_uuid;
 
   -- Update transaction with price
-  update sos."transaction" set (
-    transaction_shipping_price,
-    transaction_tax_price
-   ) = (
-    _shipping_price,
-    _tax_price
-   ) where transaction_uuid = _transaction_uuid;
+  update sos."transaction" set
+    transaction_shipping_price = _shipping_price
+  where transaction_uuid = _transaction_uuid;
 
   return query select * from sos.v_order where order_uuid = _order_uuid;
 end; $function$;
@@ -671,6 +667,16 @@ begin
   return query select * from sos.v_order where order_uuid = _order_uuid;
 end; $function$;
 
+create or replace function sos.find_order_for_transaction(_transaction_uuid uuid)
+  returns setof sos.v_order
+  language plpgsql
+as $function$
+begin
+  return query select v_order.* from sos."transaction"
+    left join sos.v_order on "transaction".transaction_order_uuid = v_order.order_uuid
+    where "transaction".transaction_uuid = _transaction_uuid;
+end; $function$;
+
 create or replace function sos.add_stripe_payment_to_transaction(_transaction_uuid uuid, _payment_value_cents integer, _stripe_intent_id text, _stripe_reciept_email citext)
   returns setof sos.v_order
   language plpgsql
@@ -806,3 +812,16 @@ begin
 
   return query select * from sos.v_item where item_uuid = any(_item_uuids);
 end; $function$;
+
+create or replace function sos.add_tax_to_transaction(_transaction_uuid uuid, _tax_price integer)
+  returns setof sos.v_order
+  language plpgsql
+as $function$
+begin
+  -- Update transaction
+  update sos."transaction" set
+    transaction_tax_price = _tax_price
+    where transaction_uuid = _transaction_uuid;
+
+  return query select * from sos.find_order_for_transaction(_transaction_uuid);
+end; $function$;