/* 
 * Copyright (c) 2008 Stiftung Deutsches Elektronen-Synchrotron, 
 * Member of the Helmholtz Association, (DESY), HAMBURG, GERMANY.
 *
 * THIS SOFTWARE IS PROVIDED UNDER THIS LICENSE ON AN "../AS IS" BASIS. 
 * WITHOUT WARRANTY OF ANY KIND, EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED 
 * TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR PARTICULAR PURPOSE AND 
 * NON-INFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE 
 * FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, 
 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR 
 * THE USE OR OTHER DEALINGS IN THE SOFTWARE. SHOULD THE SOFTWARE PROVE DEFECTIVE 
 * IN ANY RESPECT, THE USER ASSUMES THE COST OF ANY NECESSARY SERVICING, REPAIR OR 
 * CORRECTION. THIS DISCLAIMER OF WARRANTY CONSTITUTES AN ESSENTIAL PART OF THIS LICENSE. 
 * NO USE OF ANY SOFTWARE IS AUTHORIZED HEREUNDER EXCEPT UNDER THIS DISCLAIMER.
 * DESY HAS NO OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, 
 * OR MODIFICATIONS.
 * THE FULL LICENSE SPECIFYING FOR THE SOFTWARE THE REDISTRIBUTION, MODIFICATION, 
 * USAGE AND OTHER RIGHTS AND OBLIGATIONS IS INCLUDED WITH THE DISTRIBUTION OF THIS 
 * PROJECT IN THE FILE LICENSE.HTML. IF THE LICENSE IS NOT INCLUDED YOU MAY FIND A COPY 
 * AT HTTP://WWW.DESY.DE/LEGAL/LICENSE.HTM
 */
 package org.csstudio.sds.internal.connection;

import java.util.Map;

import org.csstudio.dal.DynamicValueState;
import org.csstudio.platform.simpledal.ConnectionState;
import org.csstudio.sds.internal.model.logic.RuleEngine;
import org.csstudio.sds.internal.rules.ParameterDescriptor;
import org.csstudio.sds.model.WidgetProperty;

/**
 * A channel input process encapsulates the logical rules that have to be
 * applied, when a dynamic value change occurs.
 * 
 * Dynamic value changes are delegated to these processor. Afterwards the
 * processor processes its rules to transform the received value and then it
 * forwards the transformed value to a widget property.
 * 
 * @author Sven Wende
 * 
 */
public final class ChannelInputProcessor {
	
	/**
	 * The channel, which is managed by this processor.
	 */
	private ParameterDescriptor _parameter;

	/**
	 * A rule engine.
	 */
	private RuleEngine _ruleEngine;

	/**
	 * The managed widget property.
	 */
	private WidgetProperty _widgetProperty;

	/**
	 * Property values, which are applied for certain connection states.
	 */
	private Map<ConnectionState, Object> _connectionStatePropertyValues;

	/**
	 * Property values, which are applied for certain condition states.
	 */
	private Map<DynamicValueState, Object> _conditionStatePropertyValues;

	/**
	 * Constructor.
	 * 
	 * @param parameter
	 *            a channel reference
	 * @param ruleEngine
	 *            a rule engine
	 * @param widgetProperty
	 *            a widget property
	 * @param connectionStatePropertyValues
	 *            property values, which are applied for certain connection
	 *            states
	 * @param conditionStatePropertyValues
	 *            Property values, which are applied for certain condition
	 *            states
	 */
	public ChannelInputProcessor(
			final ParameterDescriptor parameter,
			final RuleEngine ruleEngine,
			final WidgetProperty widgetProperty,
			final Map<ConnectionState, Object> connectionStatePropertyValues,
			final Map<DynamicValueState, Object> conditionStatePropertyValues) {
		assert parameter != null;
		assert ruleEngine != null;
		assert widgetProperty != null;
		_parameter = parameter;
		_ruleEngine = ruleEngine;
		_widgetProperty = widgetProperty;
		_connectionStatePropertyValues = connectionStatePropertyValues;
		_conditionStatePropertyValues = conditionStatePropertyValues;
	}

	/**
	 * This method is called by connectors, when a
	 * dynamic value has changed.
	 * 
	 * @param newValue
	 *            the new value
	 */
	public void valueChanged(final Object newValue) {
		// wenn als Value null zur�ckgegeben wird, dann bedeutet dies mitunter,  dass kein Wert gesetzt werden darf
		Object value = _ruleEngine.processRule(_parameter, newValue);
		if (value != null) {
			applyValueToProperty(value);
		}
	}

	@Deprecated
	public void connectionStateChanged(final ConnectionState state) {
		if (_connectionStatePropertyValues != null
				&& _connectionStatePropertyValues.containsKey(state)) {
			applyValueToProperty(_connectionStatePropertyValues.get(state));
		}
	}

	/**
	 * This method is called by connectors when the
	 * connection state changes.
	 * 
	 * @param state
	 *            the current connection state
	 */
	public void connectionStateChanged(org.csstudio.dal.context.ConnectionState state) {
		if (_connectionStatePropertyValues != null
				&& _connectionStatePropertyValues.containsKey(state)) {
			applyValueToProperty(_connectionStatePropertyValues.get(state));
		}
	}

	/**
	 * This method is called by connectors when the
	 * condition state changes.
	 * 
	 * @param state
	 *            the current condition state
	 *            
	 * // FIXME: {@link org.csstudio.platform.simpledal.ConnectionState} verwenden!
	 */
	public void conditionStateChanged(final DynamicValueState state) {
		if (_conditionStatePropertyValues != null
				&& _conditionStatePropertyValues.containsKey(state)) {
			applyValueToProperty(_conditionStatePropertyValues.get(state));
		}
	}

	/**
	 * Applies the specified value to the widget property.
	 * 
	 * @param value
	 *            the new value
	 */
	private void applyValueToProperty(final Object value) {
		_widgetProperty.setPropertyValue(value);
	}

}