package com.opslab.helper;


import com.opslab.util.ArrayUtil;

import java.util.*;

/**
 * 随机相关的方法封装
 */
@SuppressWarnings("unchecked")
public final class RandomHelper {
    public static final String ALLCHAR
            = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
    public static final String LETTERCHAR
            = "abcdefghijkllmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
    public static final String NUMBERCHAR
            = "0123456789";


    /**
     * 生成制定范围内的随机数
     *
     * @param scopeMin
     * @param scoeMax
     * @return
     */
    public static int integer(int scopeMin, int scoeMax) {
        Random random = new Random();
        return (random.nextInt(scoeMax) % (scoeMax - scopeMin + 1) + scopeMin);
    }

    /**
     * 返回固定长度的数字
     *
     * @param length
     * @return
     */
    public static String number(int length) {
        StringBuilder sb = new StringBuilder();
        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 string(int length) {
        StringBuilder sb = new StringBuilder();
        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 mixString(int length) {
        StringBuilder sb = new StringBuilder();
        Random random = new Random();
        for (int i = 0; i < length; i++) {
            sb.append(ALLCHAR.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 lowerString(int length) {
        return mixString(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 upperString(int length) {
        return mixString(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 zeroString(int length) {
        StringBuilder sb = new StringBuilder();
        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) {
        StringBuilder sb = new StringBuilder();
        String strNum = String.valueOf(num);
        if (fixdlenth - strNum.length() >= 0) {
            sb.append(zeroString(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) {
        StringBuilder sb = new StringBuilder();
        String strNum = String.valueOf(num);
        if (fixdlenth - strNum.length() >= 0) {
            sb.append(zeroString(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();
    }

    /**
     * 每次生成的len位数都不相同
     *
     * @param param
     * @return 定长的数字
     */
    public static int getNotSimple(int[] param, int len) {
        Random rand = new Random();
        for (int i = param.length; i > 1; i--) {
            int index = rand.nextInt(i);
            int tmp = param[index];
            param[index] = param[i - 1];
            param[i - 1] = tmp;
        }
        int result = 0;
        for (int i = 0; i < len; i++) {
            result = result * 10 + param[i];
        }
        return result;
    }

    /**
     * 从指定的数组中随机数组中的某个元素
     */
    public static <T> T randomItem(T[] param) {
        int index = integer(0, param.length);
        return param[index];
    }

    public static String uuid16() {
        String uuid = UUID.randomUUID().toString();
        char[] cs = new char[32];
        char c = 0;
        for (int i = uuid.length() / 2, j = 1; i-- > 0; ) {
            if ((c = uuid.charAt(i)) != '-') {
                cs[j++] = c;
            }
        }
        return String.valueOf(cs);
    }

    /**
     * 返回一个UUID
     *
     * @return 小写的UUID
     */
    public static String uuid() {
        return UUID.randomUUID().toString();

    }

    /**
     * 返回一个UUID
     *
     * @return 大写的UUID
     */
    public static String UUID() {
        return UUID.randomUUID().toString().toUpperCase();
    }

    /**
     * 返回一个有序列的uuid编码
     * 前11位为时间(毫秒)
     * 中间4位为主机特征码
     * 剩下的保证其唯一性
     *
     * @param hostFeature 主机特征码建议设置4位
     * @return
     */
    public static String squid(String hostFeature) {
        Long date = System.currentTimeMillis();
        String s = UUID.randomUUID().toString();
        String str = Long.toHexString(date);
        String result = str + hostFeature
                + s.substring(17, 18) + s.substring(19, 23) + s.substring(24);
        return result.toUpperCase();
    }


    /**
     * 从指定的数组中按照指定比例返回指定的随机元素
     *
     * @param param     随机数组
     * @param percentum 比例
     * @param <T>
     * @return
     */
    public static <T> T randomItem(T[] param, double[] percentum) {
        int length = percentum.length;
        Integer[] ints = ArrayUtil.doubleBitCount(percentum);
        int max = Collections.max(Arrays.asList(ints));

        int sum = 0;
        Map map = new HashMap(length);
        StringBuffer buffer = new StringBuffer();
        for (int i = 0; i < max; i++) {
            buffer.append("0");
        }
        int multiple = Integer.parseInt("1" + buffer.toString());
        for (int i = 0; i < length; i++) {
            int temp = (int) (percentum[i] * multiple);

            if (i == 0) {
                map.put(i, new int[]{1, temp});
            } else {
                map.put(i, new int[]{sum, sum + temp});
            }
            sum += temp;
        }
        int indexSum = integer(1, sum);
        int index = -1;
        for (int i = 0; i < length; i++) {
            int[] scope = (int[]) map.get(i);
            if (indexSum == 1) {
                index = 0;
                break;
            }
            if (indexSum > scope[0] && indexSum <= scope[1]) {
                index = i;
                break;
            }
        }
        if (index == -1) {
            throw new RuntimeException("随机失败");
        } else {
            return param[index];
        }
    }
}
