// /**
//  * File: Element.cs
//  * Author: haraldwolff
//  *
//  * This file and it's content is copyrighted by the Author and / or copyright holder.
//  * Any use wihtout proper permission is illegal and may lead to legal actions.
//  *
//  *
//  **/
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
namespace ln.templates.html
{
    public class Element
    {
        public string Name { get; }
        public Element Parent { get; private set; }

        public bool IsVoid => IsVoidElement(Name);

        List<Element> children = new List<Element>();
        Dictionary<string, string> attributes = new Dictionary<string, string>();
        public IEnumerable<KeyValuePair<string, string>> Attributes => attributes;

        public Element(string elementName)
        {
            Name = elementName;
        }
        public Element(string elementName,IEnumerable<KeyValuePair<string,string>> attributes)
            :this(elementName)
        {
            foreach (KeyValuePair<string, string> keyValuePair in attributes)
                this.attributes[keyValuePair.Key] = keyValuePair.Value;
        }

        public virtual bool HasAttribute(string attributeName) => attributes.ContainsKey(attributeName);
        public virtual string GetAttribute(string attributeName) => attributes[attributeName];
        public virtual void SetAttribute(string attributeName, string attributeValue) => attributes[attributeName] = attributeValue;

        public IEnumerable<Element> Children => children;
        public void AppendChild(Element element)
        {
            if (element.Parent != null)
                element.Parent.RemoveChild(element);

            if (IsVoid)
            {
                Parent.AppendChild(element);
            }
            else
            {
                children.Add(element);
                element.Parent = this;
            }
        }
        public void RemoveChild(Element element)
        {
            if (element.Parent != this)
                throw new KeyNotFoundException();

            children.Remove(element);
            element.Parent = null;
        }

        public virtual void Render(TextWriter writer)
        {
            writer.Write("<{0}", Name);
            foreach (KeyValuePair<String, String> attributePair in attributes)
                writer.Write(" {0}=\"{1}\"", attributePair.Key, attributePair.Value);
            writer.Write(">");

            if (!IsVoid)
            {
                foreach (Element element in children)
                    element.Render(writer);

                writer.Write("</{0}>",Name);
            }
        }

        public override string ToString()
        {
            StringWriter stringWriter = new StringWriter();
            Render(stringWriter);
            return stringWriter.ToString();
        }



        static HashSet<string> voidElementNames = new HashSet<string>(){
            "!doctype",
            "area", "base", "br", "col", "embed", "hr", "img", "input", "link", "meta", "param", "source", "track", "wbr"
        };
        public static string[] VoidElementNames => voidElementNames.ToArray();
        public bool IsVoidElement(string elementName) => voidElementNames.Contains(elementName);

    }
}