/*
    * #%L
    * wcm.io
    * %%
    * Copyright (C) 2023 wcm.io
    * %%
    * 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.
   * #L%
   */
  package io.wcm.siteapi.openapi.validator;
  
  import java.util.stream.Collectors;
  
  import org.jetbrains.annotations.NotNull;
  import org.openapi4j.core.util.TreeUtil;
  import org.openapi4j.core.validation.ValidationResults.ValidationItem;
  import org.openapi4j.schema.validator.ValidationData;
  import org.openapi4j.schema.validator.v3.SchemaValidator;
  
  import com.fasterxml.jackson.core.JsonProcessingException;
  import com.fasterxml.jackson.databind.JsonNode;
  
  /**
   * Validates JSON response for a given path definition and suffix against the JSON.
   * Create instance via {@link OpenApiSpec} class.
   */
  public final class OpenApiSchemaValidator {
  
    private final String suffix;
    private final SchemaValidator schemaValidator;
  
    OpenApiSchemaValidator(@NotNull String suffix, @NotNull SchemaValidator schemaValidator) {
      this.suffix = suffix;
      this.schemaValidator = schemaValidator;
    }
  
    /**
     * @return Suffix
     */
    public @NotNull String getSuffix() {
      return this.suffix;
    }
  
    /**
     * Validate the given JSON response against the operation's JSON schema.
     * @param jsonValue JSON response
     * @throws ContentValidationException Validation failed
     */
    public void validate(@NotNull String jsonValue) throws ContentValidationException {
      JsonNode node = readJson(jsonValue);
      validateAgainstSchema(node);
    }
  
    private JsonNode readJson(@NotNull String jsonValue) throws ContentValidationException {
      try {
        return TreeUtil.json.readTree(jsonValue);
      }
      catch (JsonProcessingException ex) {
        throw new ContentValidationException("Unable to parse JSON:\n" + jsonValue, ex);
      }
    }
  
    private void validateAgainstSchema(@NotNull JsonNode node) throws ContentValidationException {
      ValidationData<Void> validation = new ValidationData<>();
      schemaValidator.validate(node, validation);
      if (validation.isValid()) {
        return;
      }
      String message = "JSON invalid for suffix '" + suffix + "': " + validation.results().items().stream()
          .map(ValidationItem::toString)
          .collect(Collectors.joining("\n"));
      throw new ContentValidationException(message);
    }
  
  }