/*
 * This file is part of the Flowee project
 * Copyright (C) 2013-2015 The Bitcoin Core developers
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include "data/sighash.json.h"
#include "hash.h"
#include "validation/Engine.h" // For checkTransaction
#include "random.h"
#include "script/interpreter.h"
#include "primitives/script.h"
#include "serialize.h"
#include "streaming/streams.h"
#include "test/test_bitcoin.h"
#include "transaction_utils.h"
#include "utilstrencodings.h"
#include <univalue.h>

#include <boost/test/unit_test.hpp>

#ifdef PRINT_SIGHASH_JSON
# include <iostream>
#endif

UniValue read_json(const std::string& jsondata)
{
    UniValue v;

    if (!v.read(jsondata) || !v.isArray())
    {
        BOOST_ERROR("Parse error.");
        return UniValue(UniValue::VARR);
    }
    return v.get_array();
}

// Old script.cpp SignatureHash function
uint256 static SignatureHashOld(CScript scriptCode, const CTransaction& txTo, unsigned int nIn, int nHashType)
{
    static const uint256 one(uint256S("0000000000000000000000000000000000000000000000000000000000000001"));
    if (nIn >= txTo.vin.size())
    {
        return one;
    }
    CMutableTransaction 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())
        {
            return one;
        }
        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.finalizeHash();
}

BOOST_FIXTURE_TEST_SUITE(sighash_tests, BasicTestingSetup)

BOOST_AUTO_TEST_CASE(sighash_test)
{
    seed_insecure_rand(false);

    #if defined(PRINT_SIGHASH_JSON)
    std::cout << "[\n";
    std::cout << "\t[\"raw_transaction, script, input_index, hashType, signature_hash (result)\"],\n";
    #endif
    int nRandomTests = 50000;

    #if defined(PRINT_SIGHASH_JSON)
    nRandomTests = 500;
    #endif
    for (int i=0; i<nRandomTests; i++) {
        int nHashType = insecure_rand();

         // Clear forkid
         nHashType &= ~SIGHASH_FORKID;

        CMutableTransaction txTo;
        TxUtils::RandomTransaction(txTo, (nHashType & 0x1f) == SIGHASH_SINGLE ? TxUtils::SingleOutput: TxUtils::AnyOutputCount);
        CScript scriptCode;
        TxUtils::RandomScript(scriptCode);
        int nIn = insecure_rand() % txTo.vin.size();

        uint256 sh, sho;
        sho = SignatureHashOld(scriptCode, txTo, nIn, nHashType);
        sh = SignatureHash(scriptCode, txTo, nIn, 0, nHashType);
        #if defined(PRINT_SIGHASH_JSON)
        CDataStream ss(SER_NETWORK, PROTOCOL_VERSION);
        ss << txTo;

        std::cout << "\t[\"" ;
        std::cout << HexStr(ss.begin(), ss.end()) << "\", \"";
        std::cout << HexStr(scriptCode) << "\", ";
        std::cout << nIn << ", ";
        std::cout << nHashType << ", \"";
        std::cout << sho.GetHex() << "\"]";
        if (i+1 != nRandomTests) {
          std::cout << ",";
        }
        std::cout << "\n";
        #endif
        BOOST_CHECK(sh == sho);
    }
    #if defined(PRINT_SIGHASH_JSON)
    std::cout << "]\n";
    #endif
}

// Goal: check that SignatureHash generates correct hash
BOOST_AUTO_TEST_CASE(sighash_from_data)
{
    UniValue tests = read_json(std::string(json_tests::sighash, json_tests::sighash + sizeof(json_tests::sighash)));

    for (unsigned int idx = 0; idx < tests.size(); idx++) {
        UniValue test = tests[idx];
        std::string strTest = test.write();
        if (test.size() < 1) // Allow for extra stuff (useful for comments)
        {
            BOOST_ERROR("Bad test: " << strTest);
            continue;
        }
        if (test.size() == 1) continue; // comment

        std::string raw_tx, raw_script, sigHashHex;
        int nIn, nHashType;
        uint256 sh;
        CTransaction tx;
        CScript scriptCode = CScript();

        try {
          // deserialize test data
          raw_tx = test[0].get_str();
          raw_script = test[1].get_str();
          nIn = test[2].get_int();
          nHashType = test[3].get_int();
          sigHashHex = test[4].get_str();

          uint256 sh;
          CDataStream stream(ParseHex(raw_tx), SER_NETWORK, PROTOCOL_VERSION);
          stream >> tx;

          Validation::checkTransaction(Tx::fromOldTransaction(tx));
          std::vector<unsigned char> raw = ParseHex(raw_script);
          scriptCode.insert(scriptCode.end(), raw.begin(), raw.end());
        } catch (...) {
          BOOST_ERROR("Bad test, couldn't deserialize data: " << strTest);
          continue;
        }

        sh = SignatureHash(scriptCode, tx, nIn, 0, nHashType);
        BOOST_CHECK_MESSAGE(sh.GetHex() == sigHashHex, strTest);
    }
}
BOOST_AUTO_TEST_SUITE_END()