using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace GASi {
    public enum kType {
        STRING, INT, FLOAT, DATE, BOOL, VOID
    }

    class Conversion {
        public static kType StringToType(string str) {
            try {
                return (kType)Enum.Parse(typeof(kType), str, true);
            } catch {
                throw Transpiler.Exception("Could not determine type implied by keyword '"+ str +"'", 0, 0);
            }
        }
    }

    class ScopeTable {
        private List<Variable> Variables = new List<Variable>();

        public void AddVariable(Variable var) {
            if(!CheckVariableExists(var.Name))
                Variables.Add(var);
            else
                throw Transpiler.Exception("Variable already exists with name '" + var.Name + "' in this scope", 0, 0);
        }

        public bool CheckVariableExists(string name) {
            return Variables.FirstOrDefault(x => x.Name == name) != null;
        }

        public Variable GetVariable(string name) {
            return Variables.FirstOrDefault(x => x.Name == name);
        }

        public class Variable {
            public string Name { get; set; }
            public kType Type { get; set; }
        }
    }

    class MethodTable {
        private List<Method> Methods = new List<Method>();

        public void AddMethod(Method method) {
            // TODO determine if GAS allows function overloading
            if(!CheckMethodExists(method.Name))
                Methods.Add(method);
            else
                throw Transpiler.Exception("Method already exists with name '" + method.Name + "'", 0, 0);
        }

        public bool CheckMethodExists(string name) {
            return Methods.FirstOrDefault(x => x.Name == name) != null;
        }

        public Method GetMethod(string name) {
            return Methods.FirstOrDefault(x => x.Name == name);
        }

        public class Method {
            public string Name { get; set; }
            public kType ReturnType { get; set; }
            public List<Argument> Arguments { get; set; }
            public ScopeTable Scope { get; set; } = new ScopeTable();

            public class Argument {
                public string Name { get; set; }
                public kType Type { get; set; }
            }
        }
    }
}