DiunaBI/WebAPI/Calculators/BaseCalc.cs

using System.Globalization;
using DiunaBIWebAPI.dataProcessors;
using WebAPI.Models;
using AngouriMath;
using AngouriMath.Extensions;

namespace WebAPI.Calculator
{
    public class BaseCalc
    {
        public string Expresion { get; set; }
        
        private string ResultCode { get; set; }
        private string Formula { get; set; }

        public BaseCalc(string expresion)
        {
            Expresion = expresion;
            Formula = Expresion.Split("=")[1];
            ResultCode = Expresion.Split("=")[0];
        }

        public bool IsFormulaCorrect()
        {
            // check left side of expression
            if (!ResultCode.StartsWith("[") || !ResultCode.EndsWith("]"))
            {
                return false;
            }
            if (!ResultCode.Substring(1, ResultCode.Length - 2).All(char.IsDigit))
            {
                return false;
            }

            ResultCode = ResultCode.Substring(1, ResultCode.Length - 2);
            
            // check right side of expression
            if (!(!string.IsNullOrEmpty(Formula) &&
                Formula.All(c => char.IsDigit(c) || c == '[' || c == ']' || c == '+')))
            {
                return false;
            }
            
            return true;
        }

        public Record CalculateT3(List<Record> records)
        {
            Record result = new Record
            {
                Id = Guid.NewGuid(),
                Code = this.ResultCode,
                CreatedAt = DateTime.UtcNow,
                ModifiedAt = DateTime.UtcNow,
            };
            List<string> codes = GetCodes();
            List<Record> ingredients = new List<Record>();
            foreach (string code in codes)
            {
                Record? ingredient = records.FirstOrDefault(r => r.Code == code);
                if (ingredient == null)
                {
                    throw new Exception($"Record for code {code} not found.");
                }
                ingredients.Add(ingredient);
            }
            
            for (int i = 1; i <= 32; i++)
            {
                string formula = Formula;
                foreach (Record ingredient in ingredients)
                {
                    formula = formula.Replace($"[{ingredient.Code}]", ProcessHelper.getValue(ingredient, i)?.ToString(CultureInfo.InvariantCulture));
                }
                if (formula.Contains("["))
                {
                    throw new Exception($"Not all placeholders were replaced. Value{i} [{formula}]");
                }

                Entity expr = formula;
                double val = (double)expr.EvalNumerical();
                ProcessHelper.setValue(result, i, (double)expr.EvalNumerical());
            }
            return result;
        }

        private List<string> GetCodes()
        {
            List<string> codes = new List<string>();
            int endIndex = -1;

            while (true)
            {
                int startIndex = Formula.IndexOf("[", endIndex + 1, StringComparison.CurrentCulture);
                endIndex = Formula.IndexOf("]", startIndex + 1, StringComparison.CurrentCulture);

                if (startIndex == -1 || endIndex == -1)
                {
                    break;
                }

                string valueCode = Formula.Substring(startIndex + 1, endIndex - startIndex - 1);
                codes.Add(valueCode);
            }
            return codes;
        }
    }
}