refactor(extensions): dedupe channel config, onboarding, and monitors

src/plugin-sdk/inbound-envelope.ts

@@ -0,0 +1,41 @@
+type RouteLike = {
+  agentId: string;
+  sessionKey: string;
+};
+
+export function createInboundEnvelopeBuilder<TConfig, TEnvelope>(params: {
+  cfg: TConfig;
+  route: RouteLike;
+  sessionStore?: string;
+  resolveStorePath: (store: string | undefined, opts: { agentId: string }) => string;
+  readSessionUpdatedAt: (params: { storePath: string; sessionKey: string }) => number | undefined;
+  resolveEnvelopeFormatOptions: (cfg: TConfig) => TEnvelope;
+  formatAgentEnvelope: (params: {
+    channel: string;
+    from: string;
+    timestamp?: number;
+    previousTimestamp?: number;
+    envelope: TEnvelope;
+    body: string;
+  }) => string;
+}) {
+  const storePath = params.resolveStorePath(params.sessionStore, {
+    agentId: params.route.agentId,
+  });
+  const envelopeOptions = params.resolveEnvelopeFormatOptions(params.cfg);
+  return (input: { channel: string; from: string; body: string; timestamp?: number }) => {
+    const previousTimestamp = params.readSessionUpdatedAt({
+      storePath,
+      sessionKey: params.route.sessionKey,
+    });
+    const body = params.formatAgentEnvelope({
+      channel: input.channel,
+      from: input.from,
+      timestamp: input.timestamp,
+      previousTimestamp,
+      envelope: envelopeOptions,
+      body: input.body,
+    });
+    return { storePath, body };
+  };
+}