using System;
using Newtonsoft.Json.Linq;

namespace tlang
{
    public class TInternalMethod : TObject, ICallable
    {
         public override JToken AsToken()
        {
            return new JValue((object)null);
        }
        public override bool AsBoolean => true;
        public TInternalMethod(ClosureNode node,IScopeEnvironment env)
        {
            Body = node;
            Environment = env;
        }
        public ClosureNode Body {get;set;}
        public IScopeEnvironment Environment {get;set;}
        public TObject Call(params TObject[] args)
        {
            var env=Environment.SubEnv;
            int argCountClosure = Body.Arguments.Count;
            int argCountCaller = args.Length;
            if(argCountCaller < requiredArguments())
            {
                throw new Exception("not enough arguments");
            }
            int i = 0;
            for(;i<optionalArgs(args.Length);i++)
            {
                env[Body.Arguments[i].TrimStart('$')] = args[i];
            }
            if(i==Body.Arguments.Count-1)
            {
                var tarray = TObject.Array();
                env[Body.Arguments[i].TrimStart('$')] =tarray;
                for(int j = i;j<args.Length;j++)
                {
                    tarray.Items.Add(args[j]);
                }
                i = args.Length;
            }
            if(i<args.Length)
                throw new Exception("too many arguments");
            return Body.Node.Execute(env);
        }
        private int optionalArgs(int argLen)
        {
            
            for(int i =0;i<Body.Arguments.Count;i++)
            {
                if(Body.Arguments[i].StartsWith("$$"))
                {
                    return Math.Min(argLen,i);
                }
            }
            return Math.Min(argLen,Body.Arguments.Count);
        }
        private int requiredArguments()
        {
            for(int i =0;i<Body.Arguments.Count;i++)
            {
                if(Body.Arguments[i].StartsWith("$"))
                {
                    return i;
                }
            }
            return Body.Arguments.Count;
        }
        
    }
    public class TExternalMethod : TObject,ICallable
    {
         public override JToken AsToken()
        {
            return new JValue((object)null);
        }
        Func<TObject[],TObject> cb;
        public TExternalMethod(Func<TObject[],TObject> func)
        {
            cb = func;
        }

        public TExternalMethod(Action<TObject[]> func)
        {
            cb = (args)=>{
                func(args);
                return Uninit;
            };
        }
        public TExternalMethod(Func<TObject> func)
        {
            cb = (args)=>{
                return func();
            };
        }
        public TExternalMethod(Action func)
        {
            cb = (args)=>{
                func();
                return Uninit;
            };
        }
        
        public override bool AsBoolean => true;

        public TObject Call(params TObject[] args)
        {
            return cb(args);
        }
        

    }

    public interface ICallable
    {
        TObject Call(params TObject[] args);
    }
}