/*
 * Copyright (C) 2015 ScyllaDB
 */

/*
 * This file is part of Scylla.
 *
 * Scylla is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * Scylla is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Scylla.  If not, see <http://www.gnu.org/licenses/>.
 */

#pragma once

#include <cstdint>
#include <limits>
#include <chrono>
#include "db_clock.hh"

namespace api {

using timestamp_type = int64_t;
timestamp_type constexpr missing_timestamp = std::numeric_limits<timestamp_type>::min();
timestamp_type constexpr min_timestamp = std::numeric_limits<timestamp_type>::min() + 1;
timestamp_type constexpr max_timestamp = std::numeric_limits<timestamp_type>::max();

// Used for generating server-side mutation timestamps.
// Same epoch as Java's System.currentTimeMillis() for compatibility.
// Satisfies requirements of TrivialClock.
class timestamp_clock {
    using base = std::chrono::system_clock;
public:
    using rep = timestamp_type;
    using duration = std::chrono::microseconds;
    using period = typename duration::period;
    using time_point = std::chrono::time_point<timestamp_clock, duration>;

    static constexpr bool is_steady = base::is_steady;

    static time_point now() noexcept {
        auto now_since_epoch = base::now() - base::from_time_t(0);
        return time_point(std::chrono::duration_cast<duration>(now_since_epoch)) + get_clocks_offset();
    }
};

static inline
timestamp_type new_timestamp() {
    return timestamp_clock::now().time_since_epoch().count();
}

}