package com.usoft.bizcode.utils;

import org.apache.commons.lang3.StringUtils;

/**
 * 业务号 工具类
 *
 * @author: wangcanyi
 * @date: 2018-08-23 16:51
 **/
public class BizCodeUtil {
	private static final int BIZ_CODE_MAX_LENGTH = 10;
	private static final int PREFIX_LENGTH = 2;
	private static final int SE_MAX = 9;
	private static final int SE_LENGTH = 1;
	private static int se = 0;

	/**
	 * 创建业务号  最长10位
	 *
	 * @param prefix 前缀 - 自定义 - 长度：2位
	 * @return
	 */
	public static String genBizCode(String prefix) {
		if (StringUtils.isBlank(prefix)) {
			throw new IllegalArgumentException("prefix不能为空");
		}
		if (prefix.length() != PREFIX_LENGTH) {
			throw new IllegalArgumentException("prefix长度必须为2位");
		}
		synchronized (BizCodeUtil.class) {
			String nextCode;
			if (se > SE_MAX) {
				se = 0;
			}
			//当前精确到0.1毫秒
			String decimalCode = "" + System.currentTimeMillis() + createSerial("" + se, SE_LENGTH);
			//10进制转62进制
			nextCode = DecimalConverter.fromDecimal(decimalCode, 62);
			se++;
			if (nextCode.length() > BIZ_CODE_MAX_LENGTH) {
				throw new RuntimeException("生成业务号长度错误[" + nextCode + "]");
			}
			return prefix + nextCode;
		}
	}


	/**
	 * 生成固定长度的序列号，不足位数在前补0
	 *
	 * @param src
	 * @param len
	 * @return
	 */
	private static String createSerial(String src, int len) {
		String dest = "";
		if (src.length() >= len) {
			dest = src.substring(0, len);
		} else {
			dest = createSameChar("0", len - src.length()) + src;
		}
		return dest;
	}

	/**
	 * 返回相同字符的串
	 */
	private static String createSameChar(String src, int len) {
		StringBuffer sb = new StringBuffer();
		for (int i = 0; i < len; i++) {
			sb.append(src);
		}
		return sb.toString();
	}
}