/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.wicket.model;

import java.io.Serializable;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import java.util.Map;
import java.util.Set;

import org.apache.wicket.model.util.CollectionModel;
import org.apache.wicket.model.util.ListModel;
import org.apache.wicket.model.util.MapModel;
import org.apache.wicket.model.util.SetModel;
import org.apache.wicket.util.lang.Objects;


/**
 * <code>Model</code> is the basic implementation of an <code>IModel</code>. It just wraps a simple
 * model object. The model object must be serializable, as it is stored in the session. If you have
 * large objects to store, consider using {@link org.apache.wicket.model.LoadableDetachableModel}
 * instead of this class.
 * 
 * @author Chris Turner
 * @author Eelco Hillenius
 * 
 * @param <T>
 *            The type of the Model Object
 */
public class Model<T extends Serializable> implements IObjectClassAwareModel<T>
{
        private static final long serialVersionUID = 1L;

        /** Backing object. */
        private T object;

        /**
         * Construct the model without providing an object.
         */
        public Model()
        {
        }

        /**
         * Construct the model, setting the given object as the wrapped object.
         * 
         * @param object
         *            The model object proper
         */
        public Model(final T object)
        {
                setObject(object);
        }

        /**
         * Factory method for models that contain lists. This factory method will automatically rebuild
         * a non-serializable <code>list</code> into a serializable one.
         * 
         * @param <C>
         *            model type
         * @param list
         *            The List, which may or may not be Serializable
         * @return A Model object wrapping the List
         */
        public static <C> IModel<List<C>> ofList(final List<C> list)
        {
                return new ListModel<>(list);
        }

        /**
         * Factory method for models that contain maps. This factory method will automatically rebuild a
         * non-serializable <code>map</code> into a serializable one.
         * 
         * @param <K>
         *            key type in map
         * @param <V>
         *            value type in map
         * @param map
         *            The Map, which may or may not be Serializable
         * @return A Model object wrapping the Map
         */
        public static <K, V> IModel<Map<K, V>> ofMap(final Map<K, V> map)
        {
                return new MapModel<>(map);
        }

        /**
         * Factory method for models that contain sets. This factory method will automatically rebuild a
         * non-serializable <code>set</code> into a serializable one.
         * 
         * @param <C>
         *            model type
         * @param set
         *            The Set, which may or may not be Serializable
         * @return A Model object wrapping the Set
         */
        public static <C> IModel<Set<C>> ofSet(final Set<C> set)
        {
                return new SetModel<>(set);
        }

        /**
         * Factory method for models that contain collections. This factory method will automatically
         * rebuild a non-serializable <code>collection</code> into a serializable {@link ArrayList}.
         * 
         * @param <C>
         *            model type
         * @param collection
         *            The Collection, which may or may not be Serializable
         * @return A Model object wrapping the Set
         */
        public static <C> IModel<Collection<C>> of(final Collection<C> collection)
        {
                return new CollectionModel<>(collection);
        }


        /**
         * Factory methods for Model which uses type inference to make code shorter. Equivalent to
         * <code>new Model<TypeOfObject>(object)</code>.
         * 
         * @param <T>
         * @param object
         * @return Model that contains <code>object</code>
         */
        public static <T extends Serializable> Model<T> of(T object)
        {
                return new Model<>(object);
        }

        /**
         * Factory methods for Model which uses type inference to make code shorter. Equivalent to
         * <code>new Model<TypeOfObject>()</code>.
         * 
         * @param <T>
         * @return Model that contains <code>object</code>
         */
        public static <T extends Serializable> Model<T> of()
        {
                return new Model<>();
        }

        @Override
        public T getObject()
        {
                return object;
        }

        /**
         * Set the model object; calls setObject(java.io.Serializable). The model object must be
         * serializable, as it is stored in the session
         * 
         * @param object
         *            the model object
         * @see org.apache.wicket.model.IModel#setObject(Object)
         */
        @Override
        public void setObject(final T object)
        {
                this.object = object;
        }

        @Override
        public void detach()
        {
                if (object instanceof IDetachable)
                {
                        ((IDetachable)object).detach();
                }
        }

        @Override
        public String toString()
        {
                StringBuilder sb = new StringBuilder("Model:classname=[");
                sb.append(getClass().getName()).append(']');
                sb.append(":object=[").append(object).append(']');
                return sb.toString();
        }

        @Override
        public int hashCode()
        {
                return Objects.hashCode(object);
        }

        @Override
        public boolean equals(Object obj)
        {
                if (this == obj)
                {
                        return true;
                }
                if (!(obj instanceof Model<?>))
                {
                        return false;
                }
                Model<?> that = (Model<?>)obj;
                return Objects.equal(object, that.object);
        }

        @SuppressWarnings("unchecked")
        @Override
        public Class<T> getObjectClass()
        {
                return object != null ? (Class<T>) object.getClass() : null;
        }
}