Aktueller Stand

backend/src/mail/newsletter.ts

@@ -1,5 +1,33 @@
-const headerIncludes = (headers: Map<string, string>, key: string) =>
-  headers.has(key.toLowerCase());
+export type NewsletterConfig = {
+  threshold: number;
+  headerKeys: string[];
+  subjectTokens: string[];
+  fromTokens: string[];
+  weightHeader: number;
+  weightPrecedence: number;
+  weightSubject: number;
+  weightFrom: number;
+};
+
+const DEFAULT_CONFIG: NewsletterConfig = {
+  threshold: 2,
+  headerKeys: [
+    "list-unsubscribe",
+    "list-id",
+    "list-help",
+    "list-archive",
+    "list-post",
+    "list-owner",
+    "list-subscribe",
+    "list-unsubscribe-post"
+  ],
+  subjectTokens: ["newsletter", "unsubscribe", "update", "news", "digest"],
+  fromTokens: ["newsletter", "no-reply", "noreply", "news", "updates"],
+  weightHeader: 1,
+  weightPrecedence: 1,
+  weightSubject: 1,
+  weightFrom: 1
+};
 
 const headerValue = (headers: Map<string, string>, key: string) =>
   headers.get(key.toLowerCase()) ?? "";
@@ -7,39 +35,64 @@ const headerValue = (headers: Map<string, string>, key: string) =>
 const containsAny = (value: string, tokens: string[]) =>
   tokens.some((token) => value.includes(token));
 
+const normalizeList = (items: string[]) =>
+  items.map((item) => item.trim().toLowerCase()).filter(Boolean);
+
 export const detectNewsletter = (params: {
   headers: Map<string, string>;
   subject?: string | null;
   from?: string | null;
+  config?: Partial<NewsletterConfig>;
 }) => {
   const subject = (params.subject ?? "").toLowerCase();
   const from = (params.from ?? "").toLowerCase();
   const headers = params.headers;
+  const config: NewsletterConfig = {
+    threshold: params.config?.threshold ?? DEFAULT_CONFIG.threshold,
+    headerKeys: normalizeList(params.config?.headerKeys ?? DEFAULT_CONFIG.headerKeys),
+    subjectTokens: normalizeList(params.config?.subjectTokens ?? DEFAULT_CONFIG.subjectTokens),
+    fromTokens: normalizeList(params.config?.fromTokens ?? DEFAULT_CONFIG.fromTokens),
+    weightHeader: params.config?.weightHeader ?? DEFAULT_CONFIG.weightHeader,
+    weightPrecedence: params.config?.weightPrecedence ?? DEFAULT_CONFIG.weightPrecedence,
+    weightSubject: params.config?.weightSubject ?? DEFAULT_CONFIG.weightSubject,
+    weightFrom: params.config?.weightFrom ?? DEFAULT_CONFIG.weightFrom
+  };
 
-  const hasListUnsubscribe = headerIncludes(headers, "list-unsubscribe");
-  const hasListId = headerIncludes(headers, "list-id");
-
+  const matchedHeaderKeys = config.headerKeys.filter((key) => headers.has(key));
   const precedence = headerValue(headers, "precedence").toLowerCase();
   const bulkHeader = headerValue(headers, "x-precedence").toLowerCase();
+  const precedenceHint = containsAny(precedence, ["bulk", "list"]) || containsAny(bulkHeader, ["bulk", "list"]);
 
-  const headerHints = containsAny(precedence, ["bulk", "list"]) ||
-    containsAny(bulkHeader, ["bulk", "list"]) ||
-    headerIncludes(headers, "list-unsubscribe-post");
+  const subjectMatches = config.subjectTokens.filter((token) => subject.includes(token));
+  const fromMatches = config.fromTokens.filter((token) => from.includes(token));
 
-  const subjectHints = containsAny(subject, ["newsletter", "unsubscribe", "update", "news", "digest"]);
-  const fromHints = containsAny(from, ["newsletter", "no-reply", "noreply", "news", "updates"]);
-
-  const score = [hasListUnsubscribe, hasListId, headerHints, subjectHints, fromHints].filter(Boolean).length;
+  const headerScore = matchedHeaderKeys.length * config.weightHeader;
+  const precedenceScore = precedenceHint ? config.weightPrecedence : 0;
+  const subjectScore = subjectMatches.length ? config.weightSubject : 0;
+  const fromScore = fromMatches.length ? config.weightFrom : 0;
+  const score = headerScore + precedenceScore + subjectScore + fromScore;
 
   return {
-    isNewsletter: score >= 2,
+    isNewsletter: score >= config.threshold,
     score,
     signals: {
-      hasListUnsubscribe,
-      hasListId,
-      headerHints,
-      subjectHints,
-      fromHints
+      headerKeys: matchedHeaderKeys,
+      precedenceHint,
+      subjectTokens: subjectMatches,
+      fromTokens: fromMatches,
+      scoreBreakdown: {
+        headerMatches: matchedHeaderKeys.length,
+        headerWeight: config.weightHeader,
+        headerScore,
+        precedenceWeight: config.weightPrecedence,
+        precedenceScore,
+        subjectMatches: subjectMatches.length,
+        subjectWeight: config.weightSubject,
+        subjectScore,
+        fromMatches: fromMatches.length,
+        fromWeight: config.weightFrom,
+        fromScore
+      }
     }
   };
 };