// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2013 The Bitcoin developers
// Distributed under the MIT/X11 software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.

#include "core.h"
#include "txmempool.h"

using namespace std;

CTxMemPool::CTxMemPool()
{
    // Sanity checks off by default for performance, because otherwise
    // accepting transactions becomes O(N^2) where N is the number
    // of transactions in the pool
    fSanityCheck = false;
}

void CTxMemPool::pruneSpent(const uint256 &hashTx, CCoins &coins)
{
    LOCK(cs);

    std::map<COutPoint, CInPoint>::iterator it = mapNextTx.lower_bound(COutPoint(hashTx, 0));

    // iterate over all COutPoints in mapNextTx whose hash equals the provided hashTx
    while (it != mapNextTx.end() && it->first.hash == hashTx) {
        coins.Spend(it->first.n); // and remove those outputs from coins
        it++;
    }
}

unsigned int CTxMemPool::GetTransactionsUpdated() const
{
    LOCK(cs);
    return nTransactionsUpdated;
}

void CTxMemPool::AddTransactionsUpdated(unsigned int n)
{
    LOCK(cs);
    nTransactionsUpdated += n;
}


bool CTxMemPool::addUnchecked(const uint256& hash, const CTransaction &tx)
{
    // Add to memory pool without checking anything.
    // Used by main.cpp AcceptToMemoryPool(), which DOES do
    // all the appropriate checks.
    LOCK(cs);
    {
        mapTx[hash] = tx;
        for (unsigned int i = 0; i < tx.vin.size(); i++)
            mapNextTx[tx.vin[i].prevout] = CInPoint(&mapTx[hash], i);
        nTransactionsUpdated++;
    }
    return true;
}


bool CTxMemPool::remove(const CTransaction &tx, bool fRecursive)
{
    // Remove transaction from memory pool
    {
        LOCK(cs);
        uint256 hash = tx.GetHash();
        if (fRecursive) {
            for (unsigned int i = 0; i < tx.vout.size(); i++) {
                std::map<COutPoint, CInPoint>::iterator it = mapNextTx.find(COutPoint(hash, i));
                if (it != mapNextTx.end())
                    remove(*it->second.ptx, true);
            }
        }
        if (mapTx.count(hash))
        {
            BOOST_FOREACH(const CTxIn& txin, tx.vin)
                mapNextTx.erase(txin.prevout);
            mapTx.erase(hash);
            nTransactionsUpdated++;
        }
    }
    return true;
}

bool CTxMemPool::removeConflicts(const CTransaction &tx)
{
    // Remove transactions which depend on inputs of tx, recursively
    LOCK(cs);
    BOOST_FOREACH(const CTxIn &txin, tx.vin) {
        std::map<COutPoint, CInPoint>::iterator it = mapNextTx.find(txin.prevout);
        if (it != mapNextTx.end()) {
            const CTransaction &txConflict = *it->second.ptx;
            if (txConflict != tx)
                remove(txConflict, true);
        }
    }
    return true;
}

void CTxMemPool::clear()
{
    LOCK(cs);
    mapTx.clear();
    mapNextTx.clear();
    ++nTransactionsUpdated;
}

void CTxMemPool::check(CCoinsViewCache *pcoins) const
{
    if (!fSanityCheck)
        return;

    LogPrint("mempool", "Checking mempool with %u transactions and %u inputs\n", (unsigned int)mapTx.size(), (unsigned int)mapNextTx.size());

    LOCK(cs);
    for (std::map<uint256, CTransaction>::const_iterator it = mapTx.begin(); it != mapTx.end(); it++) {
        unsigned int i = 0;
        BOOST_FOREACH(const CTxIn &txin, it->second.vin) {
            // Check that every mempool transaction's inputs refer to available coins, or other mempool tx's.
            std::map<uint256, CTransaction>::const_iterator it2 = mapTx.find(txin.prevout.hash);
            if (it2 != mapTx.end()) {
                assert(it2->second.vout.size() > txin.prevout.n && !it2->second.vout[txin.prevout.n].IsNull());
            } else {
                CCoins &coins = pcoins->GetCoins(txin.prevout.hash);
                assert(coins.IsAvailable(txin.prevout.n));
            }
            // Check whether its inputs are marked in mapNextTx.
            std::map<COutPoint, CInPoint>::const_iterator it3 = mapNextTx.find(txin.prevout);
            assert(it3 != mapNextTx.end());
            assert(it3->second.ptx == &it->second);
            assert(it3->second.n == i);
            i++;
        }
    }
    for (std::map<COutPoint, CInPoint>::const_iterator it = mapNextTx.begin(); it != mapNextTx.end(); it++) {
        uint256 hash = it->second.ptx->GetHash();
        std::map<uint256, CTransaction>::const_iterator it2 = mapTx.find(hash);
        assert(it2 != mapTx.end());
        assert(&it2->second == it->second.ptx);
        assert(it2->second.vin.size() > it->second.n);
        assert(it->first == it->second.ptx->vin[it->second.n].prevout);
    }
}

void CTxMemPool::queryHashes(std::vector<uint256>& vtxid)
{
    vtxid.clear();

    LOCK(cs);
    vtxid.reserve(mapTx.size());
    for (map<uint256, CTransaction>::iterator mi = mapTx.begin(); mi != mapTx.end(); ++mi)
        vtxid.push_back((*mi).first);
}

bool CTxMemPool::lookup(uint256 hash, CTransaction& result) const
{
    LOCK(cs);
    std::map<uint256, CTransaction>::const_iterator i = mapTx.find(hash);
    if (i == mapTx.end()) return false;
    result = i->second;
    return true;
}

CCoinsViewMemPool::CCoinsViewMemPool(CCoinsView &baseIn, CTxMemPool &mempoolIn) : CCoinsViewBacked(baseIn), mempool(mempoolIn) { }

bool CCoinsViewMemPool::GetCoins(const uint256 &txid, CCoins &coins) {
    if (base->GetCoins(txid, coins))
        return true;
    CTransaction tx;
    if (mempool.lookup(txid, tx)) {
        coins = CCoins(tx, MEMPOOL_HEIGHT);
        return true;
    }
    return false;
}

bool CCoinsViewMemPool::HaveCoins(const uint256 &txid) {
    return mempool.exists(txid) || base->HaveCoins(txid);
}