// 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_TXDB_H

#define BITCOIN_TXDB_H

#include <coins.h>

#include <dbwrapper.h>

#include <kernel/cs_main.h>

#include <sync.h>

#include <util/fs.h>

#include <cstddef>

#include <cstdint>

#include <memory>

#include <optional>

#include <vector>

class COutPoint;

class uint256;

//! -dbcache default (MiB)

static const int64_t nDefaultDbCache = 450;

//! -dbbatchsize default (bytes)

static const int64_t nDefaultDbBatchSize = 16 << 20;

//! max. -dbcache (MiB)

static const int64_t nMaxDbCache = sizeof(void*) > 4 ? 16384 : 1024;

//! min. -dbcache (MiB)

static const int64_t nMinDbCache = 4;

//! Max memory allocated to block tree DB specific cache, if no -txindex (MiB)

static const int64_t nMaxBlockDBCache = 2;

//! Max memory allocated to block tree DB specific cache, if -txindex (MiB)

// Unlike for the UTXO database, for the txindex scenario the leveldb cache make

// a meaningful difference: https://github.com/bitcoin/bitcoin/pull/8273#issuecomment-229601991

static const int64_t nMaxTxIndexCache = 1024;

//! Max memory allocated to all block filter index caches combined in MiB.

static const int64_t max_filter_index_cache = 1024;

//! Max memory allocated to coin DB specific cache (MiB)

static const int64_t nMaxCoinsDBCache = 8;

//! User-controlled performance and debug options.

struct CoinsViewOptions {

    //! Maximum database write batch size in bytes.

    size_t batch_write_bytes = nDefaultDbBatchSize;

    //! If non-zero, randomly exit when the database is flushed with (1/ratio)

    //! probability.

    int simulate_crash_ratio = 0;

};

/** CCoinsView backed by the coin database (chainstate/) */

class CCoinsViewDB final : public CCoinsView

{

protected:

    DBParams m_db_params;

    CoinsViewOptions m_options;

    std::unique_ptr<CDBWrapper> m_db;

public:

    explicit CCoinsViewDB(DBParams db_params, CoinsViewOptions options);

    bool GetCoin(const COutPoint &outpoint, Coin &coin) const override;

    bool HaveCoin(const COutPoint &outpoint) const override;

    uint256 GetBestBlock() const override;

    std::vector<uint256> GetHeadBlocks() const override;

    bool BatchWrite(CoinsViewCacheCursor& cursor, const uint256 &hashBlock) override;

    std::unique_ptr<CCoinsViewCursor> Cursor() const override;

    //! Whether an unsupported database format is used.

    bool NeedsUpgrade();

    size_t EstimateSize() const override;

    //! Dynamically alter the underlying leveldb cache size.

    void ResizeCache(size_t new_cache_size) EXCLUSIVE_LOCKS_REQUIRED(cs_main);

    //! @returns filesystem path to on-disk storage or std::nullopt if in memory.

    std::optional<fs::path> StoragePath() { return m_db->StoragePath(); }

};

#endif // BITCOIN_TXDB_H