using System;
using System.Collections.Generic;
using System.Linq;
using BenchmarkHelper;
    
sealed class LoopsBenchmark
{
    const int Size = 100000;

    static void Main()
    {
        Random rng = new Random();
        List<double> doubleList = Enumerable.Range(0, Size)
                                      .Select(x => rng.NextDouble())
                                      .ToList();
        double[] doubleArray = doubleList.ToArray();

        var doubleArraySuite = TestSuite.Create("double[]", doubleArray, doubleArray.Sum())
            .Add(input => { double sum = 0; 
                for (int i=0; i < input.Length; i++) sum += input[i];
                return sum;
            }, "For")
            .Add(input => { double sum = 0; int length = input.Length;
                for (int i = 0; i < length; i++) sum += input[i];
                return sum;
            }, "ForHoistLength")
            .Add(input => { double sum = 0;
                foreach (double d in input) sum += d;
                return sum;
            }, "ForEach")
            .Add(IEnumerableForEach)
            .Add(Enumerable.Sum, "Enumerable.Sum")
            .RunTests();

        var doubleListSuite = TestSuite.Create("List<double>", doubleList, doubleList.Sum())
            .Add(input => { double sum = 0;
                for (int i = 0; i < input.Count; i++) sum += input[i];
                return sum;
            }, "For")
            .Add(input => { double sum = 0; int length = input.Count;
                for (int i = 0; i < length; i++) sum += input[i];
                return sum;
            }, "ForHoistLength")
            .Add(input => { double sum = 0;
                foreach (double d in input) sum += d;
                return sum;
            }, "ForEach")
            .Add(IEnumerableForEach)
            .Add(Enumerable.Sum, "Enumerable.Sum")
            .RunTests();

        GC.Collect();

        List<int> intList = Enumerable.Range(0, Size)
                                      .Select(x => rng.Next(100))
                                      .ToList();
        int[] intArray = intList.ToArray();

        var intArraySuite = TestSuite.Create("int[]", intArray, intArray.Sum())
            .Add(input => { int sum = 0;
                for (int i = 0; i < input.Length; i++) sum += input[i];
                return sum;
            }, "For")
            .Add(input => { int sum = 0; int length = input.Length;
                for (int i = 0; i < length; i++) sum += input[i];
                return sum;
            }, "ForHoistLength")
            .Add(input => { int sum = 0;
                foreach (int d in input) sum += d;
                return sum;
            }, "ForEach")
            .Add(IEnumerableForEach)
            .Add(Enumerable.Sum, "Enumerable.Sum")
            .RunTests();

        var intListSuite = TestSuite.Create("List<int>", intList, intList.Sum())
            .Add(input => { int sum = 0;
                for (int i = 0; i < input.Count; i++) sum += input[i];
                return sum;
            }, "For")
            .Add(input => { int sum = 0; int length = input.Count;
                for (int i = 0; i < length; i++) sum += input[i];
                return sum;
            }, "ForHoistLength")
            .Add(input => { int sum = 0;
                foreach (int d in input) sum += d;
                return sum;
            }, "ForEach")
            .Add(IEnumerableForEach)
            .Add(Enumerable.Sum, "Enumerable.Sum")
            .RunTests();

        var bestDouble = BenchmarkResult.FindBest(doubleArraySuite, doubleListSuite);
        var bestInt = BenchmarkResult.FindBest(intArraySuite, intListSuite);

        Console.WriteLine("-------------------- Doubles --------------------");
        doubleArraySuite.Display(ResultColumns.NameAndScore, bestDouble);
        doubleListSuite.Display(ResultColumns.NameAndScore, bestDouble);
        Console.WriteLine("-------------------- Ints --------------------");
        intArraySuite.Display(ResultColumns.NameAndScore, bestInt);
        intListSuite.Display(ResultColumns.NameAndScore, bestInt);
    }

    static double IEnumerableForEach(IEnumerable<double> input)
    {
        double sum = 0;
        foreach (double d in input)
        {
            sum += d;
        }
        return sum;
    }
    
    static int IEnumerableForEach(IEnumerable<int> input)
    {
        int sum = 0;
        foreach (int d in input)
        {
            sum += d;
        }
        return sum;
    }
}