text: #pragma once
  //------------------------------------------------------------------------------
  //
  //   Copyright 2018-2020 Fetch.AI Limited
  //
  //   Licensed under the Apache License, Version 2.0 (the "License");
  //   you may not use this file except in compliance with the License.
  //   You may obtain a copy of the License at
  //
  //       http://www.apache.org/licenses/LICENSE-2.0
  //
  //   Unless required by applicable law or agreed to in writing, software
  //   distributed under the License is distributed on an "AS IS" BASIS,
  //   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  //   See the License for the specific language governing permissions and
  //   limitations under the License.
  //
  //------------------------------------------------------------------------------
  
  #include "ledger/execution_result.hpp"
  
  namespace fetch {
  namespace chain {
  
  class Transaction;
  
  }  // namespace chain
  
  namespace ledger {
  
  class Block;
  class StorageInterface;
  class TokenContract;
  
  /**
   * Functor like object that can perform validation checks to determine if a transaction is valid to
   * be included into a specified block.
   *
   * This object is designed to be used not only in the execution phase of a node but also as a filter
   * for miners
   */
  class TransactionValidator
  {
  public:
    // Construction / Destruction
    TransactionValidator(StorageInterface &storage, TokenContract &token_contract);
    TransactionValidator(TransactionValidator const &) = delete;
    TransactionValidator(TransactionValidator &&)      = delete;
    ~TransactionValidator()                            = default;
  
    ContractExecutionStatus operator()(chain::Transaction const &tx, uint64_t block_index) const;
  
    // Operators
    TransactionValidator &operator=(TransactionValidator const &) = delete;
    TransactionValidator &operator=(TransactionValidator &&) = delete;
  
  private:
    StorageInterface &storage_;
    TokenContract &   token_contract_;
  };
  
  }  // namespace ledger
  }  // namespace fetch
  