import TransactionModel from '../../common/models/TransactionModel';

/**
 * An abstraction for the persistence of Sidetree transactions.
 * Used to avoid re-fetching and reprocessing of transactions when the Sidetree node crashes or restarts.
 */
export default interface ITransactionStore {

  /**
   * Idempotent method that adds the given transaction to the list of transactions.
   */
  addTransaction (transaction: TransactionModel): Promise<void>;

  /**
   * Gets the most recent transaction. Returns undefined if there is no transaction.
   */
  getLastTransaction (): Promise<TransactionModel | undefined>;

  /**
   * Gets a list of exponentially-spaced transactions in reverse chronological sorted order
   * where the first element in the returned list is the chronologically last transaction in the store.
   */
  getExponentiallySpacedTransactions (): Promise<TransactionModel[]>;

  /**
   * Returns the specified transaction.
   * @param transactionNumber Transaction number of the transaction to be returned.
   */
  getTransaction (transactionNumber: number): Promise<TransactionModel | undefined>;

  /**
   * Returns at most @param max transactions with transactionNumber greater than @param transactionNumber
   * If @param transactionNumber is undefined, returns transactions from index 0 in the store
   */
  getTransactionsLaterThan (transactionNumber: number | undefined, max: number): Promise<TransactionModel[]>;

  /**
   * Remove all transactions with transaction number greater than the provided parameter.
   * If `undefined` is given, remove all transactions.
   */
  removeTransactionsLaterThan (transactionNumber?: number): Promise<void>;
}