package net.sourceforge.fenixedu.applicationTier.Servico.renderers;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Hashtable;
import java.util.List;

import net.sourceforge.fenixedu.applicationTier.FenixService;
import net.sourceforge.fenixedu.domain.DomainObject;
import net.sourceforge.fenixedu.domain.RootDomainObject;

import org.apache.commons.beanutils.PropertyUtils;

public class UpdateObjects extends FenixService {

    public Collection run(List<ObjectChange> changes) throws ClassNotFoundException, IllegalAccessException,
	    NoSuchMethodException, InstantiationException {
	beforeRun(changes);

	Hashtable<ObjectKey, Object> objects = new Hashtable<ObjectKey, Object>();

	for (ObjectChange change : changes) {
	    try {
		Object object = getObject(objects, change);

		processChange(change, object);
	    } catch (InvocationTargetException e) {
		if (e.getCause() instanceof RuntimeException) {
		    throw (RuntimeException) e.getCause();
		}
	    }
	}

	afterRun(objects.values());

	return objects.values();
    }

    protected void processChange(ObjectChange change, Object object) throws IllegalAccessException, InvocationTargetException,
	    NoSuchMethodException, InstantiationException {
	if (change.slot != null) {
	    setProperty(object, change.slot, change.value);
	} else if (change.setter != null) {
	    invokeSetter(object, change.setter, change.values);
	}
    }

    private void invokeSetter(Object object, Method setter, Object[] values) {
	try {
	    setter.invoke(object, values);
	} catch (InvocationTargetException e) {
	    if (e.getCause() != null && e.getCause() instanceof RuntimeException) {
		throw (RuntimeException) e.getCause();
	    } else {
		throw new RuntimeException("error while invoking specialized setter", e.getTargetException());
	    }
	} catch (Exception e) {
	    throw new RuntimeException("error while invoking specialized setter", e);
	}
    }

    /**
     * Executed before any change is made to the domain.
     * 
     * @param changes
     *            the list of changes planed for the domain
     */
    protected void beforeRun(List<ObjectChange> changes) {
	// nothing
    }

    /**
     * Executed after all changes are made to the domain. This includes the
     * creation of new objects.
     * 
     * @param touchedObjects
     *            the objects that were edited in the interface or created
     */
    protected void afterRun(Collection<Object> touchedObjects) {
	// nothing
    }

    protected void setProperty(Object object, String slot, Object value) throws IllegalAccessException,
	    InvocationTargetException, NoSuchMethodException, InstantiationException {
	Class type = getSlotType(object, slot);

	if (type == null) {
	    throw new RuntimeException("could not find type of property " + slot + " in object " + object);
	}

	if (type.isAssignableFrom(Collection.class)) {
	    setCollectionProperty(object, slot, (List) value);
	} else {
	    try {
		setSlotProperty(object, slot, value);
	    } catch (IllegalArgumentException e) {
		throw new RuntimeException("the value '" + value + "' given for slot '" + slot + "' does not match slot's type '"
			+ type + "'");
	    } catch (IllegalAccessException e) {
		throw new RuntimeException("could not access to the slot '" + slot + "' of object '" + object
			+ "', probably is not public");
	    }
	}
    }

    protected Class getSlotType(Object object, String slot) throws IllegalAccessException, InvocationTargetException,
	    NoSuchMethodException {
	return PropertyUtils.getPropertyType(object, slot);
    }

    protected void setSlotProperty(Object object, String slot, Object value) throws IllegalAccessException,
	    InvocationTargetException, NoSuchMethodException, InstantiationException {
	PropertyUtils.setProperty(object, slot, value);
    }

    protected void setCollectionProperty(Object object, String slot, List list) throws IllegalAccessException,
	    InvocationTargetException, NoSuchMethodException, InstantiationException {
	Collection relation = (Collection) getSlotProperty(object, slot);

	if (relation == null || isWriteableSlot(object, slot)) {
	    relation = new ArrayList();
	    relation.addAll(list);

	    // ASSUMPTION: if collection is null then there is a setter that
	    // allows the value to be changed
	    setSlotProperty(object, slot, relation);
	} else {
	    // ASSUMPTION: changing the list affects the relation
	    // TODO: cfgi, I hope this is ok but must check
	    relation.clear();
	    relation.addAll(list);
	}
    }

    protected boolean isWriteableSlot(Object object, String slot) {
	return PropertyUtils.isWriteable(object, slot);
    }

    protected Object getSlotProperty(Object object, String slot) throws IllegalAccessException, InvocationTargetException,
	    NoSuchMethodException, InstantiationException {
	return PropertyUtils.getProperty(object, slot);
    }

    private Object getObject(Hashtable<ObjectKey, Object> objects, ObjectChange change) throws ClassNotFoundException,
	    InstantiationException, IllegalAccessException, IllegalArgumentException, InvocationTargetException {
	Object object = objects.get(change.key);

	if (object == null) {
	    object = getNewObject(change);
	    objects.put(change.key, object);
	}

	return object;
    }

    protected DomainObject getNewObject(ObjectChange change) throws InstantiationException, IllegalAccessException,
	    ClassNotFoundException, IllegalArgumentException, InvocationTargetException {
	return RootDomainObject.readDomainObjectByOID(change.key.getType(), change.key.getOid());
    }
}