package com.mckessonaps.jspwiki.plugin.emailnotifier;

import java.util.Arrays;
import java.util.Date;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

import org.apache.log4j.Category;

import com.ecyrd.jspwiki.WikiPage;


/**
 * Represents an individual person who is interested in being notified of changes.
 */
class Subscriber
{
    private static final Category log = Category.getInstance( Subscriber.class );


    /**
     * Attempt to parse the canidateLine into a Subscription.  If line does not look 
     * like subscription information null is returned.
     * @param canidateLine
     * @return May be <code>null</code> if <code>canidateLine</code> did not represent 
     * a subscription.
     */
    static Subscriber parse(String canidateLine)
    {
        //Simple short crcuit if the line doesn't start with a * then we can definitly ignore it.
        if (! canidateLine.startsWith( "*") )
            return null;

        String piecesArray[] = canidateLine.split("\\s"); 

        // minimumally canidate line must have: "* name domain houroffset"...
        if (piecesArray.length < 4) return null;
        
        if (!piecesArray[0].equals( "*")) 
            return null;
        
        String email = piecesArray[1] + "@" + piecesArray[2];

        int hourOffset = hourOffsetFrom(piecesArray[3]);

        //Remove the known elements from the front, the remaineder is the page list...
        List pageList = Arrays.asList( piecesArray );
        pageList = pageList.subList( 4, pageList.size());
        // 0, 1, 2, 3 Junk these list elements...
        //"*", "name", "domain", "houroffset"
        
        return new Subscriber(email, hourOffset, pageList);
    }



    /**
     * Return an hour offset from midnight, will extract 0 to 23 from given string 
     * <code>s</code>, if string is unparsable returns an offset of 0. 
     */
    private static int hourOffsetFrom(String s)
    {
        int offset = 0;
        try
        {
            offset = Integer.parseInt( s ); //anything
            offset = (offset % 23); // -23 to 23
            offset = (offset + 23); // 0 to 46
            offset = (offset % 23); // 0 to 23
        }
        catch (NumberFormatException nfe)
        {
            log.warn("Unparsable hour offset encountered.", nfe);
        }

        return offset;
    }



    /** email address of the subscriber. */
    private final String m_emailAddress;

    /** hour offset from server midnight at which the user wants to be notified. */
    private final int m_hourOffset;
    
    /** list of pages (possibly decorated) that the subscriber is interested in. */
    private final List m_pageList;
    
    

    /**
     * Constructor, doesn't do much but assign some member fields.  Private as the 
     * static parse method should be used to create subscriber instances.
     */
    private Subscriber(String emailAddress, int hourOffset, List pageList)
    {
        m_emailAddress = emailAddress;
        m_hourOffset = hourOffset;
        m_pageList = pageList;
    }
    
    
    /**
     * A subscriber specifies an hour offset from server midnight at which they want thier 
     * notifications sent, given the Date <code>d</code> should this subscriber have his 
     * notification sent now?
     */
    boolean shouldSendAt(Date d)
    {         
        return (d.getHours() == m_hourOffset) ;
    }
    

    /**
     * Returns string containing a list of the changedPages that this subscriber is interested in receiving.
     * For each subscribed page in changedPages the page's name is substituted for pageToken in pagePattern 
     */
    String getListOfChangedSubscribedPages(Map changedPageMap, String pagePattern)
    {
        StringBuffer sb = new StringBuffer();
            
        for (Iterator iter = changedPageMap.keySet().iterator(); iter.hasNext();)
        {
            String pageName = (String)iter.next();
            //If the subscribers page list is empty he wants all changes, otherwise he only wnat pages that he listed...
            if ((!m_pageList.isEmpty()) && (!m_pageList.contains( pageName )) )
                continue;
            
            String bodyElement = pagePattern.replaceAll(NotifierTask.MARKER_CHANGED_PAGE_NAME, pageName);

            List versionList = (List)changedPageMap.get(pageName);
            bodyElement = bodyElement.replaceAll(NotifierTask.MARKER_CHANGED_PAGE_INFO, buildChangeInfo(versionList));
            
            sb.append( bodyElement );
        }        
        
        return sb.toString();
    }
    
    
    private String buildChangeInfo(List pageVersions)
    {
        StringBuffer buffer = new StringBuffer();
        String previousAuthor = null;
        for (Iterator iter = pageVersions.iterator(); iter.hasNext();)
        {
            WikiPage page = (WikiPage) iter.next();
            String author = page.getAuthor();

  	   //FIX: for NPE
           if (author !=null) { 
             if (! author.equals( previousAuthor ))
             {    
                  if (buffer.length() > 0)
                      buffer.append( ", ");
                
                  buffer.append( author );
             }
            
             previousAuthor = author;
           }
        }

        return buffer.toString();
    }
    
    
    
    /**
     * Simple getter so outsiders can get what address to send to.
     */
    public String getEmailAddress()
    {
        return m_emailAddress;
    }

}