/*
 * Copyright 2014 Red Hat, Inc.
 *
 *  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.service;

import io.vertx.core.DeploymentOptions;
import io.vertx.core.Future;
import io.vertx.core.Promise;
import io.vertx.core.Verticle;
import io.vertx.core.json.DecodeException;
import io.vertx.core.json.JsonObject;
import io.vertx.core.spi.VerticleFactory;

import java.io.InputStream;
import java.util.NoSuchElementException;
import java.util.Scanner;

This verticle factory looks for a descriptor file on the classpath with a name given by the verticleName
(with ':' replaced by '.' as ':' is an illegal file name character in Windows) and
with ".json" appended to it.
When it finds that file it deploys the actual verticle that's defined by the "main" field in that file.
The descriptor file can also contain a field called "options" which is the JSON form of the DeploymentOptions
class
Author:
Tim Fox/**
 * This verticle factory looks for a descriptor file on the classpath with a name given by the verticleName
 * (with ':' replaced by '.' as ':' is an illegal file name character in Windows) and
 * with ".json" appended to it.
 * When it finds that file it deploys the actual verticle that's defined by the "main" field in that file.
 * The descriptor file can also contain a field called "options" which is the JSON form of the DeploymentOptions
 * class
 * @author <a href="http://tfox.org">Tim Fox</a>
 */
public class ServiceVerticleFactory implements VerticleFactory {

  @Override
  public boolean requiresResolve() {
    return true;
  }

  @Override
  public void resolve(String identifier, DeploymentOptions deploymentOptions, ClassLoader classLoader, Promise<String> resolution) {
    identifier = VerticleFactory.removePrefix(identifier);
    String descriptorFile = identifier + ".json";
    try {
      JsonObject descriptor;
      String main;
      try (InputStream is = classLoader.getResourceAsStream(descriptorFile)) {
        if (is == null) {
          throw new IllegalArgumentException("Cannot find service descriptor file " + descriptorFile + " on classpath");
        }
        try (Scanner scanner = new Scanner(is, "UTF-8").useDelimiter("\\A")) {
          String conf = scanner.next();
          descriptor = new JsonObject(conf);
        } catch (NoSuchElementException e) {
          throw new IllegalArgumentException(descriptorFile + " is empty");
        } catch (DecodeException e) {
          throw new IllegalArgumentException(descriptorFile + " contains invalid json");
        }
      }
      main = descriptor.getString("main");
      if (main == null) {
        throw new IllegalArgumentException(descriptorFile + " does not contain a main field");
      }

      // Any options specified in the service config will override anything specified at deployment time
      // With the exception of config which can be overridden with config provided at deployment time
      JsonObject depOptions = deploymentOptions.toJson();
      JsonObject depConfig = depOptions.getJsonObject("config", new JsonObject());
      JsonObject serviceOptions = descriptor.getJsonObject("options", new JsonObject());
      JsonObject serviceConfig = serviceOptions.getJsonObject("config", new JsonObject());
      depOptions.mergeIn(serviceOptions);
      serviceConfig.mergeIn(depConfig);
      depOptions.put("config", serviceConfig);
      deploymentOptions.fromJson(depOptions);
      resolution.complete(main);
    } catch (Exception e) {
      resolution.fail(e);
    }
  }

  @Override
  public String prefix() {
    return "service";
  }

  @Override
  public Verticle createVerticle(String verticleName, ClassLoader classLoader) throws Exception {
    throw new IllegalStateException("Shouldn't be called");
  }


}