package com.nmgs.util;

import org.springframework.stereotype.Component;

import java.io.IOException;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;
@Component
public class SensitiveFilter {
    /**
     * 敏感词过滤器：利用DFA算法  进行敏感词过滤
     */
    private Map sensitiveWordMap = null;

    /**
     * 最小匹配规则，如：敏感词库["中国","中国人"]，语句："我是中国人"，匹配结果：我是[中国]人
     */
    public static int minMatchType = 1;

    /**
     * 最大匹配规则，如：敏感词库["中国","中国人"]，语句："我是中国人"，匹配结果：我是[中国人]
     */
    public static int maxMatchType = 2;

    /**
     * 敏感词替换词
     */
    public static String placeHolder = "*";

    // 单例
    private static SensitiveFilter instance = null;

    /**
     * 构造函数，初始化敏感词库
     */
    private SensitiveFilter() throws IOException {
        sensitiveWordMap = new WordInit().initKeyWord();
    }

    /**
     * 获取单例
     */
    public static SensitiveFilter getInstance() throws IOException {
        if (null == instance) {
            instance = new SensitiveFilter();
        }
        return instance;
    }

    /**
     * 获取文字中的敏感词
     */
    public Set<String> getSensitiveWord(String txt, int matchType) {
        Set<String> sensitiveWordList = new HashSet<>();
        for (int i = 0; i < txt.length(); i++) {
            // 判断是否包含敏感字符
            int length = CheckSensitiveWord(txt, i, matchType);
            // 存在,加入list中
            if (length > 0) {
                sensitiveWordList.add(txt.substring(i, i + length));
                // 减1的原因，是因为for会自增
                i = i + length - 1;
            }
        }
        return sensitiveWordList;
    }


    /**
     * 替换敏感字字符,使用了默认的替换符合，默认最小匹配规则
     */
    public String replaceSensitiveWord(String txt) {
        return replaceSensitiveWord(txt, minMatchType ,placeHolder);
    }

    /**
     * 替换敏感字字符,使用了默认的替换符合
     */
    public String replaceSensitiveWord(String txt, int matchType) {
        return replaceSensitiveWord(txt, matchType,placeHolder);
    }

    /**
     * 替换敏感字字符
     */
    public String replaceSensitiveWord(String txt, int matchType,
                                       String replaceChar) {
        String resultTxt = txt;
        // 获取所有的敏感词
        Set<String> set = getSensitiveWord(txt, matchType);
        Iterator<String> iterator = set.iterator();
        String word = null;
        String replaceString = null;
        while (iterator.hasNext()) {
            word = iterator.next();
            replaceString = getReplaceChars(replaceChar, word.length());
            resultTxt = resultTxt.replaceAll(word, replaceString);
        }
        return resultTxt;
    }

    /**
     * 获取替换字符串
     */
    private String getReplaceChars(String replaceChar, int length) {
        StringBuilder resultReplace = new StringBuilder(replaceChar);
        for (int i = 1; i < length; i++) {
            resultReplace.append(replaceChar);
        }
        return resultReplace.toString();
    }

    /**
     * 检查文字中是否包含敏感字符，检查规则如下：<br>
     * 如果存在，则返回敏感词字符的长度，不存在返回0
     * 核心
     */
    public int CheckSensitiveWord(String txt, int beginIndex, int matchType) {
        // 敏感词结束标识位：用于敏感词只有1的情况结束
        boolean flag = false;
        // 匹配标识数默认为0
        int matchFlag = 0;
        Map nowMap = sensitiveWordMap;
        for (int i = beginIndex; i < txt.length(); i++) {
            char word = txt.charAt(i);
            // 获取指定key
            nowMap = (Map) nowMap.get(word);
            // 存在，则判断是否为最后一个
            if (nowMap != null) {
                // 找到相应key，匹配标识+1
                matchFlag++;
                // 如果为最后一个匹配规则,结束循环，返回匹配标识数
                if ("1".equals(nowMap.get("isEnd"))) {
                    // 结束标志位为true
                    flag = true;
                    // 最小规则，直接返回,最大规则还需继续查找
                    if (SensitiveFilter.minMatchType == matchType) {
                        break;
                    }
                }
            }
            // 不存在，直接返回
            else {
                break;
            }
        }

        // 匹配长度如果匹配上了最小匹配长度或者最大匹配长度
        if (SensitiveFilter.maxMatchType == matchType || SensitiveFilter.minMatchType == matchType){
            //长度必须大于等于1，为词，或者敏感词库还没有结束(匹配了一半)，flag为false
            if(matchFlag < 2 || !flag){
                matchFlag = 0;
            }
        }
        return matchFlag;
    }

    public static void main(String[] args) throws IOException {
        SensitiveFilter sensitiveFilter =new SensitiveFilter();
        String s = sensitiveFilter.replaceSensitiveWord("你大爷");
        System.out.println(s);
    }
}
