/*
 * Copyright 2011 Instituto Superior Tecnico
 * 
 *      https://fenix-ashes.ist.utl.pt/
 * 
 *   This file is part of the vaadin-framework.
 *
 *   The vaadin-framework Infrastructure is free software: you can
 *   redistribute it and/or modify it under the terms of the GNU Lesser General
 *   Public License as published by the Free Software Foundation, either version
 *   3 of the License, or (at your option) any later version.*
 *
 *   vaadin-framework is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 *   GNU Lesser General Public License for more details.
 *
 *   You should have received a copy of the GNU Lesser General Public License
 *   along with vaadin-framework. If not, see <http://www.gnu.org/licenses/>.
 * 
 */
package pt.ist.vaadinframework.data;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.UUID;

import pt.ist.fenixWebFramework.services.Service;
import pt.ist.fenixWebFramework.services.ServiceManager;
import pt.ist.fenixWebFramework.services.ServicePredicate;
import pt.ist.vaadinframework.data.util.ServiceUtils;

import com.vaadin.data.BufferedValidatable;
import com.vaadin.data.Container;
import com.vaadin.data.Item;
import com.vaadin.data.Property;
import com.vaadin.data.Validator;
import com.vaadin.data.Validator.InvalidValueException;
import com.vaadin.data.util.AbstractInMemoryContainer;
import com.vaadin.data.util.filter.UnsupportedFilterException;

public abstract class AbstractBufferedContainer<ItemId, Id, ItemType extends AbstractBufferedItem<Id, ? extends ItemId>> extends
        AbstractInMemoryContainer<Object, Id, ItemType> implements HintedProperty<List<ItemId>>, BufferedValidatable,
        Container.Sortable, Container.Filterable, Container.PropertySetChangeNotifier {
    private static Class classType;

    static {
        try {
            classType = Class.forName("java.util.List");
        } catch (ClassNotFoundException e) {
        }
    }

    public class ContainerPropertyWrapper extends BufferedProperty<List<Object>> {
        public ContainerPropertyWrapper(Property wrapped, Hint... hints) {
            super(wrapped, hints);
        }

        public ContainerPropertyWrapper(Hint... hints) {
            super(classType, hints);
        }

        public ContainerPropertyWrapper(List<Object> elements, Hint... hints) {
            super(elements, hints);
        }

        @Override
        protected List<Object> convertValue(Object value) throws ConversionException {
            ArrayList<Object> result = new ArrayList<Object>();
            if (value != null) {
                if (value instanceof Iterable) {
                    for (Object itemId : (Iterable<?>) value) {
                        result.add(itemId);
                    }
                } else {
                    throw new ConversionException();
                }
            }
            return result;
        }

        @Override
        protected void processNewCacheValue() {
            fireItemSetChange();
        }

        @Override
        public void commit() throws SourceException, InvalidValueException {
            ServiceManager.execute(new ServicePredicate() {
                @Override
                public void execute() {
                    try {
                        for (Object itemId : getAllItemIds()) {
                            if (indexPropertyId != null) {
                                getContainerProperty(itemId, indexPropertyId).setValue(indexOfId(itemId));
                            }
                            getItem(itemId).commit();
                        }
                        ContainerPropertyWrapper.super.commit();
                    } catch (Throwable e) {
                        ServiceUtils.handleException(e);
                        throw new SourceException(AbstractBufferedContainer.this, e);
                    }
                }
            });
        }

        @Override
        public void discard() throws SourceException {
            super.discard();
            for (Object itemId : getAllItemIds()) {
                getUnfilteredItem(itemId).discard();
            }
        }

        @Override
        public boolean isValid() {
            for (Object itemId : getAllItemIds()) {
                if (!getUnfilteredItem(itemId).isValid()) {
                    return false;
                }
            }
            return super.isValid();
        }

        @Override
        public void validate() throws InvalidValueException {
            for (Object itemId : getAllItemIds()) {
                getItem(itemId).validate();
            }
            super.validate();
        }
    }

    protected final ContainerPropertyWrapper value;

    protected final List<Id> propertyIds = new ArrayList<Id>();

    protected final Map<Id, Class<?>> types = new HashMap<Id, Class<?>>();

    protected final Map<ItemId, ItemType> items = new HashMap<ItemId, ItemType>();

    protected final List<ItemType> newItems = new ArrayList<ItemType>();

    protected final Map<UUID, ItemType> limboItems = new HashMap<UUID, ItemType>();

    protected final Class<? extends ItemId> elementType;

    protected Object indexPropertyId;

    private final ValueChangeListener itemChangeListener = new ValueChangeListener() {
        @Override
        public void valueChange(ValueChangeEvent event) {
            ItemType item = (ItemType) event.getProperty();
            if (newItems.contains(item)) {
                newItems.remove(item);
                // registerNewItem will add the listener again so avoid
                // duplication by removing now.
                item.removeListener(this);
            } else {
                for (Entry<UUID, ItemType> entry : limboItems.entrySet()) {
                    if (entry.getValue().equals(item)) {
                        item.removeListener(this);
                        getAllItemIds().remove(entry.getKey());
                        limboItems.remove(entry.getKey());
                    }
                }
                // we lost the old id, so search the item in the map and remove
                // by its key.
                for (Entry<ItemId, ItemType> entry : items.entrySet()) {
                    if (entry.getValue().equals(item)) {
                        removeItem(entry.getKey());
                    }
                }
            }
            internalAddItemAtEnd(item.getValue(), item, true);
        }
    };

    public AbstractBufferedContainer(Property wrapped, Class<? extends ItemId> elementType, Hint... hints) {
        super();
        value = new ContainerPropertyWrapper(wrapped, hints);
        this.elementType = elementType;
    }

    public AbstractBufferedContainer(Class<? extends ItemId> elementType, Hint... hints) {
        super();
        value = new ContainerPropertyWrapper(hints);
        this.elementType = elementType;
    }

    public AbstractBufferedContainer(List<ItemId> elements, Class<? extends ItemId> elementType, Hint... hints) {
        super();
        value = new ContainerPropertyWrapper((List<Object>) elements, hints);
        this.elementType = elementType;
    }

    public Class<? extends ItemId> getElementType() {
        return elementType;
    }

    public void setIndexProperty(Object propertyId) {
        indexPropertyId = propertyId;
    }

    // container implementation

    @Override
    protected List<Object> getAllItemIds() {
        return value.getValue();
    }

    @Override
    public Collection<Id> getContainerPropertyIds() {
        return Collections.unmodifiableCollection(propertyIds);
    }

    /**
     * Add a new property to the container. The default value is ignored, we
     * have no intention to override the values in the underlying items.
     * 
     * @see Container#addContainerProperty(Object, Class, Object)
     */
    @Override
    public boolean addContainerProperty(Object propertyId, Class<?> type, Object defaultValue)
            throws UnsupportedOperationException {
        // Fails, if nulls are given
        if (propertyId == null || type == null) {
            return false;
        }

        // Fails if the Property is already present
        if (propertyIds.contains(propertyId)) {
            return false;
        }

        // Adds the Property to Property list and types
        propertyIds.add((Id) propertyId);
        types.put((Id) propertyId, type);

        // Sends a change event
        fireContainerPropertySetChange();

        return true;
    }

    /**
     * @see Container#removeContainerProperty(Object)
     */
    @Override
    public boolean removeContainerProperty(Object propertyId) throws UnsupportedOperationException {
        // Fails if the Property is not present
        if (!propertyIds.contains(propertyId)) {
            return false;
        }

        // Removes the Property to Property list and types
        propertyIds.remove(propertyId);
        types.remove(propertyId);

        // If remove the Property from all Items
        for (Object itemId : getAllItemIds()) {
            items.get(itemId).removeItemProperty(propertyId);
        }

        // Sends a change event
        fireContainerPropertySetChange();

        return true;
    }

    /**
     * @see Container#getContainerProperty(java.lang.Object, java.lang.Object)
     */
    @Override
    public Property getContainerProperty(Object itemId, Object propertyId) {
        return getItem(itemId).getItemProperty(propertyId);
    }

    /**
     * @see Container#getType(java.lang.Object)
     */
    @Override
    public Class<?> getType(Object propertyId) {
        return types.get(propertyId);
    }

    // container filterable interface

    /**
     * @see Container.Filterable#addContainerFilter(Container.Filter)
     */
    @Override
    public void addContainerFilter(Filter filter) throws UnsupportedFilterException {
        addFilter(filter);
    }

    /**
     * @see Container.Filterable#removeContainerFilter(Container.Filter)
     */
    @Override
    public void removeContainerFilter(Filter filter) {
        removeFilter(filter);
    }

    /**
     * @see Container.Filterable#removeAllContainerFilters()
     */
    @Override
    public void removeAllContainerFilters() {
        removeAllFilters();
    }

    // container sortable interface

    /**
     * @see Container.Sortable#sort(java.lang.Object[], boolean[])
     */
    @Override
    public void sort(Object[] propertyId, boolean[] ascending) {
        sortContainer(propertyId, ascending);
    }

    /**
     * @see Container.Sortable#getSortableContainerPropertyIds()
     */
    @Override
    public Collection<?> getSortableContainerPropertyIds() {
        return getSortablePropertyIds();
    }

    @Override
    public boolean containsId(Object itemId) {
        // only look at visible items after filtering
        if (itemId == null) {
            return false;
        }
        if (isFiltered()) {
            return getFilteredItemIds().contains(itemId);
        }
        // items are lazy loaded so this next condition is not guaranteed to
        // find the item.
        if (items.containsKey(itemId)) {
            return true;
        }
        return getAllItemIds().contains(itemId);
    }

    /**
     * @see com.vaadin.data.util.AbstractInMemoryContainer#getUnfilteredItem(java.lang.Object)
     */
    @Override
    protected ItemType getUnfilteredItem(Object itemId) {
        if (itemId != null) {
            if (limboItems.containsKey(itemId)) {
                return limboItems.get(itemId);
            }
            if (!items.containsKey(itemId)) {
                items.put((ItemId) itemId, makeItem((ItemId) itemId));
            }
            return items.get(itemId);
        }
        return null;
    }

    protected abstract ItemType makeItem(ItemId itemId);

    protected abstract ItemType makeItem(Class<? extends ItemId> type);

    @Service
    public void addItemBatch(Collection<ItemId> itemIds) {
        for (ItemId itemId : itemIds) {
            addItem(itemId);
        }
    }

    @Override
    public ItemType addItemAt(int index, Object newItemId) throws UnsupportedOperationException {
        return internalAddItemAt(index, newItemId, makeItem((ItemId) newItemId), true);
    }

    @Override
    public ItemType addItemAfter(Object previousItemId, Object newItemId) throws UnsupportedOperationException {
        return internalAddItemAfter(previousItemId, newItemId, makeItem((ItemId) newItemId), true);
    }

    @Override
    public ItemType addItem(Object itemId) throws UnsupportedOperationException {
        return internalAddItemAtEnd(itemId, makeItem((ItemId) itemId), true);
    }

    public ItemType addItem(Class<? extends ItemId> type) {
        ItemType item = makeItem(type);
        newItems.add(item);
        item.addListener(itemChangeListener);
        return item;
    }

    public void addToLimbo(Item item) {
        if (newItems.contains(item)) {
            newItems.remove(item);
            UUID id = UUID.randomUUID();
            getAllItemIds().add(id);
            limboItems.put(id, (ItemType) item);
            fireItemSetChange();
        }
    }

    @Override
    public boolean removeItem(Object itemId) throws UnsupportedOperationException {
        return internalRemoveItem(itemId);
    }

    @Override
    public boolean removeAllItems() throws UnsupportedOperationException {
        internalRemoveAllItems();
        return true;
    }

    @Override
    protected void registerNewItem(int position, final Object itemId, ItemType item) {
        if (isReadOnly()) {
            // TODO: too late, changes have been made.
            throw new ReadOnlyException();
        }
        items.put((ItemId) itemId, item);
        item.addListener(itemChangeListener);
        value.modified = true;
        if (isWriteThrough()) {
            commit();
        }
    }

    @Override
    protected boolean internalRemoveItem(Object itemId) {
        if (isReadOnly()) {
            // TODO: too late, changes have been made.
            throw new ReadOnlyException();
        }
        int position = indexOfId(itemId);
        boolean result = super.internalRemoveItem(itemId);
        if (result) {
            if (limboItems.containsKey(itemId)) {
                limboItems.get(itemId).removeListener(itemChangeListener);
                limboItems.remove(itemId);
            } else if (items.containsKey(itemId)) {
                items.get(itemId).removeListener(itemChangeListener);
                items.remove(itemId);
                value.modified = true;
                if (isWriteThrough()) {
                    commit();
                }
                fireItemRemoved(position, itemId);
            }
        }
        return result;
    }

    @Override
    protected void internalRemoveAllItems() {
        if (isReadOnly()) {
            // TODO: too late, changes have been made.
            throw new ReadOnlyException();
        }
        int size = size();
        super.internalRemoveAllItems();
        for (ItemType item : limboItems.values()) {
            item.removeListener(itemChangeListener);
        }
        limboItems.clear();
        for (ItemType item : items.values()) {
            item.removeListener(itemChangeListener);
        }
        if (size > 0) {
            value.modified = true;
            if (isWriteThrough()) {
                commit();
            }
            // Sends a change event
            fireItemSetChange();
        }
    }

    @Override
    public void addListener(PropertySetChangeListener listener) {
        super.addListener(listener);
    }

    @Override
    public void removeListener(PropertySetChangeListener listener) {
        super.removeListener(listener);
    }

    // Property delegate methods

    @Override
    public List<ItemId> getValue() {
        List<ItemId> result = new ArrayList<ItemId>();
        for (Object itemId : getAllItemIds()) {
            try {
                result.add((ItemId) itemId);
            } catch (ClassCastException e) {
                // ignore this one.
            }
        }
        return result;
    }

    @Override
    public void setValue(Object newValue) throws ReadOnlyException, ConversionException {
        value.setValue(newValue);
    }

    @Override
    public void addHint(Hint hint) {
        value.addHint(hint);
    }

    @Override
    public Collection<Hint> getHints() {
        return value.getHints();
    }

    @Override
    public Class<? extends List<ItemId>> getType() {
        return (Class<? extends List<ItemId>>) value.getType();
    }

    @Override
    public boolean isReadOnly() {
        return value.isReadOnly();
    }

    @Override
    public void setReadOnly(boolean newStatus) {
        value.setReadOnly(newStatus);
    }

    @Override
    public void addListener(ReadOnlyStatusChangeListener listener) {
        value.addListener(listener);
    }

    @Override
    public void removeListener(ReadOnlyStatusChangeListener listener) {
        value.removeListener(listener);
    }

    @Override
    public void addListener(ValueChangeListener listener) {
        value.addListener(listener);
    }

    @Override
    public void removeListener(ValueChangeListener listener) {
        value.removeListener(listener);
    }

    @Override
    public void commit() throws SourceException, InvalidValueException {
        ServiceManager.execute(new ServicePredicate() {
            @Override
            public void execute() {
                try {
                    for (Object itemId : getAllItemIds()) {
                        if (indexPropertyId != null) {
                            getContainerProperty(itemId, indexPropertyId).setValue(indexOfId(itemId));
                        }
                        getItem(itemId).commit();
                    }
                    value.commit();
                } catch (Throwable e) {
                    ServiceUtils.handleException(e);
                    throw new SourceException(AbstractBufferedContainer.this, e);
                }
            }
        });
    }

    @Override
    public void discard() throws SourceException {
        value.discard();
    }

    @Override
    public boolean isWriteThrough() {
        return value.isWriteThrough();
    }

    @Override
    public void setWriteThrough(boolean writeThrough) throws SourceException, InvalidValueException {
        value.setWriteThrough(writeThrough);
    }

    @Override
    public boolean isReadThrough() {
        return value.isReadThrough();
    }

    @Override
    public void setReadThrough(boolean readThrough) throws SourceException {
        value.setReadThrough(readThrough);
    }

    @Override
    public boolean isModified() {
        return value.isModified();
    }

    @Override
    public void addValidator(Validator validator) {
        value.addValidator(validator);
    }

    @Override
    public void removeValidator(Validator validator) {
        value.removeValidator(validator);
    }

    @Override
    public Collection<Validator> getValidators() {
        return value.getValidators();
    }

    @Override
    public boolean isValid() {
        return value.isValid();
    }

    @Override
    public void validate() throws InvalidValueException {
        value.validate();
    }

    @Override
    public boolean isInvalidAllowed() {
        return value.isInvalidAllowed();
    }

    @Override
    public void setInvalidAllowed(boolean invalidAllowed) throws UnsupportedOperationException {
        value.setInvalidAllowed(invalidAllowed);
    }

    @Override
    public boolean isInvalidCommitted() {
        return value.isInvalidCommitted();
    }

    @Override
    public void setInvalidCommitted(boolean invalidCommitted) {
        value.setInvalidCommitted(invalidCommitted);
    }

    @Override
    public String toString() {
        return value.toString();
    }
}