package us.codecraft.webmagic.model;
   
   import us.codecraft.webmagic.Page;
   import us.codecraft.webmagic.Request;
   import us.codecraft.webmagic.Site;
   import us.codecraft.webmagic.processor.PageProcessor;
   import us.codecraft.webmagic.selector.Selector;
   
   import java.util.ArrayList;
  import java.util.List;
  import java.util.regex.Matcher;
  import java.util.regex.Pattern;
  
  /**
   * The extension to PageProcessor for page model extractor.
   *
   * @author code4crafter@gmail.com <br>
   * @since 0.2.0
   */
  class ModelPageProcessor implements PageProcessor {
  
      private List<PageModelExtractor> pageModelExtractorList = new ArrayList<PageModelExtractor>();
  
      private Site site;
  
      private boolean extractLinks = true;
  
      public static ModelPageProcessor create(Site site, Class... clazzs) {
          ModelPageProcessor modelPageProcessor = new ModelPageProcessor(site);
          for (Class clazz : clazzs) {
              modelPageProcessor.addPageModel(clazz);
          }
          return modelPageProcessor;
      }
  
  
      public ModelPageProcessor addPageModel(Class clazz) {
          PageModelExtractor pageModelExtractor = PageModelExtractor.create(clazz);
          pageModelExtractorList.add(pageModelExtractor);
          return this;
      }
  
      private ModelPageProcessor(Site site) {
          this.site = site;
      }
  
      @Override
      public void process(Page page) {
          for (PageModelExtractor pageModelExtractor : pageModelExtractorList) {
              if (extractLinks) {
                  extractLinks(page, pageModelExtractor.getHelpUrlRegionSelector(), pageModelExtractor.getHelpUrlPatterns());
                  extractLinks(page, pageModelExtractor.getTargetUrlRegionSelector(), pageModelExtractor.getTargetUrlPatterns());
              }
              Object process = pageModelExtractor.process(page);
              if (process == null || (process instanceof List && ((List) process).size() == 0)) {
                  continue;
              }
              postProcessPageModel(pageModelExtractor.getClazz(), process);
              page.putField(pageModelExtractor.getClazz().getCanonicalName(), process);
          }
          if (page.getResultItems().getAll().size() == 0) {
              page.getResultItems().setSkip(true);
          }
      }
  
      private void extractLinks(Page page, Selector urlRegionSelector, List<Pattern> urlPatterns) {
          List<String> links;
          if (urlRegionSelector == null) {
              links = page.getHtml().links().all();
          } else {
              links = page.getHtml().selectList(urlRegionSelector).links().all();
          }
          for (String link : links) {
              for (Pattern targetUrlPattern : urlPatterns) {
                  Matcher matcher = targetUrlPattern.matcher(link);
                  if (matcher.find()) {
                      page.addTargetRequest(new Request(matcher.group(0)));
                  }
              }
          }
      }
  
      protected void postProcessPageModel(Class clazz, Object object) {
      }
  
      @Override
      public Site getSite() {
          return site;
      }
  
      public boolean isExtractLinks() {
          return extractLinks;
      }
  
      public void setExtractLinks(boolean extractLinks) {
          this.extractLinks = extractLinks;
      }
  }