ln.templates/ln.templates/RecursiveResolver.cs

using System;
using System.Collections.Generic;
using System.IO;
using Esprima.Ast;
using ln.templates.html;

namespace ln.templates;

public class RecursiveResolver : ITemplateResolver
{
    public RecursiveResolver(string path)
    :this(null, path)
    {
    }
    
    private RecursiveResolver(RecursiveResolver parent, string path)
    {
        Parent = parent;
        Path = path;
        if (!Directory.Exists(path))
            throw new DirectoryNotFoundException(path);
    }
    
    public RecursiveResolver Root => Parent?.Root ?? this;
    public RecursiveResolver Parent { get; private set; }
    public string Path { get; private set; }

    private bool IsAlive => Directory.Exists(Path);

    private Dictionary<string, RecursiveResolver> _children = new Dictionary<string, RecursiveResolver>();
    private Dictionary<string, Template> _templates = new Dictionary<string, Template>();


    public RecursiveResolver FindResolver(string path) => FindResolver(
        System.IO.Path.GetDirectoryName(path)?.Split(System.IO.Path.PathSeparator) ?? Array.Empty<string>());
    private RecursiveResolver FindResolver(Span<string> pathElements)
    {
        if (pathElements.Length == 0)
            throw new ArgumentOutOfRangeException(nameof(pathElements));
        
        if (_children.TryGetValue(pathElements[0], out RecursiveResolver child))
        {
            if (!child.IsAlive)
            {
                _children.Remove(pathElements[0]);
                return null;
            }
            if (pathElements.Length > 1)
                return child.FindResolver(pathElements.Slice(1));
            return child;
        }

        return null;
    }
    
    
    public Template GetTemplateByPath(string templatePath)
    {
        Span<string> pathElements = templatePath.Split(System.IO.Path.DirectorySeparatorChar);
        RecursiveResolver resolver = FindResolver(pathElements.Slice(0, pathElements.Length - 1));
        return resolver?.GetTemplate(pathElements[^1]);
    }

    public Template GetTemplate(string name)
    {
        string filename = System.IO.Path.Combine(Path, name);
        if (File.Exists(filename))
        {
            if (!_templates.TryGetValue(name, out Template template))
            {
                template = new Template(filename, this);
                _templates.Add(name, template);
            }

            return template;
        }

        return null;
    }
    
    
}