/* Copyright 2004, 2005, 2006 Acegi Technology Pty Limited
 *
 * Licensed 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.springframework.security.ui.webapp;

import org.springframework.security.Authentication;
import org.springframework.security.AuthenticationException;

import org.springframework.security.providers.UsernamePasswordAuthenticationToken;

import org.springframework.security.ui.AbstractProcessingFilter;
import org.springframework.security.ui.FilterChainOrder;
import org.springframework.security.util.TextUtils;
import org.springframework.util.Assert;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;


/**
 * Processes an authentication form.
 * <p>Login forms must present two parameters to this filter: a username and
 * password. The default parameter names to use are contained in the
 * static fields {@link #SPRING_SECURITY_FORM_USERNAME_KEY} and {@link #SPRING_SECURITY_FORM_PASSWORD_KEY}.
 * The parameter names can also be changed by setting the <tt>usernameParameter</tt> and <tt>passwordParameter</tt>
 * properties.
 *
 * @author Ben Alex
 * @author Colin Sampaleanu
 * @version $Id$
 */
public class AuthenticationProcessingFilter extends AbstractProcessingFilter {
    //~ Static fields/initializers =====================================================================================

    public static final String SPRING_SECURITY_FORM_USERNAME_KEY = "j_username";
    public static final String SPRING_SECURITY_FORM_PASSWORD_KEY = "j_password";
    public static final String SPRING_SECURITY_LAST_USERNAME_KEY = "SPRING_SECURITY_LAST_USERNAME";

    private String usernameParameter = SPRING_SECURITY_FORM_USERNAME_KEY;
    private String passwordParameter = SPRING_SECURITY_FORM_PASSWORD_KEY;

    //~ Methods ========================================================================================================

    public Authentication attemptAuthentication(HttpServletRequest request) throws AuthenticationException {
        String username = obtainUsername(request);
        String password = obtainPassword(request);

        if (username == null) {
            username = "";
        }

        if (password == null) {
            password = "";
        }

        username = username.trim();

        UsernamePasswordAuthenticationToken authRequest = new UsernamePasswordAuthenticationToken(username, password);

        // Place the last username attempted into HttpSession for views
        HttpSession session = request.getSession(false);

        if (session != null || getAllowSessionCreation()) {
            request.getSession().setAttribute(SPRING_SECURITY_LAST_USERNAME_KEY, TextUtils.escapeEntities(username));
        }

        // Allow subclasses to set the "details" property
        setDetails(request, authRequest);

        return this.getAuthenticationManager().authenticate(authRequest);
    }

    /**
     * This filter by default responds to <code>/j_spring_security_check</code>.
     *
     * @return the default
     */
    public String getDefaultFilterProcessesUrl() {
        return "/j_spring_security_check";
    }

    /**
     * Enables subclasses to override the composition of the password, such as by including additional values
     * and a separator.<p>This might be used for example if a postcode/zipcode was required in addition to the
     * password. A delimiter such as a pipe (|) should be used to separate the password and extended value(s). The
     * <code>AuthenticationDao</code> will need to generate the expected password in a corresponding manner.</p>
     *
     * @param request so that request attributes can be retrieved
     *
     * @return the password that will be presented in the <code>Authentication</code> request token to the
     *         <code>AuthenticationManager</code>
     */
    protected String obtainPassword(HttpServletRequest request) {
        return request.getParameter(passwordParameter);
    }

    /**
     * Enables subclasses to override the composition of the username, such as by including additional values
     * and a separator.
     *
     * @param request so that request attributes can be retrieved
     *
     * @return the username that will be presented in the <code>Authentication</code> request token to the
     *         <code>AuthenticationManager</code>
     */
    protected String obtainUsername(HttpServletRequest request) {
        return request.getParameter(usernameParameter);
    }

    /**
     * Provided so that subclasses may configure what is put into the authentication request's details
     * property.
     *
     * @param request that an authentication request is being created for
     * @param authRequest the authentication request object that should have its details set
     */
    protected void setDetails(HttpServletRequest request, UsernamePasswordAuthenticationToken authRequest) {
        authRequest.setDetails(authenticationDetailsSource.buildDetails(request));
    }

    /**
     * Sets the parameter name which will be used to obtain the username from the login request.
     *
     * @param usernameParameter the parameter name. Defaults to "j_username".
     */
    public void setUsernameParameter(String usernameParameter) {
        Assert.hasText(usernameParameter, "Username parameter must not be empty or null");
        this.usernameParameter = usernameParameter;
    }

    /**
     * Sets the parameter name which will be used to obtain the password from the login request..
     *
     * @param passwordParameter the parameter name. Defaults to "j_password".
     */
    public void setPasswordParameter(String passwordParameter) {
        Assert.hasText(passwordParameter, "Password parameter must not be empty or null");
        this.passwordParameter = passwordParameter;
    }

    public int getOrder() {
        return FilterChainOrder.AUTHENTICATION_PROCESSING_FILTER;
    }

    String getUsernameParameter() {
        return usernameParameter;
    }

    String getPasswordParameter() {
        return passwordParameter;
    }
}
