// utils/util.js - 通用工具函数

/**
 * 格式化日期时间
 * @param {Date|number|string} date - 日期
 * @param {string} format - 格式化模板
 */
const formatTime = (date, format = 'YYYY-MM-DD HH:mm:ss') => {
  if (!date) return '';
  
  const d = new Date(date);
  if (isNaN(d.getTime())) return '';

  const year = d.getFullYear();
  const month = d.getMonth() + 1;
  const day = d.getDate();
  const hour = d.getHours();
  const minute = d.getMinutes();
  const second = d.getSeconds();

  const formatNumber = n => n.toString().padStart(2, '0');

  return format
    .replace('YYYY', year)
    .replace('MM', formatNumber(month))
    .replace('DD', formatNumber(day))
    .replace('HH', formatNumber(hour))
    .replace('mm', formatNumber(minute))
    .replace('ss', formatNumber(second));
};

/**
 * 相对时间格式化（如：刚刚、5分钟前）
 * @param {Date|number|string} date - 日期
 */
const formatRelativeTime = (date) => {
  if (!date) return '';
  
  const d = new Date(date);
  const now = new Date();
  const diff = now.getTime() - d.getTime();
  
  const minute = 60 * 1000;
  const hour = 60 * minute;
  const day = 24 * hour;
  const month = 30 * day;
  const year = 365 * day;

  if (diff < minute) {
    return '刚刚';
  } else if (diff < hour) {
    return `${Math.floor(diff / minute)}分钟前`;
  } else if (diff < day) {
    return `${Math.floor(diff / hour)}小时前`;
  } else if (diff < month) {
    return `${Math.floor(diff / day)}天前`;
  } else if (diff < year) {
    return `${Math.floor(diff / month)}个月前`;
  } else {
    return `${Math.floor(diff / year)}年前`;
  }
};

/**
 * 防抖函数
 * @param {Function} fn - 要防抖的函数
 * @param {number} delay - 延迟时间
 */
const debounce = (fn, delay = 300) => {
  let timer = null;
  return function (...args) {
    if (timer) clearTimeout(timer);
    timer = setTimeout(() => {
      fn.apply(this, args);
    }, delay);
  };
};

/**
 * 节流函数
 * @param {Function} fn - 要节流的函数
 * @param {number} interval - 间隔时间
 */
const throttle = (fn, interval = 300) => {
  let lastTime = 0;
  return function (...args) {
    const now = Date.now();
    if (now - lastTime >= interval) {
      lastTime = now;
      fn.apply(this, args);
    }
  };
};

/**
 * 深拷贝
 * @param {any} obj - 要拷贝的对象
 */
const deepClone = (obj) => {
  if (obj === null || typeof obj !== 'object') return obj;
  if (obj instanceof Date) return new Date(obj);
  if (obj instanceof Array) return obj.map(item => deepClone(item));
  if (obj instanceof Object) {
    const copy = {};
    Object.keys(obj).forEach(key => {
      copy[key] = deepClone(obj[key]);
    });
    return copy;
  }
  return obj;
};

/**
 * 生成唯一ID
 */
const generateId = () => {
  return Date.now().toString(36) + Math.random().toString(36).substr(2, 9);
};

module.exports = {
  formatTime,
  formatRelativeTime,
  debounce,
  throttle,
  deepClone,
  generateId
};