/*
 * 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.transformer.graph;

import org.mule.runtime.api.metadata.DataType;
import org.mule.runtime.core.api.transformer.Converter;

import java.util.HashSet;
import java.util.Set;

import org.jgrapht.graph.DirectedMultigraph;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Represents the set of transformations between {@link DataType} based on the available {@link Converter}.
 */
public class TransformationGraph extends DirectedMultigraph<DataType, TransformationEdge> {

  protected final Logger logger = LoggerFactory.getLogger(getClass());

  private Set<Converter> registeredConverters = new HashSet<>();

  public TransformationGraph() {
    super(TransformationEdge.class);
  }

  public void addConverter(Converter converter) {
    if (registeredConverters.contains(converter)) {
      if (logger.isDebugEnabled()) {
        logger.debug("Attempting to register an already registered converter: " + converter);
      }

      return;
    }

    DataType returnDataType = converter.getReturnDataType();
    if (!containsVertex(returnDataType)) {
      addVertex(returnDataType);
    }

    for (DataType sourceDataType : converter.getSourceDataTypes()) {
      if (!containsVertex(sourceDataType)) {
        addVertex(sourceDataType);
      }

      addEdge(sourceDataType, returnDataType, new TransformationEdge(converter));
    }

    registeredConverters.add(converter);
  }

  public void removeConverter(Converter converter) {
    if (!registeredConverters.contains(converter)) {
      if (logger.isDebugEnabled()) {
        logger.debug("Attempt to remove an unregistered converter: " + converter);
      }

      return;
    }

    DataType returnDataType = converter.getReturnDataType();

    for (DataType sourceDataType : converter.getSourceDataTypes()) {
      Set<TransformationEdge> allEdges = getAllEdges(sourceDataType, returnDataType);

      for (TransformationEdge edge : allEdges) {

        if (edge.getConverter() == converter) {
          DataType source = getEdgeSource(edge);
          DataType target = getEdgeTarget(edge);

          removeEdge(edge);

          if (inDegreeOf(source) == 0 && outDegreeOf(source) == 0) {
            removeVertex(source);
          }

          if (inDegreeOf(target) == 0 && outDegreeOf(target) == 0) {
            removeVertex(target);
          }
        }
      }
    }

    registeredConverters.remove(converter);
  }
}