import deselectCurrent from './toggle-selection'

interface Options {
  debug?: boolean
  message?: string
  format?: string // MIME type
  onCopy?: (clipboardData: object) => void
}

const clipboardToIE11Formatting = {
  'text/plain': 'Text',
  'text/html': 'Url',
  default: 'Text',
}

const defaultMessage = 'Copy to clipboard: #{key}, Enter'

function format(message: string) {
  const copyKey = `${/mac os x/i.test(navigator.userAgent) ? '⌘' : 'Ctrl'}+C`
  return message.replace(/#\{\s*key\s*\}/g, copyKey)
}

function copy(text: string, options?: Options): boolean {
  let message
  let reselectPrevious
  let range
  let selection
  let mark
  let success = false
  if (!options) {
    options = {}
  }
  const debug = options.debug || false
  try {
    reselectPrevious = deselectCurrent()

    range = document.createRange()
    selection = document.getSelection()

    mark = document.createElement('span')
    mark.textContent = text
    // reset user styles for span element
    mark.style.all = 'unset'
    // prevents scrolling to the end of the page
    mark.style.position = 'fixed'
    mark.style.top = 0
    mark.style.clip = 'rect(0, 0, 0, 0)'
    // used to preserve spaces and line breaks
    mark.style.whiteSpace = 'pre'
    // do not inherit user-select (it may be `none`)
    mark.style.webkitUserSelect = 'text'
    mark.style.MozUserSelect = 'text'
    mark.style.msUserSelect = 'text'
    mark.style.userSelect = 'text'
    mark.addEventListener('copy', (e) => {
      e.stopPropagation()
      if (options.format) {
        e.preventDefault()
        if (typeof e.clipboardData === 'undefined') {
          // IE 11
          debug && console.warn('unable to use e.clipboardData')
          debug && console.warn('trying IE specific stuff')
          ;(window as any).clipboardData.clearData()
          const format =
            clipboardToIE11Formatting[options.format] || clipboardToIE11Formatting.default
          ;(window as any).clipboardData.setData(format, text)
        } else {
          // all other browsers
          e.clipboardData.clearData()
          e.clipboardData.setData(options.format, text)
        }
      }
      if (options.onCopy) {
        e.preventDefault()
        options.onCopy(e.clipboardData)
      }
    })

    document.body.appendChild(mark)

    range.selectNodeContents(mark)
    selection.addRange(range)

    const successful = document.execCommand('copy')
    if (!successful) {
      throw new Error('copy command was unsuccessful')
    }
    success = true
  } catch (err) {
    debug && console.error('unable to copy using execCommand: ', err)
    debug && console.warn('trying IE specific stuff')
    try {
      ;(window as any).clipboardData.setData(options.format || 'text', text)
      options.onCopy && options.onCopy((window as any).clipboardData)
      success = true
    } catch (err) {
      debug && console.error('unable to copy using clipboardData: ', err)
      debug && console.error('falling back to prompt')
      message = format('message' in options ? options.message : defaultMessage)
      window.prompt(message, text)
    }
  } finally {
    if (selection) {
      if (typeof selection.removeRange == 'function') {
        selection.removeRange(range)
      } else {
        selection.removeAllRanges()
      }
    }

    if (mark) {
      document.body.removeChild(mark)
    }
    reselectPrevious()
  }

  return success
}

export default copy
