using Canon.Core.Enums;

namespace Canon.Core.SyntaxNodes;

public class VarDeclaration : NonTerminatedSyntaxNode
{
    public override NonTerminatorType Type => NonTerminatorType.VarDeclaration;

    public bool IsRecursive { get; private init; }

    /// <summary>
    /// 声明的变量
    /// </summary>
    public (IdentifierList, TypeSyntaxNode) Variable => GetVariable();

    private (IdentifierList, TypeSyntaxNode) GetVariable()
    {
        if (IsRecursive)
        {
            return (Children[2].Convert<IdentifierList>(), Children[4].Convert<TypeSyntaxNode>());
        }
        else
        {
            return (Children[0].Convert<IdentifierList>(), Children[2].Convert<TypeSyntaxNode>());
        }
    }

    public static VarDeclaration Create(List<SyntaxNodeBase> children)
    {
        bool isRecursive;

        if (children.Count == 3)
        {
            isRecursive = false;
        }
        else if (children.Count == 5)
        {
            isRecursive = true;
        }
        else
        {
            throw new InvalidOperationException();
        }

        return new VarDeclaration { Children = children, IsRecursive = isRecursive };
    }
}