/**
 * 移动端工具函数
 */

/**
 * 检测是否为移动设备
 */
export function isMobile() {
  return /Android|webOS|iPhone|iPad|iPod|BlackBerry|IEMobile|Opera Mini/i.test(navigator.userAgent) ||
    window.innerWidth < 768
}

/**
 * 检测是否为iOS设备
 */
export function isIOS() {
  return /iPad|iPhone|iPod/.test(navigator.userAgent)
}

/**
 * 检测是否为Android设备
 */
export function isAndroid() {
  return /Android/.test(navigator.userAgent)
}

/**
 * 获取设备类型
 */
export function getDeviceType() {
  if (isMobile()) {
    if (isIOS()) return 'ios'
    if (isAndroid()) return 'android'
    return 'mobile'
  }
  return 'desktop'
}

/**
 * 设置移动端视口
 */
export function setMobileViewport() {
  if (isMobile()) {
    const viewport = document.querySelector('meta[name="viewport"]')
    if (viewport) {
      viewport.setAttribute('content', 'width=device-width, initial-scale=1, maximum-scale=5, minimum-scale=1, user-scalable=yes, viewport-fit=cover')
    }
  }
}

/**
 * 防止iOS双击缩放
 */
export function preventDoubleTapZoom() {
  if (isIOS()) {
    let lastTouchEnd = 0
    document.addEventListener('touchend', (event) => {
      const now = Date.now()
      if (now - lastTouchEnd <= 300) {
        event.preventDefault()
      }
      lastTouchEnd = now
    }, false)
  }
}

/**
 * 优化移动端滚动
 */
export function optimizeMobileScroll() {
  if (isMobile()) {
    // 添加平滑滚动
    document.documentElement.style.scrollBehavior = 'smooth'
    
    // 优化触摸滚动
    const style = document.createElement('style')
    style.textContent = `
      * {
        -webkit-overflow-scrolling: touch;
      }
    `
    document.head.appendChild(style)
  }
}

/**
 * 设置安全区域适配（iOS刘海屏）
 */
export function setSafeArea() {
  if (isIOS()) {
    const style = document.createElement('style')
    style.textContent = `
      .safe-area-top {
        padding-top: env(safe-area-inset-top);
      }
      .safe-area-bottom {
        padding-bottom: env(safe-area-inset-bottom);
      }
      .safe-area-left {
        padding-left: env(safe-area-inset-left);
      }
      .safe-area-right {
        padding-right: env(safe-area-inset-right);
      }
    `
    document.head.appendChild(style)
  }
}

/**
 * 移动端初始化
 */
export function initMobile() {
  setMobileViewport()
  preventDoubleTapZoom()
  optimizeMobileScroll()
  setSafeArea()
}

/**
 * 格式化移动端表格数据为卡片数据
 */
export function formatTableToCards(tableData, columns) {
  return tableData.map(row => {
    const card = {}
    columns.forEach(column => {
      if (column.visible !== false) {
        const value = column.prop ? getNestedValue(row, column.prop) : ''
        card[column.prop || column.key] = {
          label: column.label,
          value: column.formatter ? column.formatter(row, column, value) : value,
          type: column.type || 'text'
        }
      }
    })
    return {
      ...row,
      _cardData: card
    }
  })
}

/**
 * 获取嵌套对象值
 */
function getNestedValue(obj, path) {
  return path.split('.').reduce((o, p) => o && o[p], obj)
}

/**
 * 移动端表格列配置
 */
export function getMobileTableColumns(columns) {
  return columns
    .filter(col => col.visible !== false)
    .map(col => ({
      ...col,
      label: col.label || col.prop,
      prop: col.prop || col.key
    }))
}

/**
 * 防抖函数
 */
export function debounce(func, wait) {
  let timeout
  return function executedFunction(...args) {
    const later = () => {
      clearTimeout(timeout)
      func(...args)
    }
    clearTimeout(timeout)
    timeout = setTimeout(later, wait)
  }
}

/**
 * 节流函数
 */
export function throttle(func, limit) {
  let inThrottle
  return function(...args) {
    if (!inThrottle) {
      func.apply(this, args)
      inThrottle = true
      setTimeout(() => inThrottle = false, limit)
    }
  }
}

/**
 * 移动端图片懒加载
 */
export function lazyLoadImages() {
  if ('IntersectionObserver' in window) {
    const imageObserver = new IntersectionObserver((entries, observer) => {
      entries.forEach(entry => {
        if (entry.isIntersecting) {
          const img = entry.target
          img.src = img.dataset.src
          img.classList.remove('lazy')
          imageObserver.unobserve(img)
        }
      })
    })

    document.querySelectorAll('img.lazy').forEach(img => {
      imageObserver.observe(img)
    })
  }
}

export default {
  isMobile,
  isIOS,
  isAndroid,
  getDeviceType,
  setMobileViewport,
  preventDoubleTapZoom,
  optimizeMobileScroll,
  setSafeArea,
  initMobile,
  formatTableToCards,
  getMobileTableColumns,
  debounce,
  throttle,
  lazyLoadImages
}