package votorola.a.diff.harvest.auth;// Copyright 2011-2012. Christian Weilbach.  Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Votorola Software"), to deal in the Votorola Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicence, and/or sell copies of the Votorola Software, and to permit persons to whom the Votorola Software is furnished to do so, subject to the following conditions: The preceding copyright notice and this permission notice shall be included in all copies or substantial portions of the Votorola Software. THE VOTOROLA SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE VOTOROLA SOFTWARE OR THE USE OR OTHER DEALINGS IN THE VOTOROLA SOFTWARE.

import java.io.IOException;

import votorola.a.PagePropertyReader;
import votorola.a.PageProperty;

import votorola.a.WikiCache;
import votorola.a.diff.harvest.cache.AuthDiffMessage;
import votorola.a.diff.harvest.cache.DiffMessage;
import votorola.a.diff.harvest.cache.HarvestCache;
import votorola.a.voter.IDPair;
import votorola.g.lang.ThreadSafe;

/**
 * Provide access to the semantic-mediawiki database for
 * a single property on the user's page. This is a good default location
 * for users to store their different network identities. 
 * <a href="http://obsidian.reluk.ca/w/Property:IRC_nickname">IRC nickname</a> is
 * an example.
 *
 * @see WikiCache
 * @see HarvestCache
 */
public @ThreadSafe class WikiAuthenticator implements Authenticator {

    /**
     * Use the wiki cache to store already requested pages
     * locally.
     */
    private final transient WikiCache wikiCache;

    /**
     * Semantic property to query on the user's page.
     */
    private final transient String property;

    /**
     * Construct this verifier.
     * @param wc WikiCache to (re)use.
     * @param property Property to query.
     */
    public WikiAuthenticator(final WikiCache wc, final String property) {
        this.wikiCache = wc;
        this.property = property;
    }

    /**
     * Verify a message against this property.
     * @param dmsg DiffMessage to verify.
     * @return the message with authorship information set. Otherwise returns
     * null.
     * @throws IOException if accessing the WikiCache fails.
     */
    public final AuthDiffMessage verify(final DiffMessage dmsg) throws IOException
    {
        final String sender = dmsg.message().mc().sender();
        final String aMail = dmsg.draftPair().aCore().person().email();
        final String bMail = dmsg.draftPair().bCore().person().email();
        final PagePropertyReader aPropReader 
            = new PagePropertyReader( wikiCache, "User:" + IDPair.toUsername(aMail)
                    , new PageProperty(property));
        final PagePropertyReader bPropReader 
            = new PagePropertyReader( wikiCache, "User:" + IDPair.toUsername(bMail)
                    , new PageProperty(property));
        final String aProp = aPropReader.hasNext() ? aPropReader.read().getValue() : null ;
        final String bProp = bPropReader.hasNext() ? bPropReader.read().getValue() : null ;
        if(sender.equals(aProp)) {
            return AuthDiffMessage.create(dmsg, aMail, bMail, "a");
        }
        if(sender.equals(bProp)) {
            return AuthDiffMessage.create(dmsg, bMail, aMail, "b");
        }

        return null;
    }

}