//
// Copyright (c) Microsoft. All rights reserved.
// Licensed under the MIT license. See LICENSE file in the project root for full license information.
//

using System;
using System.Threading;
using Microsoft.SqlTools.ServiceLayer.Profiler;
using Microsoft.SqlTools.ServiceLayer.Profiler.Contracts;
using Xunit;

namespace Microsoft.SqlTools.ServiceLayer.UnitTests.Profiler
{
    /// <summary>
    /// Tests for ProfilerSession class
    /// </summary>
    public class ProfilerSessionTests
    {   
        /// <summary>
        /// Test the FilterOldEvents method
        /// </summary>
        [Fact]
        public void TestFilterOldEvents()
        {
            // create a profiler session and get some test events
            var profilerSession = new ProfilerSession();
            var profilerEvents = ProfilerTestObjects.TestProfilerEvents;
            
            // filter old events shouldn't filter any new events
            var newProfilerEvents = profilerSession.FilterOldEvents(profilerEvents);
            Assert.Equal(profilerEvents.Count, newProfilerEvents.Count);

            // filter should now filter all the events since they've been seen before
            newProfilerEvents = profilerSession.FilterOldEvents(profilerEvents);
            Assert.Equal(newProfilerEvents.Count, 0);

            // add a new event
            var newEvent = new ProfilerEvent("new event", "1/1/2017");
            profilerEvents.Add(newEvent);

            // verify we only have the new event when reprocessing the event list
            newProfilerEvents = profilerSession.FilterOldEvents(profilerEvents);
            Assert.Equal(newProfilerEvents.Count, 1);
            Assert.True(newProfilerEvents[0].Equals(newEvent));

            // process whole list again and verify nothing new is available
            newProfilerEvents = profilerSession.FilterOldEvents(profilerEvents);
            Assert.Equal(newProfilerEvents.Count, 0);
        }

        /// <summary>
        /// Test the TryEnterPolling method
        /// </summary>
        [Fact]
        public void TestTryEnterPolling()
        {
            DateTime startTime = DateTime.Now;

            // create new profiler session
            var profilerSession = new ProfilerSession();
            
            // enter the polling block
            Assert.True(profilerSession.TryEnterPolling());
            Assert.True(profilerSession.IsPolling);

            // verify we can't enter again
            Assert.False(profilerSession.TryEnterPolling());

            // set polling to false to exit polling block
            profilerSession.IsPolling = false;

            bool outsideDelay = DateTime.Now.Subtract(startTime) >= profilerSession.PollingDelay;

            // verify we can only enter again if we're outside polling delay interval
            Assert.Equal(profilerSession.TryEnterPolling(), outsideDelay);

            // reset IsPolling in case the delay has elasped on slow machine or while debugging
            profilerSession.IsPolling = false;

            // wait for the polling delay to elapse
            Thread.Sleep(profilerSession.PollingDelay);

            // verify we can enter the polling block again
            Assert.True(profilerSession.TryEnterPolling());
        }
    }
}