/*
 * This file is part of the Flowee project
 * Copyright (C) 2018-2025 Tom Zander <tom@flowee.org>
 * Copyright (C) 2025 John Galt <johngaltbch@pm.me>
 *
 * 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 "AddressMonitorService.h"

// server 'lib'
#include <txmempool.h>
#include <DoubleSpendProof.h>
#include <encodings_legacy.h>
#include <chain.h>
#include <Application.h>
#include <NetworkManager.h>
#include <APIProtocol.h>

#include <Logger.h>
#include <Message.h>
#include <streaming/MessageBuilder.h>
#include <streaming/MessageParser.h>
#include <streaming/BufferPools.h>
#include <streaming/streams.h>
#include <primitives/Block.h>
#include <BitcoinVersion.h>

AddressMonitorService::AddressMonitorService()
    : NetworkService(Api::AddressMonitorService),
    m_pool(std::make_shared<Streaming::BufferPool>())
{
    ValidationNotifier().addListener(this);
}

AddressMonitorService::~AddressMonitorService()
{
    ValidationNotifier().removeListener(this);
}

void AddressMonitorService::syncTx(const Tx &tx)
{
    auto rem = remotes();
    std::map<int, Match> matchesPerRemote;
    Tx::Iterator iter(tx);
    if (!match(iter, rem, matchesPerRemote))
        return;

    for (auto i = matchesPerRemote.begin(); i != matchesPerRemote.end(); ++i) {
        const Match &data = i->second;
        if (!data.matches.empty())
            sendMatchesToRemote(rem[i->first], data, tx.createHash(), -1, -1);
    }
}

bool AddressMonitorService::match(Tx::Iterator &iter, const std::deque<NetworkService::Remote *> &remotes, std::map<int, Match> &matchingRemotes) const
{
    if (remotes.empty())
        return false;
    auto type = iter.next();
    if (type == Tx::End) // then the second end means end of block
        return false;

    MatchedOutput output;
    int index = 0; // output index
    while (type != Tx::End) {
        if (type == Tx::OutputValue) {
            output = MatchedOutput();
            output.index = index;
            output.amount = iter.longData();
        }
        else if (type == Tx::CashTokenBitfield) {
            uint8_t tokenbitfield = iter.bitfieldData();
            output.hasToken = true;
            output.tokenIsFT = (tokenbitfield & 0x10) == 0x10;
            output.tokenIsNFT = (tokenbitfield & 0x20) == 0x20;
            output.tokenIsImmutable = output.tokenIsNFT && (tokenbitfield & 0x0f) == 0x00;
            output.tokenIsMutable = output.tokenIsNFT && (tokenbitfield & 0x0f) == 0x01;
            output.tokenIsMinting = output.tokenIsNFT && (tokenbitfield & 0x0f) == 0x02;
        }
        else if (type == Tx::CashTokenCategory) {
            output.tokenCategory = iter.byteData();
        }
        else if (type == Tx::CashTokenCommitment) {
            output.tokenCommitment = iter.byteData();
        }
        else if (type == Tx::CashTokenAmount) {
            output.tokenAmount = iter.longData();
        }
        else if (type == Tx::OutputScript) {
            uint256 hashedOutScript;
            iter.hashByteData(hashedOutScript);
            for (size_t i = 0; i < remotes.size(); ++i) {
                assert(i < INT_MAX);
                RemoteWithKeys *rwk = static_cast<RemoteWithKeys*>(remotes.at(i));
                if (rwk->hashes.find(hashedOutScript) != rwk->hashes.end()) {
                    Match &m = matchingRemotes[static_cast<int>(i)];
                    MatchedOutput copy = output;             // copy for this remote
                    copy.hashedOutScript = hashedOutScript;  // per-remote tweak is fine on the copy
                    m.matches.push_back(std::move(copy));
                }
            }
            index++;
        }
        type = iter.next();
    }
    return true;
}

void AddressMonitorService::sendMatchesToRemote(Remote *remote, const Match &data, const uint256 &txid, int blockheight, int64_t offsetInBlock)
{
    const int matchCount = data.matches.size();
    int messageSize = 0;
    for (const auto &output : data.matches) {
        messageSize += output.serializedSize() + 1;
    }
    if (blockheight > 0)
        messageSize += 10;
    if (offsetInBlock > 0)
        messageSize += 10;
    std::lock_guard<std::mutex> guard(m_poolMutex);
    m_pool->reserve(messageSize);
    int count = 0;
    Streaming::MessageBuilder builder(m_pool);
    builder.add(Api::AddressMonitor::TxId, txid);
    if (blockheight > 0)
        builder.add(Api::AddressMonitor::BlockHeight, blockheight);
    if (offsetInBlock >= 0)
        builder.add(Api::AddressMonitor::OffsetInBlock, static_cast<uint64_t>(offsetInBlock));
    for (const auto &output : data.matches) {
        ++count;
        output.serialize(builder);
        if (count != matchCount)
            builder.add(Api::AddressMonitor::Separator, true);
    }
    logDebug(Log::MonitorService) << "Remote gets" << data.matches.size() << "tx notification(s)";
    remote->connection.send(builder.message(Api::AddressMonitorService, Api::AddressMonitor::TransactionFound));
}

void AddressMonitorService::syncAllTransactionsInBlock(const Block &block, CBlockIndex *index)
{
    assert(index);
    Tx::Iterator iter(block);
    auto rem = remotes();
    while (true) {
        std::map<int, Match> matchesPerRemote;
        if (!match(iter, rem, matchesPerRemote))
            return; // end of block

        // one (or zero) message per transaction
        for (auto i = matchesPerRemote.begin(); i != matchesPerRemote.end(); ++i) {
            const Match &data = i->second;
            if (!data.matches.empty()) {
                auto tx = iter.prevTx();
                sendMatchesToRemote(rem[i->first], data, tx.createHash(), index->nHeight, tx.offsetInBlock(block));
            }
        }
    }
}

void AddressMonitorService::doubleSpendFound(const Tx &first, const Tx &duplicate)
{
    logDebug(Log::MonitorService) << "Double spend found" << first.createHash() << duplicate.createHash();
    const auto rem = remotes();
    std::map<int, Match> matchesPerRemote;
    Tx::Iterator iter(first);
    if (!match(iter, rem, matchesPerRemote))
        return; // returns if no listeners

    Tx::Iterator iter2(duplicate);
    bool m = match(iter2, rem, matchesPerRemote);
    assert(m); // our duplicate tx object should have data

    for (auto i = matchesPerRemote.begin(); i != matchesPerRemote.end(); ++i) {
        Match &data = i->second;
        int messageSize = 0;
        for (const auto &output : data.matches) {
            messageSize += output.serializedSize();
        }
        std::lock_guard<std::mutex> guard(m_poolMutex);
        m_pool->reserve(messageSize);
        Streaming::MessageBuilder builder(m_pool);
        for (const auto &output : data.matches) {
            output.serialize(builder);
        }
        builder.add(Api::AddressMonitor::TxId, first.createHash());
        builder.add(Api::AddressMonitor::TransactionData, duplicate.data());
        rem[i->first]->connection.send(builder.message(Api::AddressMonitorService, Api::AddressMonitor::DoubleSpendFound));
    }
}

void AddressMonitorService::doubleSpendFound(const Tx &txInMempool, const DoubleSpendProof &proof)
{
    logDebug(Log::MonitorService) << "Double spend proof found. TxId:" << txInMempool.createHash();
    const auto rem = remotes();
    std::map<int, Match> matchesPerRemote;
    Tx::Iterator iter(txInMempool);
    if (!match(iter, rem, matchesPerRemote))
        return; // returns false if no listeners

    CDataStream stream(SER_NETWORK, PROTOCOL_VERSION);
    stream << proof;
    const std::vector<uint8_t> serializedProof(stream.begin(), stream.end());

    for (auto i = matchesPerRemote.begin(); i != matchesPerRemote.end(); ++i) {
        Match &data = i->second;
        int messageSize = 0;
        for (const auto &output : data.matches) {
            messageSize += output.serializedSize() + 1;
        }
        std::lock_guard<std::mutex> guard(m_poolMutex);
        m_pool->reserve(messageSize);
        Streaming::MessageBuilder builder(m_pool);
        for (const auto &output : data.matches) {
            output.serialize(builder);
        }
        builder.add(Api::AddressMonitor::TxId, txInMempool.createHash());
        builder.addByteArray(Api::AddressMonitor::DoubleSpendProofData, &serializedProof[0], serializedProof.size());
        rem[i->first]->connection.send(builder.message(Api::AddressMonitorService, Api::AddressMonitor::DoubleSpendFound));
    }
}

void AddressMonitorService::onIncomingMessage(Remote *remote_, const Message &message, const EndPoint &ep)
{
    assert(dynamic_cast<RemoteWithKeys*>(remote_));
    RemoteWithKeys *remote = static_cast<RemoteWithKeys*>(remote_);

    if (message.messageId() == Api::AddressMonitor::Subscribe
            || message.messageId() == Api::AddressMonitor::Unsubscribe) {
        Streaming::MessageParser parser(message.body());

        std::string error;
        int done = 0;
        while (parser.next() == Streaming::FoundTag) {
            if (parser.tag() == Api::AddressMonitor::BitcoinScriptHashed) {
                if (parser.isByteArray() && parser.dataLength() == 32) {
                    uint256 hash = parser.uint256Data();

                    ++done;
                    if (message.messageId() == Api::AddressMonitor::Subscribe) {
                        if (m_maxAddressesPerConnection > 0 && static_cast<int>(remote->hashes.size()) + 1 >= m_maxAddressesPerConnection) {
                            logInfo(Log::MonitorService) << "Remote" << ep.connectionId << "hit limit of registrations";
                            error = "Maximum number of addresses registered for watching, ask your node operator to change limits";
                            break;
                        }
                        remote->hashes.insert(hash);
                        remote->connection.postOnStrand(std::bind(&AddressMonitorService::findTxInMempool,
                                                                  this, remote->connection.connectionId(), hash));
                    } else {
                        remote->hashes.erase(hash);
                    }
                }
                else {
                    error = "BitcoinScriptHashed has to be a sha256 (bytearray of 32 bytes)";
                }
            }
        }
        if (error.empty() && !done)
            error = "Missing required field BitcoinScriptHashed (2)";

        auto pool = Streaming::pool(10 + error.size());
        Streaming::MessageBuilder builder(pool);
        builder.add(Api::AddressMonitor::Result, done);
        if (message.messageId() == Api::AddressMonitor::Subscribe)
            logInfo(Log::MonitorService) << "Remote" << ep.connectionId << "made" << done << "changes. Hashes count:"
                                         << remote->hashes.size();
        if (!error.empty())
            builder.add(Api::AddressMonitor::ErrorMessage, error);
        remote->connection.send(builder.reply(message));
        updateBools();
    }
}


void AddressMonitorService::updateBools()
{
    m_findByHash = false;
    for (auto remote : remotes()) {
        RemoteWithKeys *rwk = static_cast<RemoteWithKeys*>(remote);
        m_findByHash = m_findByHash || !rwk->hashes.empty();
    }
}

void AddressMonitorService::findTxInMempool(int connectionId, const uint256 &hash)
{
    if (m_mempool == nullptr)
        return;
    if (manager() == nullptr)
        return;

    auto connection = manager()->connection(manager()->endPoint(connectionId), NetworkManager::OnlyExisting);
    if (!connection.isValid() || !connection.isConnected())
        return;

    LOCK(m_mempool->cs);
    for (auto iter = m_mempool->mapTx.begin(); iter != m_mempool->mapTx.end(); ++iter) {
        Tx::Iterator txIter(iter->tx);
        auto type = txIter.next();

        MatchedOutput output;
        int index = 0;
        while (type != Tx::End) {
            if (type == Tx::OutputValue) {
                output = MatchedOutput();
                output.index = index;
                output.amount = txIter.longData();
            }
            else if (type == Tx::CashTokenBitfield) {
                uint8_t tokenbitfield = txIter.bitfieldData();
                output.tokenIsFT = (tokenbitfield & 0x10) == 0x10;
                output.tokenIsNFT = (tokenbitfield & 0x20) == 0x20;
                output.tokenIsImmutable = output.tokenIsNFT && (tokenbitfield & 0x0f) == 0x00;
                output.tokenIsMutable = output.tokenIsNFT && (tokenbitfield & 0x0f) == 0x01;
                output.tokenIsMinting = output.tokenIsNFT && (tokenbitfield & 0x0f) == 0x02;
            }
            else if (type == Tx::CashTokenCategory) {
                output.tokenCategory = txIter.byteData();
            }
            else if (type == Tx::CashTokenCommitment) {
                output.tokenCommitment = txIter.byteData();
            }
            else if (type == Tx::CashTokenAmount) {
                output.tokenAmount = txIter.longData();
            }
            else if (type == Tx::OutputScript) {
                uint256 hashedOutScript;
                txIter.hashByteData(hashedOutScript);

                if (txIter.hashedByteData() == hash) {
                    logDebug(Log::MonitorService) << " + Sending to peers tx from mempool!";
                    output.hashedOutScript = hash; // to serialize it
                    std::lock_guard<std::mutex> guard(m_poolMutex);
                    m_pool->reserve(output.serializedSize() + 40);
                    Streaming::MessageBuilder builder(m_pool);
                    builder.add(Api::AddressMonitor::TxId, iter->tx.createHash());
                    output.serialize(builder);
                    Message message = builder.message(Api::AddressMonitorService, Api::AddressMonitor::TransactionFound);
                    connection.send(message);
                }
                index++;
            }
            type = txIter.next();
        }
    }
}

int AddressMonitorService::maxAddressesPerConnection() const
{
    return m_maxAddressesPerConnection;
}

void AddressMonitorService::setMaxAddressesPerConnection(int maxAddressesPerConnection)
{
    m_maxAddressesPerConnection = maxAddressesPerConnection;
}

int AddressMonitorService::MatchedOutput::serializedSize() const
{
    int count = 40;
    if (hasToken)
        count += 55 + tokenCommitment.size();
    return count;
}

void AddressMonitorService::MatchedOutput::serialize(Streaming::MessageBuilder &builder) const
{
    builder.add(Api::AddressMonitor::BitcoinScriptHashed, hashedOutScript); // 22 bytes
    builder.add(Api::AddressMonitor::Amount, amount); // up to 10 bytes
    builder.add(Api::AddressMonitor::Tx_Out_Index, index); //up to 6 bytes
    builder.add(Api::AddressMonitor::Tx_Out_CT_IsFT, tokenIsFT); //1 byte
    builder.add(Api::AddressMonitor::Tx_Out_CT_IsNFT, tokenIsNFT); //1 byte
    if (hasToken) {
        assert(tokenCategory.size() == 32);
        builder.add(Api::AddressMonitor::Tx_Out_CT_Category, tokenCategory); // 35 bytes
        builder.add(Api::AddressMonitor::Tx_Out_CT_IsMutable, tokenIsMutable); //1 byte
        builder.add(Api::AddressMonitor::Tx_Out_CT_IsImmutable, tokenIsImmutable); //1 byte
        builder.add(Api::AddressMonitor::Tx_Out_CT_IsMinting, tokenIsMinting); //2 bytes
        if (!tokenCommitment.isValid())
            builder.add(Api::AddressMonitor::Tx_Out_CT_Commitment, tokenCommitment); // 4 + commitment length (assuming 2 bytes for the length indicator (14 bits) should be enough
        builder.add(Api::AddressMonitor::Tx_Out_CT_Amount, tokenAmount);   // up to 10 bytes
    }
}