/* istanbul ignore next */

import Vue from 'vue'

const isServer = Vue.prototype.$isServer
// eslint-disable-next-line no-useless-escape
const SPECIAL_CHARS_REGEXP = /([\:\-\_]+(.))/g
const MOZ_HACK_REGEXP = /^moz([A-Z])/
const ieVersion = isServer ? 0 : Number(document.documentMode)

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const trim = function(string) {
  return (string || '').replace(/^[\s\uFEFF]+|[\s\uFEFF]+$/g, '')
}
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const camelCase = function(name) {
  return name
    .replace(SPECIAL_CHARS_REGEXP, function(_, separator, letter, offset) {
      return offset ? letter.toUpperCase() : letter
    })
    .replace(MOZ_HACK_REGEXP, 'Moz$1')
}

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export const on = (function() {
  if (!isServer && document.addEventListener) {
    return function(element, event, handler) {
      if (element && event && handler) {
        element.addEventListener(event, handler, false)
      }
    }
  } else {
    return function(element, event, handler) {
      if (element && event && handler) {
        element.attachEvent('on' + event, handler)
      }
    }
  }
})()

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export const off = (function() {
  if (!isServer && document.removeEventListener) {
    return function(element, event, handler) {
      if (element && event) {
        element.removeEventListener(event, handler, false)
      }
    }
  } else {
    return function(element, event, handler) {
      if (element && event) {
        element.detachEvent('on' + event, handler)
      }
    }
  }
})()

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export const once = function(el, event, fn) {
  var listener = function() {
    if (fn) {
      fn.apply(this, arguments)
    }
    off(el, event, listener)
  }
  on(el, event, listener)
}

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export function hasClass(el, cls) {
  if (!el || !cls) return false
  if (cls.indexOf(' ') !== -1) { throw new Error('className should not contain space.') }
  if (el.classList) {
    return el.classList.contains(cls)
  } else {
    return (' ' + el.className + ' ').indexOf(' ' + cls + ' ') > -1
  }
}

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export function addClass(el, cls) {
  if (!el) return
  var curClass = el.className
  var classes = (cls || '').split(' ')

  for (var i = 0, j = classes.length; i < j; i++) {
    var clsName = classes[i]
    if (!clsName) continue

    if (el.classList) {
      el.classList.add(clsName)
    } else if (!hasClass(el, clsName)) {
      curClass += ' ' + clsName
    }
  }
  if (!el.classList) {
    el.className = curClass
  }
}

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export function removeClass(el, cls) {
  if (!el || !cls) return
  var classes = cls.split(' ')
  var curClass = ' ' + el.className + ' '

  for (var i = 0, j = classes.length; i < j; i++) {
    var clsName = classes[i]
    if (!clsName) continue

    if (el.classList) {
      el.classList.remove(clsName)
    } else if (hasClass(el, clsName)) {
      curClass = curClass.replace(' ' + clsName + ' ', ' ')
    }
  }
  if (!el.classList) {
    el.className = trim(curClass)
  }
}

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export const getStyle =
  ieVersion < 9
    ? function(element, styleName) {
      if (isServer) return
      if (!element || !styleName) return null
      styleName = camelCase(styleName)
      if (styleName === 'float') {
        styleName = 'styleFloat'
      }
      try {
        switch (styleName) {
          case 'opacity':
            try {
              return element.filters.item('alpha').opacity / 100
            } catch (e) {
              return 1.0
            }
          default:
            return element.style[styleName] || element.currentStyle
              ? element.currentStyle[styleName]
              : null
        }
      } catch (e) {
        return element.style[styleName]
      }
    }
    : function(element, styleName) {
      if (isServer) return
      if (!element || !styleName) return null
      styleName = camelCase(styleName)
      if (styleName === 'float') {
        styleName = 'cssFloat'
      }
      try {
        var computed = document.defaultView.getComputedStyle(element, '')
        return element.style[styleName] || computed
          ? computed[styleName]
          : null
      } catch (e) {
        return element.style[styleName]
      }
    }

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export function setStyle(element, styleName, value) {
  if (!element || !styleName) return

  if (typeof styleName === 'object') {
    for (var prop in styleName) {
      if (styleName.hasOwnProperty(prop)) {
        setStyle(element, prop, styleName[prop])
      }
    }
  } else {
    styleName = camelCase(styleName)
    if (styleName === 'opacity' && ieVersion < 9) {
      element.style.filter = isNaN(value)
        ? ''
        : 'alpha(opacity=' + value * 100 + ')'
    } else {
      element.style[styleName] = value
    }
  }
}

export const isScroll = (el, vertical) => {
  if (isServer) return

  const determinedDirection = vertical !== null || vertical !== undefined
  const overflow = determinedDirection
    ? vertical
      ? getStyle(el, 'overflow-y')
      : getStyle(el, 'overflow-x')
    : getStyle(el, 'overflow')

  return overflow.match(/(scroll|auto)/)
}

export const getScrollContainer = (el, vertical) => {
  if (isServer) return

  let parent = el
  while (parent) {
    if ([window, document, document.documentElement].includes(parent)) {
      return window
    }
    if (isScroll(parent, vertical)) {
      return parent
    }
    parent = parent.parentNode
  }

  return parent
}

export const isInContainer = (el, container) => {
  if (isServer || !el || !container) return false

  const elRect = el.getBoundingClientRect()
  let containerRect

  if (
    [window, document, document.documentElement, null, undefined].includes(
      container
    )
  ) {
    containerRect = {
      top: 0,
      right: window.innerWidth,
      bottom: window.innerHeight,
      left: 0
    }
  } else {
    containerRect = container.getBoundingClientRect()
  }

  return (
    elRect.top < containerRect.bottom &&
    elRect.bottom > containerRect.top &&
    elRect.right > containerRect.left &&
    elRect.left < containerRect.right
  )
}
