Hastlayer-SDK

using System.Reflection;

namespace System.Linq.Expressions
{
    public static class ExpressionExtensions
    {
        /// <summary>
        /// Gets the full name (namespace, type name, method name, return type and argument types) of an instance method
        /// called in an expression.
        /// </summary>
        /// <typeparam name="T">The type of the method's object.</typeparam>
        /// <param name="expression">An expression with a call to the method.</param>
        public static string GetMethodFullName<T>(this Expression<Action<T>> expression) =>
            expression.GetInvokedMethodInfo().GetFullName();

        /// <summary>
        /// Gets the full name (namespace, type name, method name) of an instance method called in an expression.
        /// </summary>
        /// <typeparam name="T">The type of the method's object.</typeparam>
        /// <param name="expression">An expression with a call to the method.</param>
        public static string GetMethodSimpleName<T>(this Expression<Action<T>> expression)
        {
            var methodInfo = expression.GetInvokedMethodInfo();
            return methodInfo.DeclaringType.FullName + "." + methodInfo.Name;
        }

        private static MethodInfo GetInvokedMethodInfo<T>(this Expression<Action<T>> expression)
        {
            // Since we need a specific method (i.e. if there are multiple overloads of it, then still one of them)
            // this can't be simpler than requiring an expression.

            if (expression.Body is not MethodCallExpression methodCallExpression)
            {
                throw new InvalidOperationException("The supplied expression is not a method call.");
            }

            return methodCallExpression.Method;
        }
    }
}