import * as fs from 'fs';
import * as path from 'path';
import { parseSessionKey } from '@runtime/lib/models';
import { getUserDataDir } from './paths';

const PRIMARY_TRANSCRIPT_ROOT_DIR = 'models';
const LEGACY_TRANSCRIPT_ROOT_DIR = 'agents';

function buildTranscriptFilePath(sessionKey: string, rootDirName: string): string {
  const parsed = parseSessionKey(sessionKey);
  const agentId = parsed.isAgentSession ? parsed.agentId : 'default';
  let sessionId = parsed.isAgentSession ? parsed.sessionId : sessionKey;

  if (!sessionId) {
    sessionId = 'unknown';
  }

  const baseDir = path.join(getUserDataDir(), rootDirName, agentId, 'sessions');
  return path.join(baseDir, `${sessionId}.jsonl`);
}

export function getTranscriptFilePath(sessionKey: string): string {
  return buildTranscriptFilePath(sessionKey, PRIMARY_TRANSCRIPT_ROOT_DIR);
}

export function getLegacyTranscriptFilePath(sessionKey: string): string {
  return buildTranscriptFilePath(sessionKey, LEGACY_TRANSCRIPT_ROOT_DIR);
}

export function getTranscriptPathCandidates(sessionKey: string): string[] {
  return Array.from(new Set([
    getTranscriptFilePath(sessionKey),
    getLegacyTranscriptFilePath(sessionKey),
  ]));
}

export function appendTranscriptLine(sessionKey: string, lineObject: any): void {
  const filePath = getTranscriptFilePath(sessionKey);
  fs.mkdirSync(path.dirname(filePath), { recursive: true });
  fs.appendFileSync(filePath, JSON.stringify(lineObject) + '\n', 'utf-8');
}