/**
 * 咔哒故事REM布局方案
 * @version: 1.0.2
 * @author: diaoling<jinjian@hhdd.com>
 * @date: 2018/11/07
 **/
var rembox = (function() {
  'use strict'

  var win = window
  var doc = document

  var rembox = function rembox() {
    var options = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : {}
    var normalFontSize = 14
    var _options$designWidth = options.designWidth,
      designWidth = _options$designWidth === void 0 ? 750 : _options$designWidth,
      _options$maxClientWid = options.maxClientWidth,
      maxClientWidth = _options$maxClientWid === void 0 ? 1024 : _options$maxClientWid,
      _options$bodyFontSize = options.bodyFontSize,
      bodyFontSize = _options$bodyFontSize === void 0 ? normalFontSize : _options$bodyFontSize,
      _options$viewportSett = options.viewportSettings,
      viewportSettings = _options$viewportSett === void 0 ? 'initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0, user-scalable=0, viewport-fit=cover' : _options$viewportSett
    var docEl = doc.documentElement
    var dpr = win.devicePixelRatio || 1
    var headEl = doc.head
    var rem = 16

    function detectViewWidth(body) {
      var bodyEl = body || doc.body
      var el = document.createElement('div')
      el.style.position = 'fixed'
      el.style.left = 0
      el.style.right = 0
      bodyEl.appendChild(el) // 获取fixed元素宽度

      var rect = el.getBoundingClientRect()
      var width = rect.width ? rect.width : 0
      bodyEl.removeChild(el)
      var metaEl = doc.querySelector('meta[name="viewport"]')
      var viewportWidth = width === docEl.clientWidth ? 'device-width' : width
      var metaContent = ''

      if (!metaEl) {
        metaEl = doc.createElement('meta')
        metaEl.setAttribute('name', 'viewport')
        metaContent = 'width='.concat(viewportWidth, ', ').concat(viewportSettings)
        headEl.appendChild(metaEl)
      }

      metaContent = metaEl.getAttribute('content') || ''
      var metaWidth = /width\s*=\s*([^\s,]*)\s*,/gi

      if (metaWidth.test(metaContent)) {
        metaContent = metaContent.replace(metaWidth, 'width='.concat(viewportWidth, ','))
      } else {
        metaContent = 'width='.concat(viewportWidth, ', ').concat(viewportSettings)
      }

      metaEl.setAttribute('content', metaContent)
      setRemUnit()
    }

    // adjust body font size
    function setBodyFontSize() {
      var bodyEl = doc.body // 去除 no-js 样式

      var nojsStyle = headEl.querySelector('style[env=no-js]')

      if (nojsStyle) {
        nojsStyle.parentElement.removeChild(nojsStyle)
      }

      var styleEl = headEl.querySelector('style[v-rem=flexible]')
      var ruleName = '.l-maxwidth'
      var styleRule = 'max-width: '.concat(maxClientWidth, 'px;')

      if (!styleEl) {
        styleEl = doc.createElement('style')
        styleEl.setAttribute('v-rem', 'flexible')
        headEl.appendChild(styleEl)
      }

      styleEl.innerHTML = ''.concat(ruleName, ' {').concat(styleRule, '}')

      if (bodyEl) {
        bodyEl.style.fontSize = ''.concat(bodyFontSize, 'px')
      }
    }

    // set 1rem = viewWidth / 10
    function setRemUnit() {
      rem = (Math.min(docEl.clientWidth, maxClientWidth) / designWidth) * 100
      docEl.style.fontSize = ''.concat(rem, 'px')
    }

    // detect 0.5px supports
    if (dpr >= 2) {
      var bodyEl = document.createElement('body')
      var el = document.createElement('div')
      el.style.border = '.5px solid transparent'
      bodyEl.appendChild(el)
      docEl.appendChild(bodyEl)

      if (el.offsetHeight === 1) {
        docEl.classList.add('hairlines')
      }

      detectViewWidth(bodyEl)
      docEl.removeChild(bodyEl)
    }

    setRemUnit()

    // reset rem unit on page resize
    window.addEventListener('resize', setRemUnit)
    window.addEventListener('pageshow', function(e) {
      if (e.persisted) setRemUnit()
    })

    if (doc.body) {
      setBodyFontSize()
    } else {
      doc.addEventListener('DOMContentLoaded', setBodyFontSize)
    }

    return {
      rem: rem,
      dpr: dpr,
      setRemUnit: setRemUnit,
      rem2px: function rem2px(d) {
        var val = parseFloat(d) * rem

        if (/^([0-9.]+)rem$/.test(d)) {
          return ''.concat(val, 'px')
        }

        return val
      },
      px2rem: function px2rem(d) {
        var val = parseFloat(d) / rem

        if (/^([0-9]+)px$/.test(d)) {
          return ''.concat(val, 'rem')
        }

        return val
      }
    }
  }

  var scripts = doc.scripts
  var currentScript = scripts[scripts.length - 1]
  var remboxEnable = currentScript && currentScript.getAttribute('rembox')

  if (remboxEnable !== null || remboxEnable !== undefined) {
    var dataset = currentScript.dataset || {}
    rembox(dataset)
  }

  return rembox
})()