src/ClothesGraph.Model/Formulas/FormulaFunctions.cs - main - docNemo/clothes-graph

src/ClothesGraph.Model/Formulas/FormulaFunctions.cs
88 строк3 KB
docNemo
Фундамент продукта: параметрическое построение выкроек, печать, установщик
08 авг 2026, 22:17
08 авг 2026, 22:17cd47cce
using System;
using System.Collections.Generic;

namespace ClothesGraph.Model.Formulas;

/// <summary>
/// Функции и константы, доступные в формулах.
/// </summary>
/// <remarks>
/// Тригонометрия принимает и возвращает градусы: конструктор мыслит углами
/// чертежа, а не радианами, и перевод в каждой формуле был бы лишним шумом.
/// </remarks>
public static class FormulaFunctions
{
    private static readonly Dictionary<string, (int MinArguments, int MaxArguments, Func<double[], double> Apply)>
        Functions = new(StringComparer.CurrentCultureIgnoreCase)
        {
            ["sin"] = (1, 1, a => Math.Sin(ToRadians(a[0]))),
            ["cos"] = (1, 1, a => Math.Cos(ToRadians(a[0]))),
            ["tan"] = (1, 1, a => Math.Tan(ToRadians(a[0]))),
            ["asin"] = (1, 1, a => ToDegrees(Math.Asin(a[0]))),
            ["acos"] = (1, 1, a => ToDegrees(Math.Acos(a[0]))),
            ["atan"] = (1, 1, a => ToDegrees(Math.Atan(a[0]))),
            ["atan2"] = (2, 2, a => ToDegrees(Math.Atan2(a[0], a[1]))),
            ["sqrt"] = (1, 1, a => Math.Sqrt(a[0])),
            ["abs"] = (1, 1, a => Math.Abs(a[0])),
            ["min"] = (2, int.MaxValue, Min),
            ["max"] = (2, int.MaxValue, Max),
            ["round"] = (1, 2, a => Math.Round(a[0], a.Length > 1 ? (int)a[1] : 0,
                MidpointRounding.AwayFromZero)),
            ["floor"] = (1, 1, a => Math.Floor(a[0])),
            ["ceil"] = (1, 1, a => Math.Ceiling(a[0])),
            ["sign"] = (1, 1, a => Math.Sign(a[0]))
        };

    private static readonly Dictionary<string, double> Constants =
        new(StringComparer.CurrentCultureIgnoreCase)
        {
            ["pi"] = Math.PI,
            ["e"] = Math.E
        };

    public static bool IsFunction(string name) => Functions.ContainsKey(name);

    public static bool TryGetConstant(string name, out double value)
        => Constants.TryGetValue(name, out value);

    public static bool TryGetArity(string name, out int minimum, out int maximum)
    {
        if (Functions.TryGetValue(name, out var function))
        {
            minimum = function.MinArguments;
            maximum = function.MaxArguments;
            return true;
        }

        minimum = maximum = 0;
        return false;
    }

    public static double Apply(string name, double[] arguments)
        => Functions.TryGetValue(name, out var function)
            ? function.Apply(arguments)
            : throw new InvalidOperationException($"Неизвестная функция «{name}»");

    private static double Min(double[] values)
    {
        var result = values[0];
        foreach (var value in values)
            if (value < result)
                result = value;

        return result;
    }

    private static double Max(double[] values)
    {
        var result = values[0];
        foreach (var value in values)
            if (value > result)
                result = value;

        return result;
    }

    private static double ToRadians(double degrees) => degrees * Math.PI / 180.0;
    private static double ToDegrees(double radians) => radians * 180.0 / Math.PI;
}