package com.monkeylessey.gen.utils;

import org.apache.commons.lang3.StringUtils;

/**
 * @author xp
 * @data 2022/9/24
 */
public class WordsUtils {

    /**
     * 首字母转小写
     * @param word
     * @return
     */
    public static String firstWordToLower(String word) {
        assert StringUtils.isBlank(word);
        String firstWord = word.substring(0,1).toLowerCase();
        return firstWord + word.substring(1);
    }

    /**
     * 首字母转大写
     * @param word
     * @return
     */
    public static String firstWordToUp(String word) {
        assert StringUtils.isBlank(word);
        String firstWord = word.substring(0,1).toUpperCase();
        return firstWord + word.substring(1);
    }

    /**
     * 数据库字段转java驼峰
     * @param input
     * @return
     */
    public static String convertToCamelCase(String input) {
        StringBuilder result = new StringBuilder();
        boolean capitalizeNextChar = false;
        for (int i = 0; i < input.length(); i++) {
            char currentChar = input.charAt(i);

            if (currentChar == '_') {
                capitalizeNextChar = true;
            } else {
                if (capitalizeNextChar) {
                    result.append(Character.toUpperCase(currentChar));
                    capitalizeNextChar = false;
                } else {
                    result.append(Character.toLowerCase(currentChar));
                }
            }
        }
        return result.toString();
    }

    /**
     * 获取分隔符字符串的每个单词的首位组成的字符串，"sys_user" ==> su
     *
     * @param input
     * @param delimiter
     * @return
     */
    public static String extractFirstLetters(String input, String delimiter) {
        if (input == null || input.isEmpty()) {
            return "";
        }
        String[] parts = input.split(delimiter);
        StringBuilder sb = new StringBuilder();
        for (String part : parts) {
            if (!part.isEmpty()) { // 确保单词不为空
                sb.append(Character.toUpperCase(part.charAt(0)));
            }
        }
        return sb.toString();
    }

}