/* DOM implementation */
#include <iostream>
#include <string>
#include <vector>
#include <map>

using namespace std;

/* Currently using Element for all nodes and going by the nodeName to determine the type of node */
struct Element {
    string nodeName;
    string nodeValue;
    vector<Element> childNodes;
    map<string,string> attributes;
    void appendChild( Element e ) {
        Element::childNodes.push_back( e );
    }
    vector<Element*> getElementsByTagName(const string& tag ) {
        /* doesn't support space-separated or '*' yet */
        /* Also doesn't recurse through nodes yet */
        vector<Element*> temp;
        for ( size_t i = 0; i < Element::childNodes.size(); ++i ) {
            if ( Element::childNodes[i].nodeName == tag ) {
                temp.push_back( &Element::childNodes[i] );
            }
        }
        return temp;
    }
    bool hasChildNodes() const {
        if ( !Element::childNodes.empty() ) {
            return true;
        }
        return false;
    }
    void setAttribute( const string& name, const string& value ) {
        attributes[ name ] = value;
    }
    string getAttribute( const string& name ) {
        return attributes[name];
    }
    string getOuterHTML() const {
        string temp;
        temp += "<";
        temp += Element::nodeName;
        if ( Element::nodeName != "#text") {
            for ( map<string,string>::const_iterator i = Element::attributes.begin(); i != Element::attributes.end(); ++i ) {
                temp += " ";
                temp += i->first;
                temp += "=\"";
                temp += i->second;
                temp += "\"";
            }
        }
        temp += ">";
        if ( Element::hasChildNodes() ) {
            for ( size_t i = 0; i < childNodes.size(); ++i ) {
                if ( childNodes[i].nodeName != "#text" ) {
                    temp += childNodes[i].getOuterHTML();
                } else {
                    temp += childNodes[i].nodeValue;
                }
            }
            temp += "</";
            temp += Element::nodeName;
            temp += ">";
        }
        return temp;
    }
    string getInnerHTML() const {
        if ( Element::hasChildNodes() ) {
            return Element::childNodes[0].getOuterHTML();
        }
        return "";
    }
};

struct Document : public Element {
    Element* documentElement;
    Element* body;
    Element createElement(const string& tag) const {
        Element temp;
        temp.nodeName = tag;
        return temp;
    }
    Element createTextNode( const string& text ) const {
        Element temp;
        temp.nodeValue = text;
        temp.nodeName = "#text";
        return temp;
    }
} document;

struct Window {
    Document* document;
    template<class T> void alert( const T& s ) const {
        cout << s << endl;
    }
} window;

#define alert window.alert /* making alert() global */
typedef Element TextNode; /* used to store a text node */
typedef vector<Element*> ElementPtrArray; /* used to store pointers to elements found by getElementsByTagName() */
typedef Element* ElementPtr; /* use to store a pointer to an element */
 
int main() {
    /* Give the document a nodeName and append the first ( root ) element */
    document.nodeName = "#document";
    document.appendChild( document.createElement("html") ); 
    
    /* document.documentElement is a pointer to the root element, which in this case, is html */
    document.documentElement = document.getElementsByTagName("html")[0];
    
    /* Now that the document has a root element, append stuff to the root element using the documentElement pointer */
    document.documentElement->setAttribute("lang", "en");
    document.documentElement->appendChild( document.createElement("head") );
    document.documentElement->appendChild( document.createElement("body") );
    
    /* document.body is a pointer to the first body element in the root element */
    document.body = document.documentElement->getElementsByTagName("body")[0];
    
    /*  For the next 2 lines, add a title element to the head and add its text node, but do it without creating any new element instances in main just to test. */
    document.documentElement->getElementsByTagName("head")[0]->appendChild( document.createElement("title") );
    document.documentElement->getElementsByTagName("head")[0]->getElementsByTagName("title")[0]->appendChild( document.createTextNode("c++ dom") );
    
    /* window.document is just a pointer to document. */
    window.document = &document;
    
    /* Element itself defines a new element, in which a .nodeName could be set, but doing it with document.createElement to be JS-like and because the nodeName is set automatically.  */
    Element p = document.createElement("p");
    p.setAttribute("id", "blabla");
    p.appendChild( document.createTextNode("This is a paragraph") );
    document.body->appendChild( p );
    alert( document.getInnerHTML() );
    alert( document.documentElement->getOuterHTML() );
    alert( document.body->getInnerHTML() );
    alert( document.body->getOuterHTML() );
}