fix: Major bug cleanup pass 1

toju-app/src/app/domains/authentication/domain/logic/signal-server-credential-resolution.rules.ts

@@ -0,0 +1,53 @@
+export interface ResolvableHomeUser {
+  id?: string;
+  displayName?: string;
+  homeSignalServerUrl?: string;
+}
+
+export interface ResolvedSignalIdentity {
+  userId: string;
+  token: string;
+  displayName: string;
+  homeSignalServerUrl?: string;
+}
+
+/**
+ * Resolve the identity (oder id + session token) used to `identify` on a signal
+ * server.
+ *
+ * Order of precedence:
+ *  1. The per-signal-server credential (the authoritative source for both home
+ *     and provisioned foreign servers).
+ *  2. The legacy single-session token store, reconstructed with the home user's
+ *     identity. This keeps `identify` working for sessions restored from disk
+ *     that pre-date the per-signal credential store (otherwise the client never
+ *     authenticates and the user appears alone in every room).
+ *
+ * Foreign servers are never reconstructed from the legacy token: their account
+ * id is the provisioned id, which only the per-signal credential carries.
+ */
+export function resolveSignalIdentity(
+  credential: { userId: string; token: string; displayName: string } | null,
+  legacyToken: { token: string } | null,
+  homeUser: ResolvableHomeUser | null | undefined
+): ResolvedSignalIdentity | null {
+  if (credential) {
+    return {
+      userId: credential.userId,
+      token: credential.token,
+      displayName: credential.displayName,
+      homeSignalServerUrl: homeUser?.homeSignalServerUrl
+    };
+  }
+
+  if (legacyToken && homeUser?.id) {
+    return {
+      userId: homeUser.id,
+      token: legacyToken.token,
+      displayName: homeUser.displayName ?? '',
+      homeSignalServerUrl: homeUser.homeSignalServerUrl
+    };
+  }
+
+  return null;
+}