/*-
 * ============LICENSE_START=======================================================
 * SDC
 * ================================================================================
 * Copyright (C) 2017 AT&T Intellectual Property. 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.
 * You may obtain a copy of the License at
 * 
 *      http://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.
 * ============LICENSE_END=========================================================
 */

package org.openecomp.core.utilities.json;

import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.google.gson.JsonIOException;
import com.google.gson.JsonParser;
import com.google.gson.JsonSyntaxException;
import org.apache.commons.collections4.CollectionUtils;
import org.everit.json.schema.EnumSchema;
import org.everit.json.schema.Schema;
import org.everit.json.schema.ValidationException;
import org.everit.json.schema.loader.SchemaLoader;
import org.json.JSONObject;
import org.openecomp.core.utilities.CommonMethods;
import org.openecomp.sdc.logging.api.Logger;
import org.openecomp.sdc.logging.api.LoggerFactory;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.io.StringReader;
import java.util.Collections;
import java.util.List;
import java.util.Set;
import java.util.stream.Collectors;

/**
 * The type Json util.
 */
public class JsonUtil {
  private static final Logger logger = LoggerFactory.getLogger(JsonUtil.class);

  /**
   * Object 2 json string.
   *
   * @param obj the obj
   * @return the string
   */
  //TODO: refactor all other ugly code to use this
  public static String object2Json(Object obj) {
    return sbObject2Json(obj).toString();

  }

  /**
   * Sb object 2 json string buffer.
   *
   * @param obj the obj
   * @return the string buffer
   */
  public static StringBuffer sbObject2Json(Object obj) {
    return new StringBuffer((new GsonBuilder()).setPrettyPrinting().create().toJson(obj));
  }

  /**
   * Json 2 object t.
   *
   * @param <T>      the type parameter
   * @param json     the json
   * @param classOfT the class of t
   * @return the t
   */
  public static <T> T json2Object(String json, Class<T> classOfT) {
    T typ;
    try {
      try (Reader br = new StringReader(json)) {
        typ = new Gson().fromJson(br, classOfT);
      } catch (IOException exception) {
        throw exception;
      }
    } catch (JsonIOException | JsonSyntaxException | IOException exception) {
      throw new RuntimeException(exception);
    }
    return typ;
  }

  /**
   * Json 2 object t.
   *
   * @param <T>      the type parameter
   * @param is       the is
   * @param classOfT the class of t
   * @return the t
   */
  public static <T> T json2Object(InputStream is, Class<T> classOfT) {
    T type;
    try {
      try (Reader br = new BufferedReader(new InputStreamReader(is))) {
        type = new Gson().fromJson(br, classOfT);
      }
    } catch (JsonIOException | JsonSyntaxException | IOException exception) {
      throw new RuntimeException(exception);
    } finally {
      if (is != null) {
        try {
          is.close();
        } catch (IOException ignore) {
          logger.debug("",ignore);
          //do nothing
        }
      }
    }
    return type;
  }


  /**
   * Is valid json boolean.
   *
   * @param json the json
   * @return the boolean
   */
  //todo check https://github.com/stleary/JSON-java as replacement for this code
  public static boolean isValidJson(String json) {
    try {
      return new JsonParser().parse(json).isJsonObject();
    } catch (JsonSyntaxException jse) {
      logger.debug("",jse);
      return false;
    }
  }

  /**
   * Validate list.
   *
   * @param json       the json
   * @param jsonSchema the json schema
   * @return the list
   */
  public static List<String> validate(String json, String jsonSchema) {
    List<ValidationException> validationErrors = validateUsingEverit(json, jsonSchema);
    return validationErrors == null ? null
        : validationErrors.stream().map(JsonUtil::mapValidationExceptionToMessage)
            .collect(Collectors.toList());
  }

  private static String mapValidationExceptionToMessage(ValidationException exception) {
    if (exception.getViolatedSchema() instanceof EnumSchema) {
      return mapEnumViolationToMessage(exception);
    }
    return exception.getMessage();
  }

  private static String mapEnumViolationToMessage(ValidationException exception) {
    Set<Object> possibleValues = ((EnumSchema) exception.getViolatedSchema()).getPossibleValues();
    return exception.getMessage().replaceFirst("enum value", possibleValues.size() == 1
        ? String.format("value. %s is the only possible value for this field",
        possibleValues.iterator().next())
        : String.format("value. Possible values: %s", CommonMethods
            .collectionToCommaSeparatedString(
                possibleValues.stream().map(Object::toString).collect(Collectors.toList()))));
  }

  private static List<ValidationException> validateUsingEverit(String json, String jsonSchema) {
    logger.debug(
        String.format("validateUsingEverit start, json=%s, jsonSchema=%s", json, jsonSchema));
    if (json == null || jsonSchema == null) {
      throw new IllegalArgumentException("Input strings json and jsonSchema can not be null");
    }

    Schema schemaObj = SchemaLoader.load(new JSONObject(jsonSchema));
    try {
      schemaObj.validate(new JSONObject(json));
    } catch (ValidationException ve) {
      return CollectionUtils.isEmpty(ve.getCausingExceptions()) ? Collections.singletonList(ve)
          : ve.getCausingExceptions();
    }
    return null;
  }
}