text: // Copyright (c) 2018-2020, The Investcoin Project, GRIF-IT
  
  #pragma once
  
  #include <cstdint>
  #include <future>
  #include <system_error>
  #include <unordered_set>
  
  #include "crypto/crypto.h"
  #include "CryptoNoteCore/CryptoNoteBasic.h"
  
  #include "IObservable.h"
  #include "IStreamSerializable.h"
  #include "ITransfersSynchronizer.h"
  
  namespace CryptoNote {
  
  struct CompleteBlock;
  
  class IBlockchainSynchronizerObserver {
  public:
    virtual void synchronizationProgressUpdated(uint32_t processedBlockCount, uint32_t totalBlockCount) {}
    virtual void synchronizationCompleted(std::error_code result) {}
  };
  
  class IBlockchainConsumerObserver;
  
  class IBlockchainConsumer : public IObservable<IBlockchainConsumerObserver> {
  public:
    virtual ~IBlockchainConsumer() {}
    virtual SynchronizationStart getSyncStart() = 0;
    virtual const std::unordered_set<Crypto::Hash>& getKnownPoolTxIds() const = 0;
    virtual void onBlockchainDetach(uint32_t height) = 0;
    virtual bool onNewBlocks(const CompleteBlock* blocks, uint32_t startHeight, uint32_t count) = 0;
    virtual std::error_code onPoolUpdated(const std::vector<std::unique_ptr<ITransactionReader>>& addedTransactions, const std::vector<Crypto::Hash>& deletedTransactions) = 0;
  
    virtual std::error_code addUnconfirmedTransaction(const ITransactionReader& transaction) = 0;
    virtual void removeUnconfirmedTransaction(const Crypto::Hash& transactionHash) = 0;
  };
  
  class IBlockchainConsumerObserver {
  public:
    virtual void onBlocksAdded(IBlockchainConsumer* consumer, const std::vector<Crypto::Hash>& blockHashes) {}
    virtual void onBlockchainDetach(IBlockchainConsumer* consumer, uint32_t blockIndex) {}
    virtual void onTransactionDeleteBegin(IBlockchainConsumer* consumer, Crypto::Hash transactionHash) {}
    virtual void onTransactionDeleteEnd(IBlockchainConsumer* consumer, Crypto::Hash transactionHash) {}
    virtual void onTransactionUpdated(IBlockchainConsumer* consumer, const Crypto::Hash& transactionHash, const std::vector<ITransfersContainer*>& containers) {}
  };
  
  class IBlockchainSynchronizer :
    public IObservable<IBlockchainSynchronizerObserver>,
    public IStreamSerializable {
  public:
    virtual void addConsumer(IBlockchainConsumer* consumer) = 0;
    virtual bool removeConsumer(IBlockchainConsumer* consumer) = 0;
    virtual IStreamSerializable* getConsumerState(IBlockchainConsumer* consumer) const = 0;
    virtual std::vector<Crypto::Hash> getConsumerKnownBlocks(IBlockchainConsumer& consumer) const = 0;
  
    virtual std::future<std::error_code> addUnconfirmedTransaction(const ITransactionReader& transaction) = 0;
    virtual std::future<void> removeUnconfirmedTransaction(const Crypto::Hash& transactionHash) = 0;
  
    virtual void start() = 0;
    virtual void stop() = 0;
  };
  
  }
  