/*
 * Copyright 2014 Red Hat Inc. and/or its affiliates and other contributors
 * as indicated by the @author tags. All rights reserved.
 *
 * 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.keycloak.adapters.undertow;

import io.undertow.security.api.AuthenticationMechanism;
import io.undertow.security.api.AuthenticationMechanismFactory;
import io.undertow.security.idm.Account;
import io.undertow.security.idm.Credential;
import io.undertow.security.idm.IdentityManager;
import io.undertow.server.handlers.form.FormParserFactory;
import io.undertow.servlet.ServletExtension;
import io.undertow.servlet.api.AuthMethodConfig;
import io.undertow.servlet.api.DeploymentInfo;
import io.undertow.servlet.api.InstanceFactory;
import io.undertow.servlet.api.InstanceHandle;
import io.undertow.servlet.api.ListenerInfo;
import io.undertow.servlet.api.LoginConfig;
import io.undertow.servlet.api.ServletSessionConfig;
import io.undertow.servlet.util.ImmediateInstanceHandle;
import org.jboss.logging.Logger;
import org.keycloak.adapters.AdapterConstants;
import org.keycloak.adapters.AdapterDeploymentContext;
import org.keycloak.adapters.KeycloakDeployment;
import org.keycloak.adapters.KeycloakDeploymentBuilder;
import org.keycloak.adapters.NodesRegistrationManagement;

import javax.servlet.ServletContext;
import java.io.ByteArrayInputStream;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.InputStream;
import java.util.Map;

/**
 * @author <a href="mailto:bill@burkecentral.com">Bill Burke</a>
 * @version $Revision: 1 $
 */
public class KeycloakServletExtension implements ServletExtension {

    protected static Logger log = Logger.getLogger(KeycloakServletExtension.class);

    // todo when this DeploymentInfo method of the same name is fixed.
    public boolean isAuthenticationMechanismPresent(DeploymentInfo deploymentInfo, final String mechanismName) {
        LoginConfig loginConfig = deploymentInfo.getLoginConfig();
        if(loginConfig != null) {
            for(AuthMethodConfig method : loginConfig.getAuthMethods()) {
                if(method.getName().equalsIgnoreCase(mechanismName)) {
                    return true;
                }
            }
        }
        return false;
    }

    private static InputStream getJSONFromServletContext(ServletContext servletContext) {
        String json = servletContext.getInitParameter(AdapterConstants.AUTH_DATA_PARAM_NAME);
        if (json == null) {
            return null;
        }
        return new ByteArrayInputStream(json.getBytes());
    }

    private static InputStream getConfigInputStream(ServletContext context) {
        InputStream is = getJSONFromServletContext(context);
        if (is == null) {
            String path = context.getInitParameter("keycloak.config.file");
            if (path == null) {
                log.debug("using /WEB-INF/keycloak.json");
                is = context.getResourceAsStream("/WEB-INF/keycloak.json");
            } else {
                try {
                    is = new FileInputStream(path);
                } catch (FileNotFoundException e) {
                    throw new RuntimeException(e);
                }
            }
        }
        return is;
    }


    @Override
    public void handleDeployment(DeploymentInfo deploymentInfo, ServletContext servletContext) {
        if (!isAuthenticationMechanismPresent(deploymentInfo, "KEYCLOAK")) {
            log.debug("auth-method is not keycloak!");
            return;
        }
        log.debug("KeycloakServletException initialization");
        InputStream is = getConfigInputStream(servletContext);
        final KeycloakDeployment deployment;
        if (is == null) {
            log.warn("No adapter configuration.  Keycloak is unconfigured and will deny all requests.");
            deployment = new KeycloakDeployment();
        } else {
            deployment = KeycloakDeploymentBuilder.build(is);

        }
        AdapterDeploymentContext deploymentContext = new AdapterDeploymentContext(deployment);
        servletContext.setAttribute(AdapterDeploymentContext.class.getName(), deploymentContext);
        UndertowUserSessionManagement userSessionManagement = new UndertowUserSessionManagement();
        final NodesRegistrationManagement nodesRegistrationManagement = new NodesRegistrationManagement(deployment);
        final ServletKeycloakAuthMech mech = createAuthenticationMechanism(deploymentInfo, deploymentContext, userSessionManagement, nodesRegistrationManagement);

        UndertowAuthenticatedActionsHandler.Wrapper actions = new UndertowAuthenticatedActionsHandler.Wrapper(deploymentContext);

        // setup handlers

        deploymentInfo.addOuterHandlerChainWrapper(new ServletPreAuthActionsHandler.Wrapper(deploymentContext, userSessionManagement));
        deploymentInfo.addAuthenticationMechanism("KEYCLOAK", new AuthenticationMechanismFactory() {
            @Override
            public AuthenticationMechanism create(String s, FormParserFactory formParserFactory, Map<String, String> stringStringMap) {
                return mech;
            }
        }); // authentication
        deploymentInfo.addInnerHandlerChainWrapper(actions); // handles authenticated actions and cors.

        deploymentInfo.setIdentityManager(new IdentityManager() {
            @Override
            public Account verify(Account account) {
                return account;
            }

            @Override
            public Account verify(String id, Credential credential) {
                throw new IllegalStateException("Should never be called in Keycloak flow");
            }

            @Override
            public Account verify(Credential credential) {
                throw new IllegalStateException("Should never be called in Keycloak flow");
            }
        });

        log.debug("Setting jsession cookie path to: " + deploymentInfo.getContextPath());
        ServletSessionConfig cookieConfig = new ServletSessionConfig();
        cookieConfig.setPath(deploymentInfo.getContextPath());
        deploymentInfo.setServletSessionConfig(cookieConfig);

        deploymentInfo.addListener(new ListenerInfo(UndertowNodesRegistrationManagementWrapper.class, new InstanceFactory<UndertowNodesRegistrationManagementWrapper>() {

            @Override
            public InstanceHandle<UndertowNodesRegistrationManagementWrapper> createInstance() throws InstantiationException {
                UndertowNodesRegistrationManagementWrapper listener = new UndertowNodesRegistrationManagementWrapper(nodesRegistrationManagement);
                return new ImmediateInstanceHandle<UndertowNodesRegistrationManagementWrapper>(listener);
            }

        }));
    }

    protected ServletKeycloakAuthMech createAuthenticationMechanism(DeploymentInfo deploymentInfo, AdapterDeploymentContext deploymentContext, UndertowUserSessionManagement userSessionManagement,
                                                                    NodesRegistrationManagement nodesRegistrationManagement) {
       log.debug("creating ServletKeycloakAuthMech");
       return new ServletKeycloakAuthMech(deploymentContext, userSessionManagement, nodesRegistrationManagement, deploymentInfo.getConfidentialPortManager());
    }
}
