/* eslint-disable no-plusplus */
const prefix = 'ProseMirror-prompt';

function reportInvalid(dom, message) {
  // FIXME this is awful and needs a lot more work
  let parent = dom.parentNode;
  let msg = parent.appendChild(document.createElement('div'));
  msg.style.left = dom.offsetLeft + dom.offsetWidth + 2 + 'px';
  msg.style.top = dom.offsetTop - 5 + 'px';
  msg.className = 'ProseMirror-invalid';
  msg.textContent = message;
  setTimeout(() => parent.removeChild(msg), 1500);
}

function getValues(fields, domFields) {
  let result = Object.keys(fields)
    .filter((name, index) => {
      let field = fields[name];
      let dom = domFields[index];
      let value = field.read(dom);
      let bad = field.validate(value);

      if (bad) reportInvalid(dom, bad);
      return !bad;
    })
    .reduce((acc, name, index) => {
      let field = fields[name];
      let dom = domFields[index];
      let value = field.read(dom);
      acc[name] = field.clean(value);
      return acc;
    }, {});
  return result;
}

export function openPrompt(options) {
  let wrapper = document.body.appendChild(document.createElement('div'));
  wrapper.className = prefix;

  const close = () => {
    // eslint-disable-next-line no-use-before-define
    window.removeEventListener('mousedown', mouseOutside);
    if (wrapper.parentNode) wrapper.parentNode.removeChild(wrapper);
  };

  let mouseOutside = e => {
    if (!wrapper.contains(e.target)) close();
  };
  setTimeout(() => window.addEventListener('mousedown', mouseOutside), 50);

  let domFields = [];

  Object.values(options.fields).map(field => domFields.push(field.render()));

  let submitButton = document.createElement('button');
  submitButton.type = 'submit';
  submitButton.className =
    'button tiny button--save-link ' + prefix + '-submit';
  submitButton.textContent = 'Create Link';
  let cancelButton = document.createElement('button');
  cancelButton.type = 'button';
  cancelButton.className = 'button tiny hollow secondary' + prefix + '-cancel';
  cancelButton.textContent = 'Cancel';
  cancelButton.addEventListener('click', close);

  let form = wrapper.appendChild(document.createElement('form'));
  if (options.title) {
    const titleDom = document.createElement('h5');
    titleDom.className = 'sub-block-title';
    form.appendChild(titleDom).textContent = options.title;
  }
  domFields.forEach(field => {
    form.appendChild(document.createElement('div')).appendChild(field);
  });
  let buttons = form.appendChild(document.createElement('div'));
  buttons.className = prefix + '-buttons';
  buttons.appendChild(submitButton);
  buttons.appendChild(document.createTextNode(' '));
  buttons.appendChild(cancelButton);

  let box = wrapper.getBoundingClientRect();
  wrapper.style.top = (window.innerHeight - box.height) / 2 + 'px';
  wrapper.style.left = (window.innerWidth - box.width) / 2 + 'px';

  let submit = () => {
    let params = getValues(options.fields, domFields);
    if (params) {
      close();
      options.callback(params);
    }
  };

  form.addEventListener('submit', e => {
    e.preventDefault();
    submit();
  });

  form.addEventListener('keydown', e => {
    if (e.key === 'Esc') {
      e.preventDefault();
      close();
    } else if (e.key === 'Enter' && !(e.ctrlKey || e.metaKey || e.shiftKey)) {
      e.preventDefault();
      submit();
    } else if (e.key === 'Tab') {
      window.setTimeout(() => {
        if (!wrapper.contains(document.activeElement)) close();
      }, 500);
    }
  });

  let input = form.elements[0];
  if (input) input.focus();
}