package com.github.searls.jasmine.thirdpartylibs;
   
   import org.webjars.WebJarAssetLocator;
   
   import java.io.InputStream;
   import java.util.ArrayList;
   import java.util.List;
   import java.util.regex.Pattern;
   
  public class WebJarResourceHandler extends AbstractThirdPartyLibsResourceHandler {
  
    private static final Pattern WILDCARD = Pattern.compile(".*");
  
    private final List<WebJarAssetLocator> webJarAssetLocators;
    private final ClassLoader projectClassLoader;
  
    public WebJarResourceHandler(ClassLoader projectClassLoader) {
      this.projectClassLoader = projectClassLoader;
      this.webJarAssetLocators = createWebJarAssetLocators(
        WebJarResourceHandler.class.getClassLoader(),
        projectClassLoader
      );
    }
  
    @Override
    protected InputStream findResource(String resourcePath) {
      String fullPath = findFullPath(resourcePath);
      return fullPath != null ? projectClassLoader.getResourceAsStream(fullPath) : null;
    }
  
    private String findFullPath(String resourcePath) {
      String fullPath = null;
      for (WebJarAssetLocator locator : webJarAssetLocators) {
        fullPath = findFullPath(locator, resourcePath);
        if (fullPath != null) {
          break;
        }
      }
      return fullPath;
    }
  
    private String findFullPath(WebJarAssetLocator locator, String resourcePath) {
      String fullPath = null;
      try {
        fullPath = locator.getFullPath(resourcePath);
      } catch (Exception e) {
        fullPath = findFullPathByPartial(locator, resourcePath);
      }
      return fullPath;
    }
  
    private String findFullPathByPartial(WebJarAssetLocator locator, String resourcePath) {
  
      String fullPath = null;
  
      int splitAt = resourcePath.indexOf("/");
  
      if (splitAt > 0) {
        String webjar = resourcePath.substring(0, splitAt);
        String partialPath = resourcePath.substring(splitAt + 1);
        try {
          fullPath = locator.getFullPath(webjar, partialPath);
        } catch (Exception e) {
          // TODO: at least log this exception
        }
      }
  
      return fullPath;
    }
  
    private List<WebJarAssetLocator> createWebJarAssetLocators(ClassLoader... classLoaders) {
      List<WebJarAssetLocator> locators = new ArrayList<WebJarAssetLocator>();
      for (ClassLoader classLoader : classLoaders) {
        locators.add(new WebJarAssetLocator(WebJarAssetLocator.getFullPathIndex(WILDCARD, classLoader)));
      }
      return locators;
    }
  }