using System;
using System.Linq;
using System.Linq.Expressions;
using System.Reflection;

namespace IrcStates
{
    public static class Extensions
    {
        public static Delegate CreateDelegate(this MethodInfo methodInfo, object target)
        {
            if (methodInfo == null) return null;

            var types = methodInfo.GetParameters().Select(p => p.ParameterType);

            Func<Type[], Type> getType;
            if (methodInfo.ReturnType == typeof(void))
            {
                getType = Expression.GetActionType;
            }
            else
            {
                getType = Expression.GetFuncType;
                types   = types.Concat(new[] {methodInfo.ReturnType});
            }

            return methodInfo.IsStatic
                ? Delegate.CreateDelegate(getType(types.ToArray()), methodInfo)
                : Delegate.CreateDelegate(getType(types.ToArray()), target, methodInfo);
        }
    }
}