using System.Collections.Generic;
using System.Linq;
using Upsilon.BaseTypes;

namespace Upsilon.Binder
{
    public class BoundScope
    {
        private readonly BoundScope _parentScope;
        private readonly Dictionary<string, VariableSymbol> _variables;

        public BoundScope(BoundScope parentScope)
        {
            _parentScope = parentScope;
            _variables   = new Dictionary<string, VariableSymbol>();
        }
        public BoundScope(Dictionary<VariableSymbol, LuaType> variables, BoundScope parentScope)
        {
            _parentScope = parentScope;
            _variables = variables.ToDictionary(x => x.Key.Name, x => x.Key);
        }

        public void SetVariable(VariableSymbol var)
        {
            if (_variables.ContainsKey(var.Name))
                _variables[var.Name] = var;
            else
                _variables.Add(var.Name, var);
        }

        public void SetGlobalVariable(VariableSymbol var)
        {
            if (_parentScope == null)
            {
                SetVariable(var);
            }
            else
            {
                _parentScope.SetGlobalVariable(var);
            }
        }


        public bool TryGetVariable(string key, out VariableSymbol result)
        {
            if (_variables.TryGetValue(key, out result))
            {
                return true;
            }
            if (_parentScope != null)
            {
                return _parentScope.TryGetVariable(key, out result);
            }
            return false;
        }

    }
}