// util.js - 工具函数

/**
 * 格式化日期
 */
const formatDate = (date, format = 'YYYY-MM-DD HH:mm') => {
  const d = new Date(date);
  const year = d.getFullYear();
  const month = String(d.getMonth() + 1).padStart(2, '0');
  const day = String(d.getDate()).padStart(2, '0');
  const hour = String(d.getHours()).padStart(2, '0');
  const minute = String(d.getMinutes()).padStart(2, '0');
  
  return format
    .replace('YYYY', year)
    .replace('MM', month)
    .replace('DD', day)
    .replace('HH', hour)
    .replace('mm', minute);
};

/**
 * 格式化时间显示（如：3小时前、刚刚）
 */
const formatTimeAgo = (date) => {
  const now = new Date();
  const d = new Date(date);
  const diff = Math.floor((now - d) / 1000);
  
  if (diff < 60) return '刚刚';
  if (diff < 3600) return Math.floor(diff / 60) + '分钟前';
  if (diff < 86400) return Math.floor(diff / 3600) + '小时前';
  if (diff < 604800) return Math.floor(diff / 86400) + '天前';
  return formatDate(date, 'MM-DD');
};

/**
 * 计算剩余时间
 */
const calcRemainingTime = (deadline) => {
  const now = new Date();
  const end = new Date(deadline);
  const diff = end - now;
  
  if (diff <= 0) return { text: '已截止', isOverdue: true };
  
  const hours = Math.floor(diff / 3600000);
  const minutes = Math.floor((diff % 3600000) / 60000);
  const seconds = Math.floor((diff % 60000) / 1000);
  
  return {
    hours,
    minutes,
    seconds,
    text: `${String(hours).padStart(2, '0')}:${String(minutes).padStart(2, '0')}:${String(seconds).padStart(2, '0')}`,
    isOverdue: false
  };
};

/**
 * 防抖函数
 */
const debounce = (fn, delay = 500) => {
  let timer = null;
  return function (...args) {
    if (timer) clearTimeout(timer);
    timer = setTimeout(() => fn.apply(this, args), delay);
  };
};

module.exports = {
  formatDate,
  formatTimeAgo,
  calcRemainingTime,
  debounce
};