const { migrate } = require('drizzle-orm/better-sqlite3/migrator');
const { drizzle } = require('drizzle-orm/better-sqlite3');
const Database = require('better-sqlite3');
const fs = require('node:fs');
const path = require('node:path');

const dataDir = path.resolve(
  process.env.LEISTUNGSBILANZ_DATA_DIR || 'data'
);
if (!fs.existsSync(dataDir)) fs.mkdirSync(dataDir, { recursive: true });

const databasePath = path.join(dataDir, 'leistungsbilanz.db');

async function run() {
  const sqlite = new Database(databasePath);
  try {
    if (requiresLinearXlsxBackup(sqlite)) {
      const backupDir = path.join(dataDir, 'backups');
      fs.mkdirSync(backupDir, { recursive: true });
      const timestamp = new Date().toISOString().replace(/[:.]/g, '-');
      const backupPath = path.join(
        backupDir,
        `leistungsbilanz-before-linear-xlsx-${timestamp}.db`
      );
      await sqlite.backup(backupPath);
      verifyBackup(backupPath);
      console.log(`Verified pre-migration backup created: ${backupPath}`);
    }

    migrate(drizzle(sqlite), {
      migrationsFolder: path.resolve('src/db/migrations'),
    });
  } finally {
    sqlite.close();
  }
  console.log('Migrations applied');
}

function requiresLinearXlsxBackup(sqlite) {
  const tables = new Set(
    sqlite.prepare("SELECT name FROM sqlite_master WHERE type = 'table'")
      .all()
      .map((row) => row.name)
  );
  return tables.has('external_csv_configurations') &&
    !tables.has('external_model_configurations');
}

function verifyBackup(backupPath) {
  const backup = new Database(backupPath, { readonly: true, fileMustExist: true });
  try {
    const integrity = backup.pragma('integrity_check', { simple: true });
    const foreignKeyViolations = backup.pragma('foreign_key_check');
    if (integrity !== 'ok' || foreignKeyViolations.length > 0) {
      throw new Error(
        `Pre-migration backup verification failed: integrity=${integrity}, ` +
        `foreign-key violations=${foreignKeyViolations.length}`
      );
    }
  } finally {
    backup.close();
  }
}

run().catch((error) => {
  console.error('Migration failed:', error instanceof Error ? error.message : error);
  process.exit(1);
});