// Copyright (C) 2019-2020 Zilliz. All rights reserved.
//
// Licensed 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.

package typeutil

import (
	"math"
	"time"
)

const MaxTimestamp = math.MaxUint64

// ZeroTime is a zero time.
var ZeroTime = time.Time{}

// ZeroTimestamp is a zero timestamp
var ZeroTimestamp = Timestamp(0)

// ParseTimestamp returns a timestamp for a given byte slice.
func ParseTimestamp(data []byte) (time.Time, error) {
	nano, err := BytesToUint64(data)
	if err != nil {
		return ZeroTime, err
	}

	return time.Unix(0, int64(nano)), nil
}

// SubTimeByWallClock returns the duration between two different timestamps.
func SubTimeByWallClock(after time.Time, before time.Time) time.Duration {
	return time.Duration(after.UnixNano() - before.UnixNano())
}
