package cz.cuni.amis.pogamut.sposh.executor;
   
   import cz.cuni.amis.pogamut.sposh.engine.VariableContext;
   import java.io.PrintStream;
   import java.util.HashMap;
   
   /**
    * Very simple executor for plans that will print name of primitive, that is supposed
    * to execute, to specified stream.
   * <p/>
   * There are two lists of primitives, one will always return true, other will always return false.
   * Both will be printed. Primitives that are not in either of lists will cause exception
   * {@link IllegalArgumentException}.
   * @author Honza
   */
  public class PrintWorkExecutor implements IWorkExecutor {
  
      /**
       * Stream into which we will write called primitives.
       */
      private PrintStream stream;
      /**
       * Map that stores return value of primitives.
       */
      private HashMap<String, Boolean> map = new HashMap<String, Boolean>();
  
      /**
       * Create worker that will print name of primitives into specified stream.
       * @param succeed list of non-zero length strings with names of primitives returning true
       * @param fail list of non-zero length strings with names of primitives returning false
       * @param stream stream to write into
       * @throws IllegalArgumentException If some primitive is specified twice,
       */
      public PrintWorkExecutor(String[] succeed, String[] fail, PrintStream stream) {
          this.stream = stream;
  
          addPrimitives(succeed, Boolean.TRUE);
          addPrimitives(fail, Boolean.FALSE);
      }
  
      /**
       * Add primitives to the map with specified return value. 
       * @param primitives list of primitives we want to add.
       * @param value what value should all primitives return
       * @throws IllegalArgumentException If some primitive is specified twice,
       */
      public synchronized void addPrimitives(String[] primitives, Boolean value) {
          for (String primtive : primitives) {
              if (map.put(primtive, value) != null)
                  throw new IllegalArgumentException("Primitive \"" + primtive + "\" has already been specified.");
          }
      }
  
      /**
       * Create worker that will print name of primitives into {@link System#out}.
       */
      public PrintWorkExecutor(String[] succeed, String[] fail) {
          this(succeed, fail, System.out);
      }
      
      private Object executePrimitive(String primitive, VariableContext ctx) {
          Boolean value = map.get(primitive);
          // no mapping for specified primitive
          if (value == null) {
              throw new IllegalArgumentException("Primitive \"" + primitive + "\" is not specified in the worker.");
          }
          stream.println(getClass().getSimpleName() + ": execute \"" + primitive + "\"" + ctx.toString() + " -> " + value);
          return value;
      }
      
      @Override
      public synchronized Object executeSense(String primitive, VariableContext ctx) {
          return executePrimitive(primitive, ctx);
      }
      
      @Override
      public synchronized ActionResult executeAction(String primitive, VariableContext ctx) {
      	Object result = executePrimitive(primitive, ctx);
      	if (result instanceof ActionResult) return (ActionResult)result;
          return ActionResult.FINISHED;
      }
      
  }