// 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.

#include <logging.h>

#include <node/timeoffsets.h>

#include <node/warnings.h>

#include <sync.h>

#include <tinyformat.h>

#include <util/time.h>

#include <util/translation.h>

#include <algorithm>

#include <chrono>

#include <cstdint>

#include <deque>

#include <limits>

#include <optional>

using namespace std::chrono_literals;

void TimeOffsets::Add(std::chrono::seconds offset)

{

    LOCK(m_mutex);

    if (m_offsets.size() >= MAX_SIZE) {

        m_offsets.pop_front();

    }

    m_offsets.push_back(offset);

    LogDebug(BCLog::NET, "Added time offset %+ds, total samples %d\n",

             Ticks<std::chrono::seconds>(offset), m_offsets.size());

}

std::chrono::seconds TimeOffsets::Median() const

{

    LOCK(m_mutex);

    // Only calculate the median if we have 5 or more offsets

    if (m_offsets.size() < 5) return 0s;

    auto sorted_copy = m_offsets;

    std::sort(sorted_copy.begin(), sorted_copy.end());

    return sorted_copy[sorted_copy.size() / 2];  // approximate median is good enough, keep it simple

}

bool TimeOffsets::WarnIfOutOfSync() const

{

    // when median == std::numeric_limits<int64_t>::min(), calling std::chrono::abs is UB

    auto median{std::max(Median(), std::chrono::seconds(std::numeric_limits<int64_t>::min() + 1))};

    if (std::chrono::abs(median) <= WARN_THRESHOLD) {

        m_warnings.Unset(node::Warning::CLOCK_OUT_OF_SYNC);

        return false;

    }

    bilingual_str msg{strprintf(_(

        "Your computer's date and time appear to be more than %d minutes out of sync with the network, "

        "this may lead to consensus failure. After you've confirmed your computer's clock, this message "

        "should no longer appear when you restart your node. Without a restart, it should stop showing "

        "automatically after you've connected to a sufficient number of new outbound peers, which may "

        "take some time. You can inspect the `timeoffset` field of the `getpeerinfo` and `getnetworkinfo` "

        "RPC methods to get more info."

    ), Ticks<std::chrono::minutes>(WARN_THRESHOLD))};

    LogWarning("%s\n", msg.original);

    m_warnings.Set(node::Warning::CLOCK_OUT_OF_SYNC, msg);

    return true;

}