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 "beacon/block_entropy.hpp"
  #include "core/byte_array/const_byte_array.hpp"
  
  namespace fetch {
  namespace ledger {
  
  class EntropyGeneratorInterface
  {
  public:
    using Digest = byte_array::ConstByteArray;
  
    // Construction / Destruction
    EntropyGeneratorInterface()          = default;
    virtual ~EntropyGeneratorInterface() = default;
  
    enum class Status
    {
      OK,
      NOT_READY,
      FAILED
    };
  
    /// @name Entropy Generator
    /// @{
    virtual Status GenerateEntropy(uint64_t block_number, beacon::BlockEntropy &entropy) = 0;
    /// @}
  };
  
  }  // namespace ledger
  }  // namespace fetch
  