// Copyright (c) 2019 The Dash Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.

#ifndef DASH_QUORUMS_INSTANTSEND_H
#define DASH_QUORUMS_INSTANTSEND_H

#include "quorums_signing.h"

#include "coins.h"
#include "unordered_lru_cache.h"
#include "primitives/transaction.h"

#include <unordered_map>
#include <unordered_set>

class CScheduler;

namespace llmq
{

class CInstantSendLock
{
public:
    std::vector<COutPoint> inputs;
    uint256 txid;
    CBLSSignature sig;

public:
    ADD_SERIALIZE_METHODS

    template<typename Stream, typename Operation>
    inline void SerializationOp(Stream& s, Operation ser_action)
    {
        READWRITE(inputs);
        READWRITE(txid);
        READWRITE(sig);
    }

    uint256 GetRequestId() const;
};

typedef std::shared_ptr<CInstantSendLock> CInstantSendLockPtr;

class CInstantSendDb
{
private:
    CDBWrapper& db;

    unordered_lru_cache<uint256, CInstantSendLockPtr, StaticSaltedHasher, 10000> islockCache;
    unordered_lru_cache<uint256, uint256, StaticSaltedHasher, 10000> txidCache;
    unordered_lru_cache<COutPoint, uint256, SaltedOutpointHasher, 10000> outpointCache;

public:
    CInstantSendDb(CDBWrapper& _db) : db(_db) {}

    void WriteNewInstantSendLock(const uint256& hash, const CInstantSendLock& islock);
    void RemoveInstantSendLock(const uint256& hash, CInstantSendLockPtr islock);

    CInstantSendLockPtr GetInstantSendLockByHash(const uint256& hash);
    uint256 GetInstantSendLockHashByTxid(const uint256& txid);
    CInstantSendLockPtr GetInstantSendLockByTxid(const uint256& txid);
    CInstantSendLockPtr GetInstantSendLockByInput(const COutPoint& outpoint);

    void WriteLastChainLockBlock(const uint256& hashBlock);
    uint256 GetLastChainLockBlock();
};

class CInstantSendManager : public CRecoveredSigsListener
{
private:
    CCriticalSection cs;
    CScheduler* scheduler;
    CInstantSendDb db;

    /**
     * Request ids of inputs that we signed. Used to determine if a recovered signature belongs to an
     * in-progress input lock.
     */
    std::unordered_set<uint256, StaticSaltedHasher> inputRequestIds;

    /**
     * These are the islocks that are currently in the middle of being created. Entries are created when we observed
     * recovered signatures for all inputs of a TX. At the same time, we initiate signing of our sigshare for the islock.
     * When the recovered sig for the islock later arrives, we can finish the islock and propagate it.
     */
    std::unordered_map<uint256, CInstantSendLock, StaticSaltedHasher> creatingInstantSendLocks;
    // maps from txid to the in-progress islock
    std::unordered_map<uint256, CInstantSendLock*, StaticSaltedHasher> txToCreatingInstantSendLocks;

    // Incoming and not verified yet
    std::unordered_map<uint256, std::pair<NodeId, CInstantSendLock>> pendingInstantSendLocks;
    bool hasScheduledProcessPending{false};

public:
    CInstantSendManager(CScheduler* _scheduler, CDBWrapper& _llmqDb);
    ~CInstantSendManager();

    void RegisterAsRecoveredSigsListener();
    void UnregisterAsRecoveredSigsListener();

public:
    bool ProcessTx(const CTransaction& tx, const Consensus::Params& params);
    bool CheckCanLock(const CTransaction& tx, bool printDebug, const Consensus::Params& params);
    bool CheckCanLock(const COutPoint& outpoint, bool printDebug, const uint256& txHash, CAmount* retValue, const Consensus::Params& params);
    bool IsLocked(const uint256& txHash);
    bool IsConflicted(const CTransaction& tx);
    bool GetConflictingTx(const CTransaction& tx, uint256& retConflictTxHash);

    virtual void HandleNewRecoveredSig(const CRecoveredSig& recoveredSig);
    void HandleNewInputLockRecoveredSig(const CRecoveredSig& recoveredSig, const uint256& txid);
    void HandleNewInstantSendLockRecoveredSig(const CRecoveredSig& recoveredSig);

    void TrySignInstantSendLock(const CTransaction& tx);

    void ProcessMessage(CNode* pfrom, const std::string& strCommand, CDataStream& vRecv, CConnman& connman);
    void ProcessMessageInstantSendLock(CNode* pfrom, const CInstantSendLock& islock, CConnman& connman);
    bool PreVerifyInstantSendLock(NodeId nodeId, const CInstantSendLock& islock, bool& retBan);
    void ProcessPendingInstantSendLocks();
    void ProcessInstantSendLock(NodeId from, const uint256& hash, const CInstantSendLock& islock);
    void UpdateWalletTransaction(const uint256& txid, const CTransactionRef& tx);

    void SyncTransaction(const CTransaction &tx, const CBlockIndex *pindex, int posInBlock);
    void NotifyChainLock(const CBlockIndex* pindexChainLock);
    void RemoveFinalISLock(const uint256& hash, const CInstantSendLockPtr& islock);

    void RemoveMempoolConflictsForLock(const uint256& hash, const CInstantSendLock& islock);
    void RetryLockTxs(const uint256& lockedParentTx);

    bool AlreadyHave(const CInv& inv);
    bool GetInstantSendLockByHash(const uint256& hash, CInstantSendLock& ret);
};

extern CInstantSendManager* quorumInstantSendManager;

// This involves 2 sporks: SPORK_2_INSTANTSEND_ENABLED and SPORK_20_INSTANTSEND_LLMQ_BASED
// SPORK_2_INSTANTSEND_ENABLED generally enables/disables InstantSend and SPORK_20_INSTANTSEND_LLMQ_BASED switches
// between the old and the new (LLMQ based) system
// TODO When the new system is fully deployed and enabled, we can remove this special handling in a future version
// and revert to only using SPORK_2_INSTANTSEND_ENABLED.
bool IsOldInstantSendEnabled();
bool IsNewInstantSendEnabled();
bool IsInstantSendEnabled();

}

#endif//DASH_QUORUMS_INSTANTSEND_H