/**
 * Fetch NanoClaw upstream changes without merging.
 * Safe to run on a cron — read-only git operation.
 *
 * Usage:
 *   npx tsx scripts/fetch-upstream.ts
 *
 * Output: prints divergence summary (commits in nanoclaw/main not in HEAD)
 *
 * Typical cron (weekly, run as agent user):
 *   0 3 * * 1  cd /home/<agent>/<agent>-ai && npx tsx scripts/fetch-upstream.ts >> logs/upstream.log 2>&1
 */
import { formatDisplayDate } from '../src/display-date.js';
import { classificationHint } from '../src/upstream/classify.js';
import {
  fetchRemote,
  getUpstreamConfig,
  readEnvFlag,
  remoteExists,
} from '../src/upstream/git.js';
import { getUpstreamStatus } from '../src/upstream/status.js';

function main(): void {
  const config = getUpstreamConfig({ repoDir: process.cwd() });

  if (!readEnvFlag(config.repoDir, 'NANOCLAW_UPSTREAM_ENABLED')) {
    console.log('NANOCLAW_UPSTREAM_ENABLED=false — skipping fetch');
    process.exit(0);
  }

  if (!remoteExists(config.repoDir, config.remoteName)) {
    console.error(`Remote '${config.remoteName}' not configured. Run: npx tsx setup/index.ts --step upstream --enable`);
    process.exit(1);
  }

  const timestamp = formatDisplayDate(new Date());
  console.log(`[${timestamp}] Fetching ${config.remoteName}/${config.branch}...`);

  fetchRemote(config.repoDir, config.remoteName);

  const status = getUpstreamStatus(config);

  if (status.aheadCount === 0) {
    const behindText = status.behindCount > 0
      ? ` (${status.behindCount} local commit(s) ahead of upstream)`
      : '';
    console.log(`✓ Up to date with NanoClaw upstream${behindText}`);
  } else {
    console.log(`! ${status.aheadCount} upstream commit(s) available:`);
    for (const commit of status.commits) {
      console.log(`${commit.hash.slice(0, 7)} ${commit.subject}`);
      console.log(`  ${commit.classification}: ${classificationHint(commit.classification)}`);
    }
    if (status.behindCount > 0) {
      console.log(`  (${status.behindCount} local commit(s) ahead of upstream)`);
    }
  }
}

main();