class ENode{
  constructor(tag){
    this.__tag = tag;
    this.__classes = [];
    this.__attribs = [];
    this.__children = [];
  }

  appendChild(c){
    var val = (c instanceof ENode) ? c : c.toString();
    this.__children.push(c);
    return this;
  }

  addClass(cname){
    this.__classes.push(cname);
  }

  addAttribute(aname, aval){
    this.__attribs.push([aname, aval]);
  }

  toString(){
    var r = "<" + this.__tag.toUpperCase();
    if (this.__classes.length > 0){
      var cls = this.__classes.reduce(function(a, c){
        c = c.split(" ");
        for (var i=0; i < c.length; i++){
          c[i] = c[i].trim();
          a += ((a !== "" && c[i].length > 0) ? " " : "") + c[i];
        }
        return a;
      }, "");
      r += " class=\"" + cls + "\"";
    }

    if (this.__attribs.length > 0){
      var attr = this.__attribs.reduce(function(a, at){
        a += ((a !== "") ? " " : "") + at[0].trim() + "=\"" + at[1] + "\"";
        return a;
      }, "");
      r += " " + attr;
    }

    if (this.__children.length > 0){
      r += ">";
      r += this.__children.reduce(function(a, c){
        if (c instanceof ENode){
          a += c.toString() + "\n";
        } else {
          a += c;
        }
        return a;
      }, "");
      r += "</" + this.__tag.toUpperCase() + ">";
    } else {
      r += " />";
    }
    return r;
  }
}


function appendCTX(el, ctx){
  el.appendChild((ctx instanceof ENode) ? ctx : ctx.toString());
}

function el(ename, ctx, cls, attr){
  var e = new ENode(ename);
  if (ctx){
    if (ctx instanceof Array){
      ctx.forEach(item => appendCTX(e, item));
    } else {
      appendCTX(e, ctx);
    }
  }

  if (cls){
    var cl = cls;
    if (typeof(cl) === "String")
      cl = cl.split(" ");
    if (cl instanceof Array){
      cl.forEach(c => e.addClass(c.trim()));
    }
  }
  if (attr){
    var keys = Object.keys(attr);
    keys.forEach(function(key){
      if (attr.hasOwnProperty(key)){
        if (typeof(attr[key]) === "string"){
          e.addAttribute(key.toString(), attr[key]);
        }
      }
    });
  }

  return e;
}



module.exports = {
  ENode: ENode,
  el: el,
  html: el.bind(null, "html"),
  head: el.bind(null, "head"),
  title: el.bind(null, "title"),
  script: el.bind(null, "script"),
  link: el.bind(null, "link"),
  meta: el.bind(null, "meta"),
  body: el.bind(null, "body"),
  div: el.bind(null, "div"),
  span: el.bind(null, "span"),
  a: el.bind(null, "a"),
  p: el.bind(null, "p"),
  b: el.bind(null, "b"),
  i: el.bind(null, "i"),
  br: el.bind(null, "br"),
  ol: el.bind(null, "ol"),
  ul: el.bind(null, "ul"),
  li: el.bind(null, "li"),
  em: el.bind(null, "em"),
  img: el.bind(null, "img"),
  font: el.bind(null, "font"),
  h1: el.bind(null, "h1"),
  h2: el.bind(null, "h2"),
  h3: el.bind(null, "h3"),
  h4: el.bind(null, "h4"),
  h5: el.bind(null, "h5"),
  h6: el.bind(null, "h6"),
  hr: el.bind(null, "hr"),
  blockquote: el.bind(null, "blockquote"),
  button: el.bind(null, "button"),
  nav: el.bind(null, "nav"),
  canvas: el.bind(null, "canvas"),
  caption: el.bind(null, "caption")
};