refactor: split src into domain / application / infrastructure layers

Replace the history-driven lib/ + utils/ split with DDD layers:
- domain/: aggregate, repositories, value objects, pure parsers/format
- application/: feed-service, email-processor, feed-fetcher, stats
- infrastructure/: logging, auth, KV/R2 adapters, HTTP, framework glue

Pure file relocation; imports updated mechanically. Behaviour unchanged.

Co-Authored-By: Claude Opus 4.7 <[email protected]>

src/infrastructure/unsubscribe.ts

@@ -0,0 +1,83 @@
+import { Env } from "../types";
+import { UNSUBSCRIBE_TIMEOUT_MS } from "../config/constants";
+import { bumpCounters } from "../application/stats";
+import { logger } from "../infrastructure/logger";
+
+/**
+ * Extract a one-click unsubscribe URL from a stored email's headers per
+ * RFC 8058. Returns the first `https:` URL in `List-Unsubscribe` only when
+ * `List-Unsubscribe-Post: List-Unsubscribe=One-Click` is also present — that
+ * Post header is what authorises an unattended one-click POST. `mailto:` and
+ * plaintext `http:` links are ignored (Workers cannot send SMTP and we never
+ * unsubscribe over plaintext). Header keys are matched case-insensitively;
+ * `EmailData.headers` already lowercases them, but we don't rely on it.
+ */
+export function parseOneClickUnsubscribe(
+  headers: Record<string, string>,
+): string | null {
+  let listUnsubscribe = "";
+  let post = "";
+  for (const [key, value] of Object.entries(headers)) {
+    const k = key.toLowerCase();
+    if (k === "list-unsubscribe") listUnsubscribe = value;
+    else if (k === "list-unsubscribe-post") post = value;
+  }
+
+  if (post.trim().toLowerCase() !== "list-unsubscribe=one-click") return null;
+
+  const matches = listUnsubscribe.match(/<([^>]+)>/g);
+  if (!matches) return null;
+  for (const token of matches) {
+    const url = token.slice(1, -1).trim();
+    if (/^https:\/\//i.test(url)) return url;
+  }
+  return null;
+}
+
+/**
+ * Fire a single RFC 8058 one-click unsubscribe POST. Returns whether the
+ * endpoint accepted it. Never throws: network/timeout errors are logged and
+ * reported as a failure so callers can keep going.
+ */
+export async function sendOneClickUnsubscribe(url: string): Promise<boolean> {
+  try {
+    const res = await fetch(url, {
+      method: "POST",
+      redirect: "follow",
+      signal: AbortSignal.timeout(UNSUBSCRIBE_TIMEOUT_MS),
+      headers: {
+        "Content-Type": "application/x-www-form-urlencoded",
+        "User-Agent": "kill-the-news/1.0",
+      },
+      body: "List-Unsubscribe=One-Click",
+    });
+    return res.ok;
+  } catch (error) {
+    logger.warn("One-click unsubscribe failed", { url, error: String(error) });
+    return false;
+  }
+}
+
+/**
+ * Send one-click unsubscribe requests for a batch of URLs (de-duplicated) and
+ * record the number that succeeded in the `unsubscribes_sent` counter. Never
+ * throws — intended to run in the background via ctx.waitUntil on feed deletion.
+ */
+export async function sendUnsubscribes(
+  urls: string[],
+  env: Env,
+): Promise<void> {
+  const unique = Array.from(new Set(urls.filter(Boolean)));
+  if (unique.length === 0) return;
+
+  const results = await Promise.allSettled(
+    unique.map((url) => sendOneClickUnsubscribe(url)),
+  );
+  const succeeded = results.filter(
+    (r) => r.status === "fulfilled" && r.value,
+  ).length;
+
+  if (succeeded > 0) {
+    await bumpCounters(env.EMAIL_STORAGE, { unsubscribes_sent: succeeded });
+  }
+}