using System;

using System.Collections.Generic;

using System.Linq;

​

public class Program

{

    public static void Main()

    {

        List<ReviewCalculationKpa> ratings = [new()

        {

            Weighting = 6,

            Kpis = [new()

            {

                Weighting = 6,

                Rating = 3

            }

​

            ]

        }, new()

        {

            Weighting = 2,

            Kpis = [new()

            {

                Weighting = 2,

                Rating = 5

            }

​

            ]

        }, new()

        {

            Weighting = 40,

            Kpis = [new()

            {

                Weighting = 30,

                Rating = 3

            }, new()

            {

                Weighting = 5,

                Rating = 4

            }, new()

            {

                Weighting = 2.5m,

                Rating = 5

            }, new()

            {

                Weighting = 2.5m,

                Rating = 5

            }

​

            ]

        }, new()

        {

            Weighting = 10,

            Kpis = [new()

            {

                Weighting = 10,

                Rating = 5

            }

​

            ]

        }

​

        ];

        Test(ratings);

    }

​

    public static void Test(List<ReviewCalculationKpa> projectBasedKpas)

    {

        decimal kpaWeightSum = projectBasedKpas.Sum(x => x.Weighting);

        decimal avgRating = projectBasedKpas.Select(kpa =>

        {

            try

            {

                return kpa.Kpis.Sum((kpi) =>

                {

                    // sum kpi weighted scores

                    var rating = kpi.Rating;

                    try

                    {

                        return (int)rating * (kpi.Weighting / kpa.Weighting);

                    }

                    catch (DivideByZeroException)

                    {

                        return 0;

                    }

                }) * kpa.Weighting / kpaWeightSum;

            }

            catch (DivideByZeroException)

            {

                return 0;

            }

        }).Sum(x => x);

        Console.WriteLine(avgRating);

    }

​

    public class ReviewCalculationKpa

    {

        public decimal Weighting { get; set; }

        public ICollection<ReviewCalculationKpi> Kpis { get; set; } = new List<ReviewCalculationKpi>();

    }

​

    public class ReviewCalculationKpi

    {

        public int Rating { get; set; }

        public decimal Weighting { get; set; }

    }

}