// Copyright (c) 2012-2013 The PPCoin developers

// Distributed under the MIT/X11 software license, see the accompanying

// file COPYING or http://www.opensource.org/licenses/mit-license.php.

#ifndef PPCOIN_KERNEL_H

#define PPCOIN_KERNEL_H

#include "main.h"

#include "wallet.h"

using namespace std;

// ChainDB upgrade time

extern unsigned int nModifierUpgradeTime;

// MODIFIER_INTERVAL: time to elapse before new modifier is computed

extern unsigned int nModifierInterval;

// MODIFIER_INTERVAL_RATIO:

// ratio of group interval length between the last group and the first group

static const int MODIFIER_INTERVAL_RATIO = 3;

// Whether the given block is subject to new modifier protocol

bool IsFixedModifierInterval(unsigned int nTimeBlock);

// Compute the hash modifier for proof-of-stake

bool ComputeNextStakeModifier(const CBlockIndex* pindexCurrent, uint64_t& nStakeModifier, bool& fGeneratedStakeModifier);

// The stake modifier used to hash for a stake kernel is chosen as the stake

// modifier about a selection interval later than the coin generating the kernel

bool GetKernelStakeModifier(uint256 hashBlockFrom, uint64_t& nStakeModifier);

// Check whether stake kernel meets hash target

// Sets hashProofOfStake on success return

bool CheckStakeKernelHash(unsigned int nBits, const CBlock& blockFrom, uint32_t nTxPrevOffset, const CTransaction& txPrev, const COutPoint& prevout, uint32_t nTimeTx, uint256& hashProofOfStake, uint256& targetProofOfStake, bool fPrintProofOfStake=false);

// Scan given kernel for solutions

bool ScanKernelForward(unsigned char *kernel, uint32_t nBits, uint32_t nInputTxTime, int64_t nValueIn, std::pair<uint32_t, uint32_t> &SearchInterval, std::vector<std::pair<uint256, uint32_t> > &solutions);

// Check kernel hash target and coinstake signature

// Sets hashProofOfStake on success return

bool CheckProofOfStake(const CTransaction& tx, unsigned int nBits, uint256& hashProofOfStake, uint256& targetProofOfStake);

// Get stake modifier checksum

uint32_t GetStakeModifierChecksum(const CBlockIndex* pindex);

// Check stake modifier hard checkpoints

bool CheckStakeModifierCheckpoints(int nHeight, uint32_t nStakeModifierChecksum);

// Get time weight using supplied timestamps

inline int64_t GetWeight(int64_t nIntervalBeginning, int64_t nIntervalEnd)

{

// Kernel hash weight starts from 0 at the 30-day min age

// this change increases active coins participating the hash and helps

// to secure the network when proof-of-stake difficulty is low

//

// Maximum TimeWeight is 90 days.

return min(nIntervalEnd - nIntervalBeginning - nStakeMinAge, (int64_t)nStakeMaxAge);

}

#endif // PPCOIN_KERNEL_H