package com.foxinmy.weixin4j.util;
   
   import io.netty.util.AttributeKey;
   
   import java.lang.reflect.Constructor;
   import java.lang.reflect.Modifier;
   import java.nio.charset.Charset;
   import java.security.MessageDigest;
   import java.security.NoSuchAlgorithmException;
  import java.util.Random;
  
  import com.foxinmy.weixin4j.socket.WeixinMessageTransfer;
  
  /**
   * 工具包
   * 
   * @className ServerToolkits
   * @author jinyu(foxinmy@gmail.com)
   * @date 2015年12月26日
   * @since JDK 1.7
   * @see
   */
  public final class ServerToolkits {
  	private static final String ALLCHAR = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
  	public static final Charset UTF_8 = Charset.forName("UTF-8");
  	public static final String AES = "AES";
  	public static final String SHA1 = "SHA-1";
  	public static final String PROTOCOL_FILE = "file";
  	public static final String PROTOCOL_JAR = "jar";
  	public static final String CONTENTTYPE$APPLICATION_XML = "application/xml";
  	public static final String CONTENTTYPE$TEXT_PLAIN = "text/plain";
  
  	public static final AttributeKey<WeixinMessageTransfer> MESSAGE_TRANSFER_KEY = AttributeKey
  			.valueOf("attr:MESSAGETRANSFER");
  
  	/**
  	 * 返回一个定长的随机字符串(包含数字和大小写字母)
  	 * 
  	 * @param length
  	 *            随机数的长度
  	 * @return
  	 */
  	public static String generateRandomString(int length) {
  		StringBuilder sb = new StringBuilder(length);
  		Random random = new Random();
  		for (int i = 0; i < length; i++) {
  			sb.append(ALLCHAR.charAt(random.nextInt(ALLCHAR.length())));
  		}
  		return sb.toString();
  	}
  
  	/**
  	 * 构造器设置为可见
  	 * 
  	 * @param ctor
  	 */
  	public static void makeConstructorAccessible(Constructor<?> ctor) {
  		if ((!Modifier.isPublic(ctor.getModifiers()) || !Modifier.isPublic(ctor
  				.getDeclaringClass().getModifiers())) && !ctor.isAccessible()) {
  			ctor.setAccessible(true);
  		}
  	}
  
  	/**
  	 * SHA1签名
  	 * 
  	 * @param content
  	 *            待签名字符串
  	 * @return 签名后的字符串
  	 */
  	public static String digestSHA1(String content) {
  		byte[] data = ServerToolkits.getBytesUtf8(content);
  		try {
  			return HexUtil.encodeHexString(MessageDigest.getInstance(SHA1)
  					.digest(data));
  		} catch (NoSuchAlgorithmException e) {
  			return null;
  		}
  	}
  
  	private static String newString(final byte[] bytes, final Charset charset) {
  		return bytes == null ? null : new String(bytes, charset);
  	}
  
  	public static byte[] getBytesUtf8(final String content) {
  		return content != null ? content.getBytes(UTF_8) : null;
  	}
  
  	public static String newStringUtf8(final byte[] bytes) {
  		return newString(bytes, UTF_8);
  	}
  
  	/**
  	 * 判断字符串是否为空
  	 * 
  	 * @param cs
  	 * @return
  	 */
  	public static boolean isBlank(final CharSequence cs) {
 		int strLen;
 		if (cs == null || (strLen = cs.length()) == 0) {
 			return true;
 		}
 		for (int i = 0; i < strLen; i++) {
 			if (Character.isWhitespace(cs.charAt(i)) == false) {
 				return false;
 			}
 		}
 		return true;
 	}
 }