/** File upload utility */
window.TermUpl = function (conn, input) {
  let lines, // array of lines without newlines
    line_i, // current line index
    fuTout, // timeout handle for line sending
    send_delay_ms, // delay between lines (ms)
    nl_str, // newline string to use
    curLine, // current line (when using fuOil)
    inline_pos // Offset in line (for long lines)

  // lines longer than this are split to chunks
  // sending a super-ling string through the socket is not a good idea
  const MAX_LINE_LEN = 128

  function fuOpen () {
    fuStatus('Ready...')
    Modal.show('#fu_modal', onClose)
    $('#fu_form').toggleClass('busy', false)
    input.blockKeys(true)
  }

  function onClose () {
    console.log('Upload modal closed.')
    clearTimeout(fuTout)
    line_i = 0
    input.blockKeys(false)
  }

  function fuStatus (msg) {
    qs('#fu_prog').textContent = msg
  }

  function fuSend () {
    let v = qs('#fu_text').value
    if (!v.length) {
      fuClose()
      return
    }

    lines = v.split('\n')
    line_i = 0
    inline_pos = 0 // offset in line
    send_delay_ms = qs('#fu_delay').value

    // sanitize - 0 causes overflows
    if (send_delay_ms < 0) {
      send_delay_ms = 0
      qs('#fu_delay').value = send_delay_ms
    }

    nl_str = {
      'CR': '\r',
      'LF': '\n',
      'CRLF': '\r\n'
    }[qs('#fu_crlf').value]

    $('#fu_form').toggleClass('busy', true)
    fuStatus('Starting...')
    fuSendLine()
  }

  function fuSendLine () {
    if (!$('#fu_modal').hasClass('visible')) {
      // Modal is closed, cancel
      return
    }

    if (!conn.canSend()) {
      // postpone
      fuTout = setTimeout(fuSendLine, 1)
      return
    }

    if (inline_pos === 0) {
      curLine = lines[line_i++] + nl_str
    }

    let chunk
    if ((curLine.length - inline_pos) <= MAX_LINE_LEN) {
      chunk = curLine.substr(inline_pos, MAX_LINE_LEN)
      inline_pos = 0
    } else {
      chunk = curLine.substr(inline_pos, MAX_LINE_LEN)
      inline_pos += MAX_LINE_LEN
    }

    if (!input.sendString(chunk)) {
      fuStatus('FAILED!')
      return
    }

    let all = lines.length

    fuStatus(line_i + ' / ' + all + ' (' + (Math.round((line_i / all) * 1000) / 10) + '%)')

    if (lines.length > line_i || inline_pos > 0) {
      fuTout = setTimeout(fuSendLine, send_delay_ms)
    } else {
      closeWhenReady()
    }
  }

  function closeWhenReady () {
    if (!conn.canSend()) {
      // stuck in XOFF still, wait to process...
      fuStatus('Waiting for Tx buffer...')
      setTimeout(closeWhenReady, 100)
    } else {
      fuStatus('Done.')
      // delay to show it
      setTimeout(function () {
        fuClose()
      }, 100)
    }
  }

  function fuClose () {
    Modal.hide('#fu_modal')
  }

  return {
    init: function () {
      qs('#fu_file').addEventListener('change', function (evt) {
        let reader = new FileReader()
        let file = evt.target.files[0]
        console.log('Selected file type: ' + file.type)
        if (!file.type.match(/text\/.*|application\/(json|csv|.*xml.*|.*script.*)/)) {
          // Deny load of blobs like img - can crash browser and will get corrupted anyway
          if (!confirm('This does not look like a text file: ' + file.type + '\nReally load?')) {
            qs('#fu_file').value = ''
            return
          }
        }
        reader.onload = function (e) {
          const txt = e.target.result.replace(/[\r\n]+/, '\n')
          qs('#fu_text').value = txt
        }
        console.log('Loading file...')
        reader.readAsText(file)
      }, false)
    },
    close: fuClose,
    start: fuSend,
    open: fuOpen
  }
}