// Copyright (c) 2011 The Bitcoin developers
// Distributed under the MIT/X11 software license, see the accompanying
// file license.txt or http://www.opensource.org/licenses/mit-license.php.

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

#include "headers.h"
#include "checkpoints.h"

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

    //
    // 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
        ( 0, hashGenesisBlock )
        ; // ppcoin: no checkpoint yet; to be created in future releases

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

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

    int GetTotalBlocksEstimate()
    {
        if (fTestNet) return 0;

        return mapCheckpoints.rbegin()->first;
    }

    CBlockIndex* GetLastCheckpoint(const std::map<uint256, CBlockIndex*>& mapBlockIndex)
    {
        if (fTestNet) return NULL;

        int64 nResult;
        BOOST_REVERSE_FOREACH(const MapCheckpoints::value_type& i, mapCheckpoints)
        {
            const uint256& hash = i.second;
            std::map<uint256, CBlockIndex*>::const_iterator t = mapBlockIndex.find(hash);
            if (t != mapBlockIndex.end())
                return t->second;
        }
        return NULL;
    }
}