/*
 * Copyright (c) MuleSoft, Inc.  All rights reserved.  http://www.mulesoft.com
 * The software in this package is published under the terms of the CPAL v1.0
 * license, a copy of which has been included with this distribution in the
 * LICENSE.txt file.
 */
package org.mule.runtime.core.expression.transformers;

import org.mule.runtime.api.metadata.DataType;
import org.mule.runtime.core.api.Event;
import org.mule.runtime.core.api.context.MuleContextAware;
import org.mule.runtime.core.api.expression.ExpressionRuntimeException;
import org.mule.runtime.api.lifecycle.InitialisationException;
import org.mule.runtime.core.api.object.ObjectFactory;
import org.mule.runtime.core.api.transformer.TransformerException;
import org.mule.runtime.core.config.i18n.CoreMessages;
import org.mule.runtime.core.object.PrototypeObjectFactory;
import org.mule.runtime.core.util.BeanUtils;

import java.lang.reflect.InvocationTargetException;
import java.nio.charset.Charset;
import java.util.HashMap;
import java.util.Map;

/**
 * This transformer uses the returnClass to create the return object and then will populate the bean with arguments defined as
 * expressions
 */
public class BeanBuilderTransformer extends AbstractExpressionTransformer {

  private ObjectFactory beanFactory;
  private Class<?> beanClass;

  public Class<?> getBeanClass() {
    return beanClass;
  }

  public void setBeanClass(Class<?> beanClass) {
    this.beanClass = beanClass;
  }

  public ObjectFactory getBeanFactory() {
    return beanFactory;
  }

  public void setBeanFactory(ObjectFactory beanFactory) {
    this.beanFactory = beanFactory;
  }

  /**
   * Template method were deriving classes can do any initialisation after the properties have been set on this transformer
   *
   * @throws InitialisationException
   */
  @Override
  public void initialise() throws InitialisationException {
    super.initialise();

    if (getBeanFactory() == null && getBeanClass() == null) {
      throw new InitialisationException(CoreMessages.objectIsNull("beanFactory"), this);
    } else if (getBeanClass() != null) {
      setBeanFactory(new PrototypeObjectFactory(getBeanClass()));
    }
    setReturnDataType(DataType.fromType(getBeanFactory().getObjectClass()));
    // We need to set the MuleContext if we create the factory here
    if (getBeanFactory() instanceof MuleContextAware) {
      ((MuleContextAware) getBeanFactory()).setMuleContext(muleContext);
    }
  }

  @Override
  public Object transformMessage(Event event, Charset outputEncoding) throws TransformerException {
    Object bean;
    try {
      bean = getBeanFactory().getInstance(muleContext);
    } catch (Exception e) {
      throw new TransformerException(this, e);
    }

    Map<String, Object> args = new HashMap<String, Object>(arguments.size());

    for (ExpressionArgument argument : arguments) {
      Object value = null;
      try {
        value = argument.evaluate(event);
      } catch (ExpressionRuntimeException e) {
        throw new TransformerException(this, e);
      }

      if (!argument.isOptional() && value == null) {
        throw new TransformerException(CoreMessages.expressionReturnedNull(argument.getExpressionConfig().getExpression()), this);
      }
      args.put(argument.getName(), value);
    }

    try {
      BeanUtils.populate(bean, args);
    } catch (IllegalAccessException e) {
      throw new TransformerException(this, e);
    } catch (InvocationTargetException e) {
      throw new TransformerException(this, e.getTargetException());
    }

    return bean;
  }
}