// Copyright (c) 2009-2010 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.

#ifndef BITCOIN_NET_PROCESSING_H

#define BITCOIN_NET_PROCESSING_H

#include <consensus/amount.h>

#include <net.h>

#include <node/txorphanage.h>

#include <node/types.h>

#include <private_broadcast.h>

#include <protocol.h>

#include <uint256.h>

#include <util/expected.h>

#include <validationinterface.h>

#include <atomic>

#include <chrono>

#include <cstdint>

#include <memory>

#include <optional>

#include <string>

#include <vector>

class AddrMan;

class CTxMemPool;

class ChainstateManager;

class BanMan;

class CBlockIndex;

class CScheduler;

class DataStream;

class uint256;

namespace node {

class Warnings;

} // namespace node

/** Whether transaction reconciliation protocol should be enabled by default. */

inline constexpr bool DEFAULT_TXRECONCILIATION_ENABLE{false};

/** Default number of non-mempool transactions to keep around for block reconstruction. Includes

    orphan, replaced, and rejected transactions. */

inline constexpr uint32_t DEFAULT_BLOCK_RECONSTRUCTION_EXTRA_TXN{100};

/** Default maximum per-second rate for sending transaction inventory to peers. */

inline constexpr unsigned int DEFAULT_TX_SEND_RATE{14};

inline constexpr bool DEFAULT_PEERBLOOMFILTERS = false;

inline constexpr bool DEFAULT_PEERBLOCKFILTERS = false;

/** Maximum number of outstanding CMPCTBLOCK requests for the same block. */

inline constexpr unsigned int MAX_CMPCTBLOCKS_INFLIGHT_PER_BLOCK = 3;

/** Number of headers sent in one getheaders result. We rely on the assumption that if a peer sends

 *  less than this number, we reached its tip. Changing this value is a protocol upgrade. */

inline constexpr unsigned int MAX_HEADERS_RESULTS = 2000;

/** The compactblocks version we support. See BIP 152. */

inline constexpr uint64_t CMPCTBLOCKS_VERSION{2};

struct CNodeStateStats {

    int nSyncHeight = -1;

    int nCommonHeight = -1;

    NodeClock::duration m_ping_wait;

    std::vector<int> vHeightInFlight;

    bool m_relay_txs;

    int m_inv_to_send = 0;

    uint64_t m_last_inv_seq{0};

    CAmount m_fee_filter_received;

    uint64_t m_addr_processed = 0;

    uint64_t m_addr_rate_limited = 0;

    bool m_addr_relay_enabled{false};

    ServiceFlags their_services;

    int64_t presync_height{-1};

    std::chrono::seconds time_offset{0};

    NodeClock::time_point m_last_block_announcement;

};

struct PeerManagerInfo {

    struct InvBucketInfo {

        size_t backlog_count{0};

        double count_bucket{0};

        double size_bucket{0};

    };

    std::chrono::seconds median_outbound_time_offset{0s};

    bool ignores_incoming_txs{false};

    bool private_broadcast{DEFAULT_PRIVATE_BROADCAST};

    unsigned int tx_send_rate{0};

    InvBucketInfo inbound_bucket;

    InvBucketInfo outbound_bucket;

};

class PeerManager : public CValidationInterface, public NetEventsInterface

{

public:

    struct Options {

        //! Whether this node is running in -blocksonly mode

        bool ignore_incoming_txs{DEFAULT_BLOCKSONLY};

        //! Whether transaction reconciliation protocol is enabled

        bool reconcile_txs{DEFAULT_TXRECONCILIATION_ENABLE};

        //! Number of non-mempool transactions to keep around for block reconstruction. Includes

        //! orphan, replaced, and rejected transactions.

        uint32_t max_extra_txs{DEFAULT_BLOCK_RECONSTRUCTION_EXTRA_TXN};

        //! Whether all P2P messages are captured to disk

        bool capture_messages{false};

        //! Whether or not the internal RNG behaves deterministically (this is

        //! a test-only option).

        bool deterministic_rng{false};

        //! Number of headers sent in one getheaders message result (this is

        //! a test-only option).

        uint32_t max_headers_result{MAX_HEADERS_RESULTS};

        //! Whether private broadcast is used for sending transactions.

        bool private_broadcast{DEFAULT_PRIVATE_BROADCAST};

        //! Maximum per-second rate for sending transaction inventory to peers.

        unsigned int tx_send_rate{DEFAULT_TX_SEND_RATE};

    };

    static std::unique_ptr<PeerManager> make(CConnman& connman, AddrMan& addrman,

                                             BanMan* banman, ChainstateManager& chainman,

                                             CTxMemPool& pool, node::Warnings& warnings, Options opts);

    virtual ~PeerManager() = default;

    /**

     * Attempt to manually fetch block from a given peer. We must already have the header.

     *

     * @param[in]  peer_id      The peer id

     * @param[in]  block_index  The blockindex

     */

    virtual util::Expected<void, std::string> FetchBlock(NodeId peer_id, const CBlockIndex& block_index) = 0;

    /** Begin running background tasks, should only be called once */

    virtual void StartScheduledTasks(CScheduler& scheduler) = 0;

    /** Get statistics from node state */

    virtual bool GetNodeStateStats(NodeId nodeid, CNodeStateStats& stats) const = 0;

    virtual std::vector<node::TxOrphanage::OrphanInfo> GetOrphanTransactions() = 0;

    /** Get peer manager info. */

    virtual PeerManagerInfo GetInfo() const = 0;

    /** Get info about transactions currently being privately broadcast. */

    virtual std::vector<PrivateBroadcast::TxBroadcastInfo> GetPrivateBroadcastInfo() const = 0;

    /**

     * Abort private broadcast attempts for transactions currently being privately broadcast.

     *

     * @param[in] id A transaction identifier. It will be matched against both txid and wtxid for

     *               all transactions in the private broadcast queue.

     *

     * @return Transactions removed from the private broadcast queue. If the provided id matches a

     *         txid that corresponds to multiple transactions with different wtxids, multiple

     *         transactions may be returned.

     */

    virtual std::vector<CTransactionRef> AbortPrivateBroadcast(const uint256& id) = 0;

    /**

     * Initiate a transaction broadcast to eligible peers.

     * Queue the witness transaction id to the inbound and outbound inv backlogs.

     * Later, depending on `-txsendrate`, `Peer::TxRelay::m_next_inv_send_time` and if

     * the transaction is in the mempool, an `INV` about it may be sent to the peer.

     */

    virtual void InitiateTxBroadcastToAll(const Wtxid& wtxid) = 0;

    /**

     * Initiate a private transaction broadcast. This is done

     * asynchronously via short-lived connections to peers on privacy networks.

     * @retval node::TransactionError::OK The transaction is scheduled for private broadcast (or was already scheduled).

     * @retval node::TransactionError::PRIVATE_BROADCAST_FULL Rejected because the private broadcast queue is full.

     */

    [[nodiscard]] virtual node::TransactionError InitiateTxBroadcastPrivate(const CTransactionRef& tx) = 0;

    /** Send ping message to all peers */

    virtual void SendPings() = 0;

    /** Set the height of the best block and its time (seconds since epoch). */

    virtual void SetBestBlock(int height, std::chrono::seconds time) = 0;

    /* Public for unit testing. */

    virtual void UnitTestMisbehaving(NodeId peer_id) = 0;

    /**

     * Evict extra outbound peers. If we think our tip may be stale, connect to an extra outbound.

     * Public for unit testing.

     */

    virtual void CheckForStaleTipAndEvictPeers() = 0;

    /** This function is used for testing the stale tip eviction logic, see denialofservice_tests.cpp */

    virtual void UpdateLastBlockAnnounceTime(NodeId node, NodeClock::time_point time) = 0;

    /**

     * Gets the set of service flags which are "desirable" for a given peer.

     *

     * These are the flags which are required for a peer to support for them

     * to be "interesting" to us, ie for us to wish to use one of our few

     * outbound connection slots for or for us to wish to prioritize keeping

     * their connection around.

     *

     * Relevant service flags may be peer- and state-specific in that the

     * version of the peer may determine which flags are required (eg in the

     * case of NODE_NETWORK_LIMITED where we seek out NODE_NETWORK peers

     * unless they set NODE_NETWORK_LIMITED and we are out of IBD, in which

     * case NODE_NETWORK_LIMITED suffices).

     *

     * Thus, generally, avoid calling with 'services' == NODE_NONE, unless

     * state-specific flags must absolutely be avoided. When called with

     * 'services' == NODE_NONE, the returned desirable service flags are

     * guaranteed to not change dependent on state - ie they are suitable for

     * use when describing peers which we know to be desirable, but for which

     * we do not have a confirmed set of service flags.

    */

    virtual ServiceFlags GetDesirableServiceFlags(ServiceFlags services) const = 0;

};

#endif // BITCOIN_NET_PROCESSING_H