// Copyright (c) 2010 Satoshi Nakamoto

// 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 <consensus/validation.h>

#include <index/txindex.h>

#include <net.h>

#include <net_processing.h>

#include <node/blockstorage.h>

#include <node/context.h>

#include <node/types.h>

#include <txmempool.h>

#include <validation.h>

#include <validationinterface.h>

#include <node/transaction.h>

namespace node {

static TransactionError HandleATMPError(const TxValidationState& state, std::string& err_string_out)

{

    err_string_out = state.ToString();

    if (state.IsInvalid()) {

        if (state.GetResult() == TxValidationResult::TX_MISSING_INPUTS) {

            return TransactionError::MISSING_INPUTS;

        }

        return TransactionError::MEMPOOL_REJECTED;

    } else {

        return TransactionError::MEMPOOL_ERROR;

    }

}

TransactionError BroadcastTransaction(NodeContext& node,

                                      const CTransactionRef tx,

                                      std::string& err_string,

                                      const CAmount& max_tx_fee,

                                      TxBroadcast broadcast_method,

                                      bool wait_callback)

{

    // BroadcastTransaction can be called by RPC or by the wallet.

    // chainman, mempool and peerman are initialized before the RPC server and wallet are started

    // and reset after the RPC sever and wallet are stopped.

    assert(node.chainman);

    assert(node.mempool);

    assert(node.peerman);

    Txid txid = tx->GetHash();

    Wtxid wtxid = tx->GetWitnessHash();

    bool callback_set = false;

    {

        LOCK(cs_main);

        // If the transaction is already confirmed in the chain, don't do anything

        // and return early.

        CCoinsViewCache &view = node.chainman->ActiveChainstate().CoinsTip();

        for (size_t o = 0; o < tx->vout.size(); o++) {

            const Coin& existingCoin = view.AccessCoin(COutPoint(txid, o));

            // IsSpent doesn't mean the coin is spent, it means the output doesn't exist.

            // So if the output does exist, then this transaction exists in the chain.

            if (!existingCoin.IsSpent()) return TransactionError::ALREADY_IN_UTXO_SET;

        }

        if (auto mempool_tx = node.mempool->get(txid); mempool_tx) {

            // There's already a transaction in the mempool with this txid. Don't

            // try to submit this transaction to the mempool (since it'll be

            // rejected as a TX_CONFLICT), but do attempt to reannounce the mempool

            // transaction if broadcast_method is not TxBroadcast::MEMPOOL_NO_BROADCAST.

            //

            // The mempool transaction may have the same or different witness (and

            // wtxid) as this transaction. Use the mempool's wtxid for reannouncement.

            wtxid = mempool_tx->GetWitnessHash();

        } else {

            // Transaction is not already in the mempool.

            const bool check_max_fee{max_tx_fee > 0};

            if (check_max_fee || broadcast_method == TxBroadcast::NO_MEMPOOL_PRIVATE_BROADCAST) {

                // First, call ATMP with test_accept and check the fee. If ATMP

                // fails here, return error immediately.

                const MempoolAcceptResult result = node.chainman->ProcessTransaction(tx, /*test_accept=*/ true);

                if (result.m_result_type != MempoolAcceptResult::ResultType::VALID) {

                    return HandleATMPError(result.m_state, err_string);

                } else if (check_max_fee && result.m_base_fees.value() > max_tx_fee) {

                    return TransactionError::MAX_FEE_EXCEEDED;

                }

            }

            switch (broadcast_method) {

            case TxBroadcast::MEMPOOL_NO_BROADCAST:

            case TxBroadcast::MEMPOOL_AND_BROADCAST_TO_ALL:

                // Try to submit the transaction to the mempool.

                {

                    const MempoolAcceptResult result =

                        node.chainman->ProcessTransaction(tx, /*test_accept=*/false);

                    if (result.m_result_type != MempoolAcceptResult::ResultType::VALID) {

                        return HandleATMPError(result.m_state, err_string);

                    }

                }

                // Transaction was accepted to the mempool.

                if (broadcast_method == TxBroadcast::MEMPOOL_AND_BROADCAST_TO_ALL) {

                    // the mempool tracks locally submitted transactions to make a

                    // best-effort of initial broadcast

                    node.mempool->AddUnbroadcastTx(txid);

                }

                break;

            case TxBroadcast::NO_MEMPOOL_PRIVATE_BROADCAST:

                break;

            }

            if (wait_callback && node.validation_signals) {

                // For transactions broadcast from outside the wallet, make sure

                // that the wallet has been notified of the transaction before

                // continuing.

                //

                // This prevents a race where a user might call sendrawtransaction

                // with a transaction to/from their wallet, immediately call some

                // wallet RPC, and get a stale result because callbacks have not

                // yet been processed.

                callback_set = true;

            }

        }

    } // cs_main

    if (callback_set) {

        // Wait until Validation Interface clients have been notified of the

        // transaction entering the mempool.

        node.validation_signals->SyncWithValidationInterfaceQueue();

    }

    switch (broadcast_method) {

    case TxBroadcast::MEMPOOL_NO_BROADCAST:

        break;

    case TxBroadcast::MEMPOOL_AND_BROADCAST_TO_ALL:

        node.peerman->InitiateTxBroadcastToAll(txid, wtxid);

        break;

    case TxBroadcast::NO_MEMPOOL_PRIVATE_BROADCAST:

        node.peerman->InitiateTxBroadcastPrivate(tx);

        break;

    }

    return TransactionError::OK;

}

CTransactionRef GetTransaction(const CBlockIndex* const block_index, const CTxMemPool* const mempool, const Txid& hash, const BlockManager& blockman, uint256& hashBlock)

{

    if (mempool && !block_index) {

        CTransactionRef ptx = mempool->get(hash);

        if (ptx) return ptx;

    }

    if (g_txindex) {

        CTransactionRef tx;

        uint256 block_hash;

        if (g_txindex->FindTx(hash, block_hash, tx)) {

            if (!block_index || block_index->GetBlockHash() == block_hash) {

                // Don't return the transaction if the provided block hash doesn't match.

                // The case where a transaction appears in multiple blocks (e.g. reorgs or

                // BIP30) is handled by the block lookup below.

                hashBlock = block_hash;

                return tx;

            }

        }

    }

    if (block_index) {

        CBlock block;

        if (blockman.ReadBlock(block, *block_index)) {

            for (const auto& tx : block.vtx) {

                if (tx->GetHash() == hash) {

                    hashBlock = block_index->GetBlockHash();

                    return tx;

                }

            }

        }

    }

    return nullptr;

}

} // namespace node