package mentata.ldaphttp.forum;

// import necessary classes
import java.io.IOException;
import org.xml.sax.Attributes;
import org.xml.sax.InputSource;
import org.xml.sax.XMLReader;
import org.xml.sax.SAXException;
import org.xml.sax.SAXParseException;
import org.xml.sax.helpers.XMLReaderFactory;
import org.xml.sax.helpers.DefaultHandler;
import mentata.ldaphttp.LDAPHttpException;

/**
* A directory entry that represents a comment in reference to an item in an RSS feed.
*/
public class rep extends solicitation {

	// URI for RSS feed
	private String feed = null;

	// java class for xml parser
	private final String PARSER_CLASS = "org.apache.xerces.parsers.SAXParser";

	/**
	* Instantiates an empty template for a rep.
	*/
	public rep() 
		throws LDAPHttpException {

		// set default values for this object
		setDirectoryLocation("ou=Reps, ou=Comments, ou=Expressions, o=mentata.com", ONE);
		setLabel("RSS Extracted Posting");
		setComment("rep");

		// make this an incremental object
		setIncremental("CRA", "c=CRAcounter, ou=Reps, ou=Comments, ou=Expressions, o=mentata.com", "description");

		// relabel some attributes
		relabelAttribute("description", "");
		relabelAttribute("dnqualifier", "Written");
		relabelAttribute("content", "I say...");
		relabelAttribute("commentform", "You say...");
		relabelAttribute("commenthr", "");

		// set attribute lists to support retrievability
		addAttributeList("retrieve_html", new String[] 
			{"description", "link", "commenthr", "dnqualifier", "content", "parent", "commenthr", "child",
			"commentform"} );

		// set attribute lists to support creatability
		addAttributeList("create_initialize", new String[] {"content"} );
	}

	/**
	* Retrieves and extracts information from an RSS 1.0 feed.
	*/
	public void preCreate() 
		throws LDAPHttpException {

		// perform standard comment precreation
		super.preCreate();

		// retrieve and parse the RSS feed
		String uri = getFeed();
		RSS1Handler rss_handler = new RSS1Handler();
		rss_handler.setItemSubstring( getItemSubstring() );
		try {
			XMLReader reader = XMLReaderFactory.createXMLReader(PARSER_CLASS);
			reader.setContentHandler(rss_handler);
			reader.setErrorHandler(rss_handler);
			InputSource input_source = new InputSource(uri);
			reader.parse(input_source);

		// handle feed retrieval exceptions
		} catch(IOException e) {
			throw new LDAPHttpException("Unable to fetch the RSS feed: " + e.getMessage() );

		// handle feed parsing exceptions
		} catch(SAXException e) {
			throw new LDAPHttpException("Unable to parse the RSS feed: " + e.getMessage() );
		}

		// update attribute values with those found in the feed
		if ( rss_handler.itemFound() ) {
			resetAttribute("cn", new String[] {rss_handler.getTitle()} );
			resetAttribute("description", new String[] {rss_handler.getDescription()} );
			resetAttribute("link", new String[] {rss_handler.getLink()} );

		// handle the case where the item wasn't found in the feed
		} else {
			throw new LDAPHttpException("An item matching <i>" + getItemSubstring() + "</i> was not found in the current feed: " + getFeed() );
		}
	}

    /**
    * Sets the URI for the RSS feed.
    *
    * @param feed the URI for the RSS feed
    */
    protected final void setFeed(String feed) {
        this.feed = feed;
    }

	/**
	* Returns the URI for the RSS feed.
	*
	* @return the URI for the feed 
	* @throws LDAPHttpException if no feed is specified
	*/
	public final String getFeed() 
		throws LDAPHttpException {
		if (this.feed == null) {
			throw new LDAPHttpException("No RSS feed is specified for <i>" + getLabel() + "</i> objects.");
		} else {
			return this.feed;
		}
	}

	/**
	* Constructs and returns the substring to match in an RSS item.
	*
	* @return the item substring 
	*/
	public String getItemSubstring() 
		throws LDAPHttpException {

		String current_id = getIdentifier();
		if (current_id == null) {
			throw new LDAPHttpException("No identifier was submitted to determine the appropriate RSS item.");
		} else {
			return current_id;
		}
	}

	// handler used for parsing RSS 1.0 feed
	class RSS1Handler extends DefaultHandler {

		// item number to record
		private String item_substring = "somebodyforgottosetme"; 

		// indicator for if the item was found
		private boolean item_found = false; 

		// the name of the current element in parsing
		private String current_element = null;

		// structures for storing the text of relevant elements
		private StringBuffer title_buffer = new StringBuffer();
		private StringBuffer link_buffer = new StringBuffer();
		private StringBuffer description_buffer = new StringBuffer();
		private StringBuffer creator_buffer = new StringBuffer();

		// indicator for relevant portion of feed
		private boolean in_item;

		public void startElement(String namespaceURI, String localName, String qName, Attributes atts)
			throws SAXException {

			// store the current element name
			this.current_element = localName;

			// indicate if within a relevant parent tag
			if ( localName.equalsIgnoreCase("item") ) {
				if (atts.getValue("rdf:about").indexOf(this.item_substring) > 0) {
					this.item_found = true;
					this.in_item = true;
				}
			}
		}

		public void endElement(String namespaceURI, String localName, String qName)
			throws SAXException {

			if ( localName.equalsIgnoreCase("item") )
				this.in_item = false;
		}

		public void characters(char[] ch, int start, int length)
        	throws SAXException {

			// store information from the relevant item
			if (in_item) {
				if ( this.current_element.equalsIgnoreCase("title") ) {
					this.title_buffer.append( new String(ch, start, length) );
				} else { if ( this.current_element.equalsIgnoreCase("link") ) {
					this.link_buffer.append( new String(ch, start, length) );
				} else { if ( this.current_element.equalsIgnoreCase("description") ) {
					this.description_buffer.append( new String(ch, start, length) );
				} else { if ( this.current_element.equalsIgnoreCase("creator") ) {
					this.creator_buffer.append( new String(ch, start, length) );
				}}}}
			} 
		}

		// method to set the item number
		void setItemSubstring(String item_substring) {
			this.item_substring = item_substring;
		}

		// method to return article title
		boolean itemFound() {
			return this.item_found;
		}

		// method to return article title
		String getTitle() {
			return this.title_buffer.toString().trim();
		}

		// method to return article link
		String getLink() {
			return this.link_buffer.toString().trim();
		}

		// method to return article description
		String getDescription() {
			return this.description_buffer.toString().trim() + " <b><i>" + this.creator_buffer.toString().trim() + "</i></b>";
		}

		// method for handling warnings
		public void warning(SAXParseException exception)
			throws SAXException {

			throw new SAXException("warning at line " + exception.getLineNumber() + "... " + exception.getMessage() );
		}

		// method for handling nonfatal errors
		public void error(SAXParseException exception)
			throws SAXException {

			throw new SAXException("nonfatal error at line " + exception.getLineNumber() + "... " + exception.getMessage() );
		}

		// method for handling fatal errors
		public void fatalError(SAXParseException exception)
			throws SAXException {

			throw new SAXException("fatal error at line " + exception.getLineNumber() + "... " + exception.getMessage() );
		}
	}
}