/*******************************************************************************
 *  Copyright (c) 2010 Association for Decentralized Information Management in
 *  Industry THTH ry.
 *  All rights reserved. This program and the accompanying materials
 *  are made available under the terms of the Eclipse Public License v1.0
 *  which accompanies this distribution, and is available at
 *  http://www.eclipse.org/legal/epl-v10.html
 *
 *  Contributors:
 *      VTT Technical Research Centre of Finland - initial API and implementation
 *******************************************************************************/
package org.simantics.databoard.accessor.java;

import java.lang.ref.SoftReference;
import java.util.concurrent.Executor;

import org.simantics.databoard.accessor.Accessor;
import org.simantics.databoard.accessor.RecordAccessor;
import org.simantics.databoard.accessor.error.AccessorConstructionException;
import org.simantics.databoard.accessor.error.AccessorException;
import org.simantics.databoard.accessor.error.ReferenceException;
import org.simantics.databoard.accessor.event.Event;
import org.simantics.databoard.accessor.event.ValueAssigned;
import org.simantics.databoard.accessor.impl.AccessorParams;
import org.simantics.databoard.accessor.impl.ListenerEntry;
import org.simantics.databoard.accessor.interestset.InterestSet;
import org.simantics.databoard.accessor.interestset.RecordInterestSet;
import org.simantics.databoard.accessor.reference.ChildReference;
import org.simantics.databoard.accessor.reference.IndexReference;
import org.simantics.databoard.accessor.reference.LabelReference;
import org.simantics.databoard.accessor.reference.NameReference;
import org.simantics.databoard.adapter.AdaptException;
import org.simantics.databoard.adapter.AdapterConstructionException;
import org.simantics.databoard.binding.Binding;
import org.simantics.databoard.binding.RecordBinding;
import org.simantics.databoard.binding.error.BindingException;
import org.simantics.databoard.binding.mutable.MutableVariant;
import org.simantics.databoard.type.RecordType;

/**
 * Accessor to a Java Object of Record Type.
 *
 * @author Toni Kalajainen <toni.kalajainen@vtt.fi>
 */
public class JavaRecord extends JavaObject implements RecordAccessor {

	/** Accessors to children */
	SoftReference<JavaObject>[] children;
	
	@SuppressWarnings("unchecked")
	public JavaRecord(Accessor parent, RecordBinding binding, Object object, AccessorParams params) throws AccessorConstructionException {
		super(parent, binding, object, params);
		RecordType type = (RecordType) binding.type();
		if (type.isReferable()) throw new AccessorConstructionException("Refereable record are not supported");
		
		int count = binding.type().getComponentCount();
		children = new SoftReference[count];
	}

	@Override
	public RecordBinding getBinding() {
		return (RecordBinding) binding;
	}

	@Override
	public RecordType type() {
		return (RecordType) getBinding().type();
	}	
	
	@Override
	public int count() {
		return type().getComponentCount();
	}

	@SuppressWarnings("unchecked")
	@Override
	public <T extends Accessor> T getFieldAccessor(String fieldName) throws AccessorConstructionException
	{
		int fieldIndex = type().getComponentIndex(fieldName);
		if (fieldIndex<0) throw new AccessorConstructionException("Field "+fieldName+" does not exist");
		return (T) getFieldAccessor(fieldIndex);
	}	
	
	@SuppressWarnings("unchecked")
	@Override
	public <T extends Accessor> T getFieldAccessor(int index) throws AccessorConstructionException
	{
		if (index<0 || index>=count()) throw new ReferenceException("Field index ("+index+") out of bounds ("+count()+")");
		
		readLock();
		try {
			// Get existing or create new
			SoftReference<JavaObject> ref = children[index];
			JavaObject sa = (ref!=null)?(JavaObject)ref.get():null;
			
			if (sa==null) {
				// Instantiate new accessor
				Binding cb = getBinding().getComponentBindings()[index];
				Object cv = getBinding().getComponent(object, index);
				sa = createSubAccessor(this, cb, cv, params);
				sa.keyInParent = index;
				children[index] = new SoftReference<JavaObject>(sa);

				// Add component interest sets
				ListenerEntry le = listeners;
				while (le!=null) {				
					RecordInterestSet is = le.getInterestSet();
					InterestSet cis = is.getComponentInterest(index); 
					if (cis != null) {
						try {
							ChildReference childPath = ChildReference.concatenate( le.path, new IndexReference(index) );
							sa.addListener(le.listener, cis, childPath, le.executor);
						} catch (AccessorException e) {
							throw new AccessorConstructionException(e);
						}
					}
					le = le.next;
				}				
			}		
			
			return (T) sa;
		} catch (BindingException e) {
			throw new AccessorConstructionException(e);
		} finally {
			readUnlock();
		}
	}

	/**
	 * Get existing sub accessor
	 * @param index
	 * @return sub-accessor or <code>null</code>
	 */
	JavaObject getExistingAccessor(int index)
	{
		if (index<0 || index>=count()) throw new RuntimeException("Field index ("+index+") out of bounds ("+count()+")");
		
		// Get existing or create new
		SoftReference<JavaObject> ref = children[index];
		JavaObject accessor = (ref!=null)?(JavaObject)ref.get():null;
		return accessor;
	}	
	
	@Override
	public Object getFieldValue(String fieldName, Binding fieldBinding)
			throws AccessorException {
		int fieldIndex = type().getComponentIndex(fieldName);
		if (fieldIndex<0) throw new AccessorException("Field "+fieldName+" does not exist");
		return getFieldValue(fieldIndex, fieldBinding);
	}
	
	@Override
	public Object getFieldValue(int index, Binding fieldBinding)
			throws AccessorException {
		readLock();
		try {
			Object cv = getBinding().getComponent(object, index);
			Binding cb = getBinding().getComponentBindings()[index];
			return adapt(cv, cb, fieldBinding);
		} catch (BindingException e) {
			throw new AccessorException(e);
		} catch (AdaptException e) {
			throw new AccessorException(e);
		} catch (AdapterConstructionException e) {
			throw new AccessorException(e);
		} finally {
			readUnlock();
		}
	}

	public void setFieldValue(String fieldName, Binding fieldBinding, Object value) throws AccessorException {
		int fieldIndex = type().getComponentIndex(fieldName);
		if (fieldIndex<0) throw new AccessorException("Field "+fieldName+" does not exist");
		setFieldValue(fieldIndex, fieldBinding, value);
	};
	
	@Override
	public void setFieldValue(int index, Binding binding, Object value)
	throws AccessorException {
		writeLock();
		try {			
			JavaObject sa = getExistingAccessor(index);				
			if (sa==null) {				
				// Init
				Binding lb = getBinding().getComponentBindings()[index];
				Binding rb = binding;
				//Object oldlv = getBinding().getComponent(object, index);
				Object rv = value;
				
				// Compare to existing value
//				boolean equal = Bindings.equals(lb, oldlv, lb, rv);
//				if (equal) return;

				// Write
				Object lv = adapt(rv, rb, lb);
				getBinding().setComponent(object, index, lv);
												
				// Notify Listeners
				ListenerEntry le = listeners;
				while (le!=null) {				
					RecordInterestSet is = le.getInterestSet();
					if (is.inNotificationsOf(index)) {
						MutableVariant newValue = is.inValuesOf(index) ? new MutableVariant(binding, value) : null;
						if (is.inValuesOf(index)) newValue = new MutableVariant(binding, binding.isImmutable() ? value : binding.clone(value));						
						Event e = new ValueAssigned(new IndexReference(index), newValue); 
						emitEvent(le, e);
					}
					le = le.next;
				}				
			} else {
				// Recursive write using existing sub accessor
				sa.setValue(binding, value);
			}			
		} catch (BindingException e) {
			throw new AccessorException(e);
		} catch (AdaptException e) {
			throw new AccessorException(e);
		} catch (AdapterConstructionException e) {
			throw new AccessorException(e);
		} finally {
			writeUnlock();
		}
	}
	
	@Override
	public void addListener(Listener listener, InterestSet interestSet,
			ChildReference path, Executor executor) throws AccessorException {
		RecordInterestSet is = (RecordInterestSet) interestSet;
		super.addListener(listener, interestSet, path, executor);
		// Apply component interest set to existing sub-accessors
		if (is.componentInterests!=null) {
			for (int i=0; i<count(); i++) {
				InterestSet cis = is.getComponentInterest(i);
				if (cis==null) continue;
				JavaObject childAccessor = getExistingAccessor(i);
				if (childAccessor==null) continue;
				ChildReference childPath = ChildReference.concatenate( path, new IndexReference(i));
				childAccessor.addListener(listener, cis, childPath, executor);
			}
		}
	}
	
	@Override
	public void removeListener(Listener listener) throws AccessorException {
		ListenerEntry e = detachListener(listener);
		if (e==null) return;
		RecordInterestSet is = (RecordInterestSet) e.interestSet;
		
		// Apply component interest set to existing sub-accessors
		if (is.componentInterests!=null) {
			for (int i=0; i<count(); i++) {
				InterestSet cis = is.getComponentInterest(i);
				if (cis==null) continue;
				JavaObject sa = getExistingAccessor(i);
				if (sa==null) continue;
				sa.removeListener(listener);
			}
		}
	}


	@SuppressWarnings("unchecked")
	@Override
	public <T extends Accessor> T getComponent(ChildReference reference) throws AccessorConstructionException {
		if (reference==null) return (T) this;
		
		if (reference instanceof LabelReference) {
			LabelReference lr = (LabelReference) reference;
			String fieldName = lr.label;
			Integer index = type().getComponentIndex(fieldName);
			if (index==null) throw new ReferenceException("RecordType doesn't have field by name \""+fieldName+"\"");
			JavaObject sa = getFieldAccessor(index);
			if (reference.getChildReference() != null) sa = sa.getComponent(reference.getChildReference());
			return (T) sa;			
		}		
		
		if (reference instanceof IndexReference) {
			IndexReference ref = (IndexReference) reference;
			int index = ref.getIndex();
			JavaObject sa = getFieldAccessor(index);
			if (reference.getChildReference() != null) sa = sa.getComponent(reference.getChildReference());
			return (T) sa;
		} 
		
		if (reference instanceof NameReference) {
			NameReference ref = (NameReference) reference;
			String fieldName = ref.getName();
			Integer index = type().getComponentIndex(fieldName);
			if (index==null) throw new ReferenceException("RecordType doesn't have field by name \""+fieldName+"\"");
			JavaObject sa = getFieldAccessor(index);
			if (reference.getChildReference() != null) sa = sa.getComponent(reference.getChildReference());
			return (T) sa;			
		} 
		
		throw new ReferenceException(reference.getClass()+" is not a subreference of RecordType");
		
	}

	@Override
	public void setValue(Binding binding, Object newValue) throws AccessorException {
		writeLock();
		try {
			RecordBinding rb = (RecordBinding) binding;
			for (int i=0; i<count(); i++) {
				Binding componentBinding = rb.getComponentBinding(i);
				Object componentValue = rb.getComponent(newValue, i);
				setFieldValue(i, componentBinding, componentValue);
			}
		} catch (BindingException e) {
			throw new AccessorException(e);
		} finally {
			writeUnlock();
		}
	}

	
	@Override
	Event applyLocal(Event e, boolean makeRollback) throws AccessorException {
		Event rollback = null;
		if (makeRollback) rollback = new ValueAssigned(getBinding(), getValue(getBinding())); 
		if (e instanceof ValueAssigned) {
			ValueAssigned va = (ValueAssigned) e;
			setValue(va.newValue.getBinding(), va.newValue.getValue());
			return rollback;
		} else {
			throw new AccessorException("Cannot apply "+e.getClass().getName()+" to Record Type");				
		}
	}	
	
}