#include <boost/test/unit_test.hpp>

#include "main.h"
#include "util.h"

extern uint256 SignatureHash(const CScript &scriptCode, const CTransaction& txTo, unsigned int nIn, int nHashType);

// Old script.cpp SignatureHash function
uint256 static SignatureHashOld(CScript scriptCode, const CTransaction& txTo, unsigned int nIn, int nHashType)
{
    if (nIn >= txTo.vin.size())
    {
        printf("ERROR: SignatureHash() : nIn=%d out of range\n", nIn);
        return 1;
    }
    CTransaction txTmp(txTo);

    // In case concatenating two scripts ends up with two codeseparators,
    // or an extra one at the end, this prevents all those possible incompatibilities.
    scriptCode.FindAndDelete(CScript(OP_CODESEPARATOR));

    // Blank out other inputs' signatures
    for (unsigned int i = 0; i < txTmp.vin.size(); i++)
        txTmp.vin[i].scriptSig = CScript();
    txTmp.vin[nIn].scriptSig = scriptCode;

    // Blank out some of the outputs
    if ((nHashType & 0x1f) == SIGHASH_NONE)
    {
        // Wildcard payee
        txTmp.vout.clear();

        // Let the others update at will
        for (unsigned int i = 0; i < txTmp.vin.size(); i++)
            if (i != nIn)
                txTmp.vin[i].nSequence = 0;
    }
    else if ((nHashType & 0x1f) == SIGHASH_SINGLE)
    {
        // Only lock-in the txout payee at same index as txin
        unsigned int nOut = nIn;
        if (nOut >= txTmp.vout.size())
        {
            printf("ERROR: SignatureHash() : nOut=%d out of range\n", nOut);
            return 1;
        }
        txTmp.vout.resize(nOut+1);
        for (unsigned int i = 0; i < nOut; i++)
            txTmp.vout[i].SetNull();

        // Let the others update at will
        for (unsigned int i = 0; i < txTmp.vin.size(); i++)
            if (i != nIn)
                txTmp.vin[i].nSequence = 0;
    }

    // Blank out other inputs completely, not recommended for open transactions
    if (nHashType & SIGHASH_ANYONECANPAY)
    {
        txTmp.vin[0] = txTmp.vin[nIn];
        txTmp.vin.resize(1);
    }

    // Serialize and hash
    CHashWriter ss(SER_GETHASH, 0);
    ss << txTmp << nHashType;
    return ss.GetHash();
}

void static RandomScript(CScript &script) {
    static const opcodetype oplist[] = {OP_FALSE, OP_1, OP_2, OP_3, OP_CHECKSIG, OP_IF, OP_VERIF, OP_RETURN, OP_CODESEPARATOR};
    script = CScript();
    int ops = (insecure_rand() % 10);
    for (int i=0; i<ops; i++)
        script << oplist[insecure_rand() % (sizeof(oplist)/sizeof(oplist[0]))];
}

void static RandomTransaction(CTransaction &tx, bool fSingle) {
    tx.nVersion = insecure_rand();
    tx.vin.clear();
    tx.vout.clear();
    tx.nLockTime = (insecure_rand() % 2) ? insecure_rand() : 0;
    int ins = (insecure_rand() % 4) + 1;
    int outs = fSingle ? ins : (insecure_rand() % 4) + 1;
    for (int in = 0; in < ins; in++) {
        tx.vin.push_back(CTxIn());
        CTxIn &txin = tx.vin.back();
        txin.prevout.hash = GetRandHash();
        txin.prevout.n = insecure_rand() % 4;
        RandomScript(txin.scriptSig);
        txin.nSequence = (insecure_rand() % 2) ? insecure_rand() : (unsigned int)-1;
    }
    for (int out = 0; out < outs; out++) {
        tx.vout.push_back(CTxOut());
        CTxOut &txout = tx.vout.back();
        txout.nValue = insecure_rand() % 100000000;
        RandomScript(txout.scriptPubKey);
    }
}

BOOST_AUTO_TEST_SUITE(sighash_tests)

BOOST_AUTO_TEST_CASE(sighash_test)
{
    seed_insecure_rand(false);

    for (int i=0; i<50000; i++) {
        int nHashType = insecure_rand();
        CTransaction txTo;
        RandomTransaction(txTo, (nHashType & 0x1f) == SIGHASH_SINGLE);
        CScript scriptCode;
        RandomScript(scriptCode);
        int nIn = insecure_rand() % txTo.vin.size();
        BOOST_CHECK(SignatureHash(scriptCode, txTo, nIn, nHashType) ==
        SignatureHashOld(scriptCode, txTo, nIn, nHashType));
    }
}

BOOST_AUTO_TEST_SUITE_END()