// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2015 The Bitcoin Core developers
// Copyright (c) 2014-2017 The Dash Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.

#include "miner.h"

#include "amount.h"
#include "chain.h"
#include "chainparams.h"
#include "coins.h"
#include "consensus/consensus.h"
#include "consensus/merkle.h"
#include "consensus/validation.h"
#include "hash.h"
#include "validation.h"
#include "net.h"
#include "policy/policy.h"
#include "pow.h"
#include "primitives/transaction.h"
#include "script/standard.h"
#include "timedata.h"
#include "txmempool.h"
#include "util.h"
#include "utilmoneystr.h"
#include "masternode-payments.h"
#include "masternode-sync.h"
#include "validationinterface.h"

#include <boost/thread.hpp>
#include <boost/tuple/tuple.hpp>
#include <queue>

using namespace std;

//////////////////////////////////////////////////////////////////////////////
//
// DashMiner
//

//
// Unconfirmed transactions in the memory pool often depend on other
// transactions in the memory pool. When we select transactions from the
// pool, we select by highest priority or fee rate, so we might consider
// transactions that depend on transactions that aren't yet in the block.

uint64_t nLastBlockTx = 0;
uint64_t nLastBlockSize = 0;

class ScoreCompare
{
public:
    ScoreCompare() {}

    bool operator()(const CTxMemPool::txiter a, const CTxMemPool::txiter b)
    {
        return CompareTxMemPoolEntryByScore()(*b,*a); // Convert to less than
    }
};

int64_t UpdateTime(CBlockHeader* pblock, const Consensus::Params& consensusParams, const CBlockIndex* pindexPrev)
{
    int64_t nOldTime = pblock->nTime;
    int64_t nNewTime = std::max(pindexPrev->GetMedianTimePast()+1, GetAdjustedTime());

    if (nOldTime < nNewTime)
        pblock->nTime = nNewTime;

    // Updating time can change work required on testnet:
    if (consensusParams.fPowAllowMinDifficultyBlocks)
        pblock->nBits = GetNextWorkRequired(pindexPrev, pblock, consensusParams);

    return nNewTime - nOldTime;
}

CBlockTemplate* CreateNewBlock(const CChainParams& chainparams, const CScript& scriptPubKeyIn)
{
    // Create new block
    std::unique_ptr<CBlockTemplate> pblocktemplate(new CBlockTemplate());
    if(!pblocktemplate.get())
        return NULL;
    CBlock *pblock = &pblocktemplate->block; // pointer for convenience

    // Create coinbase tx
    CMutableTransaction txNew;
    txNew.vin.resize(1);
    txNew.vin[0].prevout.SetNull();
    txNew.vout.resize(1);
    txNew.vout[0].scriptPubKey = scriptPubKeyIn;

    // Largest block you're willing to create:
    unsigned int nBlockMaxSize = GetArg("-blockmaxsize", DEFAULT_BLOCK_MAX_SIZE);
    // Limit to between 1K and MAX_BLOCK_SIZE-1K for sanity:
    nBlockMaxSize = std::max((unsigned int)1000, std::min((unsigned int)(MaxBlockSize(fDIP0001ActiveAtTip)-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", DEFAULT_BLOCK_PRIORITY_SIZE);
    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", DEFAULT_BLOCK_MIN_SIZE);
    nBlockMinSize = std::min(nBlockMaxSize, nBlockMinSize);

    // Collect memory pool transactions into the block
    CTxMemPool::setEntries inBlock;
    CTxMemPool::setEntries waitSet;

    // This vector will be sorted into a priority queue:
    vector<TxCoinAgePriority> vecPriority;
    TxCoinAgePriorityCompare pricomparer;
    std::map<CTxMemPool::txiter, double, CTxMemPool::CompareIteratorByHash> waitPriMap;
    typedef std::map<CTxMemPool::txiter, double, CTxMemPool::CompareIteratorByHash>::iterator waitPriIter;
    double actualPriority = -1;

    std::priority_queue<CTxMemPool::txiter, std::vector<CTxMemPool::txiter>, ScoreCompare> clearedTxs;
    bool fPrintPriority = GetBoolArg("-printpriority", DEFAULT_PRINTPRIORITY);
    uint64_t nBlockSize = 1000;
    uint64_t nBlockTx = 0;
    unsigned int nBlockSigOps = 100;
    int lastFewTxs = 0;
    CAmount nFees = 0;

    {
        LOCK(cs_main);

        CBlockIndex* pindexPrev = chainActive.Tip();
        const int nHeight = pindexPrev->nHeight + 1;
        pblock->nTime = GetAdjustedTime();
        const int64_t nMedianTimePast = pindexPrev->GetMedianTimePast();

        // Add our coinbase tx as first transaction
        pblock->vtx.push_back(txNew);
        pblocktemplate->vTxFees.push_back(-1); // updated at end
        pblocktemplate->vTxSigOps.push_back(-1); // updated at end
        pblock->nVersion = ComputeBlockVersion(pindexPrev, chainparams.GetConsensus());
        // -regtest only: allow overriding block.nVersion with
        // -blockversion=N to test forking scenarios
        if (chainparams.MineBlocksOnDemand())
            pblock->nVersion = GetArg("-blockversion", pblock->nVersion);

        int64_t nLockTimeCutoff = (STANDARD_LOCKTIME_VERIFY_FLAGS & LOCKTIME_MEDIAN_TIME_PAST)
                                ? nMedianTimePast
                                : pblock->GetBlockTime();

        {
            LOCK(mempool.cs);

            bool fPriorityBlock = nBlockPrioritySize > 0;
            if (fPriorityBlock) {
                vecPriority.reserve(mempool.mapTx.size());
                for (CTxMemPool::indexed_transaction_set::iterator mi = mempool.mapTx.begin();
                     mi != mempool.mapTx.end(); ++mi)
                {
                    double dPriority = mi->GetPriority(nHeight);
                    CAmount dummy;
                    mempool.ApplyDeltas(mi->GetTx().GetHash(), dPriority, dummy);
                    vecPriority.push_back(TxCoinAgePriority(dPriority, mi));
                }
                std::make_heap(vecPriority.begin(), vecPriority.end(), pricomparer);
            }

            CTxMemPool::indexed_transaction_set::index<mining_score>::type::iterator mi = mempool.mapTx.get<mining_score>().begin();
            CTxMemPool::txiter iter;

            while (mi != mempool.mapTx.get<mining_score>().end() || !clearedTxs.empty())
            {
                bool priorityTx = false;
                if (fPriorityBlock && !vecPriority.empty()) { // add a tx from priority queue to fill the blockprioritysize
                    priorityTx = true;
                    iter = vecPriority.front().second;
                    actualPriority = vecPriority.front().first;
                    std::pop_heap(vecPriority.begin(), vecPriority.end(), pricomparer);
                    vecPriority.pop_back();
                }
                else if (clearedTxs.empty()) { // add tx with next highest score
                    iter = mempool.mapTx.project<0>(mi);
                    mi++;
                }
                else {  // try to add a previously postponed child tx
                    iter = clearedTxs.top();
                    clearedTxs.pop();
                }

                if (inBlock.count(iter))
                    continue; // could have been added to the priorityBlock

                const CTransaction& tx = iter->GetTx();

                bool fOrphan = false;
                BOOST_FOREACH(CTxMemPool::txiter parent, mempool.GetMemPoolParents(iter))
                {
                    if (!inBlock.count(parent)) {
                        fOrphan = true;
                        break;
                    }
                }
                if (fOrphan) {
                    if (priorityTx)
                        waitPriMap.insert(std::make_pair(iter,actualPriority));
                    else
                        waitSet.insert(iter);
                    continue;
                }

                unsigned int nTxSize = iter->GetTxSize();
                if (fPriorityBlock &&
                    (nBlockSize + nTxSize >= nBlockPrioritySize || !AllowFree(actualPriority))) {
                    fPriorityBlock = false;
                    waitPriMap.clear();
                }
                if (!priorityTx &&
                    (iter->GetModifiedFee() < ::minRelayTxFee.GetFee(nTxSize) && nBlockSize >= nBlockMinSize)) {
                    break;
                }
                if (nBlockSize + nTxSize >= nBlockMaxSize) {
                    if (nBlockSize >  nBlockMaxSize - 100 || lastFewTxs > 50) {
                        break;
                    }
                    // Once we're within 1000 bytes of a full block, only look at 50 more txs
                    // to try to fill the remaining space.
                    if (nBlockSize > nBlockMaxSize - 1000) {
                        lastFewTxs++;
                    }
                    continue;
                }

                if (!IsFinalTx(tx, nHeight, nLockTimeCutoff))
                    continue;

                unsigned int nTxSigOps = iter->GetSigOpCount();
                unsigned int nMaxBlockSigOps = MaxBlockSigOps(fDIP0001ActiveAtTip);
                if (nBlockSigOps + nTxSigOps >= nMaxBlockSigOps) {
                    if (nBlockSigOps > nMaxBlockSigOps - 2) {
                        break;
                    }
                    continue;
                }

                CAmount nTxFees = iter->GetFee();
                // Added
                pblock->vtx.push_back(tx);
                pblocktemplate->vTxFees.push_back(nTxFees);
                pblocktemplate->vTxSigOps.push_back(nTxSigOps);
                nBlockSize += nTxSize;
                ++nBlockTx;
                nBlockSigOps += nTxSigOps;
                nFees += nTxFees;

                if (fPrintPriority)
                {
                    double dPriority = iter->GetPriority(nHeight);
                    CAmount dummy;
                    mempool.ApplyDeltas(tx.GetHash(), dPriority, dummy);
                    LogPrintf("priority %.1f fee %s txid %s\n",
                              dPriority , CFeeRate(iter->GetModifiedFee(), nTxSize).ToString(), tx.GetHash().ToString());
                }

                inBlock.insert(iter);

                // Add transactions that depend on this one to the priority queue
                BOOST_FOREACH(CTxMemPool::txiter child, mempool.GetMemPoolChildren(iter))
                {
                    if (fPriorityBlock) {
                        waitPriIter wpiter = waitPriMap.find(child);
                        if (wpiter != waitPriMap.end()) {
                            vecPriority.push_back(TxCoinAgePriority(wpiter->second,child));
                            std::push_heap(vecPriority.begin(), vecPriority.end(), pricomparer);
                            waitPriMap.erase(wpiter);
                        }
                    }
                    else {
                        if (waitSet.count(child)) {
                            clearedTxs.push(child);
                            waitSet.erase(child);
                        }
                    }
                }
            }

        }

        // NOTE: unlike in bitcoin, we need to pass PREVIOUS block height here
        CAmount blockReward = nFees + GetBlockSubsidy(pindexPrev->nBits, pindexPrev->nHeight, Params().GetConsensus());

        // Compute regular coinbase transaction.
        txNew.vout[0].nValue = blockReward;
        txNew.vin[0].scriptSig = CScript() << nHeight << OP_0;

        // Update coinbase transaction with additional info about masternode and governance payments,
        // get some info back to pass to getblocktemplate
        FillBlockPayments(txNew, nHeight, blockReward, pblock->txoutMasternode, pblock->voutSuperblock);
        // LogPrintf("CreateNewBlock -- nBlockHeight %d blockReward %lld txoutMasternode %s txNew %s",
        //             nHeight, blockReward, pblock->txoutMasternode.ToString(), txNew.ToString());

        nLastBlockTx = nBlockTx;
        nLastBlockSize = nBlockSize;
        LogPrintf("CreateNewBlock(): total size %u txs: %u fees: %ld sigops %d\n", nBlockSize, nBlockTx, nFees, nBlockSigOps);

        // Update block coinbase
        pblock->vtx[0] = txNew;
        pblocktemplate->vTxFees[0] = -nFees;

        // Fill in header
        pblock->hashPrevBlock  = pindexPrev->GetBlockHash();
        UpdateTime(pblock, chainparams.GetConsensus(), pindexPrev);
        pblock->nBits          = GetNextWorkRequired(pindexPrev, pblock, chainparams.GetConsensus());
        pblock->nNonce         = 0;
        pblocktemplate->vTxSigOps[0] = GetLegacySigOpCount(pblock->vtx[0]);

        CValidationState state;
        if (!TestBlockValidity(state, chainparams, *pblock, pindexPrev, false, false)) {
            throw std::runtime_error(strprintf("%s: TestBlockValidity failed: %s", __func__, FormatStateMessage(state)));
        }
    }

    return pblocktemplate.release();
}

void IncrementExtraNonce(CBlock* pblock, const CBlockIndex* pindexPrev, unsigned int& nExtraNonce)
{
    // Update nExtraNonce
    static uint256 hashPrevBlock;
    if (hashPrevBlock != pblock->hashPrevBlock)
    {
        nExtraNonce = 0;
        hashPrevBlock = pblock->hashPrevBlock;
    }
    ++nExtraNonce;
    unsigned int nHeight = pindexPrev->nHeight+1; // Height first in coinbase required for block.version=2
    CMutableTransaction txCoinbase(pblock->vtx[0]);
    txCoinbase.vin[0].scriptSig = (CScript() << nHeight << CScriptNum(nExtraNonce)) + COINBASE_FLAGS;
    assert(txCoinbase.vin[0].scriptSig.size() <= 100);

    pblock->vtx[0] = txCoinbase;
    pblock->hashMerkleRoot = BlockMerkleRoot(*pblock);
}