Add new Backend structure with proper .NET 8 projects

src/Backend/DiunaBI.Core/Services/Calculations/BaseCalc.cs

@@ -0,0 +1,146 @@
+using System;
+using System.Collections.Generic;
+using System.Globalization;
+using System.Linq;
+using AngouriMath;
+using DiunaBI.Core.Models;
+
+namespace DiunaBI.Core.Services.Calculations;
+
+public class BaseCalc
+{
+    public string Expression { get; }
+    private string ResultCode { get; set; }
+    private string Formula { get; }
+
+    public BaseCalc(string expression)
+    {
+        Expression = expression;
+        Formula = Expression.Split("=")[1];
+        ResultCode = Expression.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
+        return !string.IsNullOrEmpty(Formula) &&
+            Formula.All(c => char.IsDigit(c) || c == '[' || c == ']' || c == '+' || c == '-');
+    }
+
+    public Record CalculateT3(List<Record> records)
+    {
+        var resultCode = ResultCode;
+        {
+            var result = new Record
+            {
+                Id = Guid.NewGuid(),
+                Code = resultCode,
+                CreatedAt = DateTime.UtcNow,
+                ModifiedAt = DateTime.UtcNow
+            };
+            var codes = GetCodes();
+            var ingredients = new List<Record>();
+            foreach (var code in codes)
+            {
+                var ingredient = records.FirstOrDefault(r => r.Code == code);
+                if (ingredient == null)
+                {
+                    throw new Exception($"Record for code {code} not found.");
+                }
+
+                ingredients.Add(ingredient);
+            }
+
+            for (var i = 1; i <= 32; i++)
+            {
+                var formula = ingredients.Aggregate(Formula,
+                    (current, ingredient) => current.Replace($"[{ingredient.Code}]",
+                        ProcessHelper.GetValue(ingredient, i)?.ToString(CultureInfo.InvariantCulture)));
+                if (formula.Contains('['))
+                {
+                    throw new Exception($"Not all placeholders were replaced. Value{i} [{formula}]");
+                }
+
+                Entity expr = formula;
+                ProcessHelper.SetValue(result, i, (double)expr.EvalNumerical());
+            }
+
+            return result;
+        }
+    }
+
+    public Record CalculateT1(List<Record> records)
+    {
+        var resultCode = ResultCode;
+        {
+            var result = new Record
+            {
+                Id = Guid.NewGuid(),
+                Code = resultCode,
+                CreatedAt = DateTime.UtcNow,
+                ModifiedAt = DateTime.UtcNow
+            };
+            var codes = GetCodes();
+            var ingredients = new List<Record>();
+            foreach (var code in codes)
+            {
+                var ingredient = records.FirstOrDefault(r => r.Code == code);
+                if (ingredient == null)
+                {
+                    throw new Exception($"Record for code {code} not found.");
+                }
+
+                ingredients.Add(ingredient);
+            }
+
+
+            var formula = ingredients.Aggregate(Formula,
+                (current, ingredient) => current.Replace($"[{ingredient.Code}]",
+                    ProcessHelper.GetValue(ingredient, 32)?.ToString(CultureInfo.InvariantCulture)));
+            if (formula.Contains('['))
+            {
+                throw new Exception($"Not all placeholders were replaced. Value{1} [{formula}]");
+            }
+
+            Entity expr = formula;
+            ProcessHelper.SetValue(result, 32, (double)expr.EvalNumerical());
+
+            return result;
+        }
+    }
+
+    private List<string> GetCodes()
+    {
+        var codes = new List<string>();
+        var endIndex = -1;
+
+        while (true)
+        {
+            var startIndex = Formula.IndexOf("[", endIndex + 1, StringComparison.CurrentCulture);
+            endIndex = Formula.IndexOf("]", startIndex + 1, StringComparison.CurrentCulture);
+
+            if (startIndex == -1 || endIndex == -1)
+            {
+                break;
+            }
+
+            var valueCode = Formula.Substring(startIndex + 1, endIndex - startIndex - 1);
+            codes.Add(valueCode);
+        }
+
+        return codes;
+    }
+}