//
// Copyright 2022 Google LLC
//
// 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.
//

using System;

namespace Google.Solutions.Common.Util
{
    public static class DateTimeOffsetExtensions
    {
        private static readonly DateTimeOffset UnixEpoch =
            new DateTimeOffset(1970, 1, 1, 0, 0, 0, TimeSpan.Zero);

        /// <summary>
        /// Convert a <c>DateTimeOffset</c> to a Unix timestamp.
        /// </summary>
        public static long ToUnixTimeMicroseconds(this DateTimeOffset timestamp)
        {
            var duration = timestamp - UnixEpoch;
            return duration.Ticks / 10;
        }

        /// <summary>
        /// Convert a Unix timestamp to a <c>DateTimeOffset</c>.
        /// </summary>
        public static DateTimeOffset FromUnixTimeMicroseconds(long millis)
        {
            return UnixEpoch.AddMilliseconds(millis / 1000);
        }
    }
}
