/*
 * 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.services;

import org.jboss.logging.Logger;
import org.keycloak.Config;
import org.keycloak.common.util.MultivaluedHashMap;
import org.keycloak.models.KeycloakSession;
import org.keycloak.models.KeycloakSessionFactory;
import org.keycloak.provider.EnvironmentDependentProviderFactory;
import org.keycloak.provider.Provider;
import org.keycloak.provider.ProviderEvent;
import org.keycloak.provider.ProviderEventListener;
import org.keycloak.provider.ProviderFactory;
import org.keycloak.provider.ProviderManager;
import org.keycloak.provider.ProviderManagerDeployer;
import org.keycloak.provider.ProviderManagerRegistry;
import org.keycloak.provider.Spi;

import java.util.HashMap;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.CopyOnWriteArrayList;

public class DefaultKeycloakSessionFactory implements KeycloakSessionFactory, ProviderManagerDeployer {

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

    private Set<Spi> spis = new HashSet<>();
    private Map<Class<? extends Provider>, String> provider = new HashMap<>();
    private volatile Map<Class<? extends Provider>, Map<String, ProviderFactory>> factoriesMap = new HashMap<>();
    protected CopyOnWriteArrayList<ProviderEventListener> listeners = new CopyOnWriteArrayList<>();

    // TODO: Likely should be changed to int and use Time.currentTime() to be compatible with all our "time" reps
    protected long serverStartupTimestamp;

    @Override
    public void register(ProviderEventListener listener) {
        listeners.add(listener);
    }

    @Override
    public void unregister(ProviderEventListener listener) {
        listeners.remove(listener);
    }

    @Override
    public void publish(ProviderEvent event) {
        for (ProviderEventListener listener : listeners) {
            listener.onEvent(event);
        }
    }

    public void init() {
        serverStartupTimestamp = System.currentTimeMillis();

        ProviderManager pm = new ProviderManager(getClass().getClassLoader(), Config.scope().getArray("providers"));
        spis.addAll(pm.loadSpis());
        factoriesMap = loadFactories(pm);
        for (ProviderManager manager : ProviderManagerRegistry.SINGLETON.getPreBoot()) {
            Map<Class<? extends Provider>, Map<String, ProviderFactory>> factoryMap = loadFactories(manager);
            for (Map.Entry<Class<? extends Provider>,  Map<String, ProviderFactory>> entry : factoryMap.entrySet()) {
                Map<String, ProviderFactory> factories = factoriesMap.get(entry.getKey());
                if (factories == null) {
                    factoriesMap.put(entry.getKey(), entry.getValue());
                } else {
                    factories.putAll(entry.getValue());
                }
            }
        }
        checkProvider();
        for ( Map<String, ProviderFactory> factories : factoriesMap.values()) {
            for (ProviderFactory factory : factories.values()) {
                factory.postInit(this);
            }
        }
        // make the session factory ready for hot deployment
        ProviderManagerRegistry.SINGLETON.setDeployer(this);

    }
    protected Map<Class<? extends Provider>, Map<String, ProviderFactory>> getFactoriesCopy() {
        Map<Class<? extends Provider>, Map<String, ProviderFactory>> copy = new HashMap<>();
        for (Map.Entry<Class<? extends Provider>, Map<String, ProviderFactory>> entry : factoriesMap.entrySet()) {
            Map<String, ProviderFactory> valCopy = new HashMap<>();
            valCopy.putAll(entry.getValue());
            copy.put(entry.getKey(), valCopy);
        }
        return copy;

    }

    @Override
    public void deploy(ProviderManager pm) {
        Map<Class<? extends Provider>, Map<String, ProviderFactory>> copy = getFactoriesCopy();
        Map<Class<? extends Provider>, Map<String, ProviderFactory>> newFactories = loadFactories(pm);
        List<ProviderFactory> undeployed = new LinkedList<>();

        for (Map.Entry<Class<? extends Provider>, Map<String, ProviderFactory>> entry : newFactories.entrySet()) {
            Map<String, ProviderFactory> current = copy.get(entry.getKey());
            if (current == null) {
                copy.put(entry.getKey(), entry.getValue());
            } else {
                for (ProviderFactory f : entry.getValue().values()) {
                    ProviderFactory old = current.remove(f.getId());
                    if (old != null) undeployed.add(old);
                }
                current.putAll(entry.getValue());
            }

        }
        factoriesMap = copy;
        for (ProviderFactory factory : undeployed) {
            factory.close();
        }
    }

    @Override
    public void undeploy(ProviderManager pm) {
        logger.debug("undeploy");
        // we make a copy to avoid concurrent access exceptions
        Map<Class<? extends Provider>, Map<String, ProviderFactory>> copy = getFactoriesCopy();
        MultivaluedHashMap<Class<? extends Provider>, ProviderFactory> factories = pm.getLoadedFactories();
        List<ProviderFactory> undeployed = new LinkedList<>();
        for (Map.Entry<Class<? extends Provider>, List<ProviderFactory>> entry : factories.entrySet()) {
            Map<String, ProviderFactory> registered = copy.get(entry.getKey());
            for (ProviderFactory factory : entry.getValue()) {
                undeployed.add(factory);
                logger.debugv("undeploying {0} of id {1}", factory.getClass().getName(), factory.getId());
                if (registered != null) {
                    registered.remove(factory.getId());
                }
            }
        }
        factoriesMap = copy;
        for (ProviderFactory factory : undeployed) {
            factory.close();
        }
    }

    protected void checkProvider() {
        for (Spi spi : spis) {
            String provider = Config.getProvider(spi.getName());
            if (provider != null) {
                this.provider.put(spi.getProviderClass(), provider);
                if (getProviderFactory(spi.getProviderClass(), provider) == null) {
                    throw new RuntimeException("Failed to find provider " + provider + " for " + spi.getName());
                }
            } else {
                Map<String, ProviderFactory> factories = factoriesMap.get(spi.getProviderClass());
                if (factories != null && factories.size() == 1) {
                    provider = factories.values().iterator().next().getId();
                    this.provider.put(spi.getProviderClass(), provider);
                }
            }
        }
    }

    protected Map<Class<? extends Provider>, Map<String, ProviderFactory>> loadFactories(ProviderManager pm) {
        Map<Class<? extends Provider>, Map<String, ProviderFactory>> factoryMap = new HashMap<>();
        Set<Spi> spiList = spis;

        for (Spi spi : spiList) {

            Map<String, ProviderFactory> factories = new HashMap<String, ProviderFactory>();
            factoryMap.put(spi.getProviderClass(), factories);

            String provider = Config.getProvider(spi.getName());
            if (provider != null) {

                ProviderFactory factory = pm.load(spi, provider);
                if (factory == null) {
                    continue;
                }

                Config.Scope scope = Config.scope(spi.getName(), provider);
                if (isEnabled(factory, scope)) {
                    factory.init(scope);

                    if (spi.isInternal() && !isInternal(factory)) {
                        ServicesLogger.LOGGER.spiMayChange(factory.getId(), factory.getClass().getName(), spi.getName());
                    }

                    factories.put(factory.getId(), factory);

                    logger.debugv("Loaded SPI {0} (provider = {1})", spi.getName(), provider);
                }

            } else {
                for (ProviderFactory factory : pm.load(spi)) {
                    Config.Scope scope = Config.scope(spi.getName(), factory.getId());
                    if (isEnabled(factory, scope)) {
                        factory.init(scope);

                        if (spi.isInternal() && !isInternal(factory)) {
                            ServicesLogger.LOGGER.spiMayChange(factory.getId(), factory.getClass().getName(), spi.getName());
                        }

                        factories.put(factory.getId(), factory);
                    } else {
                        logger.debugv("SPI {0} provider {1} disabled", spi.getName(), factory.getId());
                    }
                }
            }
        }
        return factoryMap;
    }

    private boolean isEnabled(ProviderFactory factory, Config.Scope scope) {
        if (!scope.getBoolean("enabled", true)) {
            return false;
        }
        if (factory instanceof EnvironmentDependentProviderFactory) {
            return ((EnvironmentDependentProviderFactory) factory).isSupported();
        }
        return true;
    }

    protected void loadSPIs(ProviderManager pm, List<Spi> spiList) {
        for (Spi spi : spiList) {
            spis.add(spi);

            Map<String, ProviderFactory> factories = new HashMap<String, ProviderFactory>();
            factoriesMap.put(spi.getProviderClass(), factories);

            String provider = Config.getProvider(spi.getName());
            if (provider != null) {
                this.provider.put(spi.getProviderClass(), provider);

                ProviderFactory factory = pm.load(spi, provider);
                if (factory == null) {
                    throw new RuntimeException("Failed to find provider " + provider + " for " + spi.getName());
                }

                Config.Scope scope = Config.scope(spi.getName(), provider);
                factory.init(scope);

                if (spi.isInternal() && !isInternal(factory)) {
                    ServicesLogger.LOGGER.spiMayChange(factory.getId(), factory.getClass().getName(), spi.getName());
                }

                factories.put(factory.getId(), factory);

                logger.debugv("Loaded SPI {0} (provider = {1})", spi.getName(), provider);
            } else {
                for (ProviderFactory factory : pm.load(spi)) {
                    Config.Scope scope = Config.scope(spi.getName(), factory.getId());
                    if (scope.getBoolean("enabled", true)) {
                        factory.init(scope);

                        if (spi.isInternal() && !isInternal(factory)) {
                            ServicesLogger.LOGGER.spiMayChange(factory.getId(), factory.getClass().getName(), spi.getName());
                        }

                        factories.put(factory.getId(), factory);
                    } else {
                        logger.debugv("SPI {0} provider {1} disabled", spi.getName(), factory.getId());
                    }
                }

                if (factories.size() == 1) {
                    provider = factories.values().iterator().next().getId();
                    this.provider.put(spi.getProviderClass(), provider);

                    logger.debugv("Loaded SPI {0} (provider = {1})", spi.getName(), provider);
                } else {
                    logger.debugv("Loaded SPI {0} (providers = {1})", spi.getName(), factories.keySet());
                }
            }
        }
    }

    public KeycloakSession create() {
        KeycloakSession session =  new DefaultKeycloakSession(this);
        return session;
    }

    <T extends Provider> String getDefaultProvider(Class<T> clazz) {
        return provider.get(clazz);
    }

    @Override
    public Set<Spi> getSpis() {
        return spis;
    }

    @Override
    public Spi getSpi(Class<? extends Provider> providerClass) {
        for (Spi spi : spis) {
            if (spi.getProviderClass().equals(providerClass)) return spi;
        }
        return null;
    }

    @Override
    public <T extends Provider> ProviderFactory<T> getProviderFactory(Class<T> clazz) {
         return getProviderFactory(clazz, provider.get(clazz));
    }

    @Override
    public <T extends Provider> ProviderFactory<T> getProviderFactory(Class<T> clazz, String id) {
        Map<String, ProviderFactory> map = factoriesMap.get(clazz);
        if (map == null) {
            return null;
        }
        return map.get(id);
    }

    @Override
    public List<ProviderFactory> getProviderFactories(Class<? extends Provider> clazz) {
        List<ProviderFactory> list = new LinkedList<ProviderFactory>();
        if (factoriesMap == null) return list;
        Map<String, ProviderFactory> providerFactoryMap = factoriesMap.get(clazz);
        if (providerFactoryMap == null) return list;
        list.addAll(providerFactoryMap.values());
        return list;
    }

    <T extends Provider> Set<String> getAllProviderIds(Class<T> clazz) {
        Set<String> ids = new HashSet<String>();
        for (ProviderFactory f : factoriesMap.get(clazz).values()) {
            ids.add(f.getId());
        }
        return ids;
    }

    Class<? extends Provider> getProviderClass(String providerClassName) {
        for (Class<? extends Provider> clazz : factoriesMap.keySet()) {
            if (clazz.getName().equals(providerClassName)) {
                return clazz;
            }
        }
        return null;
    }

    public void close() {
        ProviderManagerRegistry.SINGLETON.setDeployer(null);
        for (Map<String, ProviderFactory> factories : factoriesMap.values()) {
            for (ProviderFactory factory : factories.values()) {
                factory.close();
            }
        }
    }

    private boolean isInternal(ProviderFactory<?> factory) {
        return factory.getClass().getPackage().getName().startsWith("org.keycloak");
    }

    /**
     * @return timestamp of Keycloak server startup
     */
    @Override
    public long getServerStartupTimestamp() {
        return serverStartupTimestamp;
    }

}
