var fs = require("fs");

var databases = {};

function jsondb(dbName) {
  if (databases[dbName]) {
    return databases[dbName];
  }

  let db = {};
  let filename = "./" + dbName + ".db";

  // Store context for this database
  var controller = {
    load: function () {
      if (fs.existsSync(filename)) {
        try {
          db = JSON.parse(fs.readFileSync(filename));
        } catch (err) {
          console.error("couldn't read " + filename);
          process.exit();
        }
      } else {
        db = {};
      }
    },
    save: function () {
      fs.writeFileSync(filename, JSON.stringify(db, false, 0));
    },
    reset: function () {
      db = {};
    },
    put: function (term, serialized) {
      db[term] = serialized;
    },
    get: function (term) {
      return db[term];
    },
  };
  databases[dbName] = controller;

  function exitHandler(options, err) {
    // if (db) {
    // fs.writeFileSync(fn, JSON.stringify(db, false, 0));
    // }
    // 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 }));

  controller.load();

  return controller;
}
module.exports = jsondb;