refactor: extract ForwardEmail adapter to src/lib/forwardemail.ts

Mirrors the same pattern as cloudflare-email.ts — each provider has its
own adapter that translates provider-specific input into ProcessEmailInput
and delegates to processEmail(). inbound.ts is now a thin HTTP handler.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/lib/forwardemail.ts

@@ -0,0 +1,62 @@
+import { EmailParser } from "../utils/email-parser";
+import { Env } from "../types";
+import { processEmail } from "./email-processor";
+
+export interface ForwardEmailPayload {
+  recipients?: string[];
+  from?: {
+    value?: Array<{ address?: string; name?: string }>;
+    text?: string;
+    html?: string;
+  };
+  subject?: string;
+  text?: string;
+  html?: string;
+  date?: string;
+  messageId?: string;
+  headerLines?: Array<{ key: string; line: string }>;
+  headers?: string;
+  raw?: string;
+  attachments?: Array<any>;
+}
+
+function normalizeEmail(value: string): string {
+  return value.trim().toLowerCase();
+}
+
+function extractSenderAddresses(payload: ForwardEmailPayload): string[] {
+  const valueEntries = payload.from?.value || [];
+  const structuredAddresses = valueEntries
+    .map((entry) => entry.address || "")
+    .map(normalizeEmail)
+    .filter(Boolean);
+
+  if (structuredAddresses.length > 0) {
+    return Array.from(new Set(structuredAddresses));
+  }
+
+  const fromText = payload.from?.text || "";
+  const matches =
+    fromText.match(/[A-Z0-9._%+-]+@[A-Z0-9.-]+\.[A-Z]{2,}/gi) || [];
+  return Array.from(new Set(matches.map(normalizeEmail)));
+}
+
+export async function handleForwardEmail(
+  payload: ForwardEmailPayload,
+  env: Env,
+): Promise<Response> {
+  const emailData = EmailParser.parseForwardEmailPayload(payload);
+
+  return processEmail(
+    {
+      toAddress: payload.recipients?.[0] || "",
+      from: emailData.from,
+      senders: extractSenderAddresses(payload),
+      subject: emailData.subject,
+      content: emailData.content,
+      receivedAt: emailData.receivedAt,
+      headers: emailData.headers,
+    },
+    env,
+  );
+}

src/routes/inbound.ts

@@ -1,44 +1,9 @@
 import { Context } from "hono";
-import { EmailParser } from "../utils/email-parser";
 import { Env } from "../types";
-import { processEmail } from "../lib/email-processor";
-
-interface ForwardEmailPayload {
-  recipients?: string[];
-  from?: {
-    value?: Array<{ address?: string; name?: string }>;
-    text?: string;
-    html?: string;
-  };
-  subject?: string;
-  text?: string;
-  html?: string;
-  date?: string;
-  messageId?: string;
-  headerLines?: Array<{ key: string; line: string }>;
-  headers?: string;
-  raw?: string;
-  attachments?: Array<any>;
-}
-
-function extractIncomingSenderAddresses(
-  payload: ForwardEmailPayload,
-): string[] {
-  const valueEntries = payload.from?.value || [];
-  const structuredAddresses = valueEntries
-    .map((entry) => entry.address || "")
-    .map((v) => v.trim().toLowerCase())
-    .filter(Boolean);
-
-  if (structuredAddresses.length > 0) {
-    return Array.from(new Set(structuredAddresses));
-  }
-
-  const fromText = payload.from?.text || "";
-  const matches =
-    fromText.match(/[A-Z0-9._%+-]+@[A-Z0-9.-]+\.[A-Z]{2,}/gi) || [];
-  return Array.from(new Set(matches.map((v) => v.trim().toLowerCase())));
-}
+import {
+  ForwardEmailPayload,
+  handleForwardEmail,
+} from "../lib/forwardemail";
 
 export async function handle(c: Context): Promise<Response> {
   try {
@@ -52,20 +17,7 @@ export async function handle(c: Context): Promise<Response> {
       contentType: payload.html ? "HTML" : "Text",
     });
 
-    const emailData = EmailParser.parseForwardEmailPayload(payload);
-
-    return processEmail(
-      {
-        toAddress: payload.recipients?.[0] || "",
-        from: emailData.from,
-        senders: extractIncomingSenderAddresses(payload),
-        subject: emailData.subject,
-        content: emailData.content,
-        receivedAt: emailData.receivedAt,
-        headers: emailData.headers,
-      },
-      env,
-    );
+    return handleForwardEmail(payload, env);
   } catch (error) {
     console.error("Error processing email:", error);
     return new Response("Error processing email", { status: 500 });