using System;
using System.Linq;
using Developpez.Dotnet.Linq;
using NUnit.Framework;

namespace Developpez.Dotnet.Tests.Linq
{
    [TestFixture]
    public class LinqHelperTests
    {
        #region Dummy properties and methods

        public int Foo { get; set; }

        public int Bar(int x)
        {
            return x;
        }

        public void Baz(int x)
        {
        }

        #endregion

        [Test]
        public void Test_GetPropertyName()
        {
            string expected = "Foo";
            string actual = LinqHelper.GetPropertyName(() => Foo);
            Assert.AreEqual(actual, expected);

            Assert.Throws<ArgumentException>(
                () =>
                    actual = LinqHelper.GetPropertyName(() => Bar(42)));
        }

        [Test]
        public void Test_GetMethodName()
        {
            string expected = "Bar";
            string actual = LinqHelper.GetMethodName(() => Bar(42));
            Assert.AreEqual(actual, expected);

            expected = "Baz";
            actual = LinqHelper.GetMethodName(() => Baz(42));
            Assert.AreEqual(actual, expected);

            Assert.Throws<ArgumentException>(
                () =>
                    actual = LinqHelper.GetMethodName(() => Foo));
        }

        [Test]
        public void Test_Generate()
        {
            var fibonacci =
                LinqHelper.Generate(
                    new { n = 1, value = 0, next = 1 },
                    s => s.n <= 8,
                    s => new { n = s.n + 1, value = s.next, next = s.value + s.next },
                    s => s.value);
            
            var expected = new[] { 0, 1, 1, 2, 3, 5, 8, 13 };
            var actual = fibonacci.ToArray();

            Assert.That(actual, Is.EquivalentTo(expected));
        }
    }
}