/*
 * 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.dubbo.registry.integration;

import org.apache.dubbo.common.URL;
import org.apache.dubbo.common.Version;
import org.apache.dubbo.common.config.ConfigurationUtils;
import org.apache.dubbo.common.extension.ExtensionLoader;
import org.apache.dubbo.common.logger.ErrorTypeAwareLogger;
import org.apache.dubbo.common.logger.LoggerFactory;
import org.apache.dubbo.common.utils.CollectionUtils;
import org.apache.dubbo.common.utils.NetUtils;
import org.apache.dubbo.common.utils.StringUtils;
import org.apache.dubbo.registry.AddressListener;
import org.apache.dubbo.registry.NotifyListener;
import org.apache.dubbo.registry.Registry;
import org.apache.dubbo.registry.client.event.listener.ServiceInstancesChangedListener;
import org.apache.dubbo.registry.client.migration.InvokersChangedListener;
import org.apache.dubbo.rpc.Invocation;
import org.apache.dubbo.rpc.Invoker;
import org.apache.dubbo.rpc.Protocol;
import org.apache.dubbo.rpc.RpcException;
import org.apache.dubbo.rpc.cluster.Cluster;
import org.apache.dubbo.rpc.cluster.Configurator;
import org.apache.dubbo.rpc.cluster.Constants;
import org.apache.dubbo.rpc.cluster.RouterChain;
import org.apache.dubbo.rpc.cluster.RouterFactory;
import org.apache.dubbo.rpc.cluster.SingleRouterChain;
import org.apache.dubbo.rpc.cluster.directory.AbstractDirectory;
import org.apache.dubbo.rpc.cluster.router.state.BitList;
import org.apache.dubbo.rpc.model.ModuleModel;

import java.util.List;

import static org.apache.dubbo.common.constants.CommonConstants.ANY_VALUE;
import static org.apache.dubbo.common.constants.LoggerCodeConstants.CLUSTER_FAILED_SITE_SELECTION;
import static org.apache.dubbo.common.constants.LoggerCodeConstants.REGISTRY_FAILED_DESTROY_SERVICE;
import static org.apache.dubbo.common.constants.LoggerCodeConstants.REGISTRY_FAILED_DESTROY_UNREGISTER_URL;
import static org.apache.dubbo.common.constants.RegistryConstants.CATEGORY_KEY;
import static org.apache.dubbo.common.constants.RegistryConstants.CONSUMERS_CATEGORY;
import static org.apache.dubbo.registry.Constants.REGISTER_KEY;
import static org.apache.dubbo.registry.Constants.SIMPLIFIED_KEY;
import static org.apache.dubbo.registry.integration.InterfaceCompatibleRegistryProtocol.DEFAULT_REGISTER_CONSUMER_KEYS;
import static org.apache.dubbo.remoting.Constants.CHECK_KEY;


/**
 * DynamicDirectory
 */
public abstract class DynamicDirectory<T> extends AbstractDirectory<T> implements NotifyListener {

    private static final ErrorTypeAwareLogger logger = LoggerFactory.getErrorTypeAwareLogger(DynamicDirectory.class);

    protected final Cluster cluster;

    protected final RouterFactory routerFactory;

    /**
     * Initialization at construction time, assertion not null
     */
    protected final String serviceKey;

    /**
     * Initialization at construction time, assertion not null
     */
    protected final Class<T> serviceType;

    /**
     * Initialization at construction time, assertion not null, and always assign non-null value
     */
    protected volatile URL directoryUrl;
    protected final boolean multiGroup;

    /**
     * Initialization at the time of injection, the assertion is not null
     */
    protected Protocol protocol;

    /**
     * Initialization at the time of injection, the assertion is not null
     */
    protected Registry registry;
    protected volatile boolean forbidden = false;
    protected boolean shouldRegister;
    protected boolean shouldSimplified;

    /**
     * Initialization at construction time, assertion not null, and always assign not null value
     */
    protected volatile URL subscribeUrl;
    protected volatile URL registeredConsumerUrl;

    /**
     * The initial value is null and the midway may be assigned to null, please use the local variable reference
     * override rules
     * Priority: override>-D>consumer>provider
     * Rule one: for a certain provider <ip:port,timeout=100>
     * Rule two: for all providers <* ,timeout=5000>
     */
    protected volatile List<Configurator> configurators;

    protected ServiceInstancesChangedListener serviceListener;

    /**
     * Should continue route if directory is empty
     */
    private final boolean shouldFailFast;

    private volatile InvokersChangedListener invokersChangedListener;
    private volatile boolean invokersChanged;


    public DynamicDirectory(Class<T> serviceType, URL url) {
        super(url, true);

        ModuleModel moduleModel = url.getOrDefaultModuleModel();

        this.cluster = moduleModel.getExtensionLoader(Cluster.class).getAdaptiveExtension();
        this.routerFactory = moduleModel.getExtensionLoader(RouterFactory.class).getAdaptiveExtension();

        if (serviceType == null) {
            throw new IllegalArgumentException("service type is null.");
        }

        if (StringUtils.isEmpty(url.getServiceKey())) {
            throw new IllegalArgumentException("registry serviceKey is null.");
        }

        this.shouldRegister = !ANY_VALUE.equals(url.getServiceInterface()) && url.getParameter(REGISTER_KEY, true);
        this.shouldSimplified = url.getParameter(SIMPLIFIED_KEY, false);

        this.serviceType = serviceType;
        this.serviceKey = super.getConsumerUrl().getServiceKey();

        this.directoryUrl = consumerUrl;
        String group = directoryUrl.getGroup("");
        this.multiGroup = group != null && (ANY_VALUE.equals(group) || group.contains(","));

        this.shouldFailFast = Boolean.parseBoolean(ConfigurationUtils.getProperty(moduleModel, Constants.SHOULD_FAIL_FAST_KEY, "true"));
    }

    @Override
    public void addServiceListener(ServiceInstancesChangedListener instanceListener) {
        this.serviceListener = instanceListener;
    }

    @Override
    public ServiceInstancesChangedListener getServiceListener() {
        return this.serviceListener;
    }

    public void setProtocol(Protocol protocol) {
        this.protocol = protocol;
    }

    public void setRegistry(Registry registry) {
        this.registry = registry;
    }

    public Registry getRegistry() {
        return registry;
    }

    public boolean isShouldRegister() {
        return shouldRegister;
    }

    public void subscribe(URL url) {
        setSubscribeUrl(url);
        registry.subscribe(url, this);
    }

    public void unSubscribe(URL url) {
        setSubscribeUrl(null);
        registry.unsubscribe(url, this);
    }

    @Override
    public List<Invoker<T>> doList(SingleRouterChain<T> singleRouterChain,
                                   BitList<Invoker<T>> invokers, Invocation invocation) {
        if (forbidden && shouldFailFast) {
            // 1. No service provider 2. Service providers are disabled
            throw new RpcException(RpcException.FORBIDDEN_EXCEPTION, "No provider available from registry " +
                this + " for service " + getConsumerUrl().getServiceKey() + " on consumer " +
                NetUtils.getLocalHost() + " use dubbo version " + Version.getVersion() +
                ", please check status of providers(disabled, not registered or in blacklist).");
        }

        if (multiGroup) {
            return this.getInvokers();
        }

        try {
            // Get invokers from cache, only runtime routers will be executed.
            List<Invoker<T>> result = singleRouterChain.route(getConsumerUrl(), invokers, invocation);
            return result == null ? BitList.emptyList() : result;
        } catch (Throwable t) {
            // 2-1 - Failed to execute routing.
            logger.error(CLUSTER_FAILED_SITE_SELECTION, "", "",
                "Failed to execute router: " + getUrl() + ", cause: " + t.getMessage(), t);

            return BitList.emptyList();
        }
    }

    @Override
    public Class<T> getInterface() {
        return serviceType;
    }

    @Override
    public List<Invoker<T>> getAllInvokers() {
        return this.getInvokers();
    }

    /**
     * The currently effective consumer url
     *
     * @return URL
     */
    @Override
    public URL getConsumerUrl() {
        return this.directoryUrl;
    }

    /**
     * The original consumer url
     *
     * @return URL
     */
    public URL getOriginalConsumerUrl() {
        return this.consumerUrl;
    }

    /**
     * The url registered to registry or metadata center
     *
     * @return URL
     */
    public URL getRegisteredConsumerUrl() {
        return registeredConsumerUrl;
    }

    /**
     * The url used to subscribe from registry
     *
     * @return URL
     */
    public URL getSubscribeUrl() {
        return subscribeUrl;
    }

    public void setSubscribeUrl(URL subscribeUrl) {
        this.subscribeUrl = subscribeUrl;
    }

    public void setRegisteredConsumerUrl(URL url) {
        if (!shouldSimplified) {
            this.registeredConsumerUrl = url.addParameters(CATEGORY_KEY, CONSUMERS_CATEGORY, CHECK_KEY,
                String.valueOf(false));
        } else {
            this.registeredConsumerUrl = URL.valueOf(url, DEFAULT_REGISTER_CONSUMER_KEYS, null).addParameters(
                CATEGORY_KEY, CONSUMERS_CATEGORY, CHECK_KEY, String.valueOf(false));
        }
    }

    public void buildRouterChain(URL url) {
        this.setRouterChain(RouterChain.buildChain(getInterface(), url));
    }

    @Override
    public boolean isAvailable() {
        if (isDestroyed() || this.forbidden) {
            return false;
        }
        for (Invoker<T> validInvoker : getValidInvokers()) {
            if (validInvoker.isAvailable()) {
                return true;
            } else {
                addInvalidateInvoker(validInvoker);
            }
        }
        return false;
    }

    @Override
    public void destroy() {
        if (isDestroyed()) {
            return;
        }

        // unregister.
        try {
            if (getRegisteredConsumerUrl() != null && registry != null && registry.isAvailable()) {
                registry.unregister(getRegisteredConsumerUrl());
            }
        } catch (Throwable t) {
            // 1-8: Failed to unregister / unsubscribe url on destroy.
            logger.warn(REGISTRY_FAILED_DESTROY_UNREGISTER_URL, "", "",
                "unexpected error when unregister service " + serviceKey + " from registry: " + registry.getUrl(), t);
        }

        // unsubscribe.
        try {
            if (getSubscribeUrl() != null && registry != null && registry.isAvailable()) {
                registry.unsubscribe(getSubscribeUrl(), this);
            }
        } catch (Throwable t) {
            // 1-8: Failed to unregister / unsubscribe url on destroy.
            logger.warn(REGISTRY_FAILED_DESTROY_UNREGISTER_URL, "", "",
                "unexpected error when unsubscribe service " + serviceKey + " from registry: " + registry.getUrl(), t);
        }

        ExtensionLoader<AddressListener> addressListenerExtensionLoader = getUrl().getOrDefaultModuleModel().getExtensionLoader(AddressListener.class);
        List<AddressListener> supportedListeners = addressListenerExtensionLoader.getActivateExtension(getUrl(), (String[]) null);
        if (CollectionUtils.isNotEmpty(supportedListeners)) {
            for (AddressListener addressListener : supportedListeners) {
                addressListener.destroy(getConsumerUrl(), this);
            }
        }

        synchronized (this) {
            try {
                destroyAllInvokers();
            } catch (Throwable t) {
                // 1-15 - Failed to destroy service.
                logger.warn(REGISTRY_FAILED_DESTROY_SERVICE, "", "",
                    "Failed to destroy service " + serviceKey, t);
            }
            routerChain.destroy();
            invokersChangedListener = null;
            serviceListener = null;

            super.destroy(); // must be executed after unsubscribing
        }
    }

    @Override
    public void discordAddresses() {
        try {
            destroyAllInvokers();
        } catch (Throwable t) {
            // 1-15 - Failed to destroy service.
            logger.warn(REGISTRY_FAILED_DESTROY_SERVICE, "", "",
                "Failed to destroy service " + serviceKey, t);
        }
    }

    public synchronized void setInvokersChangedListener(InvokersChangedListener listener) {
        this.invokersChangedListener = listener;
        if (invokersChangedListener != null && invokersChanged) {
            invokersChangedListener.onChange();
        }
    }

    protected synchronized void invokersChanged() {
        refreshInvoker();
        invokersChanged = true;
        if (invokersChangedListener != null) {
            invokersChangedListener.onChange();
            invokersChanged = false;
        }
    }

    @Override
    public boolean isNotificationReceived() {
        return invokersChanged;
    }

    protected abstract void destroyAllInvokers();

    protected abstract void refreshOverrideAndInvoker(List<URL> urls);

}
