// Copyright (c) 2024-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_NODE_TIMEOFFSETS_H

#define BITCOIN_NODE_TIMEOFFSETS_H

#include <sync.h>

#include <chrono>

#include <cstddef>

#include <deque>

namespace node {

class Warnings;

} // namespace node

class TimeOffsets

{

public:

    TimeOffsets(node::Warnings& warnings) : m_warnings{warnings} {}

private:

    //! Maximum number of timeoffsets stored.

    static constexpr size_t MAX_SIZE{50};

    //! Minimum difference between system and network time for a warning to be raised.

    static constexpr std::chrono::minutes WARN_THRESHOLD{10};

    mutable Mutex m_mutex;

    /** The observed time differences between our local clock and those of our outbound peers. A

     * positive offset means our peer's clock is ahead of our local clock. */

    std::deque<std::chrono::seconds> m_offsets GUARDED_BY(m_mutex){};

    node::Warnings& m_warnings;

public:

    /** Add a new time offset sample. */

    void Add(std::chrono::seconds offset) EXCLUSIVE_LOCKS_REQUIRED(!m_mutex);

    /** Compute and return the median of the collected time offset samples. The median is returned

     * as 0 when there are less than 5 samples. */

    std::chrono::seconds Median() const EXCLUSIVE_LOCKS_REQUIRED(!m_mutex);

    /** Raise warnings if the median time offset exceeds the warnings threshold. Returns true if

     * warnings were raised. */

    bool WarnIfOutOfSync() const EXCLUSIVE_LOCKS_REQUIRED(!m_mutex);

};

#endif // BITCOIN_NODE_TIMEOFFSETS_H