using BenchmarkDotNet.Attributes;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Reflection.Metadata.Ecma335;
using System.Text;
using System.Threading.Tasks;

namespace Recyclable.Collections.Benchmarks
{
	public class RefVsInstanceMemberBenchmarks
	{
		private readonly TestCase _testCase = new();
		private void DoNothing(int count)
		{
			_ = count;
		}

		private class TestCase
		{
			private int[] _items = new int[123];
			private int _count = 123;
			private int Add(int count)
			{
				return count;
			}

			public int Count
			{
				get => _count;
				set => _count = value;
			}

			public ref int GetCountAsRefCount2()
			{
				ref int count = ref _count;
				count = 234;
				return ref count;
			}

			public ref int GetCountAsRefCount3()
			{
				ref int count = ref _count;
				count = 234;
				_ = Add(count);
				return ref count;
			}

			public ref int GetCountAsRefCount4()
			{
				ref int count = ref _count;
				count = 234;
				_ = Add(count);
				_ = Add(count);
				return ref count;
			}

			public ref int GetCountAsRefCount5()
			{
				ref int count = ref _count;
				count = 234;
				_ = Add(count);
				_ = Add(count);
				_ = Add(count);
				return ref count;
			}

			public int GetCountAsInstanceMember2()
			{
				_count = 234;
				return _count;
			}

			public int GetCountAsInstanceMember3()
			{
				_count = 234;
				_ = Add(_count);
				return _count;
			}

			public int GetCountAsInstanceMember4()
			{
				_count = 234;
				_ = Add(_count);
				_ = Add(_count);
				return _count;
			}

			public int GetCountAsInstanceMember5()
			{
				_count = 234;
				_ = Add(_count);
				_ = Add(_count);
				_ = Add(_count);
				return _count;
			}

			public int GetLengthAsArray2()
			{
				_ = Add(_items.Length);
				return _items.Length;
			}

			public int GetLengthAsArray3()
			{
				_ = Add(_items.Length);
				_ = Add(_items.Length);
				return _items.Length;
			}

			public int GetLengthAsArray4()
			{
				_ = Add(_items.Length);
				_ = Add(_items.Length);
				_ = Add(_items.Length);
				return _items.Length;
			}

			public int GetLengthAsArray5()
			{
				_ = Add(_items.Length);
				_ = Add(_items.Length);
				_ = Add(_items.Length);
				_ = Add(_items.Length);
				return _items.Length;
			}

			public int GetLengthAsArray6()
			{
				_ = Add(_items.Length);
				_ = Add(_items.Length);
				_ = Add(_items.Length);
				_ = Add(_items.Length);
				_ = Add(_items.Length);
				return _items.Length;
			}

			public int GetLengthAsArrayLocalVar5()
			{
				var items = _items;
				_ = Add(items.Length);
				_ = Add(items.Length);
				_ = Add(items.Length);
				_ = Add(items.Length);
				return items.Length;
			}

			public int GetLengthAsArrayLocalVar6()
			{
				var items = _items;
				_ = Add(items.Length);
				_ = Add(items.Length);
				_ = Add(items.Length);
				_ = Add(items.Length);
				_ = Add(items.Length);
				return items.Length;
			}

			public int GetLengthAsRefArray2()
			{
				ref int[] items = ref _items;
				_ = Add(items.Length);
				return items.Length;
			}

			public int GetLengthAsRefArray3()
			{
				ref int[] items = ref _items;
				_ = Add(items.Length);
				_ = Add(items.Length);
				return items.Length;
			}

			public int GetLengthAsRefArray4()
			{
				ref int[] items = ref _items;
				_ = Add(items.Length);
				_ = Add(items.Length);
				_ = Add(items.Length);
				return items.Length;
			}

			public int GetLengthAsRefArray5()
			{
				ref int[] items = ref _items;
				_ = Add(items.Length);
				_ = Add(items.Length);
				_ = Add(items.Length);
				_ = Add(items.Length);
				return items.Length;
			}

			public int GetLengthAsRefArray6()
			{
				ref int[] items = ref _items;
				_ = Add(items.Length);
				_ = Add(items.Length);
				_ = Add(items.Length);
				_ = Add(items.Length);
				_ = Add(items.Length);
				return items.Length;
			}
		}

		[Benchmark]
		public void RefToInt2()
		{
			var count = _testCase.GetCountAsRefCount2();
			DoNothing(count);
		}

		[Benchmark]
		public void RefToInt3()
		{
			var count = _testCase.GetCountAsRefCount3();
			DoNothing(count);
		}

		[Benchmark]
		public void RefToInt4()
		{
			var count = _testCase.GetCountAsRefCount4();
			DoNothing(count);
		}

		[Benchmark]
		public void RefToInt5()
		{
			var count = _testCase.GetCountAsRefCount5();
			DoNothing(count);
		}

		[Benchmark(Baseline = true)]
		public void IntInstanceMember2()
		{
			var count = _testCase.GetCountAsInstanceMember2();
			DoNothing(count);
		}

		[Benchmark(Baseline = false)]
		public void IntInstanceMember3()
		{
			var count = _testCase.GetCountAsInstanceMember3();
			DoNothing(count);
		}

		[Benchmark(Baseline = false)]
		public void IntInstanceMember4()
		{
			var count = _testCase.GetCountAsInstanceMember4();
			DoNothing(count);
		}

		[Benchmark(Baseline = false)]
		public void IntInstanceMember5()
		{
			var count = _testCase.GetCountAsInstanceMember5();
			DoNothing(count);
		}

		[Benchmark]
		public void RefToArray2()
		{
			var count = _testCase.GetLengthAsRefArray2();
			DoNothing(count);
		}

		[Benchmark]
		public void RefToArray3()
		{
			var count = _testCase.GetLengthAsRefArray3();
			DoNothing(count);
		}

		[Benchmark]
		public void RefToArray4()
		{
			var count = _testCase.GetLengthAsRefArray4();
			DoNothing(count);
		}

		[Benchmark]
		public void RefToArray5()
		{
			var count = _testCase.GetLengthAsRefArray5();
			DoNothing(count);
		}

		[Benchmark]
		public void RefToArray6()
		{
			var count = _testCase.GetLengthAsRefArray6();
			DoNothing(count);
		}

		[Benchmark(Baseline = false)]
		public void ArrayInstanceMember2()
		{
			var count = _testCase.GetLengthAsArray2();
			DoNothing(count);
		}

		[Benchmark(Baseline = false)]
		public void ArrayInstanceMember3()
		{
			var count = _testCase.GetLengthAsArray3();
			DoNothing(count);
		}

		[Benchmark(Baseline = false)]
		public void ArrayInstanceMember4()
		{
			var count = _testCase.GetLengthAsArray4();
			DoNothing(count);
		}

		[Benchmark(Baseline = false)]
		public void ArrayInstanceMember5()
		{
			var count = _testCase.GetLengthAsArray5();
			DoNothing(count);
		}

		[Benchmark(Baseline = false)]
		public void ArrayInstanceMember6()
		{
			var count = _testCase.GetLengthAsArray6();
			DoNothing(count);
		}

		[Benchmark(Baseline = false)]
		public void ArrayInstanceMemberLocalVar5()
		{
			var count = _testCase.GetLengthAsArrayLocalVar5();
			DoNothing(count);
		}

		[Benchmark(Baseline = false)]
		public void ArrayInstanceMemberLocalVar6()
		{
			var count = _testCase.GetLengthAsArrayLocalVar6();
			DoNothing(count);
		}
	}
}