using System;
using System.Collections.Generic;
using System.Linq;
using Upsilon.BaseTypes.Number;
using Upsilon.BaseTypes.ScriptTypeInterfaces;
using Upsilon.Binder.VariableSymbols;
using Upsilon.Evaluator;
using Upsilon.Text;

namespace Upsilon.BaseTypes.ScriptTable
{
    public abstract class ScriptTable : ScriptType, IIndexable, IScopeOwner, IIterable, ILengthType
    {
        public EvaluationScope EvaluationScope { get; }

        public ScriptTable(EvaluationScope scope)
        {
            EvaluationScope = scope;
        }

        public override TypeContainer Type => BaseTypes.Type.Table;

        public ScriptType Get(Diagnostics diagnostics, TextSpan span, ScriptType index, EvaluationScope scope)
        {
            var s = index.ToString();
            if (EvaluationScope.TryGet(s, out var o))
            {
                return o;
            }
            return new ScriptNull();
        }

        public void Set(Diagnostics diagnostics, TextSpan span, ScriptType index, ScriptType value)
        {
            var s = index.ToString();
            if (value.Type == BaseTypes.Type.Nil)
            {
                EvaluationScope.Delete(s);
                return;
            }
            EvaluationScope.CreateLocal(new VariableSymbol(s, value.Type, false), value);
        }


        public ScriptType GetValueFromIndex(ScriptType index)
        {
            if (EvaluationScope.TryGet(index.ToString(), out var result))
            {
                return result;
            }
            return new ScriptNull();
        }

        public abstract IEnumerator<ScriptType> GetScriptEnumerator();
        public abstract bool Contains(ScriptType obj);
        public void Delete(ScriptType key)
        {
            EvaluationScope.Delete(key.ToString());
        }

        public ScriptNumberLong Length()
        {
            return new ScriptNumberLong(EvaluationScope.Variables.Count);
        }
    }
}