// Copyright (c) 2009-2012 The Bitcoin developers
// Copyright (c) 2017-2018 The Gostcoin Developers
// Distributed under the MIT/X11 software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.

#include <boost/assign/list_of.hpp> // for 'map_list_of()'
#include <boost/foreach.hpp>

#include "checkpoints.h"

#include "main.h"
#include "uint256.h"

namespace Checkpoints
{
    typedef std::map<int, uint256> MapCheckpoints;

    // How many times we expect transactions after the last checkpoint to
    // be slower. This number is a compromise, as it can't be accurate for
    // every system. When reindexing from a fast disk with a slow CPU, it
    // can be up to 20, while when downloading from a slow network with a
    // fast multicore CPU, it won't be much higher than 1.
    static const double fSigcheckVerificationFactor = 5.0;

    struct CCheckpointData {
        const MapCheckpoints *mapCheckpoints;
        int64 nTimeLastCheckpoint;
        int64 nTransactionsLastCheckpoint;
        double fTransactionsPerDay;
    };

    // What makes a good checkpoint block?
    // + Is surrounded by blocks with reasonable timestamps
    //   (no blocks before with a timestamp after, none after with
    //    timestamp before)
    // + Contains no strange transactions
    static MapCheckpoints mapCheckpoints =
        boost::assign::map_list_of
        (1, uint256("0x0000086f3bfd2ca98fa3f912c41d1c4482ed1f5399c289f4cae4420c9c3a3fda"))
        (7, uint256("0x00000ae8c47fc4e0498d1c569eeaa05a4c2214ef95cbef2c2906e2daf78c2c6b"))
		(777, uint256("0x0000062829795a3ffc0ae5e0f7fe5327fb134c9844b3d3755a1619f378be2de4"))
        (7777, uint256("0x0000003182844de51e83b4daa24a874c551bab3ca7d6df3722d126a81f9402b9"))
        (15417, uint256("0x0000000960989066e7b49fe2057a7c4e0f9371818d0de4767a2735f9fea0e1be"))
        (21578, uint256("0x0000000197f21c5455310f0eb87059fcf695383165e76e7eac0f0535c6912015"))
	    (62154, uint256("0x00000000588924cd98e8d11d3ad4a4d2b5dca62274e0c18390f4f903da781469"))
        (77778, uint256("0x00000000133e30988f573c4eb972c095964fbfde1ccc3300bd5485ccd05e320d"))
		(83139, uint256("0x0000000007f44e6aa08e8950851780efaa3bf40590590f31ed753c22f56e0de3"))
        (100000, uint256("0x00000000016f41b554c35a3366984ba8d6b04f388d1683caeb71b520c2a7e540"))
        /*(106000, uint256("0xbe27545eb8ea31c74878b54d500161873ed035afc2fa1f4e7cfa7e84a232b8f9"))
	(112800, uint256("0x4dbecbf0368b99c80da8406693f370b754f78a7b6d139a878bc69fb961f86383"))*/
        ;
    static const CCheckpointData data = {
        &mapCheckpoints,
		1508425220, // * UNIX timestamp of last checkpoint block
        108577,    // * total number of transactions between genesis and last checkpoint
                    //   (the tx=... number in the SetBestChain debug.log lines)
        100.0     // * estimated number of transactions per day after checkpoint
    };

    static MapCheckpoints mapCheckpointsTestnet = 
        boost::assign::map_list_of
        (   5046, uint256("000000002a936ca763904c3c35fce2f3556c559c0214345d31b1bcebf76acb70"))
        ( 35000, uint256("2af959ab4f12111ce947479bfcef16702485f04afd95210aa90fde7d1e4a64ad"))
        ;
    static const CCheckpointData dataTestnet = {
        &mapCheckpointsTestnet,
        1369685559,
        37581,
        300
    };

    const CCheckpointData &Checkpoints() {
        if (fTestNet)
            return dataTestnet;
        else
            return data;
    }

    bool CheckBlock(int nHeight, const uint256& hash)
    {
        if (fTestNet) return true; // Testnet has no checkpoints
        if (!GetBoolArg("-checkpoints", true))
            return true;

        const MapCheckpoints& checkpoints = *Checkpoints().mapCheckpoints;

        MapCheckpoints::const_iterator i = checkpoints.find(nHeight);
        if (i == checkpoints.end()) return true;
        return hash == i->second;
    }

    // Guess how far we are in the verification process at the given block index
    double GuessVerificationProgress(CBlockIndex *pindex) {
        if (pindex==NULL)
            return 0.0;

        int64 nNow = time(NULL);

        double fWorkBefore = 0.0; // Amount of work done before pindex
        double fWorkAfter = 0.0;  // Amount of work left after pindex (estimated)
        // Work is defined as: 1.0 per transaction before the last checkoint, and
        // fSigcheckVerificationFactor per transaction after.

        const CCheckpointData &data = Checkpoints();

        if (pindex->nChainTx <= data.nTransactionsLastCheckpoint) {
            double nCheapBefore = pindex->nChainTx;
            double nCheapAfter = data.nTransactionsLastCheckpoint - pindex->nChainTx;
            double nExpensiveAfter = (nNow - data.nTimeLastCheckpoint)/86400.0*data.fTransactionsPerDay;
            fWorkBefore = nCheapBefore;
            fWorkAfter = nCheapAfter + nExpensiveAfter*fSigcheckVerificationFactor;
        } else {
            double nCheapBefore = data.nTransactionsLastCheckpoint;
            double nExpensiveBefore = pindex->nChainTx - data.nTransactionsLastCheckpoint;
            double nExpensiveAfter = (nNow - pindex->nTime)/86400.0*data.fTransactionsPerDay;
            fWorkBefore = nCheapBefore + nExpensiveBefore*fSigcheckVerificationFactor;
            fWorkAfter = nExpensiveAfter*fSigcheckVerificationFactor;
        }

        return fWorkBefore / (fWorkBefore + fWorkAfter);
    }

    int GetTotalBlocksEstimate()
    {
        if (fTestNet) return 0; // Testnet has no checkpoints
        if (!GetBoolArg("-checkpoints", true))
            return 0;

        const MapCheckpoints& checkpoints = *Checkpoints().mapCheckpoints;

        return checkpoints.rbegin()->first;
    }

    CBlockIndex* GetLastCheckpoint(const std::map<uint256, CBlockIndex*>& mapBlockIndex)
    {
        if (fTestNet) return NULL; // Testnet has no checkpoints
        if (!GetBoolArg("-checkpoints", true))
            return NULL;

        const MapCheckpoints& checkpoints = *Checkpoints().mapCheckpoints;

        BOOST_REVERSE_FOREACH(const MapCheckpoints::value_type& i, checkpoints)
        {
            const uint256& hash = i.second;
            std::map<uint256, CBlockIndex*>::const_iterator t = mapBlockIndex.find(hash);
            if (t != mapBlockIndex.end())
                return t->second;
        }
        return NULL;
    }
}