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package com.github.fashionbrot.util;

import lombok.extern.slf4j.Slf4j;

import java.io.*;
import java.net.URL;
import java.net.URLConnection;
import java.nio.charset.Charset;
import java.util.Properties;

/**
 * A class to simplify access to resources through the classloader.
 *
 * @author Clinton Begin
 */
@Slf4j
public class Resources {

  private static ClassLoaderWrapper classLoaderWrapper = new ClassLoaderWrapper();

  /*
   * Charset to use when calling getResourceAsReader.
   * null means use the system default.
   */
  private static Charset charset;

  Resources() {
  }

  /*
   * Returns the default classloader (may be null).
   *
   * @return The default classloader
   */
  public static ClassLoader getDefaultClassLoader() {
    return classLoaderWrapper.defaultClassLoader;
  }

  /*
   * Sets the default classloader
   *
   * @param defaultClassLoader - the new default ClassLoader
   */
  public static void setDefaultClassLoader(ClassLoader defaultClassLoader) {
    classLoaderWrapper.defaultClassLoader = defaultClassLoader;
  }

  /*
   * Returns the URL of the resource on the classpath
   *
   * @param resource The resource to find
   * @return The resource
   * @throws java.io.IOException If the resource cannot be found or read
   */
  public static URL getResourceURL(String resource) throws IOException {
      return getResourceURL(null, resource);
  }

  /*
   * Returns the URL of the resource on the classpath
   *
   * @param loader   The classloader used to fetch the resource
   * @param resource The resource to find
   * @return The resource
   * @throws java.io.IOException If the resource cannot be found or read
   */
  public static URL getResourceURL(ClassLoader loader, String resource) throws IOException {
    URL url = classLoaderWrapper.getResourceAsURL(resource, loader);
    if (url == null) {
      throw new IOException("Could not find resource " + resource);
    }
    return url;
  }

  /*
   * Returns a resource on the classpath as a Stream object
   *
   * @param resource The resource to find
   * @return The resource
   * @throws java.io.IOException If the resource cannot be found or read
   */
  public static InputStream getResourceAsStream(String resource)  {
    try {
      return getResourceAsStream(null, resource);
    } catch (IOException e) {
      e.printStackTrace();
      log.error("get resource error:"+e.getMessage());
    }
    return null;
  }

  /*
   * Returns a resource on the classpath as a Stream object
   *
   * @param loader   The classloader used to fetch the resource
   * @param resource The resource to find
   * @return The resource
   * @throws java.io.IOException If the resource cannot be found or read
   */
  public static InputStream getResourceAsStream(ClassLoader loader, String resource) throws IOException {
    InputStream in = classLoaderWrapper.getResourceAsStream(resource, loader);
    if (in == null) {
      throw new IOException("Could not find resource " + resource);
    }
    return in;
  }

  /*
   * Returns a resource on the classpath as a Properties object
   *
   * @param resource The resource to find
   * @return The resource
   * @throws java.io.IOException If the resource cannot be found or read
   */
  public static Properties getResourceAsProperties(String resource) throws IOException {
    Properties props = new Properties();
    InputStream in = getResourceAsStream(resource);
    props.load(in);
    in.close();
    return props;
  }

  /*
   * Returns a resource on the classpath as a Properties object
   *
   * @param loader   The classloader used to fetch the resource
   * @param resource The resource to find
   * @return The resource
   * @throws java.io.IOException If the resource cannot be found or read
   */
  public static Properties getResourceAsProperties(ClassLoader loader, String resource) throws IOException {
    Properties props = new Properties();
    InputStream in = getResourceAsStream(loader, resource);
    props.load(in);
    in.close();
    return props;
  }

  /*
   * Returns a resource on the classpath as a Reader object
   *
   * @param resource The resource to find
   * @return The resource
   * @throws java.io.IOException If the resource cannot be found or read
   */
  public static Reader getResourceAsReader(String resource) {
    Reader reader;
    if (charset == null) {
      reader = new InputStreamReader(getResourceAsStream(resource));
    } else {
      reader = new InputStreamReader(getResourceAsStream(resource), charset);
    }
    return reader;
  }

  /*
   * Returns a resource on the classpath as a Reader object
   *
   * @param loader   The classloader used to fetch the resource
   * @param resource The resource to find
   * @return The resource
   * @throws java.io.IOException If the resource cannot be found or read
   */
  public static Reader getResourceAsReader(ClassLoader loader, String resource) throws IOException {
    Reader reader;
    if (charset == null) {
      reader = new InputStreamReader(getResourceAsStream(loader, resource));
    } else {
      reader = new InputStreamReader(getResourceAsStream(loader, resource), charset);
    }
    return reader;
  }

  /*
   * Returns a resource on the classpath as a File object
   *
   * @param resource The resource to find
   * @return The resource
   * @throws java.io.IOException If the resource cannot be found or read
   */
  public static File getResourceAsFile(String resource) throws IOException {
    return new File(getResourceURL(resource).getFile());
  }

  /*
   * Returns a resource on the classpath as a File object
   *
   * @param loader   - the classloader used to fetch the resource
   * @param resource - the resource to find
   * @return The resource
   * @throws java.io.IOException If the resource cannot be found or read
   */
  public static File getResourceAsFile(ClassLoader loader, String resource) throws IOException {
    return new File(getResourceURL(loader, resource).getFile());
  }

  /*
   * Gets a URL as an input stream
   *
   * @param urlString - the URL to get
   * @return An input stream with the data from the URL
   * @throws java.io.IOException If the resource cannot be found or read
   */
  public static InputStream getUrlAsStream(String urlString) throws IOException {
    URL url = new URL(urlString);
    URLConnection conn = url.openConnection();
    return conn.getInputStream();
  }

  /*
   * Gets a URL as a Reader
   *
   * @param urlString - the URL to get
   * @return A Reader with the data from the URL
   * @throws java.io.IOException If the resource cannot be found or read
   */
  public static Reader getUrlAsReader(String urlString) throws IOException {
    Reader reader;
    if (charset == null) {
      reader = new InputStreamReader(getUrlAsStream(urlString));
    } else {
      reader = new InputStreamReader(getUrlAsStream(urlString), charset);
    }
    return reader;
  }

  /*
   * Gets a URL as a Properties object
   *
   * @param urlString - the URL to get
   * @return A Properties object with the data from the URL
   * @throws java.io.IOException If the resource cannot be found or read
   */
  public static Properties getUrlAsProperties(String urlString) throws IOException {
    Properties props = new Properties();
    InputStream in = getUrlAsStream(urlString);
    props.load(in);
    in.close();
    return props;
  }

  /*
   * Loads a class
   *
   * @param className - the class to fetch
   * @return The loaded class
   * @throws ClassNotFoundException If the class cannot be found (duh!)
   */
  public static Class classForName(String className) {
    try {
      return classLoaderWrapper.classForName(className);
    } catch (ClassNotFoundException e) {
      e.printStackTrace();
      log.error("className:"+className+" ClassNotFoundException",e);
    }
    return null;
  }

  public static Charset getCharset() {
    return charset;
  }

  public static void setCharset(Charset charset) {
    Resources.charset = charset;
  }

}