/*
    * #%L
    * wcm.io
    * %%
    * Copyright (C) 2015 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.devops.conga.tooling.maven.plugin.validation;
  
  import java.nio.charset.StandardCharsets;
  
  import org.apache.commons.lang3.StringUtils;
  import org.apache.maven.plugin.MojoFailureException;
  
  import com.github.jknack.handlebars.Handlebars;
  
  import io.wcm.devops.conga.generator.handlebars.HandlebarsManager;
  import io.wcm.devops.conga.generator.plugins.handlebars.escaping.NoneEscapingStrategy;
  import io.wcm.devops.conga.resource.Resource;
  import io.wcm.devops.conga.resource.ResourceCollection;
  import io.wcm.devops.conga.tooling.maven.plugin.util.PathUtil;
  
  /**
   * Validates Handlebars templates by compiling it.
   */
  public final class TemplateValidator implements DefinitionValidator<Void> {
  
    private static final String FILE_EXTENSION = "hbs";
  
    private final ResourceCollection templateDir;
    private final HandlebarsManager handlebarsManager;
  
    /**
     * @param templateDir Template directory
     * @param handlebarsManager Handlebars Manager
     */
    public TemplateValidator(ResourceCollection templateDir, HandlebarsManager handlebarsManager) {
      this.templateDir = templateDir;
      this.handlebarsManager = handlebarsManager;
    }
  
    @Override
    @SuppressWarnings({
        "PMD.PreserveStackTrace",
        "java:S1075" // uses / by intention
    })
    public Void validate(Resource resource, String pathForLog) throws MojoFailureException {
      if (StringUtils.equalsIgnoreCase(resource.getFileExtension(), FILE_EXTENSION)) {
        String templatePath = StringUtils.substringAfter(PathUtil.unifySlashes(resource.getCanonicalPath()),
            PathUtil.unifySlashes(templateDir.getCanonicalPath()) + "/");
        Handlebars handlebars = handlebarsManager.get(NoneEscapingStrategy.NAME, StandardCharsets.UTF_8.name());
        try {
          handlebars.compile(templatePath);
        }
        /*CHECKSTYLE:OFF*/ catch (Exception ex) { /*CHECKSTYLE:ON*/
          throw new MojoFailureException("Template " + pathForLog + " is invalid:\n" + ex.getMessage());
        }
      }
      return null;
    }
  
  }