var bdb_lib = require('berkeleydb')
var dbenv = new bdb_lib.DbEnv();
var bdb_status = dbenv.open('./search/db/env')
if (bdb_status) {
  console.log('open dbenv failed:', bdb_status)
  process.exit()
}

function db(fn){
  var db
  fn = "./" + fn + ".db"

  function exitHandler(options, err) {
    if (db) db.close()
    // if (options.cleanup) console.log('clean');
    if (err) console.log(err.stack);
    if (options.exit) process.exit();
  }

  // do something when app is closing
  process.on('exit', exitHandler.bind(null, {cleanup: true}));

  // catches ctrl+c event
  process.on('SIGINT', exitHandler.bind(null, {exit: true}));

  // catches "kill pid" (for example: nodemon restart)
  process.on('SIGUSR1', exitHandler.bind(null, {exit: true}));
  process.on('SIGUSR2', exitHandler.bind(null, {exit: true}));

  //catches uncaught exceptions
  process.on('uncaughtException', exitHandler.bind(null, {exit:true}));

  function open(fn){
    if (db) db.close()
    var _db = new bdb_lib.Db(dbenv);
    var bdb_status = _db.open(fn)
    if (bdb_status) {
      console.log('open ' + fn + ' failed:', bdb_status)
      process.exit()
    }
    db = _db
  }

  open(fn)
  
  return {
    put: function(term, serialized){
      db.put(term, serialized)
    },
    get: function(term){
      return db.get(term)
    },
  }
}
module.exports = db