export async function POST()

in src/app/api/v1/user/email/route.ts [29:122]
84 lines of code
12 McCabe index (conditional complexity)

export async function POST(req: NextRequest) {
  const token = await getToken({ req });
  const l10n = getL10n(await getAcceptLangHeaderInServerComponents());

  if (typeof token?.subscriber?.fxa_uid === "string") {
    try {
      const body: EmailAddRequest = await req.json();
      const subscriber = await getSubscriberByFxaUid(token.subscriber?.fxa_uid);
      if (!subscriber) {
        throw new Error("No subscriber found for current session.");
      }
      const emailCount = 1 + (subscriber.email_addresses?.length ?? 0); // primary + verified + unverified emails
      const validatedEmail = validateEmailAddress(body.email);

      if (validatedEmail === null) {
        return NextResponse.json(
          {
            success: false,
            message: l10n.getString("user-add-invalid-email"),
          },
          { status: 400 },
        );
      }

      const maxNumEmailAddresses = hasPremium(subscriber)
        ? CONST_MAX_NUM_ADDRESSES_PLUS
        : CONST_MAX_NUM_ADDRESSES;
      if (emailCount >= maxNumEmailAddresses) {
        return NextResponse.json(
          {
            success: false,
            message: l10n.getString("user-add-too-many-emails"),
          },
          { status: 400 },
        );
      }

      // checkForDuplicateEmail
      const emailLowerCase = validatedEmail.email.toLowerCase();
      if (emailLowerCase === subscriber.primary_email.toLowerCase()) {
        return NextResponse.json(
          {
            success: false,
            message: l10n.getString("user-add-duplicate-email"),
          },
          { status: 400 },
        );
      }

      for (const secondaryEmail of subscriber.email_addresses) {
        if (emailLowerCase === secondaryEmail.email.toLowerCase()) {
          return NextResponse.json(
            {
              success: false,
              message: l10n.getString("user-add-duplicate-email"),
            },
            { status: 400 },
          );
        }
      }

      const unverifiedSubscriber = await addSubscriberUnverifiedEmailHash(
        subscriber,
        validatedEmail.email,
      );

      await initEmail();
      await sendVerificationEmail(subscriber, unverifiedSubscriber.id);

      return NextResponse.json({
        success: true,
        newEmailCount: emailCount + 1,
        message: "Sent the verification email",
      });
    } catch (e: unknown) {
      if (
        e instanceof Error &&
        e.message === "error-email-validation-pending"
      ) {
        return NextResponse.json(
          {
            success: false,
            message: "Verification email recently sent, try again later",
          },
          { status: 429 },
        );
      }
      return NextResponse.json({ success: false }, { status: 500 });
    }
  } else {
    // Not Signed in, redirect to home
    return NextResponse.redirect(process.env.SERVER_URL ?? "/", 301);
  }
}