/*
    * Copyright 2017 LINE Corporation
    *
    * LINE Corporation licenses this file to you 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:
    *
    *   https://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.linecorp.centraldogma.internal.jsonpatch;
  
  import java.io.IOException;
  
  import com.fasterxml.jackson.annotation.JsonCreator;
  import com.fasterxml.jackson.annotation.JsonProperty;
  import com.fasterxml.jackson.core.JsonGenerator;
  import com.fasterxml.jackson.core.JsonPointer;
  import com.fasterxml.jackson.databind.JsonNode;
  import com.fasterxml.jackson.databind.SerializerProvider;
  import com.fasterxml.jackson.databind.annotation.JsonSerialize;
  import com.fasterxml.jackson.databind.jsontype.TypeSerializer;
  import com.fasterxml.jackson.databind.node.ArrayNode;
  import com.fasterxml.jackson.databind.node.ObjectNode;
  import com.google.common.base.Equivalence;
  
  public final class SafeReplaceOperation extends JsonPatchOperation {
  
      private static final Equivalence<JsonNode> EQUIVALENCE = JsonNumEquals.getInstance();
  
      @JsonSerialize
      private final JsonNode oldValue;
      @JsonSerialize
      private final JsonNode newValue;
  
      @JsonCreator
      SafeReplaceOperation(@JsonProperty("path") final JsonPointer path,
                           @JsonProperty("oldValue") JsonNode oldValue,
                           @JsonProperty("value") JsonNode newValue) {
          super("safeReplace", path);
          this.oldValue = oldValue.deepCopy();
          this.newValue = newValue.deepCopy();
      }
  
      @Override
      JsonNode apply(JsonNode node) {
          final JsonNode actual = ensureExistence(node);
          if (!EQUIVALENCE.equivalent(actual, oldValue)) {
              throw new JsonPatchException("mismatching value at '" + path + "': " +
                                           actual + " (expected: " + oldValue + ')');
          }
          final JsonNode replacement = newValue.deepCopy();
          if (path.toString().isEmpty()) {
              return replacement;
          }
          final JsonNode parent = node.at(path.head());
          final String rawToken = path.last().getMatchingProperty();
          if (parent.isObject()) {
              ((ObjectNode) parent).set(rawToken, replacement);
          } else {
              ((ArrayNode) parent).set(Integer.parseInt(rawToken), replacement);
          }
          return node;
      }
  
      @Override
      public void serialize(JsonGenerator gen, SerializerProvider serializers) throws IOException {
          gen.writeStartObject();
          gen.writeStringField("op", op);
          gen.writeStringField("path", path.toString());
          gen.writeFieldName("oldValue");
          gen.writeTree(oldValue);
          gen.writeFieldName("value");
          gen.writeTree(newValue);
          gen.writeEndObject();
      }
  
      @Override
      public void serializeWithType(JsonGenerator gen, SerializerProvider serializers, TypeSerializer typeSer)
              throws IOException {
          serialize(gen, serializers);
      }
  
      @Override
      public String toString() {
          return "op: " + op + "; path: \"" + path + "\"; oldValue: " + oldValue + "; value: " + newValue;
      }
  }