/*
 * Copyright (c) 2011-2016 The original author or authors
 *
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * and Apache License v2.0 which accompanies this distribution.
 *
 *      The Eclipse Public License is available at
 *      http://www.eclipse.org/legal/epl-v10.html
 *
 *      The Apache License v2.0 is available at
 *      http://www.opensource.org/licenses/apache2.0.php
 *
 * You may elect to redistribute this code under either of these licenses.
 */

package io.vertx.servicediscovery.types;

import io.vertx.codegen.annotations.GenIgnore;
import io.vertx.codegen.annotations.VertxGen;
import io.vertx.core.AsyncResult;
import io.vertx.core.Future;
import io.vertx.core.Handler;
import io.vertx.core.json.JsonObject;
import io.vertx.servicediscovery.Record;
import io.vertx.servicediscovery.ServiceDiscovery;
import io.vertx.servicediscovery.ServiceReference;
import io.vertx.servicediscovery.spi.ServiceType;

import java.util.Objects;
import java.util.function.Function;

ServiceType for event bus services (service proxies). Consumers receive a service proxy to use the service. 
Author:
Clement Escoffier/**
 * {@link ServiceType} for event bus services (service proxies).
 * Consumers receive a service proxy to use the service.
 *
 * @author <a href="http://escoffier.me">Clement Escoffier</a>
 */
@VertxGen
public interface EventBusService extends ServiceType {

  
Name of the type.
/**
   * Name of the type.
   */
  String TYPE = "eventbus-service-proxy";

  
Sugar method to creates a record for this type.

The java interface is added to the metadata in the `service.interface` key.
Params:
name –     the name of the service.
address –  the event bus address on which the service available
itf –      the Java interface
metadata – the metadata
Returns:
the created record/**
   * Sugar method to creates a record for this type.
   * <p>
   * The java interface is added to the metadata in the `service.interface` key.
   *
   * @param name     the name of the service.
   * @param address  the event bus address on which the service available
   * @param itf      the Java interface
   * @param metadata the metadata
   * @return the created record
   */
  @GenIgnore
  static Record createRecord(String name, String address, Class itf, JsonObject metadata) {
    return createRecord(name, address, itf.getName(), metadata);
  }

  
Sugar method to creates a record for this type.

The java interface is added to the metadata in the `service.interface` key.
Params:
name –     the name of the service.
address –  the event bus address on which the service available
itf –      the Java interface (name)
metadata – the metadata
Returns:
the created record/**
   * Sugar method to creates a record for this type.
   * <p>
   * The java interface is added to the metadata in the `service.interface` key.
   *
   * @param name     the name of the service.
   * @param address  the event bus address on which the service available
   * @param itf      the Java interface (name)
   * @param metadata the metadata
   * @return the created record
   */
  static Record createRecord(String name, String address, String itf, JsonObject metadata) {
    Objects.requireNonNull(name);
    Objects.requireNonNull(itf);
    Objects.requireNonNull(address);

    JsonObject meta;
    if (metadata == null) {
      meta = new JsonObject();
    } else {
      meta = metadata.copy();
    }

    return new Record()
      .setType(TYPE)
      .setName(name)
      .setMetadata(meta.put("service.interface", itf))
      .setLocation(new JsonObject().put(Record.ENDPOINT, address));
  }

  
Same as createRecord(String, String, Class, JsonObject) but without metadata. 
Params:
name –    the name of the service
itf –     the Java interface
address – the event bus address on which the service available
Returns:
the created record/**
   * Same as {@link #createRecord(String, String, Class, JsonObject)} but without metadata.
   *
   * @param name    the name of the service
   * @param itf     the Java interface
   * @param address the event bus address on which the service available
   * @return the created record
   */
  @GenIgnore
  static Record createRecord(String name, String address, Class itf) {
    return createRecord(name, address, itf, null);
  }

  
Lookup for a service record and if found, retrieve it and return the service object (used to consume the service).
This is a convenient method to avoid explicit lookup and then retrieval of the service. A filter based on the
request interface is used.
Params:
discovery –     the service discovery instance
itf –           the service interface
resultHandler – the result handler
Type parameters:
<T> –           the service interface
Returns:
null/**
   * Lookup for a service record and if found, retrieve it and return the service object (used to consume the service).
   * This is a convenient method to avoid explicit lookup and then retrieval of the service. A filter based on the
   * request interface is used.
   *
   * @param discovery     the service discovery instance
   * @param itf           the service interface
   * @param resultHandler the result handler
   * @param <T>           the service interface
   * @return {@code null}
   */
  @GenIgnore // Java only
  static <T> T getProxy(ServiceDiscovery discovery, Class<T> itf, Handler<AsyncResult<T>>
    resultHandler) {
    JsonObject filter = new JsonObject().put("service.interface", itf.getName());
    discovery.getRecord(filter, ar -> {
      if (ar.failed()) {
        resultHandler.handle(Future.failedFuture(ar.cause()));
      } else {
        if (ar.result() == null) {
          resultHandler.handle(Future.failedFuture("Cannot find service matching with " + filter));
        } else {
          ServiceReference service = discovery.getReference(ar.result());
          resultHandler.handle(Future.succeededFuture(service.get()));
        }
      }
    });
    return null;
  }

  
Lookup for a service record and if found, retrieve it and return the service object (used to consume the service). This is a convenient method to avoid explicit lookup and then retrieval of the service. This method requires to have the clientClass set with the expected set of client. This is important for usages not using Java so you can pass the expected type. 
Params:
discovery –     the service discovery
filter –        the filter
clientClass –   the client class
resultHandler – the result handler
Type parameters:
<T> –           the type of the client class
Returns:
null - do not use/**
   * Lookup for a service record and if found, retrieve it and return the service object (used to consume the service).
   * This is a convenient method to avoid explicit lookup and then retrieval of the service. This method requires to
   * have the {@code clientClass} set with the expected set of client. This is important for usages not using Java so
   * you can pass the expected type.
   *
   * @param discovery     the service discovery
   * @param filter        the filter
   * @param clientClass   the client class
   * @param resultHandler the result handler
   * @param <T>           the type of the client class
   * @return {@code null} - do not use
   */
  static <T> T getServiceProxy(ServiceDiscovery discovery,
                               Function<Record, Boolean> filter,
                               Class<T> clientClass,
                               Handler<AsyncResult<T>> resultHandler) {
    discovery.getRecord(filter, ar -> {
      if (ar.failed()) {
        resultHandler.handle(Future.failedFuture(ar.cause()));
      } else {
        if (ar.result() == null) {
          resultHandler.handle(Future.failedFuture("Cannot find service matching with " + filter));
        } else {
          ServiceReference service = discovery.getReference(ar.result());
          resultHandler.handle(Future.succeededFuture(service.getAs(clientClass)));
        }
      }
    });
    return null;
  }

  
Lookup for a service record and if found, retrieve it and return the service object (used to consume the service). This is a convenient method to avoid explicit lookup and then retrieval of the service. This method requires to have the clientClass set with the expected set of client. This is important for usages not using Java so you can pass the expected type. 
Params:
discovery –     the service discovery
filter –        the filter as json object
clientClass –   the client class
resultHandler – the result handler
Type parameters:
<T> –           the type of the client class
Returns:
null - do not use/**
   * Lookup for a service record and if found, retrieve it and return the service object (used to consume the service).
   * This is a convenient method to avoid explicit lookup and then retrieval of the service. This method requires to
   * have the {@code clientClass} set with the expected set of client. This is important for usages not using Java so
   * you can pass the expected type.
   *
   * @param discovery     the service discovery
   * @param filter        the filter as json object
   * @param clientClass   the client class
   * @param resultHandler the result handler
   * @param <T>           the type of the client class
   * @return {@code null} - do not use
   */
  static <T> T getServiceProxyWithJsonFilter(ServiceDiscovery discovery,
                                             JsonObject filter,
                                             Class<T> clientClass,
                                             Handler<AsyncResult<T>> resultHandler) {
    discovery.getRecord(filter, ar -> {
      if (ar.failed()) {
        resultHandler.handle(Future.failedFuture(ar.cause()));
      } else {
        if (ar.result() == null) {
          resultHandler.handle(Future.failedFuture("Cannot find service matching with " + filter));
        } else {
          ServiceReference service = discovery.getReference(ar.result());
          resultHandler.handle(Future.succeededFuture(service.getAs(clientClass)));
        }
      }
    });
    return null;
  }

  
Creates a record based on the parameters.
Params:
name –      the service name
address –   the address
classname – the payload class
Returns:
the record/**
   * Creates a record based on the parameters.
   *
   * @param name      the service name
   * @param address   the address
   * @param classname the payload class
   * @return the record
   */
  static Record createRecord(String name, String address, String classname) {
    return createRecord(name, address, classname, null);
  }
}