package de.fhdw.wtf.persistence.facade;
   
   import java.sql.CallableStatement;
   import java.sql.ResultSet;
   import java.sql.SQLException;
   import java.util.Collection;
   import java.util.Iterator;
   import java.util.List;
   import java.util.Vector;
  
  import oracle.jdbc.OracleCallableStatement;
  import oracle.jdbc.OracleTypes;
  import oracle.sql.ARRAY;
  import oracle.sql.ArrayDescriptor;
  import de.fhdw.wtf.persistence.exception.ClassFacadeUninitializedException;
  import de.fhdw.wtf.persistence.exception.InitializingDatabaseContractViolationException;
  import de.fhdw.wtf.persistence.exception.OtherSQLException;
  import de.fhdw.wtf.persistence.exception.PersistenceException;
  import de.fhdw.wtf.persistence.exception.SpecializationCycleDetected;
  import de.fhdw.wtf.persistence.meta.Association;
  import de.fhdw.wtf.persistence.meta.IntegerType;
  import de.fhdw.wtf.persistence.meta.MapAssociation;
  import de.fhdw.wtf.persistence.meta.StringType;
  import de.fhdw.wtf.persistence.meta.Type;
  import de.fhdw.wtf.persistence.meta.UnidirectionalAssociation;
  import de.fhdw.wtf.persistence.meta.UserType;
  import de.fhdw.wtf.persistence.utils.IntegerConstants;
  
  /**
   * A class to represent an implementation of the ClassFacade Interface for the Oracle Database. Supports a Database
   * Initializer.
   */
  public class OracleClassFacadeImplementation implements ClassFacade {
  	
  	/**
  	 * A flag to determine, if the ClassFacade was initialized,e.g. TypeManager is filled with information and base
  	 * types are initialized.
  	 */
  	private boolean initialized;
  	
  	/**
  	 * The Type Manager which stores the Model Item informations.
  	 */
  	private TypeManagerImplementation typeManager;
  	
  	/**
  	 * The Oracle Database Manager, which is needed to call the Database.
  	 */
  	private final OracleDatabaseManager database;
  	
  	/**
  	 * Constructor for a new OracleClassFacadeImplementation.
  	 * 
  	 * @param database
  	 *            The OracleDatabaseManager, which has to be connected.
  	 */
  	public OracleClassFacadeImplementation(final OracleDatabaseManager database) {
  		this.database = database;
  		this.initialized = false;
  		this.typeManager = TypeManagerImplementation.getInstance();
  	}
  	
  	@Override
  	public UserType createUserType(final String name, final boolean abs, final boolean transaction)
  			throws PersistenceException {
  		final UserType result = new UserType(IDManager.instance().pullNextUnusedTypeID(name), name, abs, transaction);
  		try (final CallableStatement call =
  				this.database.getConnection().prepareCall(
  						"begin " + this.database.getSchemaName() + ".classfacade.createUserType(?,?,?,?); end;")) {
  			call.setLong(1, result.getId());
  			call.setString(2, result.getName());
  			call.setInt(IntegerConstants.THREE, result.isAbs() ? 1 : 0);
  			call.setInt(IntegerConstants.FOUR, result.isTrans() ? 1 : 0);
  			call.execute();
  		} catch (final SQLException e) {
  			throw new OtherSQLException(e);
  		}
  		this.typeManager.saveType(result);
  		return result;
  	}
  	
  	@Override
  	public UnidirectionalAssociation createUnidirectionalAssociation(final String name,
  			final boolean essential,
  			final boolean unique,
  			final UserType owner,
  			final Type target) throws PersistenceException {
  		final UnidirectionalAssociation result =
  				new UnidirectionalAssociation(IDManager.instance().pullNextUnusedAssociationID(name), name, owner,
  						target, essential, unique);
  		try (final CallableStatement call =
  				this.database.getConnection().prepareCall(
  						"begin " + this.database.getSchemaName()
  								+ ".classfacade.createUnidirAssociation(?,?,?,?,?,?); end;")) {
  			call.setLong(1, result.getId());
  			call.setString(2, result.getName());
  			call.setLong(IntegerConstants.THREE, result.getOwner().getId());
  			call.setLong(IntegerConstants.FOUR, result.getTarget().getId());
  			call.setInt(IntegerConstants.FIVE, result.isEssential() ? 1 : 0);
 			call.setInt(IntegerConstants.SIX, result.isUnique() ? 1 : 0);
 			call.execute();
 		} catch (final SQLException e) {
 			throw new OtherSQLException(e);
 		}
 		this.typeManager.saveAssociation(result);
 		return result;
 	}
 	
 	@Override
 	public MapAssociation createMapAssociation(final String name,
 			final boolean essential,
 			final UserType owner,
 			final Type target,
 			final Type keyType) throws PersistenceException {
 		final MapAssociation result =
 				new MapAssociation(IDManager.instance().pullNextUnusedAssociationID(name), name, owner, target,
 						keyType, essential);
 		try (final CallableStatement call =
 				this.database.getConnection().prepareCall(
 						"begin " + this.database.getSchemaName()
 								+ ".classfacade.createMapAssociation(?,?,?,?,?,?,?); end;")) {
 			call.setLong(1, result.getId());
 			call.setString(2, result.getName());
 			call.setLong(IntegerConstants.THREE, result.getOwner().getId());
 			call.setLong(IntegerConstants.FOUR, result.getTarget().getId());
 			call.setInt(IntegerConstants.FIVE, result.isEssential() ? 1 : 0);
 			call.setInt(IntegerConstants.SIX, 1);
 			call.setLong(IntegerConstants.SEVEN, result.getKeyType().getId());
 			call.execute();
 		} catch (final SQLException e) {
 			throw new OtherSQLException(e);
 		}
 		this.typeManager.saveAssociation(result);
 		return result;
 	}
 	
 	@Override
 	public void createSpecializationBetween(final UserType ancestor, final Type descendant) throws PersistenceException {
 		try (final CallableStatement call =
 				this.database.getConnection().prepareCall(
 						"begin " + this.database.getSchemaName() + ".classfacade.createSpecialization(?,?); end;")) {
 			call.setLong(1, ancestor.getId());
 			call.setLong(2, descendant.getId());
 			call.execute();
 		} catch (final SQLException e) {
 			throw new OtherSQLException(e);
 		}
 	}
 	
 	@Override
 	public void initialize() throws PersistenceException {
 		try (final CallableStatement call =
 				this.database.getConnection().prepareCall(
 						"begin " + this.database.getSchemaName() + ".classfacade.initialize; end;")) {
 			call.execute();
 		} catch (final SQLException e) {
 			throw new OtherSQLException(e);
 		}
 		
 		try (final CallableStatement call =
 				this.database.getConnection().prepareCall(
 						"begin ? :=" + this.database.getSchemaName() + ".classfacade.getMaxIdFromType; end;")) {
 			call.registerOutParameter(1, OracleTypes.NUMBER);
 			call.execute();
 			if (IDManager.getMaxBaseTypeID() != call.getLong(1)) {
 				throw new InitializingDatabaseContractViolationException();
 			}
 		} catch (final SQLException e) {
 			throw new OtherSQLException(e);
 		}
 		
 		try (final CallableStatement call =
 				this.database.getConnection().prepareCall(
 						"begin ? :=" + this.database.getSchemaName() + ".classfacade.getMaxIdFromAssociation; end;")) {
 			call.registerOutParameter(1, OracleTypes.NUMBER);
 			call.execute();
 			if (IDManager.getMaxAssociationContractID() != call.getLong(1)) {
 				throw new InitializingDatabaseContractViolationException();
 			}
 		} catch (final SQLException e) {
 			throw new OtherSQLException(e);
 		}
 		
 		this.initializeBaseTypes();
 		this.finalizeSpecialization();
 		this.initialized = true;
 	}
 	
 	@Override
 	public boolean isSuperClassTo(final Type ancestor, final Type descendant) throws PersistenceException {
 		try (final CallableStatement call =
 				this.database.getConnection().prepareCall(
 						"begin ?:=" + this.database.getSchemaName() + ".classfacade.isSuperclassTo(?,?); end;")) {
 			call.registerOutParameter(1, OracleTypes.NUMBER);
 			call.setLong(2, ancestor.getId());
 			call.setLong(IntegerConstants.THREE, descendant.getId());
 			call.execute();
 			return call.getInt(1) == 1 ? true : false;
 		} catch (final SQLException e) {
 			e.printStackTrace();
 			throw new OtherSQLException(e);
 		}
 	}
 	
 	@Override
 	public void clear() throws PersistenceException {
 		try (final CallableStatement call =
 				this.database.getConnection().prepareCall(
 						"begin " + this.database.getSchemaName() + ".classfacade.clearAll; end;")) {
 			call.execute();
 		} catch (final SQLException e) {
 			throw new OtherSQLException(e);
 		}
 	}
 	
 	@Override
 	public void finalizeSpecialization() throws PersistenceException {
 		try (final CallableStatement call =
 				this.database.getConnection().prepareCall(
 						"begin " + this.database.getSchemaName() + ".classfacade.finalizeSpecialization; end;")) {
 			call.execute();
 		} catch (final SQLException e) {
 			if (e.getErrorCode() == SpecializationCycleDetected.ERRORCODE) {
 				throw new SpecializationCycleDetected(e);
 			}
 			e.printStackTrace();
 			throw new OtherSQLException(e);
 		}
 	}
 	
 	@Override
 	public void renameType(final Long typeId, final String newName) throws PersistenceException {
 		try (final CallableStatement call =
 				this.database.getConnection().prepareCall(
 						"begin " + this.database.getSchemaName() + ".classfacade.renameType(?,?); end;")) {
 			call.setLong(1, typeId);
 			call.setString(2, newName);
 			call.execute();
 		} catch (final SQLException e) {
 			e.printStackTrace();
 			throw new OtherSQLException(e);
 		}
 	}
 	
 	@Override
 	public void renameAssociation(final Long associationId, final String newName) throws PersistenceException {
 		try (final CallableStatement call =
 				this.database.getConnection().prepareCall(
 						"begin " + this.database.getSchemaName() + ".classfacade.renameAssociation(?,?); end;")) {
 			call.setLong(1, associationId);
 			call.setString(2, newName);
 			call.execute();
 		} catch (final SQLException e) {
 			e.printStackTrace();
 			throw new OtherSQLException(e);
 		}
 	}
 	
 	@Override
 	public void deleteAssociation(final Long assoId) throws PersistenceException {
 		this.typeManager.deleteAssociation(assoId);
 		try (final CallableStatement call =
 				this.database.getConnection().prepareCall(
 						"begin " + this.database.getSchemaName() + ".classfacade.deleteAssociation(?); end;")) {
 			call.setLong(1, assoId);
 			call.execute();
 		} catch (final SQLException e) {
 			e.printStackTrace();
 			throw new OtherSQLException(e);
 		}
 	}
 	
 	@Override
 	public void updateLinksToNewAssociation(final Long assoId, final Collection<Long> newAssociationIds)
 			throws PersistenceException {
 		try (final CallableStatement call =
 				this.database.getConnection().prepareCall(
 						"begin " + this.database.getSchemaName() + ".classfacade.pushDownLinks(?,?); end;")) {
 			call.setLong(1, assoId);
 			final ArrayDescriptor des =
 					ArrayDescriptor.createDescriptor(
 							this.database.getSchemaName().toUpperCase() + ".ARRAY_INT",
 							this.database.getConnection());
 			final Long[] newAssos = newAssociationIds.toArray(new Long[newAssociationIds.size()]);
 			final ARRAY arrayNewAssociation = new ARRAY(des, this.database.getConnection(), newAssos);
 			call.setArray(2, arrayNewAssociation);
 			call.execute();
 		} catch (final SQLException e) {
 			e.printStackTrace();
 			throw new OtherSQLException(e);
 		}
 	}
 	
 	@Override
 	public void deleteUserType(final Long typeId) throws PersistenceException {
 		this.typeManager.deleteType(typeId);
 		try (final CallableStatement call =
 				this.database.getConnection().prepareCall(
 						"begin " + this.database.getSchemaName() + ".classfacade.deleteUserTypeAndSpec(?); end;")) {
 			call.setLong(1, typeId);
 			call.execute();
 		} catch (final SQLException e) {
 			e.printStackTrace();
 			throw new OtherSQLException(e);
 		}
 	}
 	
 	@Override
 	public void moveLinksAndCreateObjects(final List<Long> oldAssoIds,
 			final Association newAsso,
 			final UserType newType,
 			final List<Long> newAssoIds) throws PersistenceException {
 		try (final CallableStatement call =
 				this.database.getConnection().prepareCall(
 						"begin " + this.database.getSchemaName()
 								+ ".classfacade.moveLinksAndCreateObjects(?,?,?,?); end;")) {
 			// TODO Implement database function!
 			final ArrayDescriptor des =
 					ArrayDescriptor.createDescriptor(
 							this.database.getSchemaName().toUpperCase() + ".ARRAY_INT",
 							this.database.getConnection());
 			final Long[] oldAssosA = oldAssoIds.toArray(new Long[oldAssoIds.size()]);
 			final Long[] newAssosA = newAssoIds.toArray(new Long[newAssoIds.size()]);
 			final ARRAY arrayNewAssociations = new ARRAY(des, this.database.getConnection(), newAssosA);
 			final ARRAY arrayOldAssociations = new ARRAY(des, this.database.getConnection(), oldAssosA);
 			
 			call.setArray(1, arrayOldAssociations);
 			call.setLong(2, newAsso.getId());
 			call.setLong(IntegerConstants.THREE, newType.getId());
 			call.setArray(IntegerConstants.FOUR, arrayNewAssociations);
 			call.execute();
 		} catch (final SQLException e) {
 			e.printStackTrace();
 			throw new OtherSQLException(e);
 		}
 	}
 	
 	@Override
 	public TypeManager getTypeManager() throws ClassFacadeUninitializedException {
 		if (!this.hasBeenInitialized()) {
 			throw new ClassFacadeUninitializedException();
 		}
 		return this.typeManager;
 	}
 	
 	private void initializeBaseTypes() {
 		this.typeManager.saveType(StringType.getInstance());
 		this.typeManager.saveType(IntegerType.getInstance());
 	}
 	
 	/**
 	 * A private method to check if an Object exists in the types Collection with the type information (id, name) of the
 	 * String Type from the contract and removes this object from the types Collection, if it exists.
 	 * 
 	 * @param types
 	 *            A Collection of Types.
 	 * @return Provides true if an Object with the string type information exists.
 	 */
 	private boolean checkIfStringIsCorrect(final Collection<Type> types) {
 		final Iterator<Type> i = types.iterator();
 		while (i.hasNext()) {
 			final Type current = i.next();
 			if (current.getId() == 1 && current.getName().equals(StringType.STRING_NAME)) {
 				i.remove();
 				return true;
 			}
 		}
 		return false;
 	}
 	
 	/**
 	 * A private method to check if an Object exists in the types Collection with the type information (id, name) of the
 	 * Integer Type from the contract and removes this object from the types Collection, if it exists.
 	 * 
 	 * @param types
 	 *            A Collection of Types.
 	 * @return Provides true if an Object with the integer type information exists.
 	 */
 	private boolean checkIfIntegerIsCorrect(final Collection<Type> types) {
 		final Iterator<Type> i = types.iterator();
 		while (i.hasNext()) {
 			final Type current = i.next();
 			if (current.getId() == 2 && current.getName().equals(IntegerType.INTEGER_NAME)) {
 				i.remove();
 				return true;
 			}
 		}
 		return false;
 	}
 	
 	@Override
 	public boolean hasBeenInitialized() {
 		return this.initialized;
 	}
 	
 	@Override
 	public void initializeForRuntime() throws PersistenceException {
 		this.typeManager = TypeManagerImplementation.getInstance();
 		final Collection<Type> types = new Vector<>();
 		try (final CallableStatement call =
 				this.database.getConnection().prepareCall(
 						"begin ?:= " + this.database.getSchemaName() + ".classfacade.getAllTypes; end;")) {
 			call.registerOutParameter(1, OracleTypes.CURSOR);
 			call.execute();
 			
 			try (final ResultSet result = ((OracleCallableStatement) call).getCursor(1)) {
 				while (result.next()) {
 					types.add(new UserType(result.getLong(1), result.getString(2), result
 							.getInt(IntegerConstants.THREE) == 1 ? true : false,
 							result.getInt(IntegerConstants.FOUR) == 1 ? true : false));
 				}
 			}
 		} catch (final SQLException e) {
 			throw new OtherSQLException(e);
 		}
 		
 		if (!this.checkIfStringIsCorrect(types)) {
 			throw new InitializingDatabaseContractViolationException();
 		}
 		if (!this.checkIfIntegerIsCorrect(types)) {
 			throw new InitializingDatabaseContractViolationException();
 		}
 		this.initializeBaseTypes();
 		for (final Type t : types) {
 			this.typeManager.saveType(t);
 		}
 		
 		try (final CallableStatement call =
 				this.database.getConnection().prepareCall(
 						"begin ?:= " + this.database.getSchemaName() + ".classfacade.getAllUnidirAssociations; end;")) {
 			call.registerOutParameter(1, OracleTypes.CURSOR);
 			call.execute();
 			
 			final Collection<UnidirectionalAssociation> unidirectionalAssociations = new Vector<>();
 			try (final ResultSet result = ((OracleCallableStatement) call).getCursor(1)) {
 				while (result.next()) {
 					unidirectionalAssociations.add(new UnidirectionalAssociation(result.getLong(1),
 							result.getString(2), (UserType) this.typeManager.getTypeForId(result
 									.getLong(IntegerConstants.THREE)), this.typeManager.getTypeForId(result
 									.getLong(IntegerConstants.FOUR)), result.getInt(IntegerConstants.FIVE) == 1 ? true
 									: false, result.getInt(IntegerConstants.SIX) == 1 ? true : false));
 				}
 			}
 			final Iterator<UnidirectionalAssociation> i = unidirectionalAssociations.iterator();
 			while (i.hasNext()) {
 				final UnidirectionalAssociation current = i.next();
 				this.typeManager.saveAssociation(current);
 			}
 		} catch (final SQLException e) {
 			throw new OtherSQLException(e);
 		}
 		
 		try (final CallableStatement call =
 				this.database.getConnection().prepareCall(
 						"begin ?:= " + this.database.getSchemaName() + ".classfacade.getAllMapAssociations; end;")) {
 			call.registerOutParameter(1, OracleTypes.CURSOR);
 			call.execute();
 			
 			final Collection<MapAssociation> mapAssociations = new Vector<>();
 			try (final ResultSet result = ((OracleCallableStatement) call).getCursor(1)) {
 				while (result.next()) {
 					mapAssociations.add(new MapAssociation(result.getLong(1), result.getString(2),
 							(UserType) this.typeManager.getTypeForId(result.getLong(IntegerConstants.THREE)),
 							this.typeManager.getTypeForId(result.getLong(IntegerConstants.FOUR)), this.typeManager
 									.getTypeForId(result.getLong(IntegerConstants.FIVE)), result
 									.getInt(IntegerConstants.SIX) == 1 ? true : false));
 				}
 			}
 			final Iterator<MapAssociation> i = mapAssociations.iterator();
 			while (i.hasNext()) {
 				final MapAssociation current = i.next();
 				this.typeManager.saveAssociation(current);
 			}
 		} catch (final SQLException e) {
 			throw new OtherSQLException(e);
 		}
 		
 		this.initialized = true;
 		// TODO set the lastSetTypeId and the lastSetAssociationId correctly
 	}
 	
 }