import { spawn } from 'child_process';
import { createWriteStream, mkdirSync } from 'fs';
import { join } from 'path';

export function triggerBackup(): void {
  setImmediate(() => runBackup().catch((e) => console.error('[backup] Fehler:', e)));
}

async function runBackup(): Promise<void> {
  const sshUrl = process.env.BACKUP_SSH_URL || '';
  const localDir = process.env.BACKUP_LOCAL_DIR || '/tmp/logbuch-backup';

  const rawKeyPath = process.env.BACKUP_SSH_KEY_PATH || '';
  const keyPath = rawKeyPath.startsWith('~')
    ? rawKeyPath.replace('~', process.env.HOME || '/root')
    : rawKeyPath;

  const ts = new Date().toISOString().replace('T', '_').replace(/:/g, '-').slice(0, 19);
  const filename = `sternwarte_${ts}.sql.gz`;

  const dbHost = process.env.DB_HOST || 'db';
  const dbPort = process.env.DB_PORT || '3306';
  const dbUser = process.env.DB_USER || '';
  const dbPass = process.env.DB_PASS || '';
  const dbName = process.env.DB_NAME || 'sternwarte';
  const dumpBin = process.env.BACKUP_DUMP_CMD || 'mariadb-dump';

  mkdirSync(localDir, { recursive: true });
  const localPath = join(localDir, filename);

  // Schritt 1: Dump lokal schreiben
  await new Promise<void>((resolve, reject) => {
    const dump = spawn(dumpBin, [
      `-h${dbHost}`, `-P${dbPort}`, `-u${dbUser}`,
      '--skip-ssl',
      `--ignore-table=${dbName}.beos`,
      dbName,
    ], { env: { ...process.env, MYSQL_PWD: dbPass } });

    const gzip = spawn('gzip');
    const file = createWriteStream(localPath);

    dump.stdout.pipe(gzip.stdin);
    gzip.stdout.pipe(file);

    let dumpErr = '';
    dump.stderr.on('data', (d: Buffer) => { dumpErr += d.toString(); });
    dump.on('error', reject);
    gzip.on('error', reject);
    file.on('error', reject);
    file.on('close', () => {
      if (dumpErr.trim()) console.log('[backup] dump stderr:', dumpErr.trim());
      resolve();
    });
  });

  console.log(`[backup] Dump geschrieben: ${localPath}`);

  // Schritt 2: Per SCP auf externen Server übertragen (optional)
  if (sshUrl) {
    const match = sshUrl.match(/^([^:]+):(.+)$/);
    if (!match) {
      console.error('[backup] BACKUP_SSH_URL muss das Format user@host:/pfad haben');
    } else {
      const [, sshHost, remotePath] = match;
      const sshOpts = [
        ...(keyPath ? ['-i', keyPath] : []),
        '-o', 'StrictHostKeyChecking=no',
        '-o', 'BatchMode=yes',
        '-o', 'ConnectTimeout=15',
      ];

      await new Promise<void>((resolve, reject) => {
        const scp = spawn('scp', [...sshOpts, localPath, `${sshHost}:${remotePath}/${filename}`]);
        let scpErr = '';
        scp.stderr.on('data', (d: Buffer) => { scpErr += d.toString(); });
        scp.on('error', reject);
        scp.on('close', (code) => {
          if (code === 0) {
            resolve();
          } else {
            reject(new Error(`scp exit ${code}${scpErr ? ': ' + scpErr.trim() : ''}`));
          }
        });
      });

      console.log(`[backup] ${filename} → ${sshHost}:${remotePath}`);

      // Backups älter als 30 Tage auf Remote löschen
      await new Promise<void>((resolve) => {
        const ssh = spawn('ssh', [
          ...sshOpts, sshHost,
          `find ${remotePath} -name 'sternwarte_*.sql.gz' -mtime +30 -delete`,
        ]);
        ssh.on('error', (e) => { console.error('[backup] Cleanup spawn-Fehler:', e.message); resolve(); });
        ssh.on('close', (code) => {
          if (code !== 0) console.error('[backup] Cleanup fehlgeschlagen (exit ' + code + ')');
          resolve();
        });
      });
    }
  }
}