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package fourty2ia.builder;

import org.w3c.dom.Element;
import org.w3c.dom.Document;

import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import java.util.Stack;

public class XmlDocumentBuilder {

    private Document document;

    private Stack<Element> stack;

    public XmlDocumentBuilder(DocumentBuilderFactory docBuilderFactory)
            throws ParserConfigurationException {

        this.document = docBuilderFactory.newDocumentBuilder().newDocument(); 
        stack = new Stack<Element>();

    }

    public XmlDocumentBuilder() throws ParserConfigurationException {
        this(DocumentBuilderFactory.newInstance());
    }

    public Document build(){
        return document;
    }

    public XmlDocumentBuilder beginElement(String name){

        Element elem = document.createElement(name);

        // if stack empty, then we have the root element
        if(stack.isEmpty()){
           document.appendChild(elem); 
        }
        else {
            stack.peek().appendChild(elem);
        }

        stack.push(elem);

        return this;
    }

    public XmlDocumentBuilder endElement(){

        if(stack.isEmpty()){
            throw new IllegalStateException("No matching beginElement()");
        }
        stack.pop();

        return this;
    }

    public XmlDocumentBuilder attr(String name,String value){
        if(stack.isEmpty()){
            throw new IllegalStateException("Empty stack");
        }
        stack.peek().setAttribute(name,value);

        return this;
    }
    
    public XmlDocumentBuilder attr(String name,Object value){
        return attr(name,value.toString());
    }

    public XmlDocumentBuilder text(String text){
        if(stack.isEmpty()){
            throw new IllegalStateException("Empty Stack");
        }
        stack.peek().appendChild(document.createTextNode(text));
        return this;
    }

    public XmlDocumentBuilder element(String name,String ... attrs){
        if(attrs.length % 2 != 0){
            throw new IllegalArgumentException("Attribute name without value");
        }

        beginElement(name);
        return endElement();
    }

    public XmlDocumentBuilder element(String name){
        beginElement(name);
        return endElement();
    }
}