package com.ruoyi.common.utils;


import java.util.*;

/**
 * 随机数、随机字符串生成工具
 */
public class RandomUtil extends Random {
    /**
     * 所有大小写字母和数字
     */
    public static final String ALLCHAR = "123456789abcdefghijkmnpqrstuvwxyzABCDEFGHJKLMNPQRSTUVWXYZ";

    public static final String NUMBERLECHAR = "123456789abcdefghijkmnpqrstuvwxyz";
    /**
     * 所有大小写字母
     */
    public static final String LETTERCHAR = "abcdefghijkmnpqrstuvwxyzABCDEFGHJKLMNPQRSTUVWXYZ";
    /**
     * 所有数字
     */
    public static final String NUMBERCHAR = "0123456789";

    /**
     * 返回一个定长的随机纯数字字符串(只包含数字)
     * @param length
     *            随机字符串长度
     * @return 随机字符串
     */
    public static String generateDigitalString(int length) {
        StringBuffer sb = new StringBuffer();
        Random random = new Random();
        for (int i = 0; i < length; i++) {
            sb.append(NUMBERCHAR.charAt(random.nextInt(NUMBERCHAR.length())));
        }
        return sb.toString();
    }

    /**
     * 返回一个定长的随机字符串(只包含大小写字母、数字)
     * @param length
     *            随机字符串长度
     * @return 随机字符串
     */
    public static String generateString(int length) {
        StringBuffer sb = new StringBuffer();
        Random random = new Random();
        for (int i = 0; i < length; i++) {
            sb.append(ALLCHAR.charAt(random.nextInt(ALLCHAR.length())));
        }
        return sb.toString();
    }
    /**
     * 返回一个定长的随机字符串(只包含小写字母、数字)
     * @param length
     *            随机字符串长度
     * @return 随机字符串
     */
    public static String getString(int length) {
        StringBuffer sb = new StringBuffer();
        Random random = new Random();
        for (int i = 0; i < length; i++) {
            sb.append(NUMBERLECHAR.charAt(random.nextInt(NUMBERLECHAR.length())));
        }
        return sb.toString();
    }

    /**
     * 返回一个定长的随机纯字母字符串(只包含大小写字母)
     * @param length
     *            随机字符串长度
     * @return 随机字符串
     */
    public static String generateMixString(int length) {
        StringBuffer sb = new StringBuffer();
        Random random = new Random();
        for (int i = 0; i < length; i++) {
            sb.append(LETTERCHAR.charAt(random.nextInt(LETTERCHAR.length())));
        }
        return sb.toString();
    }

    /**
     * 返回一个定长的随机纯大写字母字符串(只包含大小写字母)
     * @param length
     *            随机字符串长度
     * @return 随机字符串
     */
    public static String generateLowerString(int length) {
        return generateMixString(length).toLowerCase();
    }

    /**
     * 返回一个定长的随机纯小写字母字符串(只包含大小写字母)
     * @param length
     *            随机字符串长度
     * @return 随机字符串
     */
    public static String generateUpperString(int length) {
        return generateMixString(length).toUpperCase();
    }

    /**
     * 生成一个定长的纯0字符串
     * @param length
     *            字符串长度
     * @return 纯0字符串
     */
    public static String generateZeroString(int length) {
        StringBuffer sb = new StringBuffer();
        for (int i = 0; i < length; i++) {
            sb.append('0');
        }
        return sb.toString();
    }

    /**
     * 根据数字生成一个定长的字符串，长度不够前面补0
     * @param num
     *            数字
     * @param fixdlenth
     *            字符串长度
     * @return 定长的字符串
     */
    public static String toFixdLengthString(long num, int fixdlenth) {
        StringBuffer sb = new StringBuffer();
        String strNum = String.valueOf(num);
        if (fixdlenth - strNum.length() >= 0) {
            sb.append(generateZeroString(fixdlenth - strNum.length()));
        } else {
            throw new RuntimeException("将数字" + num + "转化为长度为" + fixdlenth
                    + "的字符串发生异常！");
        }
        sb.append(strNum);
        return sb.toString();
    }

    /**
     * 根据数字生成一个定长的字符串，长度不够前面补0
     * @param num
     *            数字
     * @param fixdlenth
     *            字符串长度
     * @return 定长的字符串
     */
    public static String toFixdLengthString(int num, int fixdlenth) {
        StringBuffer sb = new StringBuffer();
        String strNum = String.valueOf(num);
        if (fixdlenth - strNum.length() >= 0) {
            sb.append(generateZeroString(fixdlenth - strNum.length()));
        } else {
            throw new RuntimeException("将数字" + num + "转化为长度为" + fixdlenth
                    + "的字符串发生异常！");
        }
        sb.append(strNum);
        return sb.toString();
    }


    /**
     * serialVersionUID:序列化id
     *
     * @since 1.0.0
     */

    private static final long serialVersionUID = 1L;

    public static RandomUtil getInstance() {
        return _instance;
    }

    public RandomUtil() {
        super();
    }

    public RandomUtil(long seed) {
        super(seed);
    }

//    public int[] nextInt(int n, int size) {
//        if (size > n) {
//            size = n;
//        }
//
//        Set set = new LinkedHashSet();
//
//        for (int i = 0; i < size; i++) {
//            while (true) {
//                Integer value = new Integer(nextInt(n));
//
//                if (!set.contains(value)) {
//                    set.add(value);
//
//                    break;
//                }
//            }
//        }
//
//        int[] array = new int[set.size()];
//
//        Iterator itr = set.iterator();
//
//        for (int i = 0; i < array.length; i++) {
//            array[i] = (Integer) itr.next();
//        }
//
//        return array;
//    }

    public void randomize(char[] array) {
        int length = array.length;

        for(int i = 0; i < length - 1; i++) {
            int x = nextInt(length);
            char y = array[i];

            array[i] = array[i + x];
            array[i + x] = y;

            length--;
        }
    }

    public void randomize(int[] array) {
        int length = array.length;

        for(int i = 0; i < length - 1; i++) {
            int x = nextInt(length);
            int y = array[i];

            array[i] = array[i + x];
            array[i + x] = y;

            length--;
        }
    }

    public void randomize(List list) {
        int size = list.size();

        for(int i = 0; i <= size; i++) {
            int j = nextInt(size);
            Object obj = list.get(i);

            list.set(i, list.get(i + j));
            list.set(i + j, obj);

            size--;
        }
    }

    public void randomize(Object[] array) {
        int length = array.length;

        for(int i = 0; i < length - 1; i++) {
            int x = nextInt(length);
            Object y = array[i];

            array[i] = array[i + x];
            array[i + x] = y;

            length--;
        }
    }

    public String randomize(String s) {
        if (s == null) {
            return null;
        }

        char[] array = s.toCharArray();

        randomize(array);

        return new String(array);
    }

    private static RandomUtil _instance = new RandomUtil();
}
