using System;
using System.Linq;
using System.Utility;
using Chernobyl.Generation.Old;
using NUnit.Framework;
using ChEnumerable = Chernobyl.Collections.Generic.Enumerable;

namespace Chernobyl.Generation.Test.Old
{
    [TestFixture, Description("Tests for the Pattern type.")]
    public class PatternTests
    {
        readonly Random _rand = new Random();

        [Test, Description("Ensures CreateParent throws when available patterns is empty.")]
        public void CreateParentThrowsWhenAvailablePatternsIsEmpty()
        {
            Assert.Throws<ArgumentOutOfRangeException>(() => Enumerable.Empty<IPattern>().CreateParent(_rand));
        }

        [Test, Description("Ensures CreateParent returns the one pattern it is given.")]
        public void CreateParentReturnsTheOnePatternItIsGiven()
        {
            var pattern = new BasicPattern(3);

            var result = ChEnumerable.From(() => pattern).Take(1).CreateParent(_rand);
            var patterns = result.Data.ToArray();

            patterns.Length.IsEqualTo(1, "Length");
            result.IsEqualTo(pattern, "patterns");
        }

        [Test, Description("Ensures CreateParent creates correct pattern based on parameters provided.")]
        public void CreateParentCreatesCorrectPatternBasedOnProvidedParameters()
        {
            var available = ChEnumerable.From(index => new BasicPattern(index)).Take(9);
            var random = new NotRandom(new [] { 3.0, 1.0, 4.0, 2.0, 5.0, 6.0, 0.0, 1.0, 7.0 }.ToList());

            var pattern = available.CreateParent(random);
            var actual = pattern.Data.ToArray();

            actual.Length.IsEqualTo(9, "Length");

            actual[0].IsEqualTo(3, "first value");
            actual[1].IsEqualTo(1, "second value");
            actual[2].IsEqualTo(3, "third value");

            actual[3].IsEqualTo(4, "fourth value");
            actual[4].IsEqualTo(2, "fifth value");
            actual[5].IsEqualTo(2, "sixth value");

            actual[6].IsEqualTo(3, "seventh value");
            actual[7].IsEqualTo(1, "eigth value");
            actual[8].IsEqualTo(3, "ninth value");
        }
    }
}