// Copyright (c) 2009-2010 Satoshi Nakamoto

// Copyright (c) 2009-2022 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_NODE_MINER_H

#define BITCOIN_NODE_MINER_H

#include <interfaces/types.h>

#include <node/types.h>

#include <policy/policy.h>

#include <primitives/block.h>

#include <txmempool.h>

#include <util/feefrac.h>

#include <memory>

#include <optional>

#include <stdint.h>

#include <boost/multi_index/identity.hpp>

#include <boost/multi_index/indexed_by.hpp>

#include <boost/multi_index/ordered_index.hpp>

#include <boost/multi_index/tag.hpp>

#include <boost/multi_index_container.hpp>

class ArgsManager;

class CBlockIndex;

class CChainParams;

class CScript;

class Chainstate;

class ChainstateManager;

namespace Consensus { struct Params; };

using interfaces::BlockRef;

namespace node {

class KernelNotifications;

static const bool DEFAULT_PRINT_MODIFIED_FEE = false;

struct CBlockTemplate

{

    CBlock block;

    // Fees per transaction, not including coinbase transaction (unlike CBlock::vtx).

    std::vector<CAmount> vTxFees;

    // Sigops per transaction, not including coinbase transaction (unlike CBlock::vtx).

    std::vector<int64_t> vTxSigOpsCost;

    std::vector<unsigned char> vchCoinbaseCommitment;

    /* A vector of package fee rates, ordered by the sequence in which

     * packages are selected for inclusion in the block template.*/

    std::vector<FeeFrac> m_package_feerates;

};

// Container for tracking updates to ancestor feerate as we include (parent)

// transactions in a block

struct CTxMemPoolModifiedEntry {

    explicit CTxMemPoolModifiedEntry(CTxMemPool::txiter entry)

    {

        iter = entry;

        nSizeWithAncestors = entry->GetSizeWithAncestors();

        nModFeesWithAncestors = entry->GetModFeesWithAncestors();

        nSigOpCostWithAncestors = entry->GetSigOpCostWithAncestors();

    }

    CAmount GetModifiedFee() const { return iter->GetModifiedFee(); }

    uint64_t GetSizeWithAncestors() const { return nSizeWithAncestors; }

    CAmount GetModFeesWithAncestors() const { return nModFeesWithAncestors; }

    size_t GetTxSize() const { return iter->GetTxSize(); }

    const CTransaction& GetTx() const { return iter->GetTx(); }

    CTxMemPool::txiter iter;

    uint64_t nSizeWithAncestors;

    CAmount nModFeesWithAncestors;

    int64_t nSigOpCostWithAncestors;

};

/** Comparator for CTxMemPool::txiter objects.

 *  It simply compares the internal memory address of the CTxMemPoolEntry object

 *  pointed to. This means it has no meaning, and is only useful for using them

 *  as key in other indexes.

 */

struct CompareCTxMemPoolIter {

    bool operator()(const CTxMemPool::txiter& a, const CTxMemPool::txiter& b) const

    {

        return &(*a) < &(*b);

    }

};

struct modifiedentry_iter {

    typedef CTxMemPool::txiter result_type;

    result_type operator() (const CTxMemPoolModifiedEntry &entry) const

    {

        return entry.iter;

    }

};

// A comparator that sorts transactions based on number of ancestors.

// This is sufficient to sort an ancestor package in an order that is valid

// to appear in a block.

struct CompareTxIterByAncestorCount {

    bool operator()(const CTxMemPool::txiter& a, const CTxMemPool::txiter& b) const

    {

        if (a->GetCountWithAncestors() != b->GetCountWithAncestors()) {

  Branch (104:13): [True: 0, False: 0]

            return a->GetCountWithAncestors() < b->GetCountWithAncestors();

        }

        return CompareIteratorByHash()(a, b);

    }

};

struct CTxMemPoolModifiedEntry_Indices final : boost::multi_index::indexed_by<

    boost::multi_index::ordered_unique<

        modifiedentry_iter,

        CompareCTxMemPoolIter

    >,

    // sorted by modified ancestor fee rate

    boost::multi_index::ordered_non_unique<

        // Reuse same tag from CTxMemPool's similar index

        boost::multi_index::tag<ancestor_score>,

        boost::multi_index::identity<CTxMemPoolModifiedEntry>,

        CompareTxMemPoolEntryByAncestorFee

    >

>

{};

typedef boost::multi_index_container<

    CTxMemPoolModifiedEntry,

    CTxMemPoolModifiedEntry_Indices

> indexed_modified_transaction_set;

typedef indexed_modified_transaction_set::nth_index<0>::type::iterator modtxiter;

typedef indexed_modified_transaction_set::index<ancestor_score>::type::iterator modtxscoreiter;

struct update_for_parent_inclusion

{

    explicit update_for_parent_inclusion(CTxMemPool::txiter it) : iter(it) {}

    void operator() (CTxMemPoolModifiedEntry &e)

    {

        e.nModFeesWithAncestors -= iter->GetModifiedFee();

        e.nSizeWithAncestors -= iter->GetTxSize();

        e.nSigOpCostWithAncestors -= iter->GetSigOpCost();

    }

    CTxMemPool::txiter iter;

};

/** Generate a new block, without valid proof-of-work */

class BlockAssembler

{

private:

    // The constructed block template

    std::unique_ptr<CBlockTemplate> pblocktemplate;

    // Information on the current status of the block

    uint64_t nBlockWeight;

    uint64_t nBlockTx;

    uint64_t nBlockSigOpsCost;

    CAmount nFees;

    std::unordered_set<Txid, SaltedTxidHasher> inBlock;

    // Chain context for the block

    int nHeight;

    int64_t m_lock_time_cutoff;

    const CChainParams& chainparams;

    const CTxMemPool* const m_mempool;

    Chainstate& m_chainstate;

public:

    struct Options : BlockCreateOptions {

        // Configuration parameters for the block size

        size_t nBlockMaxWeight{DEFAULT_BLOCK_MAX_WEIGHT};

        CFeeRate blockMinFeeRate{DEFAULT_BLOCK_MIN_TX_FEE};

        // Whether to call TestBlockValidity() at the end of CreateNewBlock().

        bool test_block_validity{true};

        bool print_modified_fee{DEFAULT_PRINT_MODIFIED_FEE};

    };

    explicit BlockAssembler(Chainstate& chainstate, const CTxMemPool* mempool, const Options& options);

    /** Construct a new block template */

    std::unique_ptr<CBlockTemplate> CreateNewBlock();

    /** The number of transactions in the last assembled block (excluding coinbase transaction) */

    inline static std::optional<int64_t> m_last_block_num_txs{};

    /** The weight of the last assembled block (including reserved weight for block header, txs count and coinbase tx) */

    inline static std::optional<int64_t> m_last_block_weight{};

private:

    const Options m_options;

    // utility functions

    /** Clear the block's state and prepare for assembling a new block */

    void resetBlock();

    /** Add a tx to the block */

    void AddToBlock(CTxMemPool::txiter iter);

    // Methods for how to add transactions to a block.

    /** Add transactions based on feerate including unconfirmed ancestors

      * Increments nPackagesSelected / nDescendantsUpdated with corresponding

      * statistics from the package selection (for logging statistics).

      *

      * @pre BlockAssembler::m_mempool must not be nullptr

    */

    void addPackageTxs(int& nPackagesSelected, int& nDescendantsUpdated) EXCLUSIVE_LOCKS_REQUIRED(!m_mempool->cs);

    // helper functions for addPackageTxs()

    /** Remove confirmed (inBlock) entries from given set */

    void onlyUnconfirmed(CTxMemPool::setEntries& testSet);

    /** Test if a new package would "fit" in the block */

    bool TestPackage(uint64_t packageSize, int64_t packageSigOpsCost) const;

    /** Perform checks on each transaction in a package:

      * locktime, premature-witness, serialized size (if necessary)

      * These checks should always succeed, and they're here

      * only as an extra check in case of suboptimal node configuration */

    bool TestPackageTransactions(const CTxMemPool::setEntries& package) const;

    /** Sort the package in an order that is valid to appear in a block */

    void SortForBlock(const CTxMemPool::setEntries& package, std::vector<CTxMemPool::txiter>& sortedEntries);

};

/**

 * Get the minimum time a miner should use in the next block. This always

 * accounts for the BIP94 timewarp rule, so does not necessarily reflect the

 * consensus limit.

 */

int64_t GetMinimumTime(const CBlockIndex* pindexPrev, const int64_t difficulty_adjustment_interval);

int64_t UpdateTime(CBlockHeader* pblock, const Consensus::Params& consensusParams, const CBlockIndex* pindexPrev);

/** Update an old GenerateCoinbaseCommitment from CreateNewBlock after the block txs have changed */

void RegenerateCommitments(CBlock& block, ChainstateManager& chainman);

/** Apply -blockmintxfee and -blockmaxweight options from ArgsManager to BlockAssembler options. */

void ApplyArgsManOptions(const ArgsManager& gArgs, BlockAssembler::Options& options);

/* Compute the block's merkle root, insert or replace the coinbase transaction and the merkle root into the block */

void AddMerkleRootAndCoinbase(CBlock& block, CTransactionRef coinbase, uint32_t version, uint32_t timestamp, uint32_t nonce);

/**

 * Return a new block template when fees rise to a certain threshold or after a

 * new tip; return nullopt if timeout is reached.

 */

std::unique_ptr<CBlockTemplate> WaitAndCreateNewBlock(ChainstateManager& chainman,

                                                      KernelNotifications& kernel_notifications,

                                                      CTxMemPool* mempool,

                                                      const std::unique_ptr<CBlockTemplate>& block_template,

                                                      const BlockWaitOptions& options,

                                                      const BlockAssembler::Options& assemble_options);

/* Locks cs_main and returns the block hash and block height of the active chain if it exists; otherwise, returns nullopt.*/

std::optional<BlockRef> GetTip(ChainstateManager& chainman);

/* Waits for the connected tip to change until timeout has elapsed. During node initialization, this will wait until the tip is connected (regardless of `timeout`).

 * Returns the current tip, or nullopt if the node is shutting down. */

std::optional<BlockRef> WaitTipChanged(ChainstateManager& chainman, KernelNotifications& kernel_notifications, const uint256& current_tip, MillisecondsDouble& timeout);

} // namespace node

#endif // BITCOIN_NODE_MINER_H