package net.gdface.thrift;

import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Executor;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
import java.util.concurrent.atomic.AtomicBoolean;

import org.apache.commons.pool2.PooledObject;
import org.apache.commons.pool2.PooledObjectFactory;
import org.apache.commons.pool2.impl.DefaultPooledObject;
import org.apache.commons.pool2.impl.GenericObjectPool;
import org.apache.commons.pool2.impl.GenericObjectPoolConfig;

import com.facebook.nifty.client.FramedClientConnector;
import com.facebook.nifty.client.NiftyClientChannel;
import com.facebook.nifty.client.NiftyClientConnector;
import com.facebook.swift.service.ThriftClient;
import com.facebook.swift.service.ThriftClientConfig;
import com.facebook.swift.service.ThriftClientManager;
import com.google.common.base.Function;
import com.google.common.base.Throwables;
import com.google.common.cache.Cache;
import com.google.common.cache.CacheBuilder;
import com.google.common.net.HostAndPort;
import com.google.common.util.concurrent.FutureCallback;
import com.google.common.util.concurrent.ListenableFuture;
import com.google.common.util.concurrent.MoreExecutors;

import static com.google.common.net.HostAndPort.fromParts;
import static com.google.common.net.HostAndPort.fromString;
import static com.google.common.base.Preconditions.*;

import io.airlift.units.Duration;
/**
 * Factory class for creating client instance <br>
 * Example:<br>
 * <pre>
 * // get a FaceApi synchronized instance
 * FaceApi client = ClientFactory.builder()
 * .setHostAndPort("127.0.0.1",9090)
 * .setTimeout(10,TimeUnit.SECONDS)
 * .build(FaceApi.class,FaceApiThriftClient.class);
 * </pre>
 * @author guyadong
 *
 */
public class ClientFactory {

    private static class Singleton{
        private static final ThriftClientManager CLIENT_MANAGER = new ThriftClientManager();    
        static{
            Runtime.getRuntime().addShutdownHook(new Thread(){
                @Override
                public void run() {
                    CLIENT_MANAGER.close();
                }});
        }
    }    
    private static final Cache<Class<?>, ThriftClient<?>> THRIFT_CLIENT_CACHE = CacheBuilder.newBuilder().softValues().build();
    private static final Cache<Class<?>, Object> CLIENT_CACHE = CacheBuilder.newBuilder().softValues().build();
    /** 接口类 -- å®žä¾‹èµ„æºæ± ç¼“å­˜ */
    private static final Cache<Class<?>,GenericObjectPool<?>> INSTANCE_POOL_CACHE = CacheBuilder.newBuilder().softValues().build();;
        private ThriftClientManager clientManager; 
    private ThriftClientConfig thriftClientConfig = new ThriftClientConfig();
    private HostAndPort hostAndPort;
    private volatile NiftyClientConnector<? extends NiftyClientChannel> connector;
    private String clientName = ThriftClientManager.DEFAULT_NAME;
    private GenericObjectPoolConfig poolConfig = new GenericObjectPoolConfig();
    private Executor executor = MoreExecutors.directExecutor();
    /**
     * 接口实例代理函数对象,
     * 如果提供了该函数对象(不为null),则在创建接口实例时调用该函数，
     * 将thrift/swift创建的接口实例转为代理实例,
     */
    private Function<Object, Object> decorator = null;
    protected ClientFactory() {
    }

    public ClientFactory setManager(ThriftClientManager clientManager){
        this.clientManager = clientManager;
        return this;
    }
    public ClientFactory setThriftClientConfig(ThriftClientConfig thriftClientConfig) {
        this.thriftClientConfig = thriftClientConfig;
        return this;
    }
    /**
     * set all timeout arguments
     * @param time
     * @param unit
     * @return
     * @see #setConnectTimeout(Duration)
     * @see #setReceiveTimeout(Duration)
     * @see #setReadTimeout(Duration)
     * @see #setWriteTimeout(Duration)
     */
    public ClientFactory setTimeout(Duration timeout){
        setConnectTimeout(timeout);
        setReceiveTimeout(timeout);
        setReadTimeout(timeout);
        setWriteTimeout(timeout);
        return this;
    }
    public ClientFactory setTimeout(long time,TimeUnit unit){
        return setTimeout(new Duration(time,unit));
    }
    public ClientFactory setConnectTimeout(Duration connectTimeout) {
        thriftClientConfig.setConnectTimeout(connectTimeout);
        return this;
    }
    public ClientFactory setReceiveTimeout(Duration receiveTimeout) {
        thriftClientConfig.setReceiveTimeout(receiveTimeout);
        return this;
    }
    public ClientFactory setReadTimeout(Duration readTimeout) {
        thriftClientConfig.setReadTimeout(readTimeout);
        return this;
    }
    public ClientFactory setWriteTimeout(Duration writeTimeout) {
        thriftClientConfig.setWriteTimeout(writeTimeout);
        return this;
    }
    public ClientFactory setSocksProxy(HostAndPort socksProxy) {
        thriftClientConfig.setSocksProxy(socksProxy);
        return this;
    }
    public ClientFactory setMaxFrameSize(int maxFrameSize) {
        thriftClientConfig.setMaxFrameSize(maxFrameSize);
        return this;
    }
    public ClientFactory setHostAndPort(HostAndPort hostAndPort) {
        if(null == this.hostAndPort){
                synchronized(this){
                        if(null == this.hostAndPort){
                                this.hostAndPort = checkNotNull(hostAndPort,"hostAndPort must not be null");
                        }
                }
        }else{
                throw new IllegalStateException("the memeber hostAndPort be initialized always");
        }
        return this;
    }
    public ClientFactory setHostAndPort(String host,int port) {
        return setHostAndPort(fromParts(host, port));
    }
    public ClientFactory setHostAndPort(String host) {
        return setHostAndPort(fromString(host));
    }
    public ClientFactory setConnector(NiftyClientConnector<? extends NiftyClientChannel> connector) {
        this.connector = connector;
        return this;
    }
    public ClientFactory setClientName(String clientName) {
        this.clientName = clientName;
        return this;
    }
    /**
     * è®¾ç½®èµ„æºæ± é…ç½®å‚æ•°
     * @param poolConfig
     * @return
     */
    public synchronized ClientFactory setPoolConfig(GenericObjectPoolConfig poolConfig) {
                this.poolConfig = checkNotNull(poolConfig,"poolConfig is null");
                return this;
        }

        public synchronized ClientFactory setExecutor(Executor executor) {
                this.executor = checkNotNull(executor,"executor is null");
                return this;
        }

        public Executor getExecutor() {
                return executor;
        }

        @SuppressWarnings("unchecked")
        public <T> ClientFactory setDecorator(Function<T, T> decorator) {
                this.decorator = (Function<Object, Object>) decorator;
                return this;
        }
        public HostAndPort getHostAndPort(){
        return checkNotNull(this.hostAndPort,"hostAndPort is null");
    }
    private NiftyClientConnector<? extends NiftyClientChannel> getConnector(){
        if(null == this.connector){
                synchronized(this){
                        if(null == this.connector){
                                this.connector = new FramedClientConnector(this.getHostAndPort());
                        }                       
                }
        }
        return this.connector;
    }
    private ThriftClientManager getClientManager(){
        if(null == this.clientManager){
                synchronized(this){
                        if(null == this.clientManager){
                                this.clientManager = Singleton.CLIENT_MANAGER;
                        }
                }
        }
        return this.clientManager;
    }

    @SuppressWarnings("unchecked")
        private <T>ThriftClient<T> getThriftClient(final Class<T> interfaceClass) {
        try {
                        return (ThriftClient<T>) THRIFT_CLIENT_CACHE.get(checkNotNull(interfaceClass,"interfaceClass is null"), new Callable<ThriftClient<?>>(){
                                        @Override
                                        public ThriftClient<?> call() throws Exception {
                                                return new ThriftClient<T>(
                                                getClientManager(),
                                                interfaceClass,
                                                thriftClientConfig,
                                                clientName);
                                        }});
                } catch (Exception e) {
                Throwables.throwIfUnchecked(e);
            throw new RuntimeException(e);
        }
    }
        @SuppressWarnings("unchecked")
        private <T> GenericObjectPool<T> getObjectPool(final Class<T> interfaceClass){
                try{
                        return (GenericObjectPool<T>) INSTANCE_POOL_CACHE.get(checkNotNull(interfaceClass,"interfaceClass is null"), 
                                        new Callable<GenericObjectPool<T>>(){
                                @Override
                                public GenericObjectPool<T> call() throws Exception {
                                        return new GenericObjectPool<T>(new ClientInstanceFactory<T>(interfaceClass),poolConfig);
                                }});
                } catch (Exception e) {
                Throwables.throwIfUnchecked(e);
            throw new RuntimeException(e);
        }
        }
    /**
         * 返回{@code instance}å¯¹åº”çš„èµ„æºæ± å¯¹è±¡
         * @param instance
         * @return
         */
        @SuppressWarnings("unchecked")
        private <T> GenericObjectPool<T> getObjectPoolByInstance(T instance){
                checkArgument(null != instance,"intance is null");
                List<GenericObjectPool<?>> found = new ArrayList<GenericObjectPool<?>>(1);
                for(Class<?> clazz : instance.getClass().getInterfaces()){
                        GenericObjectPool<?> pool = INSTANCE_POOL_CACHE.getIfPresent(clazz) ;
                        if(null !=pool){
                                found.add(pool);
                        }
                }
                checkState(found.size() ==1,"%s is not valid instance of thrift client",instance.getClass().getName());
                return (GenericObjectPool<T>) found.get(0);
        }

        public <T>void closeObjectPool(Class<T> interfaceClass){
                if(null != interfaceClass){
                        GenericObjectPool<?> pool = INSTANCE_POOL_CACHE.getIfPresent(interfaceClass);
                        if(null != pool){
                                pool.close();
                        }
                }
        }

        /**
         * thrift client å®žä¾‹ä¸æ˜¯çº¿ç¨‹å®‰å…¨çš„ï¼Œåªå¯å•çº¿ç¨‹ç‹¬å ä½¿ç”¨ï¼Œæ‰€ä»¥æ¯æ¬¡è°ƒç”¨å®žä¾‹æ—¶è¦å‘èµ„æºæ± {@link GenericObjectPool}
     * 申请一个{@code interfaceClass}的实例,用完后调用{@link #releaseInstance(Object)}归还,其他线程才可重复使用。
     * @param interfaceClass 接口类，不可为{@code null}
     * @return
     */
    public <T>T applyInstance(Class<T> interfaceClass) {
        try {
                return getObjectPool(interfaceClass).borrowObject();
                } catch (Exception e) {
                Throwables.throwIfUnchecked(e);
            throw new RuntimeException(e);
        }
    }
    /**
     * 释放{@code instance}实例使用权,必须和{@link #applyInstance(Class)}配对使用
     * @param instance 接口实例
     */
    public <T>void releaseInstance(T instance){
        if(null != instance){
                getObjectPoolByInstance(instance).returnObject(instance);
        }
    }
    private class ClientInstanceFactory<T> implements PooledObjectFactory<T>{
        private final Class<T> interfaceClass;

                private ClientInstanceFactory(Class<T> interfaceClass) {
                        checkArgument(null != interfaceClass && interfaceClass.isInterface());
                        this.interfaceClass = interfaceClass;
                }
                private NiftyClientChannel getChannel(PooledObject<T>p){
                return (NiftyClientChannel) getClientManager().getRequestChannel(p.getObject());
                }
                @Override
                public PooledObject<T> makeObject() throws Exception {
                        T obj = getThriftClient(interfaceClass).open(getClientManager().createChannel(getConnector()).get());
                        return new DefaultPooledObject<T>(obj);
                }

                @Override
                public void destroyObject(PooledObject<T> p) throws Exception {
                getChannel(p).close();
                }

                @Override
                public boolean validateObject(PooledObject<T> p) {
                        return getChannel(p).getNettyChannel().isConnected();
                }

                @Override
                public void activateObject(PooledObject<T> p) throws Exception {
                        // socket连接长时间空闲会被自动关闭,
                        // 为确保borrowObject方法返回的实例有效,在这里要检查对象是否被关闭
                        // å¦åˆ™è¿”å›žçš„å¯¹è±¡å¯èƒ½å› ä¸ºé•¿æ—¶é—´ç©ºé—²è¿žæŽ¥è¢«å…³é—­è€Œåœ¨ä½¿ç”¨æ—¶å¯¼è‡´è¿žæŽ¥å…³é—­å¼‚å¸¸
                        if(!validateObject(p)){
                                throw new IllegalStateException();
                        }
                }

                @Override
                public void passivateObject(PooledObject<T> p) throws Exception {
                }
        
    }
        public static ClientFactory builder() {
                return new ClientFactory();
        }
    /**
     * æž„é€ {@code interfaceClass}实例<br>
     * thriftyImplClass为null时,假设destClass为thrifty 异步实例类型
     * @param <I> 接口类
     * @param <O> 返回实例类型
     * @param <T> 基于thrifty实现接口类的实例类型
     * @param interfaceClass
     * @param thriftyImplClass
     * @param destClass 返回的实例类型，如果interfaceClasså’ŒthriftyImplClass为null,必须有参数为{@link ClientFactory}çš„æž„é€ å‡½æ•°
     * 否则必须有参数类型为interfaceClassçš„æž„é€ å‡½æ•°
     * @return 返回 {@code destClass }实例
     */
    @SuppressWarnings("unchecked")
    public<I,T extends I,O> O  build(final Class<I> interfaceClass,final Class<T> thriftyImplClass,final Class<O> destClass){
        try {
            return (O) CLIENT_CACHE.get(interfaceClass, new Callable<Object>(){
                @Override
                public Object call() throws Exception {
                        if(thriftyImplClass == null){
                                // destClass 为异步模式实例
                        return destClass.getDeclaredConstructor(ClientFactory.class).newInstance(ClientFactory.this); 
                        }
                                T instance =thriftyImplClass.getDeclaredConstructor(ClientFactory.class).newInstance(ClientFactory.this);
                        if(decorator !=null){
                                instance = (T) decorator.apply(instance);
                        }
                    return destClass.getDeclaredConstructor(interfaceClass).newInstance(instance);
                }});
        } catch (ExecutionException e) {
                Throwables.throwIfUnchecked(e.getCause());
            throw new RuntimeException(e.getCause());
                }
    }
        /**
         * æž„é€ {@code interfaceClass}实例<br>
         * {@link #build(Class, Class, Class)}的简化版本，当thriftImplClass只实现了一个接口时，自动推断接口类型
         * @param thriftyImplClass
         * @param destClass
         * @return
         * @see #build(Class, Class, Class)
         */
        @SuppressWarnings("unchecked")
        public<I,O,T extends I> O  build(Class<T> thriftyImplClass,Class<O> destClass){
                checkArgument(thriftyImplClass != null);
                checkArgument(thriftyImplClass.getInterfaces().length ==1,
                                "can't determines interface class from %s",thriftyImplClass.getName());
                Class<I> interfaceClass = (Class<I>) thriftyImplClass.getInterfaces()[0];
                return build(interfaceClass,thriftyImplClass,destClass);
    }
        
        /**
         * 测试当前连接是否有效
         * @return 连接有效返回{@code true},否则返回{@code false}
         */
        public boolean testConnect(){
                try {
                        NiftyClientChannel channel = getClientManager().createChannel(getConnector()).get();
                        channel.close();
                        return true;
                } catch (Exception e) {                 
                }
                return false;
        }
    public <V> void addCallback(
            final ListenableFuture<V> future,
            final FutureCallback<? super V> callback) {
        ThriftUtils.addCallback(future, callback, getExecutor());
    }
        @Override
        public String toString() {
                StringBuilder builder = new StringBuilder();
                builder.append("ClientFactory [hostAndPort=");
                builder.append(hostAndPort);
                builder.append(", clientName=");
                builder.append(clientName);
                builder.append("]");
                return builder.toString();
        }
        /**
         * 将{@code future} 封装为{@link ListenableFutureDecorator}实例
         * @param async thrift 异步接口实例
         * @param future 异步返回结果实例
         * @return {@link ListenableFutureDecorator}实例
         */
        @SuppressWarnings("unchecked")
        public <A,V>ListenableFutureDecorator<A,V>wrap(A async,ListenableFuture<V> future){
                if(future instanceof ListenableFutureDecorator){
                        return (ListenableFutureDecorator<A,V>)future;
                }
                return new ListenableFutureDecorator<A, V>(async,future);       
        }
    /**
     * {@link ListenableFuture}接口的装饰类，
     * 用于确保异步调用结束时释放异步接口实例,参见{@link ClientFactory#releaseInstance(Object)}
     * @author guyadong
     *
     * @param <A> thrift 异步接口类型
     * @param <V> 方法返回值类型
     */
    public class ListenableFutureDecorator<A,V> implements ListenableFuture<V>{
        private final A async;
        private final ListenableFuture<V> future;
        /** 确保 {@link #releaseAsync()}æ–¹æ³•åªè¢«è°ƒç”¨ä¸€æ¬¡çš„æ ‡å¿—å­—æ®µ */
        private final AtomicBoolean released = new AtomicBoolean(false);
                public ListenableFutureDecorator(A async, ListenableFuture<V> future) {
                        this.async = checkNotNull(async,"async is null");
                        this.future = checkNotNull(future,"future is null");
                }
                private void releaseAsync(){
                        if(released.compareAndSet(false, true)){
                                releaseInstance(async); 
                        }
                }
                @Override
                public boolean cancel(boolean mayInterruptIfRunning) {
                        return future.cancel(mayInterruptIfRunning);
                }

                @Override
                public V get() throws InterruptedException, ExecutionException {
                        try{
                                return future.get();
                        }finally{
                                releaseAsync();                         
                        }
                }

                @Override
                public V get(long timeout, TimeUnit unit) throws InterruptedException, ExecutionException, TimeoutException {
                        try{
                                return future.get(timeout, unit);
                        }finally{
                                releaseAsync();
                        }
                }

                @Override
                public boolean isCancelled() {
                        return future.isCancelled();
                }

                @Override
                public boolean isDone() {
                        return future.isDone();
                }

                @Override
                public void addListener(Runnable listener, Executor executor) {
                        future.addListener(listener, executor);                 
                }       
    }
    static{
                // JVM ç»“æŸæ—¶è‡ªåŠ¨æ¸…é™¤èµ„æºæ± ä¸­æ‰€æœ‰å¯¹è±¡
                Runtime.getRuntime().addShutdownHook(new Thread(){

                        @Override
                        public void run() {
                                for(GenericObjectPool<?> pool:INSTANCE_POOL_CACHE.asMap().values()){
                                        pool.close();
                                }
                        }                       
                });
    }
}