/*
 Wotonomy: OpenStep design patterns for pure Java applications.
 Copyright (C) 2001 Michael Powers

 This library is free software; you can redistribute it and/or
 modify it under the terms of the GNU Lesser General Public
 License as published by the Free Software Foundation; either
 version 2.1 of the License, or (at your option) any later version.

 This library is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 Lesser General Public License for more details.

 You should have received a copy of the GNU Lesser General Public
 License along with this library; if not, see http://www.gnu.org
 */
package net.wotonomy.access;

import java.util.Enumeration;
import java.util.List;
import java.util.Map;

import net.wotonomy.control.EOAndQualifier;
import net.wotonomy.control.EOCooperatingObjectStore;
import net.wotonomy.control.EOEditingContext;
import net.wotonomy.control.EOEnterpriseObject;
import net.wotonomy.control.EOFaultHandler;
import net.wotonomy.control.EOFaulting;
import net.wotonomy.control.EOFetchSpecification;
import net.wotonomy.control.EOGlobalID;
import net.wotonomy.control.EOKeyGlobalID;
import net.wotonomy.control.EOKeyValueCoding;
import net.wotonomy.control.EOKeyValueCodingSupport;
import net.wotonomy.control.EOKeyValueQualifier;
import net.wotonomy.control.EOObjectStoreCoordinator;
import net.wotonomy.control.EOQualifier;
import net.wotonomy.foundation.NSArray;
import net.wotonomy.foundation.NSDictionary;
import net.wotonomy.foundation.NSLocking;
import net.wotonomy.foundation.NSMutableArray;
import net.wotonomy.foundation.NSMutableDictionary;

/**
 *
 * @author ezamudio@nasoft.com
 * @author $Author: cgruber $
 * @version $Revision: 894 $
 */
public class EODatabaseContext extends EOCooperatingObjectStore implements NSLocking {

	private static Class _contextClass;
	protected EODatabase _database;
	protected EOAdaptorContext _context;
	protected NSMutableArray _channels = new NSMutableArray();
	protected NSMutableArray _lockedObjects = new NSMutableArray();

	protected NSMutableDictionary _simpleSnaps;
	protected NSMutableDictionary _manySnaps;

	protected EOObjectStoreCoordinator _coordinator;
	protected EOEditingContext _currEC;
	protected int _updateStrategy;

	public EODatabaseContext(EODatabase database) {
		super();
		_database = database;
		_context = _database.adaptor().createAdaptorContext();
	}

	public EOAdaptorContext adaptorContext() {
		return _context;
	}

	public EODatabase database() {
		return _database;
	}

	public EODatabaseChannel availableChannel() {
		for (int i = 0; i < _channels.count(); i++) {
			EODatabaseChannel c = (EODatabaseChannel) _channels.objectAtIndex(i);
			if (!c.isFetchInProgress())
				return c;
		}
		EODatabaseChannel c = new EODatabaseChannel(this);
		registerChannel(c);
		return c;
	}

	public void batchFetchRelationship(EORelationship rel, NSArray arr, EOEditingContext ec) {
	}

	public static void setContextClassToRegister(Class contextClass) {
		_contextClass = contextClass;
	}

	public static Class contextClassToRegister() {
		if (_contextClass == null)
			_contextClass = EODatabaseContext.class;
		return _contextClass;
	}

	public EOObjectStoreCoordinator coordinator() {
		return _coordinator;
	}

	public void editingContextDidForgetObjectWithGlobalID(EOEditingContext ec, EOGlobalID gid) {
		database().decrementSnapshotCountForGlobalID(gid);
	}

	public void handleDroppedConnection() {
		// TODO: unregister channels
		adaptorContext().handleDroppedConnection();
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see net.wotonomy.control.EOCooperatingObjectStore#ownsGlobalID(net.wotonomy.
	 * control.EOGlobalID)
	 */
	public boolean ownsGlobalID(EOGlobalID gid) {
		if (!(gid instanceof EOKeyGlobalID))
			return false;
		return (database().entityNamed(((EOKeyGlobalID) gid).entityName()) != null);
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * net.wotonomy.control.EOCooperatingObjectStore#ownsObject(net.wotonomy.control
	 * .EOEnterpriseObject)
	 */
	public boolean ownsObject(EOEnterpriseObject eo) {
		if (eo.entityName() == null)
			return false;
		return (database().entityNamed(eo.entityName()) != null);
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * net.wotonomy.control.EOCooperatingObjectStore#handlesFetchSpecification(net.
	 * wotonomy.control.EOFetchSpecification)
	 */
	public boolean handlesFetchSpecification(EOFetchSpecification fspec) {
		String ename = fspec.entityName();
		return (database().entityNamed(ename) != null);
	}

	public boolean hasBusyChannels() {
		return adaptorContext().hasBusyChannels();
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * net.wotonomy.control.EOCooperatingObjectStore#prepareForSaveWithCoordinator(
	 * net.wotonomy.control.EOObjectStoreCoordinator,
	 * net.wotonomy.control.EOEditingContext)
	 */
	public void prepareForSaveWithCoordinator(EOObjectStoreCoordinator coord, EOEditingContext ec) {
		// TODO Auto-generated method stub
		_coordinator = coord;
		_currEC = ec;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * net.wotonomy.control.EOCooperatingObjectStore#recordChangesInEditingContext()
	 */
	public void recordChangesInEditingContext() {
		// TODO insert, delete, update
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see net.wotonomy.control.EOCooperatingObjectStore#recordUpdateForObject(net.
	 * wotonomy.control.EOEnterpriseObject, net.wotonomy.foundation.NSDictionary)
	 */
	public void recordUpdateForObject(EOEnterpriseObject eo, NSDictionary changes) {
		// TODO Auto-generated method stub
	}

	public void recordSnapshotForGlobalID(NSDictionary snap, EOGlobalID gid) {
		if (_simpleSnaps == null)
			throw new IllegalArgumentException("Attempt to record a snapshot without a transaction in progress");
		_simpleSnaps.setObjectForKey(snap, gid);
	}

	public void recordSnapshotForSourceGlobalID(NSArray gids, EOGlobalID gid, String relationName) {
		if (_manySnaps == null)
			throw new IllegalArgumentException("Attempt to record a snapshot without a transaction in progress");
		NSMutableDictionary d = (NSMutableDictionary) _manySnaps.objectForKey(gid);
		if (d == null) {
			d = new NSMutableDictionary();
			_manySnaps.setObjectForKey(d, gid);
		}
		d.setObjectForKey(gids, relationName);
	}

	public void recordSnapshots(NSDictionary snaps) {
		if (_simpleSnaps == null)
			throw new IllegalArgumentException("Attempt to record snapshots without a transaction in progress.");
		_simpleSnaps.addEntriesFromDictionary(snaps);
		/*
		 * Make sure we don't need to do this instead Enumeration enumeration =
		 * snaps.keyEnumerator(); while (enumeration.hasMoreElements()) { EOGlobalID g =
		 * (EOGlobalID)enumeration.nextElement(); NSDictionary d =
		 * (NSDictionary)snaps.objectForKey(g); recordSnapshotForGlobalID(d, g); }
		 */
	}

	public void recordToManySnapshots(NSDictionary snaps) {
		if (_manySnaps == null)
			throw new IllegalArgumentException("Attempt to record snapshots without a transaction in progress.");
		Enumeration enumeration = snaps.keyEnumerator();
		while (enumeration.hasMoreElements()) {
			Object key = enumeration.nextElement();
			NSDictionary d = (NSDictionary) snaps.objectForKey(key);
			NSMutableDictionary d2 = (NSMutableDictionary) _manySnaps.objectForKey(key);
			if (d2 == null) {
				d2 = new NSMutableDictionary();
				_manySnaps.setObjectForKey(d2, key);
			}
			// this could also be done with many calls to recordSnapshotForSourceGID
			d2.addEntriesFromDictionary(d);
		}
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see net.wotonomy.control.EOCooperatingObjectStore#performChanges()
	 */
	public void performChanges() {
		// TODO Auto-generated method stub

	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see net.wotonomy.control.EOCooperatingObjectStore#commitChanges()
	 */
	public void commitChanges() {
		adaptorContext().commitTransaction();
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see net.wotonomy.control.EOCooperatingObjectStore#rollbackChanges()
	 */
	public void rollbackChanges() {
		adaptorContext().rollbackTransaction();
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * net.wotonomy.control.EOCooperatingObjectStore#valuesForKeys(net.wotonomy.
	 * foundation.NSArray, net.wotonomy.control.EOEnterpriseObject)
	 */
	public NSDictionary valuesForKeys(NSArray keys, EOEnterpriseObject eo) {
		// TODO check snapshots; eo could be a fault
		return eo.valuesForKeys(keys);
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see net.wotonomy.foundation.NSLocking#lock()
	 */
	public void lock() {
		EOAccessLock.lock();
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see net.wotonomy.foundation.NSLocking#unlock()
	 */
	public void unlock() {
		EOAccessLock.unlock();
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * net.wotonomy.control.EOObjectStore#arrayFaultWithSourceGlobalID(net.wotonomy.
	 * control.EOGlobalID, java.lang.String, net.wotonomy.control.EOEditingContext)
	 */
	public NSArray arrayFaultWithSourceGlobalID(EOGlobalID gid, String relName, EOEditingContext ec) {
		if (!(gid instanceof EOKeyGlobalID))
			throw new IllegalArgumentException("an EOKeyGlobalID is needed.");
		EOAccessArrayFaultHandler handler = new EOAccessArrayFaultHandler((EOKeyGlobalID) gid, relName, this, ec);
		return new NSArray(handler);
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * net.wotonomy.control.EOObjectStore#faultForGlobalID(net.wotonomy.control.
	 * EOGlobalID, net.wotonomy.control.EOEditingContext)
	 */
	public /* EOEnterpriseObject */Object faultForGlobalID(EOGlobalID gid, EOEditingContext ec) {
		if (!(gid instanceof EOKeyGlobalID))
			throw new IllegalArgumentException("Cannot fault an object that doesn't have a key global ID.");
		EOAccessFaultHandler handler = new EOAccessFaultHandler((EOKeyGlobalID) gid, this, ec);
		EOEntity e = database().entityNamed(((EOKeyGlobalID) gid).entityName());
		Object o = e.classDescriptionForInstances().createInstanceWithEditingContext(ec, gid);
		EOFaultHandler.makeObjectIntoFault(o, handler);
		return o;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see net.wotonomy.control.EOObjectStore#faultForRawRow(java.util.Map,
	 * java.lang.String, net.wotonomy.control.EOEditingContext)
	 */
	public /* EOEnterpriseObject */ Object faultForRawRow(Map row, String entityName, EOEditingContext ec) {
		EOEntity e = database().entityNamed(entityName);
		EOGlobalID gid = e.globalIDForRow(row);
		return faultForGlobalID(gid, ec);
	}

	public void forgetSnapshotForGlobalID(EOGlobalID gid) {
		if (_simpleSnaps == null)
			throw new IllegalArgumentException("Attempt to forget snapshot with no transaction in progress.");
		_simpleSnaps.removeObjectForKey(gid);
		_manySnaps.removeObjectForKey(gid);
	}

	public void forgetSnapshotsForGlobalIDs(List gids) {
		for (int i = 0; i < gids.size(); i++) {
			EOGlobalID g = (EOGlobalID) gids.get(i);
			forgetSnapshotForGlobalID(g);
			database().forgetSnapshotForGlobalID(g);
		}
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see net.wotonomy.control.EOObjectStore#initializeObject(java.lang.Object,
	 * net.wotonomy.control.EOGlobalID, net.wotonomy.control.EOEditingContext)
	 */
	public void initializeObject(/* EOEnterpriseObject */Object eo, EOGlobalID gid, EOEditingContext ec) {
		if (gid.isTemporary())
			return;
		NSDictionary snap = snapshotForGlobalID(gid);
		Object obj = ec.objectForGlobalID(gid);
		EOEntity e = database().entityNamed(((EOKeyGlobalID) gid).entityName());
		NSArray props = e.classProperties();
		for (int i = 0; i < props.count(); i++) {
			EOProperty p = (EOProperty) props.objectAtIndex(i);
			Object val = snap.objectForKey(p.name());
			if (p instanceof EOAttribute) {
				if (eo instanceof EOKeyValueCoding) {
					((EOKeyValueCoding) eo).takeValueForKey(val, p.name());
				} else {
					EOKeyValueCodingSupport.takeValueForKey(eo, val, p.name());
				}
			} else if (p instanceof EORelationship) {
				if (((EORelationship) p).isToMany()) {
					val = arrayFaultWithSourceGlobalID(gid, p.name(), ec);
				} else {
					EOEntity dest = ((EORelationship) p).destinationEntity();
					EOKeyGlobalID kgid = (EOKeyGlobalID) dest.globalIDForRow(snap);
					val = ec.objectForGlobalID(kgid);
					if (val == null)
						val = new EOAccessFaultHandler(kgid, this, ec);
				}
				if (val == EOKeyValueCoding.NullValue)
					val = null;
				if (eo instanceof EOKeyValueCoding) {
					((EOKeyValueCoding) eo).takeValueForKey(val, p.name());
				} else {
					EOKeyValueCodingSupport.takeValueForKey(eo, val, p.name());
				}
			}
		}
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see net.wotonomy.control.EOObjectStore#invalidateAllObjects()
	 */
	public void invalidateAllObjects() {
		invalidateObjectsWithGlobalIDs(database().snapshots().allKeys());
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * net.wotonomy.control.EOObjectStore#invalidateObjectsWithGlobalIDs(java.util.
	 * List)
	 */
	public void invalidateObjectsWithGlobalIDs(List aList) {
		forgetSnapshotsForGlobalIDs(aList);
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * net.wotonomy.control.EOObjectStore#isObjectLockedWithGlobalID(net.wotonomy.
	 * control.EOGlobalID, net.wotonomy.control.EOEditingContext)
	 */
	public boolean isObjectLockedWithGlobalID(EOGlobalID gid, EOEditingContext ec) {
		return isObjectLockedWithGlobalID(gid);
	}

	public boolean isObjectLockedWithGlobalID(EOGlobalID gid) {
		return _lockedObjects.containsObject(gid);
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see net.wotonomy.control.EOObjectStore#lockObjectWithGlobalID(net.wotonomy.
	 * control.EOGlobalID, net.wotonomy.control.EOEditingContext)
	 */
	public void lockObjectWithGlobalID(EOGlobalID gid, EOEditingContext ec) {
		NSDictionary snap = snapshotForGlobalID(gid);
		if (snap == null)
			return;
		if (!(gid instanceof EOKeyGlobalID))
			return;
		EOEntity e = database().entityNamed(((EOKeyGlobalID) gid).entityName());
		EOQualifier q = e.qualifierForPrimaryKey(snap);
		EOFetchSpecification fspec = new EOFetchSpecification(e.name(), q, null);
		fspec.setLocksObjects(true);
		NSArray arr = ec.objectsWithFetchSpecification(fspec);
		if (arr.count() != 1)
			throw new IllegalStateException("Cannot lock object with Global ID " + gid);
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * net.wotonomy.control.EOObjectStore#objectsForSourceGlobalID(net.wotonomy.
	 * control.EOGlobalID, java.lang.String, net.wotonomy.control.EOEditingContext)
	 */
	public NSArray objectsForSourceGlobalID(EOGlobalID gid, String relationName, EOEditingContext ec) {
		EOEnterpriseObject eo = (EOEnterpriseObject) ec.objectForGlobalID(gid);
		if (eo == null)
			throw new IllegalStateException(
					"Cannot find object for global ID " + gid + " in specified editing context.");
		// Get the source object
		EOEnterpriseObject source = (EOEnterpriseObject) faultForGlobalID(gid, ec);
		if (source == null)
			throw new IllegalStateException("There is no snapshot for source global ID " + gid);

		// Check if there is already a value here
		NSArray value = (NSArray) source.valueForKey(relationName);
		EOAccessArrayFaultHandler handler = null;
		if (value != null) {
			if (EOFaultHandler.isFault(value)) {
				handler = new EOAccessArrayFaultHandler((EOKeyGlobalID) gid, relationName, this, ec);
				// TODO: fire the fault an return the value
			} else
				return value;
		}

		// Get the relationship
		EOEntity entity = database().entityNamed(eo.entityName());
		EORelationship rel = entity.relationshipNamed(relationName);
		if (rel == null)
			throw new IllegalStateException(
					"Cannot find relationship named " + relationName + " in entity " + entity.name());

		// create a fetch specification for this
		EOQualifier q = null;
		NSArray joins = rel.joins();
		NSMutableArray subq = new NSMutableArray(joins.count());
		for (int i = 0; i < joins.count(); i++) {
			EOJoin j = (EOJoin) joins.objectAtIndex(i);
			String key = j.destinationAttribute().name();
			Object val = eo.valueForKey(j.sourceAttribute().name());
			subq.addObject(new EOKeyValueQualifier(key, EOQualifier.QualifierOperatorEqual, val));
		}
		if (subq.count() == 1) {
			q = (EOQualifier) subq.objectAtIndex(0);
		} else {
			q = new EOAndQualifier(subq);
		}
		EOFetchSpecification fspec = new EOFetchSpecification(rel.destinationEntity().name(), q, null);
		NSArray res = ec.objectsWithFetchSpecification(fspec, ec);
		NSMutableArray gids = new NSMutableArray(res.count());
		for (int i = 0; i < res.count(); i++)
			gids.addObject(ec.globalIDForObject(res.objectAtIndex(i)));
		recordSnapshotForSourceGlobalID(gids, gid, relationName);
		return res;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * net.wotonomy.control.EOObjectStore#objectsWithFetchSpecification(net.wotonomy
	 * .control.EOFetchSpecification, net.wotonomy.control.EOEditingContext)
	 */
	public NSArray objectsWithFetchSpecification(EOFetchSpecification fspec, EOEditingContext ec) {
		EODatabaseChannel channel = availableChannel();
		channel.selectObjectsWithFetchSpecification(fspec, ec);
		NSMutableArray arr = new NSMutableArray();
		while (channel.isFetchInProgress()) {
			Object o = channel.fetchObject();
			if (o != null) {
				arr.addObject(o);
			}
		}
		return arr;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see net.wotonomy.control.EOObjectStore#refaultObject(java.lang.Object,
	 * net.wotonomy.control.EOGlobalID, net.wotonomy.control.EOEditingContext)
	 */
	public void refaultObject(Object obj, EOGlobalID gid, EOEditingContext ec) {
		if (!(gid instanceof EOKeyGlobalID))
			throw new IllegalArgumentException("GlobalID must be an EOKeyGlobalID");
		if (obj instanceof EOFaulting)
			// check if it's already a fault
			if (!EOFaultHandler.isFault(obj)) {
				((EOFaulting) obj).turnIntoFault(EOFaultHandler.handlerForFault(obj));
			}
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * net.wotonomy.control.EOObjectStore#saveChangesInEditingContext(net.wotonomy.
	 * control.EOEditingContext)
	 */
	public void saveChangesInEditingContext(EOEditingContext ec) {
		prepareForSaveWithCoordinator(null, ec);
		recordChangesInEditingContext();
		performChanges();
		commitChanges();
	}

	public void registerChannel(EODatabaseChannel channel) {
		if (channel.databaseContext() != this)
			throw new IllegalArgumentException("Cannot register a channel on a context other than its own.");
		if (_channels.containsObject(channel))
			throw new IllegalArgumentException("Attempt to register a channel more than once.");
		_channels.addObject(channel);
	}

	public void unregisterChannel(EODatabaseChannel channel) {
		if (channel.databaseContext() != this)
			throw new IllegalArgumentException("Attempt to unregister a channel from a context other than its own.");
		_channels.removeObject(channel);
	}

	public NSArray registeredChannels() {
		return new NSArray(_channels);
	}

	public NSDictionary snapshotForGlobalID(EOGlobalID gid) {
		NSDictionary d = null;
		if (_simpleSnaps != null) {
			d = (NSDictionary) _simpleSnaps.objectForKey(gid);
		}
		if (d == null)
			d = database().snapshotForGlobalID(gid);
		return d;
	}

	public NSArray snapshotForSourceGlobalID(EOGlobalID gid, String name) {
		NSArray a = null;
		if (_manySnaps != null) {
			NSDictionary d = (NSDictionary) _manySnaps.objectForKey(gid);
			a = (NSArray) d.objectForKey(name);
		}
		if (a == null)
			a = database().snapshotForSourceGlobalID(gid, name);
		return a;
	}

	public void setUpdateStrategy(int strategy) {
		_updateStrategy = strategy;
	}

	public int updateStrategy() {
		return _updateStrategy;
	}

}
/*
 * $Log$ Revision 1.2 2006/02/16 16:47:13 cgruber Move some classes in to
 * "internal" packages and re-work imports, etc.
 *
 * Also use UnsupportedOperationExceptions where appropriate, instead of
 * WotonomyExceptions.
 *
 * Revision 1.1 2006/02/16 13:19:57 cgruber Check in all sources in
 * eclipse-friendly maven-enabled packages.
 *
 * Revision 1.5 2005/05/11 15:21:53 cgruber Change enum to enumeration, since
 * enum is now a keyword as of Java 5.0
 *
 * A few other comments in the code.
 *
 * Revision 1.4 2003/12/18 15:37:38 mpowers Changes to retain ability to work
 * with objects that don't necessarily implement EOEnterpriseObject. I would
 * still like to preserve this case for general usage, however the access
 * package is free to assume that those objects will be EOs and cast
 * appropriately.
 *
 * Revision 1.3 2003/08/29 21:14:44 chochos implement a couple more methods.
 *
 * Revision 1.2 2003/08/20 01:16:22 chochos more methods have code now, but
 * there's no way to test this yet. The core is still pending.
 *
 * Revision 1.1 2003/08/19 01:54:43 chochos The EODatabase layer still needs a
 * lot of work, but it's on its way...
 *
 */