#nullable enable

​

using System;

using System.Linq;

using System.Collections.Generic;

using NCalc;

​

public class ExerciseRequest {

    public class Award {

        public AwardExerciseConfig ExerciseConfig { get; set; }

        public AwardShareClass ShareClass { get; set; }

    }

    public class AwardShareClass {

        public string Name { get; set; }

        public decimal? ParValue { get; set; }

    }

    public class AwardExerciseConfig {

        public string? MinExercisePrice { get; set; }

        public string? MaxExercisePrice { get; set; }

        public string? MinExerciseAmount { get; set; }

        public string? MaxExerciseAmount { get; set; }

        public decimal ConversionRatio { get; set; }

    }

    // all the formulae (explicit and implicit) get converted to values

    public record Computations {

        // TODO: What about currency?

        // Tax by Award, etc.

        public IReadOnlyList<AwardComputations> Awards { get; init; }

        // TotalTax

        // TotalExerciseAmount

        // SharesToBeIssuedByShareClass  -> Dictionary<string, decimal> ??

    }

    public record AwardComputations {

        public PriceRange ExercisePrice { get; init; }

        public PriceRange ExerciseAmount { get; init; }

        public string ShareClass { get; init; }

        public decimal? SharesToIssue { get; init; }

        public decimal? SharesParValueAmount { get; init; }

        // Tax Amount

        // Charges

        // etc., etc., etc.

    }

    // todo: ensure that min <= max

    public record PriceRange(decimal? Min, decimal? Max){

        public bool IsInRange(decimal value) {

            return false;

        }

        public override string ToString(){

            return $"[{Min}, {Max}]";   

        }

    }

    public DateOnly Date { get; set; }

    public List<Award> Awards { get; set; }

    public Computations GetComputations(){

        var awardComputations = Awards.Select(GetAwardComputations).ToArray();

        return new Computations{

            Awards = awardComputations

        };

    }

    private AwardComputations GetAwardComputations(Award award){

        ArgumentNullException.ThrowIfNull(award);

        decimal? minExercisePrice = Evaluate(award, award.ExerciseConfig.MinExercisePrice);

        decimal? maxExercisePrice = Evaluate(award, award.ExerciseConfig.MaxExercisePrice);

        PriceRange exercisePriceRange = new PriceRange(minExercisePrice, maxExercisePrice);

        decimal? minExerciseAmount = Evaluate(award, award.ExerciseConfig.MinExerciseAmount);

        decimal? maxExerciseAmount = Evaluate(award, award.ExerciseConfig.MaxExerciseAmount);

        PriceRange exerciseAmountRange = new PriceRange(minExerciseAmount, maxExerciseAmount);

        return new AwardComputations {

            ExercisePrice = exercisePriceRange,

            ExerciseAmount = exerciseAmountRange

        };

    }

    private decimal? Evaluate(Award? award, string formula){

        decimal? result = default;

        if(string.IsNullOrWhiteSpace(formula)){

            return result;

        }

        var expression = new Expression(formula);

        ConfigureParameters(award, expression);

        var evaluationResult = expression.Evaluate();

        result = Convert.ToDecimal(evaluationResult);

        return result;

    }

    private void ConfigureParameters(Award? award, Expression expression){

        // load the parameters

        // expression.Parameters["ExerciseDate"] = request.Date;

        expression.Parameters["ShareClass.ParValue"] = award?.ShareClass.ParValue;

        expression.Parameters["ConversionRatio"] = award?.ExerciseConfig.ConversionRatio;

    }

}

​

public class Program

{

    public static void Main()

    {

        var request1 = new ExerciseRequest {

            Date = new DateOnly(2024, 08, 15),

            Awards = [

                new ExerciseRequest.Award {

                    ShareClass = new ExerciseRequest.AwardShareClass{

                        Name = "Ordinary",

                        ParValue = 10m

                    },

                    ExerciseConfig = new ExerciseRequest.AwardExerciseConfig {

                        ConversionRatio = 3,

                        MinExercisePrice = "[ShareClass.ParValue] * [ConversionRatio]"

                    }

                }

            ]

        };

        ProcessRequest(request1);

        /*

        var expression = new Expression("2 * [ShareClass.ParValue]");

        expression.Parameters["ShareClass.ParValue"] = 10.0m;

        Console.WriteLine("value=" + expression.Evaluate());

        */

    }

    private static void ProcessRequest(ExerciseRequest request){

        ArgumentNullException.ThrowIfNull(request);

        // we might have to pass currency conversion service, fmv service, etc. to the GetComputations method

        var requestComputations = request.GetComputations();

        foreach(var award in requestComputations.Awards){

            Console.WriteLine("ExercisePrice=" + award.ExercisePrice);

            Console.WriteLine("ExerciseAmount=" + award.ExerciseAmount);

        }

    }

}