using System;
using NUnit.Framework;

namespace Chernobyl.Switch
{
    [TestFixture, Description("A set of tests which test the CountdownSwitch class.")]
    public class CountdownSwitchTests : SwitchTests<CountdownSwitch>
    {
        [Test, Description("A test that ensures an ArgumentException is properly " +
            "thrown a zero count is given to the constructor of a CountdownSwitch")]
        public void ConstructionArgumentExceptionTest()
        {
            // ReSharper disable ObjectCreationAsStatement
            Assert.Throws<ArgumentException>(() => new CountdownSwitch(0));
            // ReSharper restore ObjectCreationAsStatement
        }

        [Test, Description("A test that ensures the count given to the " +
            "CountdownSwitch is what gets set on the CountdownSwitch.Count " +
            "property and the CountdownSwitch.StartingCount property.")]
        public void ConstructionCountTest()
        {
            const uint expectedCount = 3;
            CountdownSwitch testSwitch = new CountdownSwitch(expectedCount);
            Assert.AreEqual(expectedCount, testSwitch.Count, "Count is not set to the appropriate value.");
            Assert.AreEqual(expectedCount, testSwitch.StartingCount, "StartingCount is not set to the appropriate value.");
        }

        [Test, Description("A test that ensures the count is properly reduced " +
            "by one if the Countdown(object, EventArgs) method is invoked.")]
        public void CountReductionTest()
        {
            const uint expectedCount = 3;
            CountdownSwitch testSwitch = new CountdownSwitch(expectedCount);
            testSwitch.Countdown(this, EventArgs.Empty);
            Assert.AreEqual(expectedCount - 1, testSwitch.Count, "Count is not set to the appropriate value.");
        }

        [Test, Description("A test that ensures the count given to the " +
            "CountdownSwitch is still the value of the StartingCount after " +
            "Countdown(object, EventArgs) method is invoked.")]
        public void StartingCountTest()
        {
            const uint expectedCount = 3;
            CountdownSwitch testSwitch = new CountdownSwitch(3);
            testSwitch.Countdown(this, EventArgs.Empty);
            Assert.AreEqual(expectedCount, testSwitch.StartingCount, "StartingCount is not set to the appropriate value.");
        }

        protected override CountdownSwitch CreateSwitch()
        {
            return new CountdownSwitch(3);
        }

        protected override void FireSwitchedOnEvent(CountdownSwitch testSwitch)
        {
            while(testSwitch.Count != 0)
                testSwitch.Countdown(this, EventArgs.Empty);
        }

        protected override void FireSwitchedOffEvent(CountdownSwitch testSwitch)
        {
            testSwitch.Reset();
        }
    }
}