/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

package org.mozilla.gecko.annotationProcessors.utils;

import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.Member;
import java.lang.reflect.Method;
import java.util.Comparator;

public class AlphabeticAnnotatableEntityComparator<T extends Member> implements Comparator<T> {
  @Override
  public int compare(T aLhs, T aRhs) {
    // Constructors, Methods, Fields.
    boolean lIsConstructor = aLhs instanceof Constructor;
    boolean rIsConstructor = aRhs instanceof Constructor;
    boolean lIsMethod = aLhs instanceof Method;
    boolean rIsField = aRhs instanceof Field;

    if (lIsConstructor) {
      if (!rIsConstructor) {
        return -1;
      }
    } else if (lIsMethod) {
      if (rIsConstructor) {
        return 1;
      } else if (rIsField) {
        return -1;
      }
    } else {
      if (!rIsField) {
        return 1;
      }
    }

    // Verify these objects are the same type and cast them.
    if (aLhs instanceof Method) {
      return compare((Method) aLhs, (Method) aRhs);
    } else if (aLhs instanceof Field) {
      return compare((Field) aLhs, (Field) aRhs);
    } else {
      return compare((Constructor) aLhs, (Constructor) aRhs);
    }
  }

  // Alas, the type system fails us.
  private static int compare(Method aLhs, Method aRhs) {
    // Initially, attempt to differentiate the methods be name alone..
    String lName = aLhs.getName();
    String rName = aRhs.getName();

    int ret = lName.compareTo(rName);
    if (ret != 0) {
      return ret;
    }

    // The names were the same, so we need to compare signatures to find their uniqueness..
    lName = Utils.getSignature(aLhs);
    rName = Utils.getSignature(aRhs);

    return lName.compareTo(rName);
  }

  private static int compare(Constructor<?> aLhs, Constructor<?> aRhs) {
    // The names will be the same, so we need to compare signatures to find their uniqueness..
    String lName = Utils.getSignature(aLhs);
    String rName = Utils.getSignature(aRhs);

    return lName.compareTo(rName);
  }

  private static int compare(Field aLhs, Field aRhs) {
    // Compare field names..
    String lName = aLhs.getName();
    String rName = aRhs.getName();

    return lName.compareTo(rName);
  }
}