add team invitation functionality [WIP]

lib/api/sendInvitationRequest.ts

@@ -0,0 +1,56 @@
+import { readFileSync } from "fs";
+import path from "path";
+import Handlebars from "handlebars";
+import transporter from "./transporter";
+
+type Params = {
+  parentSubscriptionEmail: string;
+  identifier: string;
+  url: string;
+  from: string;
+  token: string;
+};
+
+export default async function sendInvitationRequest({
+  parentSubscriptionEmail,
+  identifier,
+  url,
+  from,
+  token,
+}: Params) {
+  const emailsDir = path.resolve(process.cwd(), "templates");
+
+  const templateFile = readFileSync(
+    path.join(emailsDir, "acceptInvitation.html"),
+    "utf8"
+  );
+
+  const emailTemplate = Handlebars.compile(templateFile);
+
+  const { host } = new URL(url);
+  const result = await transporter.sendMail({
+    to: identifier,
+    from: {
+      name: "Linkwarden",
+      address: from as string,
+    },
+    subject: `You have been invited to join Linkwarden`,
+    text: text({ url, host }),
+    html: emailTemplate({
+      parentSubscriptionEmail,
+      identifier,
+      url: `${
+        process.env.NEXTAUTH_URL
+      }/callback/email?token=${token}&email=${encodeURIComponent(identifier)}`,
+    }),
+  });
+  const failed = result.rejected.concat(result.pending).filter(Boolean);
+  if (failed.length) {
+    throw new Error(`Email (${failed.join(", ")}) could not be sent`);
+  }
+}
+
+/** Email Text body (fallback for email clients that don't render HTML, e.g. feature phones) */
+function text({ url, host }: { url: string; host: string }) {
+  return `Sign in to ${host}\n${url}\n\n`;
+}