/*
 * Created on Nov 2, 2004
 * Copyright (C) Andrea Schweer, 2004
 *
 * This file is part of the Greenstone Alerting Service.
 * Refer to the COPYING file in the base directory of this package
 * for licensing information.
 */
package org.greenstone.gsdlas.profiles;

import java.sql.*;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.*;
import java.util.Set;
import java.util.TreeSet;

import org.greenstone.gsdlas.database.DatabaseException;
import org.greenstone.gsdlas.database.DatabaseManager;
import org.greenstone.gsdlas.util.ArrayHelper;

/**
 * @author schweer
 *
 * TODO To change the template for this generated type comment go to
 * Window - Preferences - Java - Code Style - Code Templates
 */
public abstract class Predicate implements Comparable {

    protected Set subscriptions = new TreeSet();
    protected String field;
    protected String value;
    protected int id;
    

    public static final String[] singleValueFields = new String[] {
            "document_title",
            "document_content",
            "metadata_has_field",
            "host_query",
            "collection_query" };
    public static final String[] multiValueFields = new String[] {
            "type",
            "hostID",
            "collectionID",
            "documentID" };
    
    public void addSubscription(int subscriptionID) {
        subscriptions.add(new Integer(subscriptionID));
    }

    /* (non-Javadoc)
     * @see org.greenstone.gsdlas.profiles.Predicate#getSubscriptions()
     */
    public Set getSubscriptionIDs() {
        return Collections.unmodifiableSet(subscriptions);
    }

    public int getID() {
        return id;
    }
    
    public void setID(int i) {
        this.id = i;
    }

    /* (non-Javadoc)
     * @see org.greenstone.gsdlas.profiles.Predicate#getKey()
     */
    public String getField() {
        return field;
    }

    /* (non-Javadoc)
     * @see org.greenstone.gsdlas.profiles.Predicate#getValue()
     */
    public String getValue() {
        return value;
    }

    public String toString() {
        return field + "=" + value;
    }
    
    public boolean equals(Object other) {
        if (other == null || !(other instanceof Predicate)) return false;
        return id == ((Predicate)other).getID();
    }
    
    public int compareTo(Object other) {
        Predicate otherPredicate = (Predicate) other;
        return new Integer(id).compareTo(new Integer(otherPredicate.getID()));
    }
    
    public abstract boolean isSatisfied(Map event);

    /**
     * @param key
     * @return
     */
    public static boolean isSingleValued(String key) {
        return ArrayHelper.contains(singleValueFields, key);
    }

    /**
     * @param key
     * @return
     */
    public static boolean isMultiValued(String key) {
        return ArrayHelper.contains(multiValueFields, key);
    }

    /**
     * @return
     * @throws DatabaseException
     * @throws SQLException
     */
    int saveToDatabase() throws SQLException, DatabaseException {
        String query = "SELECT id FROM predicates " +
        		"WHERE field = '" + field + 
        		"' AND value = '" + value + "';";
        Statement statement = DatabaseManager.getInstance().getDatabaseConnection().createStatement();
        System.out.println(query);
        ResultSet result = statement.executeQuery(query);
        if (result.next()) { // predicate already exists in database
            System.out.println("predicate " + id + " already exists");
            return result.getInt("id");
        }
        // predicate has been newly created
        String insert = "INSERT INTO predicates (field, value) " +
        "VALUES ('" + field + "', '" + value + "');";
        System.out.println(insert);
        statement.execute(insert);
        result = statement.executeQuery(query);
        if (result.next()) {
            return result.getInt("id");
        } else {
            throw new DatabaseException("could not save predicate");
        }
    }

    /**
     * @return
     */
    public List getValueList() {
        throw new UnsupportedOperationException("you can only call this method for multi-valued predicates");
    }

    /**
     * @param key
     * @return
     */
    public static boolean isFieldName(String key) {
        return ArrayHelper.contains(singleValueFields, key) || ArrayHelper.contains(multiValueFields, key);
    }
    
}