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

namespace Upsilon.Binder.VariableSymbols
{
    public abstract class  FunctionVariableSymbol : VariableSymbol
    {
        public List<FunctionVariableSymbolOption> FunctionOption { get; protected set; } = new List<FunctionVariableSymbolOption>();
        public bool IsCoroutine { get; }

        public FunctionVariableSymbol(string name, bool local, bool isCoroutine)
            : base(name, Type.Function, local)
        {
            IsCoroutine = isCoroutine;
        }

        public abstract bool ValidateParameters(
            ImmutableArray<BoundExpression> callingParameters);

        public FunctionVariableSymbolOption GetFirstValid(TypeContainer[] types)
        {
            return FunctionOption.FirstOrDefault(x =>
            {
                var parTypes = x.GetParameterTypes();
                for (var i = 0; i < parTypes.Length; i++)
                {
                    var parType   = parTypes[i];
                    var givenType = types[i];
                    if (parType == Type.Unknown || givenType == Type.Unknown)
                        continue;
                    if (!parType.Type.HasFlag(givenType))
                        return false;
                }
                return true;
            });
        }
    }

    public abstract class FunctionVariableSymbolOption
    {
        public FunctionVariableSymbolOption(TypeContainer resultType)
        {
            ResultType = resultType;
        }

        public abstract TypeContainer[] GetParameterTypes();
        public TypeContainer ResultType { get; internal set; }
    }
}