/*
 * JBoss, Home of Professional Open Source.
 * Copyright 2014 Red Hat, Inc., and individual contributors
 * as indicated by the @author tags.
 *
 * 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 io.undertow.servlet.test.security.digest;

import io.undertow.security.idm.DigestAlgorithm;
import io.undertow.security.impl.DigestAuthorizationToken;
import io.undertow.security.impl.DigestWWWAuthenticateToken;
import io.undertow.server.handlers.PathHandler;
import io.undertow.servlet.api.DeploymentInfo;
import io.undertow.servlet.api.DeploymentManager;
import io.undertow.servlet.api.LoginConfig;
import io.undertow.servlet.api.SecurityConstraint;
import io.undertow.servlet.api.SecurityInfo.EmptyRoleSemantic;
import io.undertow.servlet.api.ServletContainer;
import io.undertow.servlet.api.ServletInfo;
import io.undertow.servlet.api.WebResourceCollection;
import io.undertow.servlet.test.SimpleServletTestCase;
import io.undertow.servlet.test.security.SendAuthTypeServlet;
import io.undertow.servlet.test.security.SendUsernameServlet;
import io.undertow.servlet.test.security.constraint.ServletIdentityManager;
import io.undertow.servlet.test.util.TestClassIntrospector;
import io.undertow.testutils.DefaultServer;
import io.undertow.testutils.HttpClientUtils;
import io.undertow.testutils.TestHttpClient;
import io.undertow.util.HexConverter;
import io.undertow.util.StatusCodes;
import org.apache.http.Header;
import org.apache.http.HttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.junit.BeforeClass;
import org.junit.Test;
import org.junit.runner.RunWith;

import java.nio.charset.Charset;
import java.nio.charset.StandardCharsets;
import java.security.MessageDigest;
import java.util.Map;
import javax.servlet.ServletException;

import static io.undertow.util.Headers.AUTHORIZATION;
import static io.undertow.util.Headers.DIGEST;
import static io.undertow.util.Headers.WWW_AUTHENTICATE;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertTrue;

/**
 * Test case to test authentication using HTTP Digest.
 *
 * @author <a href="mailto:darran.lofthouse@jboss.com">Darran Lofthouse</a>
 */
@RunWith(DefaultServer.class)
public class DigestAuthTestCase {

    private static final String REALM_NAME = "Servlet_Realm";
    private static final Charset UTF_8 = StandardCharsets.UTF_8;

    @BeforeClass
    public static void setup() throws ServletException {

        final PathHandler path = new PathHandler();

        final ServletContainer container = ServletContainer.Factory.newInstance();

        ServletInfo usernameServlet = new ServletInfo("Username Servlet", SendUsernameServlet.class)
                .addMapping("/secured/username");

        ServletInfo authTypeServlet = new ServletInfo("Auth Type Servlet", SendAuthTypeServlet.class)
                .addMapping("/secured/authType");

        ServletIdentityManager identityManager = new ServletIdentityManager();
        identityManager.addUser("user1", "password1", "role1");

        DeploymentInfo builder = new DeploymentInfo()
                .setClassLoader(SimpleServletTestCase.class.getClassLoader())
                .setContextPath("/servletContext")
                .setClassIntrospecter(TestClassIntrospector.INSTANCE)
                .setDeploymentName("servletContext.war")
                .setIdentityManager(identityManager)
                .setLoginConfig(new LoginConfig("DIGEST", REALM_NAME))
                .addServlets(usernameServlet, authTypeServlet);

        builder.addSecurityConstraint(new SecurityConstraint()
                .addWebResourceCollection(new WebResourceCollection()
                .addUrlPattern("/secured/*"))
                .addRoleAllowed("role1")
                .setEmptyRoleSemantic(EmptyRoleSemantic.DENY));

        DeploymentManager manager = container.addDeployment(builder);
        manager.deploy();
        path.addPrefixPath(builder.getContextPath(), manager.start());

        DefaultServer.setRootHandler(path);
    }

    @Test
    public void testUserName() throws Exception {
        testCall("username", "user1");
    }

    @Test
    public void testAuthType() throws Exception {
        testCall("authType", "DIGEST");
    }

    public void testCall(final String path, final String expectedResponse) throws Exception {
        TestHttpClient client = new TestHttpClient();
        String servletPath = "/servletContext/secured/" + path;
        String url = DefaultServer.getDefaultServerURL() + servletPath;
        HttpGet get = new HttpGet(url);
        HttpResponse result = client.execute(get);
        assertEquals(StatusCodes.UNAUTHORIZED, result.getStatusLine().getStatusCode());
        Header[] values = result.getHeaders(WWW_AUTHENTICATE.toString());
        assertEquals(1, values.length);
        String value = values[0].getValue();
        assertTrue(value.startsWith(DIGEST.toString()));
        Map<DigestWWWAuthenticateToken, String> parsedHeader = DigestWWWAuthenticateToken.parseHeader(value.substring(7));
        assertEquals(REALM_NAME, parsedHeader.get(DigestWWWAuthenticateToken.REALM));
        assertEquals(DigestAlgorithm.MD5.getToken(), parsedHeader.get(DigestWWWAuthenticateToken.ALGORITHM));
        assertTrue(parsedHeader.containsKey(DigestWWWAuthenticateToken.MESSAGE_QOP));

        String nonce = parsedHeader.get(DigestWWWAuthenticateToken.NONCE);

        String clientResponse = createResponse("user1", REALM_NAME, "password1", "GET", servletPath, nonce);

        client = new TestHttpClient();
        get = new HttpGet(url);
        StringBuilder sb = new StringBuilder(DIGEST.toString());
        sb.append(" ");
        sb.append(DigestAuthorizationToken.USERNAME.getName()).append("=").append("\"user1\"").append(",");
        sb.append(DigestAuthorizationToken.REALM.getName()).append("=\"").append(REALM_NAME).append("\",");
        sb.append(DigestAuthorizationToken.NONCE.getName()).append("=\"").append(nonce).append("\",");
        sb.append(DigestAuthorizationToken.DIGEST_URI.getName()).append("=\"" + servletPath + "\",");
        sb.append(DigestAuthorizationToken.RESPONSE.getName()).append("=\"").append(clientResponse).append("\"");

        get.addHeader(AUTHORIZATION.toString(), sb.toString());
        result = client.execute(get);
        assertEquals(StatusCodes.OK, result.getStatusLine().getStatusCode());

        final String response = HttpClientUtils.readResponse(result);
        assertEquals(expectedResponse, response);
    }

    /**
     * Creates a response value from the supplied parameters.
     *
     * @return The generated Hex encoded MD5 digest based response.
     */
    private String createResponse(final String userName, final String realm, final String password, final String method,
            final String uri, final String nonce) throws Exception {
        MessageDigest digest = MessageDigest.getInstance("MD5");
        digest.update(userName.getBytes(UTF_8));
        digest.update((byte) ':');
        digest.update(realm.getBytes(UTF_8));
        digest.update((byte) ':');
        digest.update(password.getBytes(UTF_8));

        byte[] ha1 = HexConverter.convertToHexBytes(digest.digest());

        digest.update(method.getBytes(UTF_8));
        digest.update((byte) ':');
        digest.update(uri.getBytes(UTF_8));

        byte[] ha2 = HexConverter.convertToHexBytes(digest.digest());

        digest.update(ha1);
        digest.update((byte) ':');
        digest.update(nonce.getBytes(UTF_8));
        digest.update((byte) ':');
        digest.update(ha2);

        return HexConverter.convertToHexString(digest.digest());
    }

}
