/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.apache.shenyu.plugin.apache.dubbo.cache;

import com.google.common.cache.CacheBuilder;
import com.google.common.cache.CacheLoader;
import com.google.common.cache.LoadingCache;
import com.google.common.cache.RemovalListener;
import org.apache.commons.lang3.StringUtils;
import org.apache.dubbo.config.ApplicationConfig;
import org.apache.dubbo.config.ReferenceConfig;
import org.apache.dubbo.config.RegistryConfig;
import org.apache.dubbo.rpc.service.GenericService;
import org.apache.shenyu.common.constant.Constants;
import org.apache.shenyu.common.dto.MetaData;
import org.apache.shenyu.common.dto.convert.plugin.DubboRegisterConfig;
import org.apache.shenyu.common.exception.ShenyuException;
import org.apache.shenyu.plugin.dubbo.common.cache.DubboConfigCache;
import org.apache.shenyu.plugin.dubbo.common.cache.DubboParam;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import javax.annotation.Nonnull;
import java.util.HashMap;
import java.util.Map;
import java.util.Objects;
import java.util.Optional;
import java.util.concurrent.ExecutionException;


/**
 * The type Application config cache.
 */
public final class ApacheDubboConfigCache extends DubboConfigCache {
    
    private static final Logger LOG = LoggerFactory.getLogger(ApacheDubboConfigCache.class);
    
    private ApplicationConfig applicationConfig;
    
    private RegistryConfig registryConfig;
    
    private final LoadingCache<String, ReferenceConfig<GenericService>> cache = CacheBuilder.newBuilder()
            .maximumSize(Constants.CACHE_MAX_COUNT)
            .removalListener((RemovalListener<Object, ReferenceConfig<GenericService>>) notification -> {
                ReferenceConfig<GenericService> config = notification.getValue();
                if (Objects.nonNull(config)) {
                    // After the configuration change, Dubbo destroys the instance, but does not empty it. If it is not handled,
                    // it will get NULL when reinitializing and cause a NULL pointer problem.
                    config.destroy();
                }
            })
            .build(new CacheLoader<String, ReferenceConfig<GenericService>>() {
                @Override
                @Nonnull
                public ReferenceConfig<GenericService> load(@Nonnull final String key) {
                    return new ReferenceConfig<>();
                }
            });
    
    
    /**
     * Gets instance.
     *
     * @return the instance
     */
    public static ApacheDubboConfigCache getInstance() {
        return ApplicationConfigCacheInstance.INSTANCE;
    }
    
    /**
     * Init.
     *
     * @param dubboRegisterConfig the dubbo register config
     */
    public void init(final DubboRegisterConfig dubboRegisterConfig) {
        if (Objects.isNull(applicationConfig)) {
            applicationConfig = new ApplicationConfig("shenyu_proxy");
        }
        if (needUpdateRegistryConfig(dubboRegisterConfig)) {
            RegistryConfig registryConfigTemp = new RegistryConfig();
            registryConfigTemp.setProtocol(dubboRegisterConfig.getProtocol());
            registryConfigTemp.setId("shenyu_proxy");
            registryConfigTemp.setRegister(false);
            registryConfigTemp.setAddress(dubboRegisterConfig.getRegister());
            Optional.ofNullable(dubboRegisterConfig.getGroup()).ifPresent(registryConfigTemp::setGroup);
            registryConfig = registryConfigTemp;
        }
    }
    
    private boolean needUpdateRegistryConfig(final DubboRegisterConfig dubboRegisterConfig) {
        if (Objects.isNull(registryConfig)) {
            return true;
        }
        return !Objects.equals(dubboRegisterConfig.getProtocol(), registryConfig.getProtocol())
                || !Objects.equals(dubboRegisterConfig.getRegister(), registryConfig.getAddress())
                || !Objects.equals(dubboRegisterConfig.getProtocol(), registryConfig.getProtocol());
    }
    
    /**
     * Init ref reference config.
     *
     * @param metaData the meta data
     * @return the reference config
     */
    public ReferenceConfig<GenericService> initRef(final MetaData metaData) {
        try {
            ReferenceConfig<GenericService> referenceConfig = cache.get(metaData.getPath());
            if (StringUtils.isNoneBlank(referenceConfig.getInterface())) {
                return referenceConfig;
            }
        } catch (ExecutionException e) {
            LOG.error("init dubbo ref exception", e);
        }
        return build(metaData);
    }
    
    /**
     * Build reference config.
     *
     * @param metaData the meta data
     * @return the reference config
     */
    @SuppressWarnings("deprecation")
    public ReferenceConfig<GenericService> build(final MetaData metaData) {
        if (Objects.isNull(applicationConfig) || Objects.isNull(registryConfig)) {
            return new ReferenceConfig<>();
        }
        ReferenceConfig<GenericService> reference = new ReferenceConfig<>();
        reference.setGeneric("true");
        reference.setAsync(true);
        
        reference.setApplication(applicationConfig);
        reference.setRegistry(registryConfig);
        reference.setInterface(metaData.getServiceName());
        reference.setProtocol("dubbo");
        reference.setCheck(false);
        reference.setLoadbalance("gray");
        
        Map<String, String> parameters = new HashMap<>(2);
        parameters.put("dispatcher", "direct");
        reference.setParameters(parameters);
        
        String rpcExt = metaData.getRpcExt();
        DubboParam dubboParam = parserToDubboParam(rpcExt);
        if (Objects.nonNull(dubboParam)) {
            if (StringUtils.isNoneBlank(dubboParam.getVersion())) {
                reference.setVersion(dubboParam.getVersion());
            }
            if (StringUtils.isNoneBlank(dubboParam.getGroup())) {
                reference.setGroup(dubboParam.getGroup());
            }
            if (StringUtils.isNoneBlank(dubboParam.getUrl())) {
                reference.setUrl(dubboParam.getUrl());
            }
            if (StringUtils.isNoneBlank(dubboParam.getCluster())) {
                reference.setCluster(dubboParam.getCluster());
            }
            Optional.ofNullable(dubboParam.getTimeout()).ifPresent(reference::setTimeout);
            Optional.ofNullable(dubboParam.getRetries()).ifPresent(reference::setRetries);
            Optional.ofNullable(dubboParam.getSent()).ifPresent(reference::setSent);
        }
        try {
            Object obj = reference.get();
            if (Objects.nonNull(obj)) {
                LOG.info("init apache dubbo reference success there meteData is :{}", metaData);
                cache.put(metaData.getPath(), reference);
            }
        } catch (Exception e) {
            LOG.error("init apache dubbo reference exception", e);
        }
        return reference;
    }
    
    /**
     * Get reference config.
     *
     * @param path the path
     * @return the reference config
     */
    public ReferenceConfig<GenericService> get(final String path) {
        try {
            return cache.get(path);
        } catch (ExecutionException e) {
            throw new ShenyuException(e.getCause());
        }
    }
    
    /**
     * Invalidate.
     *
     * @param path the path
     */
    public void invalidate(final String path) {
        cache.invalidate(path);
    }
    
    /**
     * Invalidate all.
     */
    public void invalidateAll() {
        cache.invalidateAll();
    }
    
    /**
     * The type Application config cache instance.
     */
    static final class ApplicationConfigCacheInstance {
        /**
         * The Instance.
         */
        static final ApacheDubboConfigCache INSTANCE = new ApacheDubboConfigCache();
        
        private ApplicationConfigCacheInstance() {
        
        }
    }
}
