// Copyright (c) 2020-2022 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_INDEX_COINSTATSINDEX_H

#define BITCOIN_INDEX_COINSTATSINDEX_H

#include <crypto/muhash.h>

#include <index/base.h>

class CBlockIndex;

class CDBBatch;

namespace kernel {

struct CCoinsStats;

}

static constexpr bool DEFAULT_COINSTATSINDEX{false};

/**

 * CoinStatsIndex maintains statistics on the UTXO set.

 */

class CoinStatsIndex final : public BaseIndex

{

private:

    std::unique_ptr<BaseIndex::DB> m_db;

    MuHash3072 m_muhash;

    uint64_t m_transaction_output_count{0};

    uint64_t m_bogo_size{0};

    CAmount m_total_amount{0};

    CAmount m_total_subsidy{0};

    CAmount m_total_unspendable_amount{0};

    CAmount m_total_prevout_spent_amount{0};

    CAmount m_total_new_outputs_ex_coinbase_amount{0};

    CAmount m_total_coinbase_amount{0};

    CAmount m_total_unspendables_genesis_block{0};

    CAmount m_total_unspendables_bip30{0};

    CAmount m_total_unspendables_scripts{0};

    CAmount m_total_unspendables_unclaimed_rewards{0};

    [[nodiscard]] bool ReverseBlock(const CBlock& block, const CBlockIndex* pindex);

    bool AllowPrune() const override { return true; }

protected:

    bool CustomInit(const std::optional<interfaces::BlockRef>& block) override;

    bool CustomCommit(CDBBatch& batch) override;

    bool CustomAppend(const interfaces::BlockInfo& block) override;

    bool CustomRewind(const interfaces::BlockRef& current_tip, const interfaces::BlockRef& new_tip) override;

    BaseIndex::DB& GetDB() const override { return *m_db; }

public:

    // Constructs the index, which becomes available to be queried.

    explicit CoinStatsIndex(std::unique_ptr<interfaces::Chain> chain, size_t n_cache_size, bool f_memory = false, bool f_wipe = false);

    // Look up stats for a specific block using CBlockIndex

    std::optional<kernel::CCoinsStats> LookUpStats(const CBlockIndex& block_index) const;

};

/// The global UTXO set hash object.

extern std::unique_ptr<CoinStatsIndex> g_coin_stats_index;

#endif // BITCOIN_INDEX_COINSTATSINDEX_H