/*
 * Copyright 2016 Red Hat, Inc. and/or its affiliates
 * and other 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 org.keycloak.exportimport.util;

import com.fasterxml.jackson.core.JsonFactory;
import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.core.JsonToken;
import com.fasterxml.jackson.databind.ObjectMapper;
import org.jboss.logging.Logger;
import org.keycloak.Config;
import org.keycloak.exportimport.ExportImportConfig;
import org.keycloak.exportimport.Strategy;
import org.keycloak.models.KeycloakSession;
import org.keycloak.models.RealmModel;
import org.keycloak.models.RealmProvider;
import org.keycloak.models.utils.RealmImporter;
import org.keycloak.models.utils.RepresentationToModel;
import org.keycloak.representations.idm.RealmRepresentation;
import org.keycloak.representations.idm.UserRepresentation;
import org.keycloak.services.managers.RealmManager;

import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * @author <a href="mailto:mposolda@redhat.com">Marek Posolda</a>
 */
public class ImportUtils {

    private static final Logger logger = Logger.getLogger(ImportUtils.class);

    public static void importRealms(KeycloakSession session, Collection<RealmRepresentation> realms, Strategy strategy) {
        boolean masterImported = false;

        // Import admin realm first
        for (RealmRepresentation realm : realms) {
            if (Config.getAdminRealm().equals(realm.getRealm())) {
                if (importRealm(session, realm, strategy)) {
                    masterImported = true;
                }
            }
        }

        for (RealmRepresentation realm : realms) {
            if (!Config.getAdminRealm().equals(realm.getRealm())) {
                importRealm(session, realm, strategy);
            }
        }

        // If master was imported, we may need to re-create realm management clients
        if (masterImported) {
            for (RealmModel realm : session.realms().getRealms()) {
                if (realm.getMasterAdminClient() == null) {
                    logger.infof("Re-created management client in master realm for realm '%s'", realm.getName());
                    new RealmManager(session).setupMasterAdminManagement(realm);
                }
            }
        }
    }

    /**
     * Fully import realm from representation, save it to model and return model of newly created realm
     *
     * @param session
     * @param rep
     * @param strategy specifies whether to overwrite or ignore existing realm or user entries
     * @return newly imported realm (or existing realm if ignoreExisting is true and realm of this name already exists)
     */
    public static boolean importRealm(KeycloakSession session, RealmRepresentation rep, Strategy strategy) {
        String realmName = rep.getRealm();
        RealmProvider model = session.realms();
        RealmModel realm = model.getRealmByName(realmName);

        if (realm != null) {
            if (strategy == Strategy.IGNORE_EXISTING) {
                logger.infof("Realm '%s' already exists. Import skipped", realmName);
                return false;
            } else {
                logger.infof("Realm '%s' already exists. Removing it before import", realmName);
                if (Config.getAdminRealm().equals(realm.getId())) {
                    // Delete all masterAdmin apps due to foreign key constraints
                    for (RealmModel currRealm : model.getRealms()) {
                        currRealm.setMasterAdminClient(null);
                    }
                }
                // TODO: For migration between versions, it should be possible to delete just realm but keep it's users
                model.removeRealm(realm.getId());
            }
        }

        RealmImporter realmManager = session.getContext().getRealmManager();
        realmManager.importRealm(rep);

        if (System.getProperty(ExportImportConfig.ACTION) != null) {
            logger.infof("Realm '%s' imported", realmName);
        }
        
        return true;
    }

    /**
     * Fully import realm (or more realms from particular stream)
     *
     * @param session
     * @param mapper
     * @param is
     * @param strategy
     * @throws IOException
     */
    public static void importFromStream(KeycloakSession session, ObjectMapper mapper, InputStream is, Strategy strategy) throws IOException {
        Map<String, RealmRepresentation> realmReps = getRealmsFromStream(mapper, is);
        importRealms(session, realmReps.values(), strategy);
    }

    public static Map<String, RealmRepresentation> getRealmsFromStream(ObjectMapper mapper, InputStream is) throws IOException {
        Map<String, RealmRepresentation> result = new HashMap<String, RealmRepresentation>();

        JsonFactory factory = mapper.getFactory();
        JsonParser parser = factory.createParser(is);
        try {
            parser.nextToken();

            if (parser.getCurrentToken() == JsonToken.START_ARRAY) {
                // Case with more realms in stream
                parser.nextToken();

                List<RealmRepresentation> realmReps = new ArrayList<RealmRepresentation>();
                while (parser.getCurrentToken() == JsonToken.START_OBJECT) {
                    RealmRepresentation realmRep = parser.readValueAs(RealmRepresentation.class);
                    parser.nextToken();

                    // Ensure that master realm is imported first
                    if (Config.getAdminRealm().equals(realmRep.getRealm())) {
                        realmReps.add(0, realmRep);
                    } else {
                        realmReps.add(realmRep);
                    }
                }

                for (RealmRepresentation realmRep : realmReps) {
                    result.put(realmRep.getRealm(), realmRep);
                }
            } else if (parser.getCurrentToken() == JsonToken.START_OBJECT) {
                // Case with single realm in stream
                RealmRepresentation realmRep = parser.readValueAs(RealmRepresentation.class);
                result.put(realmRep.getRealm(), realmRep);
            }
        } finally {
            parser.close();
        }

        return result;
    }


    // Assuming that it's invoked inside transaction
    public static void importUsersFromStream(KeycloakSession session, String realmName, ObjectMapper mapper, InputStream is) throws IOException {
        RealmProvider model = session.realms();
        JsonFactory factory = mapper.getJsonFactory();
        JsonParser parser = factory.createJsonParser(is);
        try {
            parser.nextToken();

            while (parser.nextToken() == JsonToken.FIELD_NAME) {
                if ("realm".equals(parser.getText())) {
                    parser.nextToken();
                    String currRealmName = parser.getText();
                    if (!currRealmName.equals(realmName)) {
                        throw new IllegalStateException("Trying to import users into invalid realm. Realm name: " + realmName + ", Expected realm name: " + currRealmName);
                    }
                } else if ("users".equals(parser.getText())) {
                    parser.nextToken();

                    if (parser.getCurrentToken() == JsonToken.START_ARRAY) {
                        parser.nextToken();
                    }

                    // TODO: support for more transactions per single users file (if needed)
                    List<UserRepresentation> userReps = new ArrayList<UserRepresentation>();
                    while (parser.getCurrentToken() == JsonToken.START_OBJECT) {
                        UserRepresentation user = parser.readValueAs(UserRepresentation.class);
                        userReps.add(user);
                        parser.nextToken();
                    }

                    importUsers(session, model, realmName, userReps);

                    if (parser.getCurrentToken() == JsonToken.END_ARRAY) {
                        parser.nextToken();
                    }
                }
            }
        } finally {
            parser.close();
        }
    }

    private static void importUsers(KeycloakSession session, RealmProvider model, String realmName, List<UserRepresentation> userReps) {
        RealmModel realm = model.getRealmByName(realmName);
        for (UserRepresentation user : userReps) {
            RepresentationToModel.createUser(session, realm, user);
        }
    }

}
