using Nub.Lang.Frontend.Lexing;

namespace Nub.Lang.Frontend.Parsing;

public interface IFuncSignature
{
    public string Name { get; }
    public List<FuncParameter> Parameters { get; }
    public Optional<NubType> ReturnType { get; }

    public bool SignatureMatches(string name, List<NubType> parameters)
    {
        if (Name != name) return false;
        if (Parameters.Count == 0 && parameters.Count == 0) return true;
        if (Parameters.Count > parameters.Count) return false;
            
        for (var i = 0; i < parameters.Count; i++)
        {
            if (i > Parameters.Count)
            {
                if (Parameters[^1].Variadic)
                {
                    if (!NubType.IsCompatibleWith(parameters[i], Parameters[^1].Type))
                    {
                        return false;
                    }
                }
                else
                {
                    return false;
                }
            }
            else if (!NubType.IsCompatibleWith(parameters[i], Parameters[i].Type))
            {
                return false;
            }
        }
            
        return true;
    }

    public string ToString() => $"{Name}({string.Join(", ", Parameters.Select(p => p.ToString()))}){(ReturnType.HasValue ? ": " + ReturnType.Value : "")}";
}

public class LocalFuncDefinitionNode(IReadOnlyList<Token> tokens, Optional<string> documentation, string name, List<FuncParameter> parameters, BlockNode body, Optional<NubType> returnType, bool global) : DefinitionNode(tokens, documentation), IFuncSignature
{
    public string Name { get; } = name;
    public List<FuncParameter> Parameters { get; } = parameters;
    public BlockNode Body { get; } = body;
    public Optional<NubType> ReturnType { get; } = returnType;
    public bool Global { get; } = global;

    public override string ToString() => $"{Name}({string.Join(", ", Parameters.Select(p => p.ToString()))}){(ReturnType.HasValue ? ": " + ReturnType.Value : "")}";
}

public class ExternFuncDefinitionNode(IReadOnlyList<Token> tokens, Optional<string> documentation, string name, List<FuncParameter> parameters, Optional<NubType> returnType) : DefinitionNode(tokens, documentation), IFuncSignature
{
    public string Name { get; } = name;
    public List<FuncParameter> Parameters { get; } = parameters;
    public Optional<NubType> ReturnType { get; } = returnType;

    public override string ToString() => $"{Name}({string.Join(", ", Parameters.Select(p => p.ToString()))}){(ReturnType.HasValue ? ": " + ReturnType.Value : "")}";
}