/*
 * Copyright (c) 2014 DataTorrent, Inc. ALL Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.datatorrent.lib.script;

import com.datatorrent.api.Context.OperatorContext;
import org.jruby.embed.LocalVariableBehavior;
import org.jruby.embed.ScriptingContainer;
import org.jruby.javasupport.JavaEmbedUtils.EvalUnit;

import java.util.Map;

/**
 * An implementation of ScriptOperator that executes ruby script on tuples
 * <p>
 * @displayName: Ruby Operator
 * @category: script
 * @tag: script operator, map, string
 * @since 1.0.4
 */
public class RubyOperator extends ScriptOperator {

  public enum Type
  {
    EVAL, INVOKE
  };

  protected Type type = Type.EVAL;
  protected transient Object evalResult;
  private transient ScriptingContainer sc = null;
  private transient EvalUnit unit;


  public void setEval(String script) {

    this.type = Type.EVAL;
    this.script = script;
  }

  public void setInvoke(String functionName) {

    this.type = Type.INVOKE;
    this.script = functionName;
  }

  @Override
  public void setup(OperatorContext context) {

    sc = new ScriptingContainer(LocalVariableBehavior.PERSISTENT);
    for (String s : setupScripts) {
      EvalUnit unit = sc.parse(s);
      unit.run();
    }
    if (type == Type.EVAL) {
      unit = sc.parse(script);
    }
  }

  @Override
  public void process(Map<String, Object> tuple) {

    try {
      if(type == Type.EVAL) {
        for (Map.Entry<String, Object> entry : tuple.entrySet()) {
          sc.put(entry.getKey(), entry.getValue());
        }
        evalResult = unit.run();
      }
      else {
        Object[] args = new Object[tuple.size()];
        int index = 0;
        for (Map.Entry<String, Object> entry : tuple.entrySet()) {
          args[index++] = entry.getValue();
        }
        evalResult = sc.callMethod(evalResult, script, args);
      }
      if (isPassThru && result.isConnected()) {
        result.emit(evalResult);
      }
      if (isPassThru && outBindings.isConnected()) {
        outBindings.emit(getBindings());
      }
      sc.clear();
    }
    catch (Exception ex) {
      throw new RuntimeException(ex);
    }
  }

  @Override
  public void endWindow() {

    if (!isPassThru) {
      if(result.isConnected())
        result.emit(evalResult);
      if(outBindings.isConnected())
        outBindings.emit(getBindings());
    }
  }

  @SuppressWarnings("unchecked")
  @Override
  public Map<String, Object> getBindings() {

    if(sc == null)
      return null;
    if(sc.getVarMap() != null) {
      return sc.getVarMap().getMap();
    }
    else
      return null;
  }
}