Cis/EC.Helper/RabbitFunc/Expressions/BinaryExpression.cs

using EC.Helper.RabbitFunc.Runtime;
using System.Text;

namespace EC.Helper.RabbitFunc.Expressions;

public class BinaryExpression : Expression
{
    internal BinaryExpression(ExpressionType nodeType, Expression left, Expression right)
        : base(nodeType)
    {
        Left = left;
        Right = right;
    }

    public Expression Left { get; }

    public Expression Right { get; }

    public override object Eval(RuntimeContext context)
    {
        if (context == null)
            throw new ArgumentNullException(nameof(context));

        var leftResult = Left.Eval(context);
        var rightResult = Right.Eval(context);
        return NodeType switch
        {
            ExpressionType.Add => System.Convert.ToDouble(leftResult) + System.Convert.ToDouble(rightResult),
            ExpressionType.Subtract => System.Convert.ToDouble(leftResult) - System.Convert.ToDouble(rightResult),
            ExpressionType.Multiply => System.Convert.ToDouble(leftResult) * System.Convert.ToDouble(rightResult),
            ExpressionType.Divide => System.Convert.ToDouble(leftResult) / System.Convert.ToDouble(rightResult),
            ExpressionType.Modulo => System.Convert.ToDouble(leftResult) % System.Convert.ToDouble(rightResult),
            ExpressionType.Power => Math.Pow(System.Convert.ToDouble(leftResult), System.Convert.ToDouble(rightResult)),
            ExpressionType.LessThan => System.Convert.ToDouble(leftResult) < System.Convert.ToDouble(rightResult),
            ExpressionType.LessThanOrEqual => System.Convert.ToDouble(leftResult) <= System.Convert.ToDouble(rightResult),
            ExpressionType.Equal => leftResult is bool ? System.Convert.ToBoolean(leftResult) == System.Convert.ToBoolean(rightResult) : System.Convert.ToDouble(leftResult) == System.Convert.ToDouble(rightResult),
            ExpressionType.GreaterThanOrEqual => System.Convert.ToDouble(leftResult) >= System.Convert.ToDouble(rightResult),
            ExpressionType.GreaterThan => System.Convert.ToDouble(leftResult) > System.Convert.ToDouble(rightResult),
            ExpressionType.NotEqual => leftResult is bool ? System.Convert.ToBoolean(leftResult) != System.Convert.ToBoolean(rightResult) : System.Convert.ToDouble(leftResult) != System.Convert.ToDouble(rightResult),
            _ => throw new RuntimeException("unknown operator:" + NodeType.ToString()),
        };
    }

    public override string ToString()
    {
        var sb = new StringBuilder();
        if (Left is BinaryExpression)
        {
            sb.Append('(');
            sb.Append(Left.ToString());
            sb.Append(')');
        }
        else
        {
            sb.Append(Left.ToString());
        }
        switch (NodeType)
        {
            case ExpressionType.Add:
                sb.Append('+');
                break;

            case ExpressionType.Subtract:
                sb.Append('-');
                break;

            case ExpressionType.Multiply:
                sb.Append('*');
                break;

            case ExpressionType.Divide:
                sb.Append('/');
                break;

            case ExpressionType.Modulo:
                sb.Append('%');
                break;

            case ExpressionType.Power:
                sb.Append('^');
                break;

            case ExpressionType.LessThan:
                sb.Append('<');
                break;

            case ExpressionType.LessThanOrEqual:
                sb.Append("<=");
                break;

            case ExpressionType.Equal:
                sb.Append("==");
                break;

            case ExpressionType.GreaterThanOrEqual:
                sb.Append(">=");
                break;

            case ExpressionType.GreaterThan:
                sb.Append('>');
                break;

            case ExpressionType.NotEqual:
                sb.Append("!=");
                break;

            default:
                throw new RuntimeException("unknown operator:" + NodeType.ToString());
        }
        if (Right is BinaryExpression)
            sb.Append('(');

        sb.Append(Right.ToString());
        if (Right is BinaryExpression)
            sb.Append(')');

        return sb.ToString();
    }
}