package cn.org.hentai.jtt1078.util;
import java.nio.ByteBuffer;
import java.time.Instant;
import java.time.ZoneOffset;
import java.time.ZonedDateTime;
import java.time.format.DateTimeFormatter;

public class TimeUtils {

    /**
     * 将8字节时间戳字节数组（大端序）转成格式化时间字符串（UTC时区）
     * @param bytes 8字节数组，表示自Unix纪元以来的毫秒数
     * @return 格式化时间字符串，例如："2025-07-30 12:34:56"
     */
    public static String bytes8ToTimeString(byte[] bytes) {
        if (bytes == null || bytes.length != 8) {
            throw new IllegalArgumentException("字节数组必须为8字节长度");
        }
        // 默认大端字节序读取long
        long timestampMillis = ByteBuffer.wrap(bytes).getLong();

        Instant instant = Instant.ofEpochMilli(timestampMillis);
        ZonedDateTime utcTime = instant.atZone(ZoneOffset.UTC);

        DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss").withZone(ZoneOffset.UTC);
        return formatter.format(utcTime);
    }

    public static long bytes8ToLong(byte[] bytes) {
        if (bytes == null || bytes.length != 8) throw new IllegalArgumentException("Invalid byte array");
        return ((long)(bytes[0] & 0xFF) << 56) |
                ((long)(bytes[1] & 0xFF) << 48) |
                ((long)(bytes[2] & 0xFF) << 40) |
                ((long)(bytes[3] & 0xFF) << 32) |
                ((long)(bytes[4] & 0xFF) << 24) |
                ((long)(bytes[5] & 0xFF) << 16) |
                ((long)(bytes[6] & 0xFF) << 8)  |
                ((long)(bytes[7] & 0xFF));
    }

    public static void main(String[] args) {
        // 示例8字节时间戳
        byte[] tsBytes = new byte[]{0, 0, 1, 122, 68, 95, -54, 0}; // 例子
        System.out.println(bytes8ToTimeString(tsBytes));
    }
}