package org.apache.turbine.services.security.torque;

/* ====================================================================
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 2001-2003 The Apache Software Foundation.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Apache" and "Apache Software Foundation" and
 *    "Apache Turbine" must not be used to endorse or promote products
 *    derived from this software without prior written permission. For
 *    written permission, please contact apache@apache.org.
 *
 * 5. Products derived from this software may not be called "Apache",
 *    "Apache Turbine", nor may "Apache" appear in their name, without
 *    prior written permission of the Apache Software Foundation.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 */
import java.beans.PropertyDescriptor;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

import org.apache.commons.configuration.Configuration;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import org.apache.torque.TorqueException;
import org.apache.torque.om.Persistent;
import org.apache.torque.util.BasePeer;
import org.apache.torque.util.Criteria;

import org.apache.turbine.om.security.Group;
import org.apache.turbine.services.InitializationException;
import org.apache.turbine.services.security.TurbineSecurity;
import org.apache.turbine.util.security.DataBackendException;
import org.apache.turbine.util.security.GroupSet;

/**
 * This class capsulates all direct Peer access for the Group entities.
 * It allows the exchange of the default Turbine supplied TurbineGroupPeer
 * class against a custom class.
 *
 * @author <a href="mailto:hps@intermeta.de">Henning P. Schmiedehausen</a>
 * @version $Id$
 *
 */
public class GroupPeerManager
    implements GroupPeerManagerConstants
{
    /** The class of the Peer the TorqueSecurityService uses */
    private static Class groupPeerClass = null;

    /** The class name of the objects returned by the configured peer. */
    private static Class groupObject = null;

    /** The name of the Table used for Group Object queries  */
    private static String tableName = null;

    /** The name of the column used as "Name" Column */
    private static String nameColumn = null;

    /** The name of the column used as "Id" Column */
    private static String idColumn = null;

    /** The "Name" property descriptor */
    private static PropertyDescriptor namePropDesc = null;

    /** The "Id" property descriptor */
    private static PropertyDescriptor idPropDesc = null;

    /** Logging */
    static Log log = LogFactory.getLog(GroupPeerManager.class);

    /**
     * Initializes the GroupPeerManager, loading the class object for the
     * Peer used to retrieve Group objects
     *
     * @param conf The configuration object used to configure the Manager
     *
     * @exception InitializationException A problem occured during initialization
     */

    public static void init(Configuration conf)
        throws InitializationException
    {
        String groupPeerClassName = conf.getString(GROUP_PEER_CLASS_KEY,
                                                   GROUP_PEER_CLASS_DEFAULT);
        String groupObjectName = null;

        try
        {
            groupPeerClass = Class.forName(groupPeerClassName);

            tableName  = (String) groupPeerClass.getField("TABLE_NAME").get(null);

            //
            // We have either an user configured Object class or we use the default
            // as supplied by the Peer class
            //
            groupObject = getPersistenceClass(); // Default from Peer, can be overridden

            groupObjectName = conf.getString(GROUP_CLASS_KEY,
                    groupObject.getName());

            groupObject = Class.forName(groupObjectName); // Maybe the user set a new value...

            // If any of the following Field queries fails, the group subsystem 
            // is unusable. So check this right here at init time, which saves 
            // us much time and hassle if it fails...
            nameColumn = (String) groupPeerClass.getField(conf
                    .getString(GROUP_NAME_COLUMN_KEY, GROUP_NAME_COLUMN_DEFAULT)
                    ).get(null);

            idColumn = (String) groupPeerClass.getField(conf
                    .getString(GROUP_ID_COLUMN_KEY, GROUP_ID_COLUMN_DEFAULT)
                    ).get(null);

            namePropDesc = new PropertyDescriptor(conf
                    .getString(GROUP_NAME_PROPERTY_KEY, 
                    GROUP_NAME_PROPERTY_DEFAULT), groupObject);

            idPropDesc = new PropertyDescriptor(conf
                    .getString(GROUP_ID_PROPERTY_KEY, 
                    GROUP_ID_PROPERTY_DEFAULT), groupObject);
        }
        catch (Exception e)
        {
            if (groupPeerClassName == null || groupPeerClass == null)
            {
                throw new InitializationException(
                    "Could not find GroupPeer class ("
                    + groupPeerClassName + ")", e);
            }
            if (tableName == null)
            {
                throw new InitializationException(
                    "Failed to get the table name from the Peer object", e);
            }

            if (groupObject == null || groupObjectName == null)
            {
                throw new InitializationException(
                    "Failed to get the object type from the Peer object", e);
            }

            if (nameColumn == null || namePropDesc == null)
            {
                throw new InitializationException(
                    "GroupPeer " + groupPeerClassName + " has no name column information!", e);
            }
            if (idColumn == null || idPropDesc == null)
            {
                throw new InitializationException(
                    "GroupPeer " + groupPeerClassName + " has no id column information!", e);
            }
        }
    }

    /**
     * Get the name of this table.
     *
     * @return A String with the name of the table.
     */
    public static String getTableName()
    {
        return tableName;
    }

    /**
     * Returns the fully qualified name of the Column to
     * use as the Name Column for a group
     *
     * @return A String containing the column name
     */
    public static String getNameColumn()
    {
        return nameColumn;
    }

    /**
     * Returns the fully qualified name of the Column to
     * use as the Id Column for a group
     *
     * @return A String containing the column id
     */
    public static String getIdColumn()
    {
        return idColumn;
    }

    /**
     * Returns the full name of a column.
     *
     * @param name The column to fully qualify
     *
     * @return A String with the full name of the column.
     */
    public static String getColumnName(String name)
    {
        StringBuffer sb = new StringBuffer();
        sb.append(getTableName());
        sb.append(".");
        sb.append(name);
        return sb.toString();
    }

    /**
     * Returns a new, empty object for the underlying peer.
     * Used to create a new underlying object
     *
     * @return A new object which is compatible to the Peer
     *         and can be used as a Group object
     *
     */

    public static Persistent newPersistentInstance()
    {
        Persistent obj = null;

        if(groupObject == null)
        {
            // This can happen if the Turbine wants to determine the
            // name of the anonymous user before the security service
            // has been initialized. In this case, the Peer Manager
            // has not yet been inited and the groupObject is still
            // null. Return null in this case.
            //
            return obj;
        }

        try
        {
            obj = (Persistent) groupObject.newInstance();
        }
        catch (Exception e)
        {
            log.error("Could not instantiate a group object", e);
            obj = null;
        }
        return obj;
    }

    /**
     * Retrieves/assembles a GroupSet of all of the Groups.
     *
     * @return A set of all the Groups in the system
     * @exception Exception A generic exception.
     */
    public static GroupSet retrieveSet()
        throws Exception
    {
        return retrieveSet(new Criteria());
    }

    /**
     * Retrieves/assembles a GroupSet based on the Criteria passed in
     *
     * @param criteria A criteria containing a pre-assembled set of criterias
     *                 for the GroupSet
     *
     * @return A Set of groups which fulfil the required criterias
     *
     * @exception Exception A generic exception
     *
     */
    public static GroupSet retrieveSet(Criteria criteria)
        throws Exception
    {
        List results = doSelect(criteria);
        GroupSet gs = new GroupSet();

        for(Iterator it = results.iterator(); it.hasNext(); )
        {
            gs.add((Group) it.next());
        }
        return gs;
    }

    /**
     * Checks if a Group is defined in the system. The name
     * is used as query criteria.
     *
     * @param group The Group to be checked.
     * @return <code>true</code> if given Group exists in the system.
     * @throws DataBackendException when more than one Group with
     *         the same name exists.
     * @throws Exception A generic exception.
     */
    public static boolean checkExists(Group group)
        throws DataBackendException, Exception
    {
        Criteria criteria = new Criteria();

        criteria.addSelectColumn(getIdColumn());

        criteria.add(getNameColumn(), group.getName());

        List results = BasePeer.doSelect(criteria);

        if (results.size() > 1)
        {
            throw new DataBackendException("Multiple groups named '" +
                                           group.getName() + "' exist!");
        }

        return (results.size() == 1);
    }

    /*
     * ========================================================================
     *
     * WARNING! Do not read on if you have a weak stomach. What follows here
     * are some abominations thanks to the braindead static peers of Torque
     * and the rigidity of Java....
     *
     * ========================================================================
     *
     */

    /**
     * Calls buildCriteria(Group group) in the configured GroupPeer. If you get
     * a ClassCastException in this routine, you put a Group object into this
     * method which can't be cast into an object for the TorqueSecurityService. This is a
     * configuration error most of the time.
     *
     * @param group An object which implements the Group interface
     *
     * @return A criteria for the supplied group object
     */

    public static Criteria buildCriteria(Group group)
    {
        Criteria crit;

        try
        {
            Class[] clazz = new Class[] { groupObject };
            Object[] params =
              new Object[] { ((TorqueGroup) group).getPersistentObj() };

            crit =  (Criteria) groupPeerClass
                .getMethod("buildCriteria", clazz)
                .invoke(null, params);
        }
        catch (Exception e)
        {
            crit = null;
        }

        return crit;
    }

    /**
     * Invokes doUpdate(Criteria c) on the configured Peer Object
     *
     * @param criteria  A Criteria Object
     *
     * @exception TorqueException A problem occured.
     */

    public static void doUpdate(Criteria criteria)
        throws TorqueException
    {
        try
        {
            Class[] clazz = new Class[] { Criteria.class };
            Object[] params = new Object[] { criteria };

            groupPeerClass
                .getMethod("doUpdate", clazz)
                .invoke(null, params);
        }
        catch (Exception e)
        {
            throw new TorqueException("doUpdate failed", e);
        }
    }

    /**
     * Invokes doInsert(Criteria c) on the configured Peer Object
     *
     * @param criteria  A Criteria Object
     *
     * @exception TorqueException A problem occured.
     */

    public static void doInsert(Criteria criteria)
        throws TorqueException
    {
        try
        {
            Class[] clazz = new Class[] { Criteria.class };
            Object[] params = new Object[] { criteria };

            groupPeerClass
                .getMethod("doInsert", clazz)
                .invoke(null, params);
        }
        catch (Exception e)
        {
            throw new TorqueException("doInsert failed", e);
        }
    }

    /**
     * Invokes doSelect(Criteria c) on the configured Peer Object
     *
     * @param criteria  A Criteria Object
     *
     * @return A List of Group Objects selected by the Criteria
     *
     * @exception TorqueException A problem occured.
     */
    public static List doSelect(Criteria criteria)
        throws TorqueException
    {
        List list;

        try
        {
            Class[] clazz = new Class[] { Criteria.class };
            Object[] params = new Object[] { criteria };

            list = (List) groupPeerClass
                .getMethod("doSelect", clazz)
                .invoke(null, params);
        }
        catch (Exception e)
        {
            throw new TorqueException("doSelect failed", e);
        }
        List newList = new ArrayList(list.size());

        //
        // Wrap the returned Objects into the configured Peer Objects.
        //
        for (Iterator it = list.iterator(); it.hasNext(); )
        {
            Group dr = getNewGroup((Persistent) it.next());
            newList.add(dr);
        }

        return newList;
    }

    /**
     * Invokes doDelete(Criteria c) on the configured Peer Object
     *
     * @param criteria  A Criteria Object
     *
     * @exception TorqueException A problem occured.
     */
    public static void doDelete(Criteria criteria)
        throws TorqueException
    {
        try
        {
            Class[] clazz =
              new Class[] { Criteria.class };
            Object[] params = new Object[] { criteria };

            groupPeerClass
                .getMethod("doDelete", clazz)
                .invoke(null, params);
        }
        catch (Exception e)
        {
            throw new TorqueException("doDelete failed", e);
        }
    }

    /**
     * Invokes setName(String s) on the supplied base object
     *
     * @param obj The object to use for setting the name
     *
     * @param name The Name to set
     */
    public static void setGroupName(Persistent obj, String name)
    {
        if(obj == null)
        {
            return;
        }

        try
        {
            Object[] params = new Object[] { name };
            namePropDesc.getWriteMethod().invoke(obj, params);
        }
        catch (ClassCastException cce)
        {
            String msg = obj.getClass().getName() + " does not seem to be a Group Object!";
            log.error(msg);
            throw new RuntimeException(msg);
        }
        catch (Exception e)
        {
            log.error(e, e);
        }
    }

    /**
     * Invokes getName() on the supplied base object
     *
     * @param obj The object to use for getting the name
     *
     * @return A string containing the name
     */
    public static String getGroupName(Persistent obj)
    {
        String name = null;

        if(obj == null)
        {
            return null;
        }

        try
        {
            name = (String) namePropDesc
                .getReadMethod()
                .invoke(obj, new Object[] {});
        }
        catch (ClassCastException cce)
        {
            String msg = obj.getClass().getName() + " does not seem to be a Group Object!";
            log.error(msg);
            throw new RuntimeException(msg);
        }
        catch (Exception e)
        {
            log.error(e, e);
        }
        return name;
    }

    /**
     * Invokes setId(int n) on the supplied base object
     *
     * @param obj The object to use for setting the name
     * @param id The new Id
     */
    public static void setId(Persistent obj, int id)
    {
        if(obj == null)
        {
            return;
        }

        try
        {
            Object[] params = new Object[] { Integer.TYPE };
            idPropDesc.getWriteMethod().invoke(obj, params);
        }
        catch (ClassCastException cce)
        {
            String msg = obj.getClass().getName() + " does not seem to be a Group Object!";
            log.error(msg);
            throw new RuntimeException(msg);
        }
        catch (Exception e)
        {
            log.error(e, e);
        }
    }

    /**
     * Invokes getId() on the supplied base object
     *
     * @param obj The object to use for getting the id
     *
     * @return The Id of this object
     */
    public static Integer getIdAsObj(Persistent obj)
    {
        Integer id = null;

        if(obj == null)
        {
            return new Integer(0);
        }

        try
        {
            id = (Integer) idPropDesc
                .getReadMethod()
                .invoke(obj, new Object[] {});
        }
        catch (ClassCastException cce)
        {
            String msg = obj.getClass().getName() + " does not seem to be a Group Object!";
            log.error(msg);
            throw new RuntimeException(msg);
        }
        catch (Exception e)
        {
            log.error(e, e);
        }
        return id;
    }

    /**
     * Returns the Class of the configured Object class
     * from the peer
     *
     * @return The class of the objects returned by the configured peer
     *
     */

    private static Class getPersistenceClass()
    {
        Class persistenceClass = null;

        try
        {
            Object[] params = new Object[0];

            persistenceClass =  (Class) groupPeerClass
                .getMethod("getOMClass", null)
                .invoke(null, params);
        }
        catch (Exception e)
        {
            persistenceClass = null;
        }

        return persistenceClass;
    }

    /**
     * Returns a new, configured Group Object with
     * a supplied Persistent object at its core
     *
     * @param p The persistent object
     *
     * @return a new, configured Group Object
     *
     * @exception Exception Could not create a new Object
     *
     */

    public static Group getNewGroup(Persistent p)
    {
        Group g = null;
        try
        {
            Class groupWrapperClass = TurbineSecurity.getGroupClass();

            Class [] clazz = new Class [] { Persistent.class };
            Object [] params = new Object [] { p };

            g = (Group) groupWrapperClass
                .getConstructor(clazz)
                .newInstance(params);
        }
        catch (Exception e)
        {
            log.error("Could not instantiate a new group from supplied persistent: ", e);
        }

        return g;
    }
}