/*
 * 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.myfaces.test.mock;

import java.util.ArrayList;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;

import javax.servlet.ServletContext;
import javax.servlet.http.HttpSession;
import javax.servlet.http.HttpSessionAttributeListener;
import javax.servlet.http.HttpSessionBindingEvent;
import javax.servlet.http.HttpSessionContext;

/**
 * <p>Mock implementation of <code>HttpSession</code>.</p>
 *
 * $Id$
 */

public class MockHttpSession implements HttpSession {


    // ------------------------------------------------------------ Constructors


    /**
     * <p>Configure a default instance.</p>
     */
    public MockHttpSession() {

        super();

    }


    /**
     * <p>Configure a session instance associated with the specified
     * servlet context.</p>
     *
     * @param servletContext The associated servlet context
     */
    public MockHttpSession(ServletContext servletContext) {

        super();
        setServletContext(servletContext);

    }


    // ----------------------------------------------------- Mock Object Methods


    /**
     * <p>Add a new listener instance that should be notified about
     * attribute changes.</p>
     *
     * @param listener The new listener to be added
     */
    public void addAttributeListener(HttpSessionAttributeListener listener) {
        attributeListeners.add(listener);
    }


    /**
     * <p>Set the ServletContext associated with this session.</p>
     *
     * @param servletContext The associated servlet context
     */
    public void setServletContext(ServletContext servletContext) {

        this.servletContext = servletContext;

    }


    // ------------------------------------------------------ Instance Variables


    private List attributeListeners = new ArrayList();
    private HashMap attributes = new HashMap();
    private String id = "123";
    private ServletContext servletContext = null;
    private boolean invalid = false;


    // ---------------------------------------------------------- Public Methods


    /**
     * <p>Set the session identifier of this session.</p>
     *
     * @param id The new session identifier
     */
    public void setId(String id) {
        this.id = id;
    }


    // ----------------------------------------------------- HttpSession Methods


    /** {@inheritDoc} */
    public Object getAttribute(String name) {

        assertValidity();

        return attributes.get(name);

    }


    /** {@inheritDoc} */
    public Enumeration getAttributeNames() {

        assertValidity();

        return new MockEnumeration(attributes.keySet().iterator());

    }


    /** {@inheritDoc} */
    public long getCreationTime() {

        throw new UnsupportedOperationException();

    }


    /** {@inheritDoc} */
    public String getId() {

        return this.id;

    }


    /** {@inheritDoc} */
    public long getLastAccessedTime() {

        throw new UnsupportedOperationException();

    }


    /** {@inheritDoc} */
    public int getMaxInactiveInterval() {

        throw new UnsupportedOperationException();

    }


    /** {@inheritDoc} */
    public ServletContext getServletContext() {

        return this.servletContext;

    }


    /** {@inheritDoc} */
    public HttpSessionContext getSessionContext() {

        throw new UnsupportedOperationException();

    }


    /** {@inheritDoc} */
    public Object getValue(String name) {

        throw new UnsupportedOperationException();

    }


    /** {@inheritDoc} */
    public String[] getValueNames() {

        throw new UnsupportedOperationException();

    }


    /** {@inheritDoc} */
    public void invalidate() {
        
        assertValidity();

        attributes.clear();
        invalid = true;
    }


    /** {@inheritDoc} */
    public boolean isNew() {

        throw new UnsupportedOperationException();

    }


    /** {@inheritDoc} */
    public void putValue(String name, Object value) {

        throw new UnsupportedOperationException();

    }


    /** {@inheritDoc} */
    public void removeAttribute(String name) {

        assertValidity();

        if (attributes.containsKey(name)) {
            Object value = attributes.remove(name);
            fireAttributeRemoved(name, value);
        }

    }


    /** {@inheritDoc} */
    public void removeValue(String name) {

        throw new UnsupportedOperationException();

    }


    /** {@inheritDoc} */
    public void setAttribute(String name, Object value) {

        assertValidity();

        if (name == null) {
            throw new IllegalArgumentException("Attribute name cannot be null");
        }
        if (value == null) {
            removeAttribute(name);
            return;
        }
        if (attributes.containsKey(name)) {
            Object oldValue = attributes.get(name);
            attributes.put(name, value);
            fireAttributeReplaced(name, oldValue);
        } else {
            attributes.put(name, value);
            fireAttributeAdded(name, value);
        }

    }


    /** {@inheritDoc} */
    public void setMaxInactiveInterval(int interval) {

        throw new UnsupportedOperationException();

    }


    // --------------------------------------------------------- Support Methods


    /**
     * <p>Fire an attribute added event to interested listeners.</p>
     *
     * @param key Attribute whose value was added
     * @param value The new value
     */
    private void fireAttributeAdded(String key, Object value) {
        if (attributeListeners.size() < 1) {
            return;
        }
        HttpSessionBindingEvent event =
                new HttpSessionBindingEvent(this, key, value);
        Iterator listeners = attributeListeners.iterator();
        while (listeners.hasNext()) {
            HttpSessionAttributeListener listener =
                    (HttpSessionAttributeListener) listeners.next();
            listener.attributeAdded(event);
        }
    }


    /**
     * <p>Fire an attribute removed event to interested listeners.</p>
     *
     * @param key Attribute whose value was removed
     * @param value The removed value
     */
    private void fireAttributeRemoved(String key, Object value) {
        if (attributeListeners.size() < 1) {
            return;
        }
        HttpSessionBindingEvent event =
                new HttpSessionBindingEvent(this, key, value);
        Iterator listeners = attributeListeners.iterator();
        while (listeners.hasNext()) {
            HttpSessionAttributeListener listener =
                    (HttpSessionAttributeListener) listeners.next();
            listener.attributeRemoved(event);
        }
    }


    /**
     * <p>Fire an attribute replaced event to interested listeners.</p>
     *
     * @param key Attribute whose value was replaced
     * @param value The original value
     */
    private void fireAttributeReplaced(String key, Object value) {
        if (attributeListeners.size() < 1) {
            return;
        }
        HttpSessionBindingEvent event =
                new HttpSessionBindingEvent(this, key, value);
        Iterator listeners = attributeListeners.iterator();
        while (listeners.hasNext()) {
            HttpSessionAttributeListener listener =
                    (HttpSessionAttributeListener) listeners.next();
            listener.attributeReplaced(event);
        }
    }


    /**
     * <p>Throws an {@link IllegalStateException} if this session is invalid.</p>
     */
    private void assertValidity() 
    {
        if (invalid) 
        {
            throw new IllegalStateException("Session is invalid.");
        }
    }

}