/*
    * scriptable-dataset (https://github.com/hazendaz/scriptable-dataset)
    *
    * Copyright 2011-2024 Hazendaz.
    *
    * All rights reserved. This program and the accompanying materials
    * are made available under the terms of The Apache Software License,
    * Version 2.0 which accompanies this distribution, and is available at
    * https://www.apache.org/licenses/LICENSE-2.0.txt
   *
   * Contributors:
   *     Gunnar Morling
   *     Hazendaz (Jeremy Landis).
   */
  package de.gmorling.scriptabledataset.handlers;
  
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.HashMap;
  import java.util.List;
  import java.util.Map;
  import java.util.ServiceConfigurationError;
  import java.util.ServiceLoader;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * Manages handlers, that shall always executed for scripts in a given language. These standard handlers will be called
   * <b>before</b> any custom handlers in the pre invocation and <b>after</b> any custom handlers in the post invocation.
   */
  public class StandardHandlerConfig {
  
      /** The standard handlers. */
      private static Map<String, List<ScriptInvocationHandler>> standardHandlers;
  
      /**
       * Instantiates a new standard handler config.
       */
      private StandardHandlerConfig() {
          // Prevent Instantiation
      }
  
      static {
  
          standardHandlers = new HashMap<>();
  
          ServiceLoader<ScriptInvocationHandler> serviceLoader = ServiceLoader.load(ScriptInvocationHandler.class);
          try {
              for (ScriptInvocationHandler scriptInvocationHandler : serviceLoader) {
  
                  List<ScriptInvocationHandler> handlersForLanguage = standardHandlers
                          .get(scriptInvocationHandler.getLanguageName());
  
                  if (handlersForLanguage == null) {
                      handlersForLanguage = new ArrayList<>();
                      standardHandlers.put(scriptInvocationHandler.getLanguageName(), handlersForLanguage);
                  }
  
                  handlersForLanguage.add(scriptInvocationHandler);
              }
          } catch (ServiceConfigurationError error) {
              Logger logger = LoggerFactory.getLogger(StandardHandlerConfig.class);
              logger.error(
                      "Loading of standard script invocation handlers failed, most likely due to an unknown handler implementation given in META-INF/services {}",
                      ScriptInvocationHandler.class.getName());
              standardHandlers = Collections.emptyMap();
          }
      }
  
      /**
       * Gets the standard handlers by language.
       *
       * @param language
       *            the language
       *
       * @return the standard handlers by language
       */
      public static List<ScriptInvocationHandler> getStandardHandlersByLanguage(String language) {
          if (standardHandlers.containsKey(language)) {
              return Collections.unmodifiableList(standardHandlers.get(language));
          }
          return Collections.emptyList();
      }
  }