// Licensed to the Apache Software Foundation (ASF) under one

// or more contributor license agreements.  See the NOTICE file

// distributed with this work for additional information

// regarding copyright ownership.  The ASF licenses this file

// to you under the Apache License, Version 2.0 (the

// "License"); you may not use this file except in compliance

// with the License.  You may obtain a copy of the License at

//

//   http://www.apache.org/licenses/LICENSE-2.0

//

// Unless required by applicable law or agreed to in writing,

// software distributed under the License is distributed on an

// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY

// KIND, either express or implied.  See the License for the

// specific language governing permissions and limitations

// under the License.

#pragma once

#include <cctz/time_zone.h>

#include <cstdint>

#include "common/check.h"

namespace doris::format {

inline int64_t floor_epoch_seconds(int64_t value, int64_t units_per_second) {

    DORIS_CHECK(units_per_second > 0);

    auto seconds = value / units_per_second;

    if (value < 0 && value % units_per_second != 0) {

        --seconds;

    }

    return seconds;

}

// UTC instants are ordered, but converting them to civil DATETIMEV2 values is not monotonic when

// a timezone moves its clock backward. Metadata min/max converted across such a transition cannot

// safely form a ZoneMap: the true civil minimum or maximum may occur inside the UTC interval.

inline bool utc_timestamp_range_is_monotonic(int64_t min_seconds, int64_t max_seconds,

                                             const cctz::time_zone& timezone) {

    // These endpoints come from external file metadata. An inverted range is corrupt rather than

    // a valid precondition violation, so report it as unusable statistics and let every caller

    // take its conservative scan/fallback path instead of terminating the BE.

    if (min_seconds > max_seconds) {

        return false;

    }

    auto current = cctz::time_point<cctz::seconds>(cctz::seconds(min_seconds));

    const auto range_end = cctz::time_point<cctz::seconds>(cctz::seconds(max_seconds));

    cctz::time_zone::civil_transition transition;

    while (timezone.next_transition(current, &transition)) {

        const auto transition_time = timezone.lookup(transition.to).trans;

        if (transition_time > range_end) {

            return true;

        }

        if (transition.to < transition.from) {

            return false;

        }

        // Move past the transition that was just inspected. Some cctz implementations return the

        // same transition again when queried at its exact instant, which would otherwise prevent

        // us from seeing a later rollback in the requested range.

        current = transition_time + cctz::seconds(1);

    }

    return true;

}

} // namespace doris::format