package com.tzld.piaoquan.wecom.utils;

import java.nio.charset.StandardCharsets;

public class ToolUtils {
    public static String truncateString(String input, int maxBytes) {
        if (input == null || maxBytes <= 0) {
            return "";
        }

        byte[] bytes = input.getBytes(StandardCharsets.UTF_8);
        if (bytes.length <= maxBytes) {
            return input; // 如果字节数已经在限制内，直接返回原字符串
        }

        // 截取字节数组
        byte[] truncatedBytes = new byte[maxBytes];
        System.arraycopy(bytes, 0, truncatedBytes, 0, maxBytes);

        // 将截取的字节数组转换回字符串
        String truncatedString = new String(truncatedBytes, StandardCharsets.UTF_8);

        // 处理可能的字符截断问题
        // 如果截取后字符串的字节数仍然大于 maxBytes，向前查找直到找到有效字符
        while (truncatedString.getBytes(StandardCharsets.UTF_8).length > maxBytes) {
            truncatedString = truncatedString.substring(0, truncatedString.length() - 1);
        }

        return truncatedString;
    }
}