Lewerow/Zurvan

'use strict';
var TypeChecks = require('./TypeChecks');
var SequenceGenerator = require('./SequenceGenerator');

function UIDManager() {
  this._sequenceGenerator = new SequenceGenerator();
  this._issuedUids = {};
}

function serialize(value) {
  var serialized;
  try {
    serialized = JSON.stringify(value);
    if (!serialized) {
      serialized = value.toString();
    }
  } catch (err) {
    serialized = 'not easily serializable: <<' + value + '>>';
  }

  return serialized;
}

function failure(reason) {
  return {
    passed: false,
    failureReason: reason
  };
}

function success() {
  return {
    passed: true
  };
}

UIDManager.prototype.setUp = function(throwOnValidationFailure, uidUser) {
  this._throwOnValidationFailure = throwOnValidationFailure;
  this._uidUser = uidUser;
};

UIDManager.prototype.isAcceptableUidImpl = function(uid) {
  if (!TypeChecks.isObject(uid)) {
    return failure(serialize(uid) + ' is not an object');
  }

  if (this._issuedUids[uid.uid] !== uid) {
    return failure(serialize(uid) + ' was not issued');
  }

  return success();
};

UIDManager.prototype.isAcceptableUid = function(uid) {
  var uidValidation = this.isAcceptableUidImpl(uid);
  if (!uidValidation.passed) {
    if (this._throwOnValidationFailure) {
      throw new Error(
        'Invalid UID during clearing ' +
          this._uidUser +
          '. Reason: ' +
          uidValidation.failureReason
      );
    }

    return false;
  }
  return true;
};

UIDManager.prototype.getUid = function() {
  var sequenceNumber = this._sequenceGenerator.generate();

  var uid = { uid: sequenceNumber };
  uid.ref = uid;

  this._issuedUids[uid.uid] = uid;

  return uid;
};

UIDManager.prototype.clear = function() {
  this._issuedUids = {};
};

module.exports = UIDManager;