/*
 * 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.models.cache.infinispan;

import org.infinispan.Cache;
import org.infinispan.notifications.Listener;
import org.infinispan.notifications.cachelistener.annotation.*;
import org.infinispan.notifications.cachelistener.event.*;
import org.jboss.logging.Logger;
import org.keycloak.Config;
import org.keycloak.connections.infinispan.InfinispanConnectionProvider;
import org.keycloak.models.KeycloakSession;
import org.keycloak.models.KeycloakSessionFactory;
import org.keycloak.models.cache.CacheUserProvider;
import org.keycloak.models.cache.CacheUserProviderFactory;
import org.keycloak.models.cache.infinispan.entities.CachedUser;

import java.util.concurrent.ConcurrentHashMap;

/**
 * @author <a href="mailto:sthorger@redhat.com">Stian Thorgersen</a>
 */
public class InfinispanCacheUserProviderFactory implements CacheUserProviderFactory {

    private static final Logger log = Logger.getLogger(InfinispanCacheUserProviderFactory.class);

    protected volatile InfinispanUserCache userCache;

    protected final RealmLookup usernameLookup = new RealmLookup();

    protected final RealmLookup emailLookup = new RealmLookup();

    @Override
    public CacheUserProvider create(KeycloakSession session) {
        lazyInit(session);
        return new DefaultCacheUserProvider(userCache, session);
    }

    private void lazyInit(KeycloakSession session) {
        if (userCache == null) {
            synchronized (this) {
                if (userCache == null) {
                    Cache<String, CachedUser> cache = session.getProvider(InfinispanConnectionProvider.class).getCache(InfinispanConnectionProvider.USER_CACHE_NAME);
                    cache.addListener(new CacheListener());
                    userCache = new InfinispanUserCache(cache, usernameLookup, emailLookup);
                }
            }
        }
    }

    @Override
    public void init(Config.Scope config) {
    }

    @Override
    public void postInit(KeycloakSessionFactory factory) {

    }

    @Override
    public void close() {
    }

    @Override
    public String getId() {
        return "default";
    }

    @Listener
    public class CacheListener {

        @CacheEntryCreated
        public void userCreated(CacheEntryCreatedEvent<String, CachedUser> event) {
            if (!event.isPre()) {
                CachedUser user = event.getValue();
                if (user != null) {
                    String realm = user.getRealm();

                    usernameLookup.put(realm, user.getUsername(), user.getId());
                    if (user.getEmail() != null) {
                        emailLookup.put(realm, user.getEmail(), user.getId());
                    }

                    log.tracev("User added realm={0}, id={1}, username={2}", realm, user.getId(), user.getUsername());
                }
            }
        }

        @CacheEntryRemoved
        public void userRemoved(CacheEntryRemovedEvent<String, CachedUser> event) {
            if (event.isPre()) {
                CachedUser user = event.getValue();
                if (user != null) {
                    removeUser(user);

                    log.tracev("User invalidated realm={0}, id={1}, username={2}", user.getRealm(), user.getId(), user.getUsername());
                }
            }
        }

        @CacheEntryInvalidated
        public void userInvalidated(CacheEntryInvalidatedEvent<String, CachedUser> event) {
            if (event.isPre()) {
                CachedUser user = event.getValue();
                if (user != null) {
                    removeUser(user);

                    log.tracev("User invalidated realm={0}, id={1}, username={2}", user.getRealm(), user.getId(), user.getUsername());
                }
            }
        }

        @CacheEntriesEvicted
        public void userEvicted(CacheEntriesEvictedEvent<String, CachedUser> event) {
            for (CachedUser user : event.getEntries().values()) {
                removeUser(user);

                log.tracev("User evicted realm={0}, id={1}, username={2}", user.getRealm(), user.getId(), user.getUsername());
            }
        }

        private void removeUser(CachedUser cachedUser) {
            String realm = cachedUser.getRealm();
            usernameLookup.remove(realm, cachedUser.getUsername());
            if (cachedUser.getEmail() != null) {
                emailLookup.remove(realm, cachedUser.getEmail());
            }
        }

    }

    static class RealmLookup {

        protected final ConcurrentHashMap<String, ConcurrentHashMap<String, String>> lookup = new ConcurrentHashMap<>();

        public void put(String realm, String key, String value) {
            ConcurrentHashMap<String, String> map = lookup.get(realm);
            if(map == null) {
                map = new ConcurrentHashMap<>();
                ConcurrentHashMap<String, String> p = lookup.putIfAbsent(realm, map);
                if (p != null) {
                    map = p;
                }
            }
            map.put(key, value);
        }

        public String get(String realm, String key) {
            ConcurrentHashMap<String, String> map = lookup.get(realm);
            return map != null ? map.get(key) : null;
        }

        public void remove(String realm, String key) {
            ConcurrentHashMap<String, String> map = lookup.get(realm);
            if (map != null) {
                map.remove(key);
                if (map.isEmpty()) {
                    lookup.remove(realm);
                }
            }
        }

    }

}
