// Copyright (c) 2009-present The Bitcoin Core developers

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

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

#include <pubkey.h>

#include <script/interpreter.h>

#include <test/fuzz/FuzzedDataProvider.h>

#include <test/fuzz/fuzz.h>

#include <test/fuzz/util.h>

#include <test/util/script.h>

#include <cstdint>

#include <limits>

#include <string>

#include <vector>

namespace {

class FuzzedSignatureChecker : public BaseSignatureChecker

{

    FuzzedDataProvider& m_fuzzed_data_provider;

public:

    explicit FuzzedSignatureChecker(FuzzedDataProvider& fuzzed_data_provider) : m_fuzzed_data_provider(fuzzed_data_provider)

    {

    }

    bool CheckECDSASignature(const std::vector<unsigned char>& scriptSig, const std::vector<unsigned char>& vchPubKey, const CScript& scriptCode, SigVersion sigversion) const override

    {

        return m_fuzzed_data_provider.ConsumeBool();

    }

    bool CheckSchnorrSignature(std::span<const unsigned char> sig, std::span<const unsigned char> pubkey, SigVersion sigversion, ScriptExecutionData& execdata, ScriptError* serror = nullptr) const override

    {

        return m_fuzzed_data_provider.ConsumeBool();

    }

    bool CheckLockTime(const CScriptNum& nLockTime) const override

    {

        return m_fuzzed_data_provider.ConsumeBool();

    }

    bool CheckSequence(const CScriptNum& nSequence) const override

    {

        return m_fuzzed_data_provider.ConsumeBool();

    }

    virtual ~FuzzedSignatureChecker() = default;

};

} // namespace

FUZZ_TARGET(signature_checker)

{

    FuzzedDataProvider fuzzed_data_provider(buffer.data(), buffer.size());

    const unsigned int flags = fuzzed_data_provider.ConsumeIntegral<unsigned int>();

    const SigVersion sig_version = fuzzed_data_provider.PickValueInArray({SigVersion::BASE, SigVersion::WITNESS_V0});

    const auto script_1{ConsumeScript(fuzzed_data_provider)};

    const auto script_2{ConsumeScript(fuzzed_data_provider)};

    std::vector<std::vector<unsigned char>> stack;

    (void)EvalScript(stack, script_1, flags, FuzzedSignatureChecker(fuzzed_data_provider), sig_version, nullptr);

    if (!IsValidFlagCombination(flags)) {

        return;

    }

    (void)VerifyScript(script_1, script_2, nullptr, flags, FuzzedSignatureChecker(fuzzed_data_provider), nullptr);

}