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,
    reselectPrevious,
    range,
    selection,
    mark,
    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', function(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;