import { mkdir, rm, writeFile } from "node:fs/promises";
import { join } from "node:path";
import { readJsonIfExists } from "./fs-errors.js";
import type { RecordSession } from "./record-types.js";

export const RECORDS_DIR = ".pi/playbook-records";
const ACTIVE_FILE = "active.json";
const SESSION_ID_PATTERN = /^record-[a-z0-9][a-z0-9-]*-\d+$/;

function assertValidSessionId(sessionId: string): string {
  if (!SESSION_ID_PATTERN.test(sessionId)) {
    throw new Error(`Invalid record session id '${sessionId}'.`);
  }
  return sessionId;
}

export function recordsDir(cwd: string): string {
  return join(cwd, RECORDS_DIR);
}

export function sessionFile(cwd: string, sessionId: string): string {
  return join(recordsDir(cwd), `${assertValidSessionId(sessionId)}.json`);
}

export function activeRecordFile(cwd: string): string {
  return join(recordsDir(cwd), ACTIVE_FILE);
}

export async function saveRecordSession(cwd: string, session: RecordSession): Promise<void> {
  await mkdir(recordsDir(cwd), { recursive: true });
  await writeFile(sessionFile(cwd, session.sessionId), `${JSON.stringify(session, null, 2)}\n`, "utf8");
}

export async function loadRecordSession(cwd: string, sessionId: string): Promise<RecordSession | undefined> {
  return readJsonIfExists<RecordSession>(sessionFile(cwd, sessionId));
}

export async function setActiveRecordSession(cwd: string, sessionId: string): Promise<void> {
  assertValidSessionId(sessionId);
  await mkdir(recordsDir(cwd), { recursive: true });
  await writeFile(activeRecordFile(cwd), `${JSON.stringify({ sessionId }, null, 2)}\n`, "utf8");
}

export async function loadActiveRecordSessionId(cwd: string): Promise<string | undefined> {
  const state = await readJsonIfExists<{ sessionId?: string }>(activeRecordFile(cwd));
  return typeof state?.sessionId === "string" && SESSION_ID_PATTERN.test(state.sessionId)
    ? state.sessionId
    : undefined;
}

export async function clearActiveRecordSession(cwd: string): Promise<void> {
  await rm(activeRecordFile(cwd), { force: true });
}

export async function loadActiveRecordSession(cwd: string): Promise<RecordSession | undefined> {
  const sessionId = await loadActiveRecordSessionId(cwd);
  if (!sessionId) return undefined;
  return loadRecordSession(cwd, sessionId);
}