﻿// 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;
using Org.Apache.REEF.Tang.Annotations;

namespace Org.Apache.REEF.Wake.Time.Runtime
{
    public sealed class RealTimer : ITimer
    {
        [Inject]
        private RealTimer()
        {
        }

        /// <summary>
        /// Gets the number of milliseconds since Epoch
        /// </summary>
        public long CurrentTime
        {
            get { return DateTime.Now.Ticks / TimeSpan.TicksPerMillisecond; }
        }

        /// <summary>
        /// Gets the difference between the given time and the current time
        /// </summary>
        /// <param name="time">The time to compare against the current time</param>
        public long GetDuration(long time)
        {
            return time - CurrentTime;
        }

        /// <summary>
        /// Checks if the given time has already passed.
        /// </summary>
        /// <param name="time">The time to check if it has passed or not</param>
        public bool IsReady(long time)
        {
            return GetDuration(time) <= 0;
        }
    }
}