add invoice action

media-store/srv/browse-tracks-service.cds

@@ -14,4 +14,12 @@ service BrowseTracks {
     entity Genres       as projection on my.Genres {
         * , tracks : redirected to Tracks
     };
+
+    @readonly
+    entity Albums       as projection on my.Albums {
+        * , tracks : redirected to Tracks
+    };
+
+    @readonly
+    entity Artists      as projection on my.Artists;
 }

media-store/srv/invoices-service.cds

@@ -3,9 +3,12 @@ using {sap.capire.media.store as my} from '../db/schema';
 @(requires : 'authenticated-user')
 service InvoicesService {
     @readonly
-    entity Invoices     as projection on my.Invoices actions {
-        action invoice();
-    }
+    entity Invoices     as projection on my.Invoices;
+
+    action invoice(tracks : array of {
+        track_ID  : Integer;
+        unitPrice : Decimal(10, 2);
+    });
 
     @readonly
     entity InvoiceItems as projection on my.InvoiceItems;

media-store/srv/invoices-service.js

@@ -2,6 +2,7 @@ const cds = require("@sap/cds");
 
 module.exports = async function () {
   const db = await cds.connect.to("db"); // connect to database service
+  const { Invoices, InvoiceItems } = db.entities;
 
   this.before("*", (req) => {
     console.log(
@@ -14,7 +15,36 @@ module.exports = async function () {
     );
   });
 
-  this.on("READ", "Invoices", async (req) => {
-    return await db.run(req.query.where({ customer_ID: req.user.attr.ID }));
+  this.on("invoice", async (req) => {
+    const { tracks } = req.data;
+    const customerId = req.user.attr.ID;
+    const total = tracks.reduce((acc, { unitPrice }) => acc + unitPrice, 0);
+
+    const { ID: lastInvoiceItemId } = await db.run(
+      SELECT.one(InvoiceItems).columns("ID").orderBy({ ID: "desc" })
+    );
+    const { ID: lastInvoiceId } = await db.run(
+      SELECT.one(Invoices).columns("ID").orderBy({ ID: "desc" })
+    );
+
+    const transaction = await db.tx(req);
+    await transaction.run(
+      INSERT.into(Invoices)
+        .columns("ID", "customer_ID", "total")
+        .values(lastInvoiceId + 1, customerId, total)
+    );
+    await transaction.run(
+      INSERT.into(InvoiceItems)
+        .columns("ID", "invoice_ID", "track_ID", "unitPrice")
+        .rows(
+          tracks.map(({ track_ID, unitPrice }, index) => [
+            lastInvoiceItemId + (index + 1),
+            lastInvoiceId + 1,
+            track_ID,
+            unitPrice,
+          ])
+        )
+    );
+    await transaction.commit();
   });
 };