export class TransactionManager {
  constructor (options = {}) {
    this._isInTransaction = false
    this._rollbacks = []
  }

  begin () {
    if (this._isInTransaction) {
      throw (new Error('Already in transaction status.'))
    }
    this._rollbacks = []
    this._isInTransaction = true
  }

  addRollback (rollback) {
    this._rollbacks.push(rollback)
  }

  triggerRollback () {
    for (let i = this._rollbacks.length - 1; i >= 0; i--) {
      this._rollbacks[i]()
    }
  }

  success () {
    this.end()
  }

  fail () {
    this.triggerRollback()
    this.end()
  }

  end () {
    this._isInTransaction = false
    this._rollbacks = []
  }
}