/*
    * Copyright (c) 2007, James Leigh All rights reserved.
    * 
    * Redistribution and use in source and binary forms, with or without
    * modification, are permitted provided that the following conditions are met:
    * 
    * - Redistributions of source code must retain the above copyright notice, this
    *   list of conditions and the following disclaimer.
    * - 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. 
   * - Neither the name of the openrdf.org nor the names of its contributors may
   *   be used to endorse or promote products derived from this software without
   *   specific prior written permission.
   * 
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
   * AND ANY EXPRESS 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 COPYRIGHT OWNER OR 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.
   * 
   */
  package org.openrdf.elmo.sesame;
  
  import info.aduna.iteration.CloseableIteration;
  
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.Collections;
  import java.util.HashSet;
  import java.util.Iterator;
  import java.util.List;
  import java.util.Set;
  
  import org.openrdf.elmo.ElmoProperty;
  import org.openrdf.elmo.exceptions.ElmoPersistException;
  import org.openrdf.elmo.exceptions.ElmoIOException;
  import org.openrdf.elmo.sesame.helpers.PropertyChanger;
  import org.openrdf.elmo.sesame.iterators.ElmoIteration;
  import org.openrdf.elmo.sesame.roles.SesameEntity;
  import org.openrdf.model.Resource;
  import org.openrdf.model.Statement;
  import org.openrdf.model.URI;
  import org.openrdf.model.Value;
  import org.openrdf.repository.RepositoryConnection;
  import org.openrdf.repository.RepositoryException;
  import org.openrdf.repository.contextaware.ContextAwareConnection;
  
  /**
   * A set for a given getResource(), predicate.
   * 
   * @author James Leigh
   * 
   * @param <E>
   */
  public class SesameProperty<E> implements ElmoProperty<E>, Set<E> {
  
  	private final SesameEntity bean;
  
  	protected PropertyChanger property;
  
  	private boolean singleCached;
  
  	private E single;
  
  	public SesameProperty(SesameEntity bean, PropertyChanger property) {
  		assert bean != null;
  		assert property != null;
  		this.bean = bean;
  		this.property = property;
  	}
  
  	public void refresh() {
  		singleCached = false;
  		single = null;
  	}
  
  	public boolean add(E o) {
  		Value val = getValue(o);
  		if (contains(val))
  			return false;
  		ContextAwareConnection conn = getConnection();
  		try {
  			add(conn, getResource(), val);
  		} catch (RepositoryException e) {
  			throw new ElmoPersistException(e);
  		}
  		return true;
  	}
  
  	public boolean addAll(Collection<? extends E> c) {
  		RepositoryConnection conn = getConnection();
  		boolean modified = false;
 		try {
 			boolean autoCommit = conn.isAutoCommit();
 			if (autoCommit)
 				conn.setAutoCommit(false);
 			for (E o : c)
 				if (add(o))
 					modified = true;
 			if (autoCommit)
 				conn.setAutoCommit(true);
 		} catch (RepositoryException e) {
 			throw new ElmoPersistException(e);
 		}
 		return modified;
 	}
 
 	public void clear() {
 		ContextAwareConnection conn = getConnection();
 		try {
 			boolean autoCommit = conn.isAutoCommit();
 			conn.setAutoCommit(false);
 			CloseableIteration<? extends Statement, RepositoryException> stmts;
 			stmts = getStatements();
 			try {
 				while (stmts.hasNext()) {
 					remove(conn, stmts.next());
 				}
 			} finally {
 				stmts.close();
 			}
 			conn.setAutoCommit(autoCommit);
 		} catch (RepositoryException e) {
 			throw new ElmoPersistException(e);
 		}
 	}
 
 	public boolean contains(Object o) {
 		Value val = getValue(o);
 		ContextAwareConnection conn = getConnection();
 		try {
 			return conn.hasStatement(getResource(), getURI(), val);
 		} catch (RepositoryException e) {
 			throw new ElmoPersistException(e);
 		}
 	}
 
 	public boolean containsAll(Collection<?> c) {
 		Iterator<?> e = c.iterator();
 		while (e.hasNext())
 			if (!contains(e.next()))
 				return false;
 		return true;
 	}
 
 	@Override
 	public boolean equals(Object o) {
 		if (o == this)
 			return true;
 		if (!o.getClass().equals(this.getClass()))
 			return false;
 		SesameProperty<?> p = (SesameProperty<?>) o;
 		if (!getManager().equals(p.getManager()))
 			return false;
 		if (!getResource().equals(p.getResource()))
 			return false;
 		if (!property.equals(p.property))
 			return false;
 		return true;
 	}
 
 	public Set<E> getAll() {
 		return this;
 	}
 
 	public E getSingle() {
 		if (singleCached)
 			return single;
 		ElmoIteration<Statement, E> iter = getElmoIteration();
 		try {
 			if (iter.hasNext()) {
 				single = iter.next();
 			} else {
 				single = null;
 			}
 			singleCached = true;
 			return single;
 		} finally {
 			iter.close();
 		}
 	}
 
 	@Override
 	public int hashCode() {
 		int hashCode = bean.hashCode();
 		hashCode ^= property.hashCode();
 		return hashCode;
 	}
 
 	public boolean isEmpty() {
 		ElmoIteration<Statement, E> iter = getElmoIteration();
 		try {
 			return !iter.hasNext();
 		} finally {
 			iter.close();
 		}
 	}
 
 	public Iterator<E> iterator() {
 		ElmoIteration<Statement, E> iter = getElmoIteration();
 		if (iter.hasNext()) {
 			bean.opened(iter);
 		}
 		return iter;
 	}
 
 	public boolean remove(Object o) {
 		Value val = getValue(o);
 		if (!contains(val))
 			return false;
 		ContextAwareConnection conn = getConnection();
 		try {
 			remove(conn, getResource(), val);
 		} catch (RepositoryException e) {
 			throw new ElmoPersistException(e);
 		}
 		return true;
 	}
 
 	public boolean removeAll(Collection<?> c) {
 		RepositoryConnection conn = getConnection();
 		boolean modified = false;
 		try {
 			boolean autoCommit = conn.isAutoCommit();
 			if (autoCommit)
 				conn.setAutoCommit(false);
 			for (Object o : c)
 				if (remove(o))
 					modified = true;
 			if (autoCommit)
 				conn.setAutoCommit(true);
 		} catch (RepositoryException e) {
 			throw new ElmoPersistException(e);
 		}
 		return modified;
 	}
 
 	public boolean retainAll(Collection<?> c) {
 		RepositoryConnection conn = getConnection();
 		boolean modified = false;
 		try {
 			boolean autoCommit = conn.isAutoCommit();
 			if (autoCommit)
 				conn.setAutoCommit(false);
 			Iterator<E> e = iterator();
 			while (e.hasNext()) {
 				if (!c.contains(e.next())) {
 					e.remove();
 					modified = true;
 				}
 			}
 			if (autoCommit)
 				conn.setAutoCommit(true);
 		} catch (RepositoryException e) {
 			throw new ElmoPersistException(e);
 		}
 		return modified;
 	}
 
 	public void setAll(Set<E> set) {
 		if (this == set)
 			return;
 		if (set == null) {
 			clear();
 			return;
 		}
 		Set<E> c = new HashSet<E>(set);
 		RepositoryConnection conn = getConnection();
 		try {
 			boolean autoCommit = conn.isAutoCommit();
 			if (autoCommit)
 				conn.setAutoCommit(false);
 			Iterator<E> e = iterator();
 			while (e.hasNext()) {
 				Object next = e.next();
 				if (c.contains(next)) {
 					c.remove(next);
 				} else {
 					e.remove();
 				}
 			}
 			if (c.size() > 0)
 				addAll(c);
 			if (autoCommit)
 				conn.setAutoCommit(true);
 		} catch (RepositoryException e) {
 			throw new ElmoPersistException(e);
 		}
 	}
 
 	public void setSingle(E o) {
 		if (o == null) {
 			clear();
 		} else {
 			setAll(Collections.singleton(o));
 		}
 		single = null;
 		singleCached = false;
 	}
 
 	public int size() {
 		CloseableIteration<? extends Statement, RepositoryException> iter;
 		try {
 			iter = getStatements();
 			try {
 				int size;
 				for (size = 0; iter.hasNext(); size++)
 					iter.next();
 				return size;
 			} finally {
 				iter.close();
 			}
 		} catch (RepositoryException e) {
 			throw new ElmoIOException(e);
 		}
 	}
 
 	public Object[] toArray() {
 		List<E> list = new ArrayList<E>();
 		ElmoIteration<Statement, E> iter = getElmoIteration();
 		try {
 			while (iter.hasNext()) {
 				list.add(iter.next());
 			}
 		} finally {
 			iter.close();
 		}
 		return list.toArray();
 	}
 
 	public <T> T[] toArray(T[] a) {
 		List<E> list = new ArrayList<E>();
 		ElmoIteration<Statement, E> iter = getElmoIteration();
 		try {
 			while (iter.hasNext()) {
 				list.add(iter.next());
 			}
 		} finally {
 			iter.close();
 		}
 		return list.toArray(a);
 	}
 
 	@Override
 	public String toString() {
 		StringBuilder sb = new StringBuilder();
 		ElmoIteration<Statement, E> iter = getElmoIteration();
 		try {
 			if (iter.hasNext()) {
 				sb.append(iter.next().toString());
 			}
 			while (iter.hasNext()) {
 				sb.append(", ");
 				sb.append(iter.next());
 			}
 		} finally {
 			iter.close();
 		}
 		return sb.toString();
 	}
 
 	final SesameManager getManager() {
 		return bean.getSesameManager();
 	}
 
 	final ContextAwareConnection getConnection() {
 		return getManager().getConnection();
 	}
 
 	final Resource getResource() {
 		return bean.getSesameResource();
 	}
 
 	final URI getURI() {
 		return property.getPredicate();
 	}
 
 	void add(ContextAwareConnection conn, Resource subj, Value obj)
 			throws RepositoryException {
 		property.add(conn, subj, obj);
 	}
 
 	void remove(ContextAwareConnection conn, Resource subj, Value obj)
 			throws RepositoryException {
 		property.remove(conn, subj, obj);
 	}
 
 	void remove(ContextAwareConnection conn, Statement stmt)
 			throws RepositoryException {
 		assert stmt.getPredicate().equals(getURI());
 		remove(conn, stmt.getSubject(), stmt.getObject());
 	}
 
 	@SuppressWarnings("unchecked")
 	E createInstance(Statement stmt) {
 		Value value = stmt.getObject();
 		return (E) getManager().getInstance(value);
 	}
 
 	CloseableIteration<? extends Statement, RepositoryException> getStatements()
 			throws RepositoryException {
 		ContextAwareConnection conn = getConnection();
 		return conn.getStatements(getResource(), getURI(), null);
 	}
 
 	Value getValue(Object instance) {
 		if (instance instanceof Value)
 			return (Value) instance;
 		return getManager().getValue(instance);
 	}
 
 	private ElmoIteration<Statement, E> getElmoIteration() {
 		try {
 			return new ElmoIteration<Statement, E>(getStatements()) {
 
 				@Override
 				protected E convert(Statement stmt) {
 					return createInstance(stmt);
 				}
 
 				@Override
 				protected void remove(Statement stmt) {
 					try {
 						ContextAwareConnection conn = getConnection();
 						SesameProperty.this.remove(conn, stmt);
 					} catch (RepositoryException e) {
 						throw new ElmoPersistException(e);
 					}
 				}
 
 			};
 		} catch (RepositoryException e) {
 			throw new ElmoPersistException(e);
 		}
 	}
 
 }