/*
    * #%L
    * wcm.io
    * %%
    * Copyright (C) 2014 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.handler.url.rewriter.impl;
  
  import java.util.HashMap;
  import java.util.Map;
  
  import org.apache.commons.lang3.StringUtils;
  import org.apache.sling.api.resource.ValueMap;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * Configuration for {@link UrlExternalizerTransformer}.
   */
  class UrlExternalizerTransformerConfig {
  
    static final String PN_REWRITE_ELEMENTS = "rewriteElements";
  
    private static final String[] REWRITE_ELEMENTS_DEFAULT = {
        "img:src", "link:href", "script:src"
    };
  
    private static final String ELEMENT_ATTRIBUTE_SEPARATOR = ":";
  
    private final Map<String, String> elementAttributeNames;
  
    private static final Logger log = LoggerFactory.getLogger(UrlExternalizerTransformerConfig.class.getName());
  
    UrlExternalizerTransformerConfig(ValueMap config) {
      this.elementAttributeNames = toElementAttributeNamesMap(config.get(PN_REWRITE_ELEMENTS, REWRITE_ELEMENTS_DEFAULT));
    }
  
    private static Map<String, String> toElementAttributeNamesMap(String[] elementAttributeNames) {
      Map<String, String> map = new HashMap<>();
      for (String item : elementAttributeNames) {
        String elementName = StringUtils.trim(StringUtils.substringBefore(item, ELEMENT_ATTRIBUTE_SEPARATOR));
        String attributeName = StringUtils.trim(StringUtils.substringAfter(item, ELEMENT_ATTRIBUTE_SEPARATOR));
        if (StringUtils.isBlank(elementName) || StringUtils.isBlank(attributeName)) {
          log.info("Invalid URL externalizier transformer configuration - skipping invalid element entry: {}", item);
        }
        else if (map.containsKey(elementName)) {
          log.info("Invalid URL externalizier transformer configuration - skipping duplicate element name: {}", item);
        }
        else {
          map.put(elementName, attributeName);
        }
      }
      return map;
    }
  
    public Map<String, String> getElementAttributeNames() {
      return this.elementAttributeNames;
    }
  
  }