// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2012 The Bitcoin developers
// Copyright (c) 2014-2015 Triangles team
// Distributed under the MIT/X11 software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.

#include "txdb.h"
#include "miner.h"
#include "kernel.h"

using namespace std;

//////////////////////////////////////////////////////////////////////////////
//
// TrianglesMiner
//

//

// PoW mining helpers (SHA256Transform, FormatHashBlocks, FormatHashBuffers,
// IncrementExtraNonce, CheckWork) removed - PoW ended at block 9000.

// Some explaining would be appreciated
class COrphan
{
public:
    CTransaction* ptx;
    set<uint256> setDependsOn;
    double dPriority;
    double dFeePerKb;

    COrphan(CTransaction* ptxIn)
    {
        ptx = ptxIn;
        dPriority = dFeePerKb = 0;
    }

    void print() const
    {
        printf("COrphan(hash=%s, dPriority=%.1f, dFeePerKb=%.1f)\n",
               ptx->GetHash().ToString().substr(0,10).c_str(), dPriority, dFeePerKb);
        for (uint256 hash : setDependsOn)
            printf("   setDependsOn %s\n", hash.ToString().substr(0,10).c_str());
    }
};


uint64_t nLastBlockTx = 0;
uint64_t nLastBlockSize = 0;
int64_t nLastCoinStakeSearchInterval = 0;
 
// We want to sort transactions by priority and fee, so:
using TxPriority = std::tuple<double, double, CTransaction*>;
class TxPriorityCompare
{
    bool byFee;
public:
    TxPriorityCompare(bool _byFee) : byFee(_byFee) { }
    bool operator()(const TxPriority& a, const TxPriority& b)
    {
        // #8: Fee-weighted priority for PoS staking.
        // When sorting by fee (PoS mode), apply a 2x weight to fees so
        // higher-fee transactions are prioritized over coin-age-only ones.
        // This maximizes staking rewards for the minter.
        if (byFee)
        {
            double feeA = std::get<1>(a) * 2.0;  // fee boost
            double feeB = std::get<1>(b) * 2.0;
            if (feeA == feeB)
                return std::get<0>(a) < std::get<0>(b);
            return feeA < feeB;
        }
        else
        {
            if (std::get<0>(a) == std::get<0>(b))
                return std::get<1>(a) < std::get<1>(b);
            return std::get<0>(a) < std::get<0>(b);
        }
    }
};

// CreateNewBlock: fProofOfStake: try (best effort) to make a proof-of-stake block
CBlock* CreateNewBlock(CWallet* pwallet, bool fProofOfStake, int64_t* pFees)
{
    // Create new block
    unique_ptr<CBlock> pblock(new CBlock());
    if (!pblock.get())
        return nullptr;

    CBlockIndex* pindexPrev = pindexBest;

    // Create coinbase tx
    CTransaction txNew;
    txNew.vin.resize(1);
    txNew.vin[0].prevout.SetNull();
    txNew.vout.resize(1);

    if (!fProofOfStake)
    {
        CReserveKey reservekey(pwallet);
        txNew.vout[0].scriptPubKey.SetDestination(reservekey.GetReservedKey().GetID());
    }
    else
    {
        // Height first in coinbase required for block.version=2
        txNew.vin[0].scriptSig = (CScript() << pindexPrev->nHeight+1) + COINBASE_FLAGS;
        assert(txNew.vin[0].scriptSig.size() <= 100);

        txNew.vout[0].SetEmpty();
    }

    // Add our coinbase tx as first transaction
    pblock->vtx.push_back(txNew);

    // Largest block you're willing to create:
    unsigned int nBlockMaxSize = GetArg("-blockmaxsize", MAX_BLOCK_SIZE_GEN/2);
    // Limit to betweeen 1K and MAX_BLOCK_SIZE-1K for sanity:
    nBlockMaxSize = std::max((unsigned int)1000, std::min((unsigned int)(MAX_BLOCK_SIZE-1000), nBlockMaxSize));

    // How much of the block should be dedicated to high-priority transactions,
    // included regardless of the fees they pay
    unsigned int nBlockPrioritySize = GetArg("-blockprioritysize", 27000);
    nBlockPrioritySize = std::min(nBlockMaxSize, nBlockPrioritySize);

    // Minimum block size you want to create; block will be filled with free transactions
    // until there are no more or the block reaches this size:
    unsigned int nBlockMinSize = GetArg("-blockminsize", 0);
    nBlockMinSize = std::min(nBlockMaxSize, nBlockMinSize);

    // Fee-per-kilobyte amount considered the same as "free"
    // Be careful setting this: if you set it to zero then
    // a transaction spammer can cheaply fill blocks using
    // 1-satoshi-fee transactions. It should be set above the real
    // cost to you of processing a transaction.
    int64_t nMinTxFee = MIN_TX_FEE;
    if (mapArgs.count("-mintxfee"))
        ParseMoney(mapArgs["-mintxfee"], nMinTxFee);

    pblock->nBits = GetNextTargetRequired(pindexPrev, fProofOfStake);

    // Collect memory pool transactions into the block
    int64_t nFees = 0;
    {
        LOCK2(cs_main, mempool.cs);
        auto txdb_holder = MakeChainDB("r"); CTxDBBase& txdb = *txdb_holder;

        // Priority order to process transactions
        list<COrphan> vOrphan; // list memory doesn't move
        map<uint256, vector<COrphan*> > mapDependers;

        // This vector will be sorted into a priority queue:
        vector<TxPriority> vecPriority;
        vecPriority.reserve(mempool.mapTx.size());
        for (auto& [hash, tx] : mempool.mapTx)
        {
            if (tx.IsCoinBase() || tx.IsCoinStake() || !tx.IsFinal())
                continue;

            COrphan* porphan = nullptr;
            double dPriority = 0;
            int64_t nTotalIn = 0;
            bool fMissingInputs = false;
            for (const CTxIn& txin : tx.vin)
            {
                // Read prev transaction
                CTransaction txPrev;
                CTxIndex txindex;
                if (!txPrev.ReadFromDisk(txdb, txin.prevout, txindex))
                {
                    // This should never happen; all transactions in the memory
                    // pool should connect to either transactions in the chain
                    // or other transactions in the memory pool.
                    if (!mempool.mapTx.count(txin.prevout.hash))
                    {
                        printf("ERROR: mempool transaction missing input\n");
                        if (fDebug) assert("mempool transaction missing input" == 0);
                        fMissingInputs = true;
                        if (porphan)
                            vOrphan.pop_back();
                        break;
                    }

                    // Has to wait for dependencies
                    if (!porphan)
                    {
                        // Use list for automatic deletion
                        vOrphan.push_back(COrphan(&tx));
                        porphan = &vOrphan.back();
                    }
                    mapDependers[txin.prevout.hash].push_back(porphan);
                    porphan->setDependsOn.insert(txin.prevout.hash);
                    nTotalIn += mempool.mapTx[txin.prevout.hash].vout[txin.prevout.n].nValue;
                    continue;
                }
                int64_t nValueIn = txPrev.vout[txin.prevout.n].nValue;
                nTotalIn += nValueIn;

                int nConf = txindex.GetDepthInMainChain();
                dPriority += (double)nValueIn * nConf;
            }
            if (fMissingInputs) continue;

            // Priority is sum(valuein * age) / txsize
            unsigned int nTxSize = ::GetSerializeSize(tx, SER_NETWORK, PROTOCOL_VERSION);
            dPriority /= nTxSize;

            // This is a more accurate fee-per-kilobyte than is used by the client code, because the
            // client code rounds up the size to the nearest 1K. That's good, because it gives an
            // incentive to create smaller transactions.
            double dFeePerKb =  double(nTotalIn-tx.GetValueOut()) / (double(nTxSize)/1000.0);

            if (porphan)
            {
                porphan->dPriority = dPriority;
                porphan->dFeePerKb = dFeePerKb;
            }
            else
                vecPriority.push_back(TxPriority(dPriority, dFeePerKb, &tx));
        }

        // Collect transactions into block
        uint64_t nBlockSize = 1000;
        uint64_t nBlockTx = 0;
        int nBlockSigOps = 100;
        bool fSortedByFee = (nBlockPrioritySize <= 0);

        TxPriorityCompare comparer(fSortedByFee);
        std::make_heap(vecPriority.begin(), vecPriority.end(), comparer);

        while (!vecPriority.empty())
        {
            // Take highest priority transaction off the priority queue:
            double dPriority = std::get<0>(vecPriority.front());
            double dFeePerKb = std::get<1>(vecPriority.front());
            CTransaction& tx = *(std::get<2>(vecPriority.front()));

            std::pop_heap(vecPriority.begin(), vecPriority.end(), comparer);
            vecPriority.pop_back();

            // Size limits
            unsigned int nTxSize = ::GetSerializeSize(tx, SER_NETWORK, PROTOCOL_VERSION);
            if (nBlockSize + nTxSize >= nBlockMaxSize)
                continue;

            // Legacy limits on sigOps:
            unsigned int nTxSigOps = tx.GetLegacySigOpCount();
            if (nBlockSigOps + nTxSigOps >= MAX_BLOCK_SIGOPS)
                continue;

            // Timestamp limit
            if (tx.nTime > GetAdjustedTime() || (fProofOfStake && tx.nTime > pblock->vtx[0].nTime))
                continue;

            // Transaction fee
            int64_t nMinFee = tx.GetMinFee(nBlockSize, GetMinFeeMode::Block);

            // Skip free transactions if we're past the minimum block size:
            if (fSortedByFee && (dFeePerKb < nMinTxFee) && (nBlockSize + nTxSize >= nBlockMinSize))
                continue;

            // Prioritize by fee once past the priority size or we run out of high-priority
            // transactions:
            if (!fSortedByFee &&
                ((nBlockSize + nTxSize >= nBlockPrioritySize) || (dPriority < COIN * 144 / 250)))
            {
                fSortedByFee = true;
                comparer = TxPriorityCompare(fSortedByFee);
                std::make_heap(vecPriority.begin(), vecPriority.end(), comparer);
            }

            // Connecting shouldn't fail due to dependency on other memory pool transactions
            // because we're already processing them in order of dependency
            MapPrevTx mapInputs;
            MapPrevTx mapEmpty;
            bool fInvalid;
            if (!tx.FetchInputs(txdb, mapEmpty, false, true, mapInputs, fInvalid))
                continue;

            int64_t nTxFees = tx.GetValueIn(mapInputs)-tx.GetValueOut();
            if (nTxFees < nMinFee)
                continue;

            nTxSigOps += tx.GetP2SHSigOpCount(mapInputs);
            if (nBlockSigOps + nTxSigOps >= MAX_BLOCK_SIGOPS)
                continue;

            if (!tx.ConnectInputs(txdb, mapInputs, pindexPrev, false, true))
                continue;

            // Added
            pblock->vtx.push_back(tx);
            nBlockSize += nTxSize;
            ++nBlockTx;
            nBlockSigOps += nTxSigOps;
            nFees += nTxFees;

            if (fDebug && GetBoolArg("-printpriority"))
            {
                printf("priority %.1f feeperkb %.1f txid %s\n",
                       dPriority, dFeePerKb, tx.GetHash().ToString().c_str());
            }

            // Add transactions that depend on this one to the priority queue
            uint256 hash = tx.GetHash();
            if (mapDependers.count(hash))
            {
                for (COrphan* porphan : mapDependers[hash])
                {
                    if (!porphan->setDependsOn.empty())
                    {
                        porphan->setDependsOn.erase(hash);
                        if (porphan->setDependsOn.empty())
                        {
                            vecPriority.push_back(TxPriority(porphan->dPriority, porphan->dFeePerKb, porphan->ptx));
                            std::push_heap(vecPriority.begin(), vecPriority.end(), comparer);
                        }
                    }
                }
            }
        }

        nLastBlockTx = nBlockTx;
        nLastBlockSize = nBlockSize;

        if (fDebug && GetBoolArg("-printpriority"))
            printf("CreateNewBlock(): total size %" PRIu64 "\n", nBlockSize);

        if (!fProofOfStake)
            pblock->vtx[0].vout[0].nValue = GetProofOfWorkReward(nFees);

        if (pFees)
            *pFees = nFees;

        // Fill in header
        pblock->hashPrevBlock  = pindexPrev->GetBlockHash();
        pblock->nTime          = max(pindexPrev->GetPastTimeLimit()+1, pblock->GetMaxTransactionTime());
        pblock->nTime          = max(pblock->GetBlockTime(), PastDrift(pindexPrev->GetBlockTime(), pindexPrev->nHeight + 1));
        if (!fProofOfStake)
            pblock->UpdateTime(pindexPrev);
        pblock->nNonce         = 0;
    }

    return pblock.release();
}


bool CheckStake(CBlock* pblock, CWallet& wallet)
{
    uint256 proofHash = 0, hashTarget = 0;
    uint256 hash = pblock->GetHash();

    if(!pblock->IsProofOfStake())
        return error("CheckStake() : %s is not a proof-of-stake block", hash.GetHex().c_str());

    if (pblock->vtx.size() < 2)
        return error("CheckStake() : block has no coinstake transaction");

    // verify hash target and signature of coinstake tx
    if (!CheckProofOfStake(pblock->vtx[1], pblock->nBits, proofHash, hashTarget))
        return error("CheckStake() : proof-of-stake checking failed");

    //// debug print
    printf("CheckStake() : new proof-of-stake block found  \n  hash: %s \nproofhash: %s  \ntarget: %s\n", hash.GetHex().c_str(), proofHash.GetHex().c_str(), hashTarget.GetHex().c_str());
    pblock->print();
    printf("out %s\n", FormatMoney(pblock->vtx[1].GetValueOut()).c_str());

    // Found a solution
    {
        LOCK(cs_main);
        if (pblock->hashPrevBlock != hashBestChain)
            return error("CheckStake() : generated block is stale");

        // Track how many getdata requests this block gets
        {
            LOCK(wallet.cs_wallet);
            wallet.mapRequestCount[hash] = 0;
        }

        // Process this block the same as if we had received it from another node
        if (!ProcessBlock(nullptr, pblock))
            return error("CheckStake() : ProcessBlock, block not accepted");
    }

    return true;
}

void StakeMiner(CWallet *pwallet)
{
    SetThreadPriority(THREAD_PRIORITY_LOWEST);

    // Make this thread recognisable as the mining thread
    RenameThread("Triangles-miner");

    bool fTryToSync = true;
    bool fForceStaking = GetBoolArg("-forcestaking", false);

    while (true)
    {
        if (fShutdown)
            return;

        while (pwallet->IsLocked())
        {
            nLastCoinStakeSearchInterval = 0;
            MilliSleep(1000);
            if (fShutdown)
                return;
        }

        while (!fForceStaking && (vNodes.empty() || IsInitialBlockDownload()))
        {
            nLastCoinStakeSearchInterval = 0;
            fTryToSync = true;
            MilliSleep(1000);
            if (fShutdown)
                return;
        }

        if (fTryToSync && !fForceStaking)
        {
            fTryToSync = false;
            if (vNodes.size() < 2 || nBestHeight < GetNumBlocksOfPeers())
            {
                MilliSleep(60000);
                continue;
            }
        }

        //
        // Update cached stake weight for UI display (avoids heavy work on UI thread)
        //
        {
            uint64_t nMinWeight = 0, nMaxWeight = 0, nWeight = 0;
            pwallet->GetStakeWeight(*pwallet, nMinWeight, nMaxWeight, nWeight);
            pwallet->nCachedStakeWeight = nWeight;
            pwallet->nCachedStakeWeightTime = GetTime();
        }

        //
        // Create new block
        //
        int64_t nFees;
        unique_ptr<CBlock> pblock(CreateNewBlock(pwallet, true, &nFees));
        if (!pblock.get())
        {
            MilliSleep(5000);
            continue;
        }

        // Try to sign the block
        if (pblock->SignBlock(*pwallet, nFees))
        {
            printf("StakeMiner(): A proof-of-stake block has been found! %s\n", pblock->GetHash().ToString().c_str());
            SetThreadPriority(THREAD_PRIORITY_NORMAL);
            bool fAccepted = CheckStake(pblock.get(), *pwallet);
            SetThreadPriority(THREAD_PRIORITY_LOWEST);
            if (fAccepted)
            {
                MilliSleep(500);
            }
            else
            {
                // Block was orphaned or rejected — apply a cooldown to reduce
                // fork oscillation. Without this, the staker immediately retries
                // with a different timestamp, potentially creating competing forks.
                printf("StakeMiner(): block not accepted, cooldown 30s\n");
                MilliSleep(30000);
            }
        }
        else
          MilliSleep(500);
    }
}