// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2014 The Bitcoin Core developers
// Copyright (c) 2018 The Verus developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.

#include "script_ext.h"

using namespace std;

bool CScriptExt::IsPayToScriptHash(CScriptID *scriptID) const
{
    if (((CScript *)this)->IsPayToScriptHash())
    {
        *scriptID = CScriptID(uint160(std::vector<unsigned char>(this->begin() + 2, this->end() - 1)));
        return true;
    }
    return false;
}

// P2PKH script, adds to whatever is already in the script (for example CLTV)
const CScriptExt &CScriptExt::AddPayToPubKeyHash(const CKeyID &key) const
{
    *((CScript *)this) << OP_DUP;
    *((CScript *)this) << OP_HASH160;
    *((CScript *)this) << ToByteVector(key);
    *((CScript *)this) << OP_EQUALVERIFY;
    *((CScript *)this) << OP_CHECKSIG;
    return *this;
}

// push data into an op_return script with an opret type indicator, fails if the op_return is too large
const CScriptExt &CScriptExt::OpReturnScript(const vector<unsigned char> &data, unsigned char opretType) const
{
    ((CScript *)this)->clear();
    if (data.size() < MAX_SCRIPT_ELEMENT_SIZE)
    {
        vector<unsigned char> scratch = vector<unsigned char>(data);
        scratch.insert(data.begin(), opretType);
        *((CScript *)this) << OP_RETURN;
        *((CScript *)this) << scratch;
    }
    return *this;
}

// P2SH script, adds to whatever is already in the script (for example CLTV)
const CScriptExt &CScriptExt::PayToScriptHash(const CScriptID &scriptID) const
{
    ((CScript *)this)->clear();
    *((CScript *)this) << OP_HASH160;
    *((CScript *)this) << ToByteVector(scriptID);
    *((CScript *)this) << OP_EQUAL;
    return *this;
}

// P2SH script, adds to whatever is already in the script (for example CLTV)
const CScriptExt &CScriptExt::AddCheckLockTimeVerify(int64_t unlocktime) const
{
    unlocktime = unlocktime < 0 ? 0 : unlocktime;
    *((CScript *)this) << CScriptNum::serialize(unlocktime);
    *((CScript *)this) << OP_CHECKLOCKTIMEVERIFY;
    *((CScript *)this) << OP_DROP;
    return *this;
}

// combined CLTV script and P2PKH
const CScriptExt &CScriptExt::TimeLockSpend(const CKeyID &key, int64_t unlocktime) const
{
    ((CScript *)this)->clear();
    this->AddCheckLockTimeVerify(unlocktime);
    this->AddPayToPubKeyHash(key);
    return *this;
}

// if the front of the script has check lock time verify. this is a fairly simple check.
// accepts NULL as parameter if unlockTime is not needed.
bool CScriptExt::IsCheckLockTimeVerify(int64_t *unlockTime) const
{
    opcodetype op;
    std::vector<unsigned char> unlockTimeParam = std::vector<unsigned char>();

    CScript::const_iterator it = this->begin();
    if (this->GetOp2(it, op, &unlockTimeParam))
    {
        if (unlockTimeParam.size() > 1 && unlockTimeParam.size() < 6 &&
            *(this->data() + unlockTimeParam.size() + 1) == OP_CHECKLOCKTIMEVERIFY)
        {
            int i = unlockTimeParam.size() - 1;
            for (*unlockTime = 0; i >= 0; i--)
            {
                *unlockTime <<= 8;
                *unlockTime |= *((unsigned char *)unlockTimeParam.data() + i);
            }
            return true;
        }
    }
    return false;
}

bool CScriptExt::IsCheckLockTimeVerify() const
{
    int64_t ult;
    return this->IsCheckLockTimeVerify(&ult);
}