// Copyright (c) 2020-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 <addrman.h>
#include <banman.h>
#include <consensus/consensus.h>
#include <kernel/chainparams.h>
#include <net.h>
#include <net_processing.h>
#include <node/mining_types.h>
#include <primitives/block.h>
#include <primitives/transaction.h>
#include <protocol.h>
#include <sync.h>
#include <test/fuzz/FuzzedDataProvider.h>
#include <test/fuzz/fuzz.h>
#include <test/fuzz/util.h>
#include <test/fuzz/util/net.h>
#include <test/util/mining.h>
#include <test/util/net.h>
#include <test/util/random.h>
#include <test/util/setup_common.h>
#include <test/util/time.h>
#include <test/util/validation.h>
#include <util/time.h>
#include <validation.h>
#include <validationinterface.h>

#include <functional>
#include <ios>
#include <memory>
#include <optional>
#include <string>
#include <utility>
#include <vector>

namespace {
TestingSetup* g_setup;

void ResetChainman(TestingSetup& setup)
{
    SetMockTime(setup.m_node.chainman->GetParams().GenesisBlock().Time());
    setup.m_node.chainman.reset();
    setup.m_make_chainman();
    setup.LoadVerifyActivateChainstate();
    node::BlockCreateOptions options;
    for (int i = 0; i < 2 * COINBASE_MATURITY; i++) {
        MineBlock(setup.m_node, options);
    }
}
} // namespace

void initialize_process_messages()
{
    static const auto testing_setup{
        MakeNoLogFileContext<TestingSetup>(
            /*chain_type=*/ChainType::REGTEST,
            {}),
    };
    g_setup = testing_setup.get();
    ResetChainman(*g_setup);
}

FUZZ_TARGET(process_messages, .init = initialize_process_messages)
{
    SeedRandomStateForTest(SeedRand::ZEROS);
    FuzzedDataProvider fuzzed_data_provider(buffer.data(), buffer.size());

    auto& node{g_setup->m_node};
    auto& connman{static_cast<ConnmanTestMsg&>(*node.connman)};
    connman.Reset();
    auto& chainman{static_cast<TestChainstateManager&>(*node.chainman)};
    const auto block_index_size{WITH_LOCK(chainman.GetMutex(), return chainman.BlockIndex().size())};
    NodeClockContext clock_ctx{1610000000s}; // any time to successfully reset ibd
    chainman.ResetIbd();
    chainman.DisableNextWrite();

    // Reset, so that dangling pointers can be detected by sanitizers.
    node.banman.reset();
    node.addrman.reset();
    node.peerman.reset();
    node.addrman = std::make_unique<AddrMan>(*node.netgroupman, /*deterministic=*/true, /*consistency_check_ratio=*/0);
    node.peerman = PeerManager::make(connman, *node.addrman,
                                     /*banman=*/nullptr, chainman,
                                     *node.mempool, *node.warnings,
                                     PeerManager::Options{
                                         .reconcile_txs = true,
                                         .deterministic_rng = true,
                                     });
    connman.SetMsgProc(node.peerman.get());
    connman.SetAddrman(*node.addrman);

    node.validation_signals->RegisterValidationInterface(node.peerman.get());

    LOCK(NetEventsInterface::g_msgproc_mutex);

    std::vector<CNode*> peers;
    const auto num_peers_to_add = fuzzed_data_provider.ConsumeIntegralInRange(1, 3);
    for (int i = 0; i < num_peers_to_add; ++i) {
        peers.push_back(ConsumeNodeAsUniquePtr(fuzzed_data_provider, i).release());
        CNode& p2p_node = *peers.back();

        FillNode(fuzzed_data_provider, connman, p2p_node);

        connman.AddTestNode(p2p_node);
    }

    LIMITED_WHILE(fuzzed_data_provider.ConsumeBool(), 30)
    {
        const std::string random_message_type{fuzzed_data_provider.ConsumeBytesAsString(CMessageHeader::MESSAGE_TYPE_SIZE).c_str()};

        clock_ctx.set(ConsumeTime(fuzzed_data_provider));

        CSerializedNetMsg net_msg;
        net_msg.m_type = random_message_type;
        net_msg.data = ConsumeRandomLengthByteVector(fuzzed_data_provider, MAX_PROTOCOL_MESSAGE_LENGTH);

        CNode& random_node = *PickValue(fuzzed_data_provider, peers);

        connman.FlushSendBuffer(random_node);
        (void)connman.ReceiveMsgFrom(random_node, std::move(net_msg));

        bool more_work{true};
        while (more_work) { // Ensure that every message is eventually processed in some way or another
            random_node.fPauseSend = false;

            try {
                more_work = connman.ProcessMessagesOnce(random_node);
            } catch (const std::ios_base::failure&) {
            }
            node.peerman->SendMessages(random_node);
        }
    }
    node.validation_signals->SyncWithValidationInterfaceQueue();
    node.validation_signals->UnregisterValidationInterface(node.peerman.get());
    node.connman->StopNodes();
    if (block_index_size != WITH_LOCK(chainman.GetMutex(), return chainman.BlockIndex().size())) {
        // Reuse the global chainman, but reset it when it is dirty
        ResetChainman(*g_setup);
    }
}
