package io.dropwizard.client;

import com.codahale.metrics.MetricRegistry;
import com.codahale.metrics.httpclient.HttpClientMetricNameStrategy;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.google.common.annotations.VisibleForTesting;
import io.dropwizard.jersey.gzip.ConfiguredGZipEncoder;
import io.dropwizard.jersey.gzip.GZipDecoder;
import io.dropwizard.jersey.jackson.JacksonBinder;
import io.dropwizard.jersey.validation.HibernateValidationFeature;
import io.dropwizard.jersey.validation.Validators;
import io.dropwizard.lifecycle.Managed;
import io.dropwizard.setup.Environment;
import org.apache.http.client.CredentialsProvider;
import org.apache.http.client.HttpRequestRetryHandler;
import org.apache.http.client.ServiceUnavailableRetryStrategy;
import org.apache.http.config.Registry;
import org.apache.http.conn.DnsResolver;
import org.apache.http.conn.routing.HttpRoutePlanner;
import org.apache.http.conn.socket.ConnectionSocketFactory;
import org.glassfish.jersey.client.ClientConfig;
import org.glassfish.jersey.client.rx.Rx;
import org.glassfish.jersey.client.rx.RxClient;
import org.glassfish.jersey.client.rx.RxInvoker;
import org.glassfish.jersey.client.spi.ConnectorProvider;

import javax.annotation.Nullable;
import javax.net.ssl.HostnameVerifier;
import javax.validation.Validator;
import javax.ws.rs.client.Client;
import javax.ws.rs.client.ClientBuilder;
import javax.ws.rs.core.Configuration;
import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.ExecutorService;

import static java.util.Objects.requireNonNull;


A convenience class for building Client instances. 

Among other things,

Backed by Apache HttpClient
Disables stale connection checks
Disables Nagle's algorithm
Disables cookie management by default
Compress requests and decompress responses using GZIP
Supports parsing and generating JSON data using Jackson


See Also:
HttpClientBuilder/**
 * A convenience class for building {@link Client} instances.
 * <p>
 * Among other things,
 * <ul>
 * <li>Backed by Apache HttpClient</li>
 * <li>Disables stale connection checks</li>
 * <li>Disables Nagle's algorithm</li>
 * <li>Disables cookie management by default</li>
 * <li>Compress requests and decompress responses using GZIP</li>
 * <li>Supports parsing and generating JSON data using Jackson</li>
 * </ul>
 * </p>
 *
 * @see HttpClientBuilder
 */
public class JerseyClientBuilder {

    private final List<Object> singletons = new ArrayList<>();
    private final List<Class<?>> providers = new ArrayList<>();
    private final Map<String, Object> properties = new LinkedHashMap<>();
    private JerseyClientConfiguration configuration = new JerseyClientConfiguration();

    private HttpClientBuilder apacheHttpClientBuilder;
    private Validator validator = Validators.newValidator();

    @Nullable
    private Environment environment;

    @Nullable
    private ObjectMapper objectMapper;

    @Nullable
    private ExecutorService executorService;

    @Nullable
    private ConnectorProvider connectorProvider;

    public JerseyClientBuilder(Environment environment) {
        this.apacheHttpClientBuilder = new HttpClientBuilder(environment);
        this.environment = environment;
    }

    public JerseyClientBuilder(MetricRegistry metricRegistry) {
        this.apacheHttpClientBuilder = new HttpClientBuilder(metricRegistry);
    }

    @VisibleForTesting
    public void setApacheHttpClientBuilder(HttpClientBuilder apacheHttpClientBuilder) {
        this.apacheHttpClientBuilder = apacheHttpClientBuilder;
    }

    
Adds the given object as a Jersey provider.
Params:
provider – a Jersey provider
Returns:
this/**
     * Adds the given object as a Jersey provider.
     *
     * @param provider a Jersey provider
     * @return {@code this}
     */
    public JerseyClientBuilder withProvider(Object provider) {
        singletons.add(requireNonNull(provider));
        return this;
    }

    
Adds the given class as a Jersey provider. 
N.B.: This class must either have a
no-args constructor or use Jersey's built-in dependency injection.
Params:
klass – a Jersey provider class
Returns:
this/**
     * Adds the given class as a Jersey provider. <p/><b>N.B.:</b> This class must either have a
     * no-args constructor or use Jersey's built-in dependency injection.
     *
     * @param klass a Jersey provider class
     * @return {@code this}
     */
    public JerseyClientBuilder withProvider(Class<?> klass) {
        providers.add(requireNonNull(klass));
        return this;
    }

    
Sets the state of the given Jersey property.

WARNING: The default connector ignores Jersey properties. Use JerseyClientConfiguration instead. 
Params:
propertyName –  the name of the Jersey property
propertyValue – the state of the Jersey property
Returns:
this/**
     * Sets the state of the given Jersey property.
     * <p/>
     * <p/><b>WARNING:</b> The default connector ignores Jersey properties.
     * Use {@link JerseyClientConfiguration} instead.
     *
     * @param propertyName  the name of the Jersey property
     * @param propertyValue the state of the Jersey property
     * @return {@code this}
     */
    public JerseyClientBuilder withProperty(String propertyName, Object propertyValue) {
        properties.put(propertyName, propertyValue);
        return this;
    }

    
Uses the given JerseyClientConfiguration. 
Params:
configuration – a configuration object
Returns:
this/**
     * Uses the given {@link JerseyClientConfiguration}.
     *
     * @param configuration a configuration object
     * @return {@code this}
     */
    public JerseyClientBuilder using(JerseyClientConfiguration configuration) {
        this.configuration = configuration;
        apacheHttpClientBuilder.using(configuration);
        return this;
    }

    
Uses the given Environment. 
Params:
environment – a Dropwizard Environment
See Also:
using(ExecutorService, ObjectMapper)
Returns:
this/**
     * Uses the given {@link Environment}.
     *
     * @param environment a Dropwizard {@link Environment}
     * @return {@code this}
     * @see #using(java.util.concurrent.ExecutorService, com.fasterxml.jackson.databind.ObjectMapper)
     */
    public JerseyClientBuilder using(Environment environment) {
        this.environment = environment;
        return this;
    }

    
Use the given Validator instance. 
Params:
validator – a Validator instance
Returns:
this/**
     * Use the given {@link Validator} instance.
     *
     * @param validator a {@link Validator} instance
     * @return {@code this}
     */
    public JerseyClientBuilder using(Validator validator) {
        this.validator = validator;
        return this;
    }

    
Uses the given ExecutorService and ObjectMapper. 
Params:
executorService – a thread pool
objectMapper –    an object mapper
See Also:
using(Environment)
Returns:
this/**
     * Uses the given {@link ExecutorService} and {@link ObjectMapper}.
     *
     * @param executorService a thread pool
     * @param objectMapper    an object mapper
     * @return {@code this}
     * @see #using(io.dropwizard.setup.Environment)
     */
    public JerseyClientBuilder using(ExecutorService executorService, ObjectMapper objectMapper) {
        this.executorService = executorService;
        this.objectMapper = objectMapper;
        return this;
    }

    
Uses the given ExecutorService. 
Params:
executorService – a thread pool
See Also:
using(Environment)
Returns:
this/**
     * Uses the given {@link ExecutorService}.
     *
     * @param executorService a thread pool
     * @return {@code this}
     * @see #using(io.dropwizard.setup.Environment)
     */
    public JerseyClientBuilder using(ExecutorService executorService) {
        this.executorService = executorService;
        return this;
    }

    
Uses the given ObjectMapper. 
Params:
objectMapper –    an object mapper
See Also:
using(Environment)
Returns:
this/**
     * Uses the given {@link ObjectMapper}.
     *
     * @param objectMapper    an object mapper
     * @return {@code this}
     * @see #using(io.dropwizard.setup.Environment)
     */
    public JerseyClientBuilder using(ObjectMapper objectMapper) {
        this.objectMapper = objectMapper;
        return this;
    }

    
Use the given ConnectorProvider instance. 
WARNING: Use it with a caution. Most of features will not
work in a custom connection provider.
Params:
connectorProvider – a ConnectorProvider instance
Returns:
this/**
     * Use the given {@link ConnectorProvider} instance.
     * <p/><b>WARNING:</b> Use it with a caution. Most of features will not
     * work in a custom connection provider.
     *
     * @param connectorProvider a {@link ConnectorProvider} instance
     * @return {@code this}
     */
    public JerseyClientBuilder using(ConnectorProvider connectorProvider) {
        this.connectorProvider = connectorProvider;
        return this;
    }

    
Uses the HttpRequestRetryHandler for handling request retries. 
Params:
httpRequestRetryHandler – a HttpRequestRetryHandler
Returns:
this/**
     * Uses the {@link org.apache.http.client.HttpRequestRetryHandler} for handling request retries.
     *
     * @param httpRequestRetryHandler a HttpRequestRetryHandler
     * @return {@code this}
     */
    public JerseyClientBuilder using(HttpRequestRetryHandler httpRequestRetryHandler) {
        apacheHttpClientBuilder.using(httpRequestRetryHandler);
        return this;
    }

    
Use the given DnsResolver instance. 
Params:
resolver – a DnsResolver instance
Returns:
this/**
     * Use the given {@link DnsResolver} instance.
     *
     * @param resolver a {@link DnsResolver} instance
     * @return {@code this}
     */
    public JerseyClientBuilder using(DnsResolver resolver) {
        apacheHttpClientBuilder.using(resolver);
        return this;
    }

    
Use the given HostnameVerifier instance. Note that if TlsConfiguration.isVerifyHostname() returns false, all host name verification is bypassed, including host name verification performed by a verifier specified through this interface. 
Params:
verifier – a HostnameVerifier instance
Returns:
this/**
     * Use the given {@link HostnameVerifier} instance.
     *
     * Note that if {@link io.dropwizard.client.ssl.TlsConfiguration#isVerifyHostname()}
     * returns false, all host name verification is bypassed, including
     * host name verification performed by a verifier specified
     * through this interface.
     *
     * @param verifier a {@link HostnameVerifier} instance
     * @return {@code this}
     */
    public JerseyClientBuilder using(HostnameVerifier verifier) {
        apacheHttpClientBuilder.using(verifier);
        return this;
    }

    
Use the given Registry instance of connection socket factories. 
Params:
registry – a Registry instance of connection socket factories
Returns:
this/**
     * Use the given {@link Registry} instance of connection socket factories.
     *
     * @param registry a {@link Registry} instance of connection socket factories
     * @return {@code this}
     */
    public JerseyClientBuilder using(Registry<ConnectionSocketFactory> registry) {
        apacheHttpClientBuilder.using(registry);
        return this;
    }

    
Use the given HttpClientMetricNameStrategy instance. 
Params:
metricNameStrategy – a HttpClientMetricNameStrategy instance
Returns:
this/**
     * Use the given {@link HttpClientMetricNameStrategy} instance.
     *
     * @param metricNameStrategy a {@link HttpClientMetricNameStrategy} instance
     * @return {@code this}
     */
    public JerseyClientBuilder using(HttpClientMetricNameStrategy metricNameStrategy) {
        apacheHttpClientBuilder.using(metricNameStrategy);
        return this;
    }

    
Use the given environment name. This is used in the user agent.
Params:
environmentName – an environment name to use in the user agent.
Returns:
this/**
     * Use the given environment name. This is used in the user agent.
     *
     * @param environmentName an environment name to use in the user agent.
     * @return {@code this}
     */
    public JerseyClientBuilder name(String environmentName) {
        apacheHttpClientBuilder.name(environmentName);
        return this;
    }

    
Use the given HttpRoutePlanner instance. 
Params:
routePlanner – a HttpRoutePlanner instance
Returns:
this/**
     * Use the given {@link HttpRoutePlanner} instance.
     *
     * @param routePlanner a {@link HttpRoutePlanner} instance
     * @return {@code this}
     */
    public JerseyClientBuilder using(HttpRoutePlanner routePlanner) {
        apacheHttpClientBuilder.using(routePlanner);
        return this;
    }

    
Use the given CredentialsProvider instance. 
Params:
credentialsProvider – a CredentialsProvider instance
Returns:
this/**
     * Use the given {@link CredentialsProvider} instance.
     *
     * @param credentialsProvider a {@link CredentialsProvider} instance
     * @return {@code this}
     */
    public JerseyClientBuilder using(CredentialsProvider credentialsProvider) {
        apacheHttpClientBuilder.using(credentialsProvider);
        return this;
    }

    
Use the given ServiceUnavailableRetryStrategy instance. 
Params:
serviceUnavailableRetryStrategy – a ServiceUnavailableRetryStrategy instance
Returns:
this/**
     * Use the given {@link ServiceUnavailableRetryStrategy} instance.
     *
     * @param serviceUnavailableRetryStrategy a {@link ServiceUnavailableRetryStrategy} instance
     * @return {@code this}
     */
    public JerseyClientBuilder using(ServiceUnavailableRetryStrategy serviceUnavailableRetryStrategy) {
        apacheHttpClientBuilder.using(serviceUnavailableRetryStrategy);
        return this;
    }

    
Builds the RxClient instance. 
Returns:
a fully-configured RxClient/**
     * Builds the {@link RxClient} instance.
     *
     * @return a fully-configured {@link RxClient}
     */
    public <RX extends RxInvoker> RxClient<RX> buildRx(String name, Class<RX> invokerType) {
        return Rx.from(build(name), invokerType, executorService);
    }

    
Builds the Client instance. 
Returns:
a fully-configured Client/**
     * Builds the {@link Client} instance.
     *
     * @return a fully-configured {@link Client}
     */
    public Client build(String name) {
        if ((environment == null) && ((executorService == null) || (objectMapper == null))) {
            throw new IllegalStateException("Must have either an environment or both " +
                    "an executor service and an object mapper");
        }

        if (executorService == null) {
            // Create an ExecutorService based on the provided
            // configuration. The DisposableExecutorService decorator
            // is used to ensure that the service is shut down if the
            // Jersey client disposes of it.
            executorService = requireNonNull(environment).lifecycle()
                .executorService("jersey-client-" + name + "-%d")
                .minThreads(configuration.getMinThreads())
                .maxThreads(configuration.getMaxThreads())
                .workQueue(new ArrayBlockingQueue<>(configuration.getWorkQueueSize()))
                .build();
        }

        if (objectMapper == null) {
            objectMapper = requireNonNull(environment).getObjectMapper();
        }

        if (environment != null) {
            validator = environment.getValidator();
        }

        return build(name, executorService, objectMapper, validator);
    }

    private Client build(String name, ExecutorService threadPool,
                         ObjectMapper objectMapper,
                         Validator validator) {
        if (!configuration.isGzipEnabled()) {
            apacheHttpClientBuilder.disableContentCompression(true);
        }

        final Client client = ClientBuilder.newClient(buildConfig(name, threadPool, objectMapper, validator));
        client.register(new JerseyIgnoreRequestUserAgentHeaderFilter());

        // Tie the client to server lifecycle
        if (environment != null) {
            environment.lifecycle().manage(new Managed() {
                @Override
                public void start() throws Exception {
                }

                @Override
                public void stop() throws Exception {
                    client.close();
                }
            });
        }
        if (configuration.isGzipEnabled()) {
            client.register(new GZipDecoder());
            client.register(new ConfiguredGZipEncoder(configuration.isGzipEnabledForRequests()));
        }

        return client;
    }

    private Configuration buildConfig(final String name, final ExecutorService threadPool,
                                      final ObjectMapper objectMapper,
                                      final Validator validator) {
        final ClientConfig config = new ClientConfig();

        for (Object singleton : this.singletons) {
            config.register(singleton);
        }

        for (Class<?> provider : this.providers) {
            config.register(provider);
        }

        config.register(new JacksonBinder(objectMapper));
        config.register(new HibernateValidationFeature(validator));

        for (Map.Entry<String, Object> property : this.properties.entrySet()) {
            config.property(property.getKey(), property.getValue());
        }

        config.register(new DropwizardExecutorProvider(threadPool));
        if (connectorProvider == null) {
            final ConfiguredCloseableHttpClient apacheHttpClient =
                    apacheHttpClientBuilder.buildWithDefaultRequestConfiguration(name);
            connectorProvider = (client, runtimeConfig) -> createDropwizardApacheConnector(apacheHttpClient);
        }
        config.connectorProvider(connectorProvider);

        return config;
    }

    
Builds DropwizardApacheConnector based on the configured Apache HTTP client as ConfiguredCloseableHttpClient and the chunked encoding configuration set by the user. /**
     * Builds {@link DropwizardApacheConnector} based on the configured Apache HTTP client
     * as {@link ConfiguredCloseableHttpClient} and the chunked encoding configuration set by the user.
     */
    protected DropwizardApacheConnector createDropwizardApacheConnector(ConfiguredCloseableHttpClient configuredClient) {
        return new DropwizardApacheConnector(configuredClient.getClient(), configuredClient.getDefaultRequestConfig(),
                configuration.isChunkedEncodingEnabled());
    }
}