feat: integrate Pi backend and Pi Web

pi/packages/agent/src/harness/session/repo-utils.ts

@@ -0,0 +1,51 @@
+import { uuidv7 } from "@earendil-works/pi-ai";
+import {
+	type FileError,
+	type Result,
+	SessionError,
+	type SessionMetadata,
+	type SessionStorage,
+	type SessionTreeEntry,
+} from "../types.ts";
+import { Session } from "./session.ts";
+
+export function createSessionId(): string {
+	return uuidv7();
+}
+
+export function createTimestamp(): string {
+	return new Date().toISOString();
+}
+
+export function toSession<TMetadata extends SessionMetadata>(storage: SessionStorage<TMetadata>): Session<TMetadata> {
+	return new Session(storage);
+}
+
+export function getFileSystemResultOrThrow<TValue>(result: Result<TValue, FileError>, message: string): TValue {
+	if (!result.ok) {
+		const code = result.error.code === "not_found" ? "not_found" : "storage";
+		throw new SessionError(code, `${message}: ${result.error.message}`, result.error);
+	}
+	return result.value;
+}
+
+export async function getEntriesToFork(
+	storage: SessionStorage,
+	options: { entryId?: string; position?: "before" | "at" },
+): Promise<SessionTreeEntry[]> {
+	if (!options.entryId) return storage.getEntries();
+	const target = await storage.getEntry(options.entryId);
+	if (!target) {
+		throw new SessionError("invalid_fork_target", `Entry ${options.entryId} not found`);
+	}
+	let effectiveLeafId: string | null;
+	if ((options.position ?? "before") === "at") {
+		effectiveLeafId = target.id;
+	} else {
+		if (target.type !== "message" || target.message.role !== "user") {
+			throw new SessionError("invalid_fork_target", `Entry ${options.entryId} is not a user message`);
+		}
+		effectiveLeafId = target.parentId;
+	}
+	return storage.getPathToRootOrCompaction(effectiveLeafId);
+}