/*
 * Copyright 2014 Amazon.com, Inc. or its affiliates. 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.
 * A copy of the License is located at
 *
 *  http://aws.amazon.com/apache2.0
 *
 * or in the "license" file accompanying this file. This file 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.amazonaws.services.dynamodbv2.testing;

import com.amazonaws.services.dynamodbv2.model.AttributeValue;
import java.util.Collection;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
import org.hamcrest.BaseMatcher;
import org.hamcrest.Description;

public class AttrMatcher extends BaseMatcher<Map<String, AttributeValue>> {
  private final Map<String, AttributeValue> expected;
  private final boolean invert;

  public static AttrMatcher invert(Map<String, AttributeValue> expected) {
    return new AttrMatcher(expected, true);
  }

  public static AttrMatcher match(Map<String, AttributeValue> expected) {
    return new AttrMatcher(expected, false);
  }

  public AttrMatcher(Map<String, AttributeValue> expected, boolean invert) {
    this.expected = expected;
    this.invert = invert;
  }

  @Override
  public boolean matches(Object item) {
    @SuppressWarnings("unchecked")
    Map<String, AttributeValue> actual = (Map<String, AttributeValue>) item;
    if (!expected.keySet().equals(actual.keySet())) {
      return invert;
    }
    for (String key : expected.keySet()) {
      AttributeValue e = expected.get(key);
      AttributeValue a = actual.get(key);
      if (!attrEquals(a, e)) {
        return invert;
      }
    }
    return !invert;
  }

  public static boolean attrEquals(AttributeValue e, AttributeValue a) {
    if (!isEqual(e.getB(), a.getB())
        || !isEqual(e.getBOOL(), a.getBOOL())
        || !isSetEqual(e.getBS(), a.getBS())
        || !isEqual(e.getN(), a.getN())
        || !isSetEqual(e.getNS(), a.getNS())
        || !isEqual(e.getNULL(), a.getNULL())
        || !isEqual(e.getS(), a.getS())
        || !isSetEqual(e.getSS(), a.getSS())) {
      return false;
    }
    // Recursive types need special handling
    if (e.getM() == null ^ a.getM() == null) {
      return false;
    } else if (e.getM() != null) {
      if (!e.getM().keySet().equals(a.getM().keySet())) {
        return false;
      }
      for (final String key : e.getM().keySet()) {
        if (!attrEquals(e.getM().get(key), a.getM().get(key))) {
          return false;
        }
      }
    }
    if (e.getL() == null ^ a.getL() == null) {
      return false;
    } else if (e.getL() != null) {
      if (e.getL().size() != a.getL().size()) {
        return false;
      }
      for (int x = 0; x < e.getL().size(); x++) {
        if (!attrEquals(e.getL().get(x), a.getL().get(x))) {
          return false;
        }
      }
    }
    return true;
  }

  @Override
  public void describeTo(Description description) {}

  private static boolean isEqual(Object o1, Object o2) {
    if (o1 == null ^ o2 == null) {
      return false;
    }
    if (o1 == o2) return true;
    return o1.equals(o2);
  }

  private static <T> boolean isSetEqual(Collection<T> c1, Collection<T> c2) {
    if (c1 == null ^ c2 == null) {
      return false;
    }
    if (c1 != null) {
      Set<T> s1 = new HashSet<T>(c1);
      Set<T> s2 = new HashSet<T>(c2);
      if (!s1.equals(s2)) {
        return false;
      }
    }
    return true;
  }
}