refactor(src): split oversized modules

src/agents/pi-embedded-runner/session-manager-init.ts

@@ -0,0 +1,59 @@
+import fs from "node:fs/promises";
+
+type SessionHeaderEntry = { type: "session"; id?: string; cwd?: string };
+type SessionMessageEntry = { type: "message"; message?: { role?: string } };
+
+/**
+ * pi-coding-agent SessionManager persistence quirk:
+ * - If the file exists but has no assistant message, SessionManager marks itself `flushed=true`
+ *   and will never persist the initial user message.
+ * - If the file doesn't exist yet, SessionManager builds a new session in memory and flushes
+ *   header+user+assistant once the first assistant arrives (good).
+ *
+ * This normalizes the file/session state so the first user prompt is persisted before the first
+ * assistant entry, even for pre-created session files.
+ */
+export async function prepareSessionManagerForRun(params: {
+  sessionManager: unknown;
+  sessionFile: string;
+  hadSessionFile: boolean;
+  sessionId: string;
+  cwd: string;
+}): Promise<void> {
+  const sm = params.sessionManager as {
+    sessionId: string;
+    flushed: boolean;
+    fileEntries: Array<
+      SessionHeaderEntry | SessionMessageEntry | { type: string }
+    >;
+    byId?: Map<string, unknown>;
+    labelsById?: Map<string, unknown>;
+    leafId?: string | null;
+  };
+
+  const header = sm.fileEntries.find(
+    (e): e is SessionHeaderEntry => e.type === "session",
+  );
+  const hasAssistant = sm.fileEntries.some(
+    (e) =>
+      e.type === "message" &&
+      (e as SessionMessageEntry).message?.role === "assistant",
+  );
+
+  if (!params.hadSessionFile && header) {
+    header.id = params.sessionId;
+    header.cwd = params.cwd;
+    sm.sessionId = params.sessionId;
+    return;
+  }
+
+  if (params.hadSessionFile && header && !hasAssistant) {
+    // Reset file so the first assistant flush includes header+user+assistant in order.
+    await fs.writeFile(params.sessionFile, "", "utf-8");
+    sm.fileEntries = [header];
+    sm.byId?.clear?.();
+    sm.labelsById?.clear?.();
+    sm.leafId = null;
+    sm.flushed = false;
+  }
+}