(() => {
  let currentPageMatches = null;
  let currentForm = null;
  let successfulAttachment = false;
  let focusedField = null;

  function generateQuerySelector(el) {
    if (el.tagName.toLowerCase() === 'html') {
      return 'HTML';
    }

    let str = el.tagName;
    str += el.id != '' ? '#' + el.id : '';
    if (el.className) {
      const classes = el.className.split(/\s/);
      for (let i = 0; i < classes.length; i++) {
        str += '.' + classes[i];
      }
    }

    return generateQuerySelector(el.parentNode) + ' > ' + str;
  }

  function lookForLoginForms() {
    const allPasswordInputs = document.querySelectorAll(
      'input[type="password"]'
    );
    let loginForms = [];

    allPasswordInputs.forEach((field) => {
      const closestForm = field.closest('form');
      if (!closestForm) {
        return;
      }

      const existing = loginForms.find(({ form }) => form === closestForm);
      if (existing) {
        existing.passwordAgain = field;
        return;
      }

      let usernameField;
      const allInputs = Array.from(closestForm.querySelectorAll('input'));
      const contenders = allInputs.filter((element) => {
        const nameAttr = (element.getAttribute('name') || '').toLowerCase();
        const idAttr = (element.getAttribute('id') || '').toLowerCase();
        const closestLabel = closestForm.querySelector(
          `label[for="${idAttr}"]`
        );

        if (closestLabel) {
          const labelText = closestLabel.innerText.toLowerCase().trim();
          if (
            labelText.startsWith('user') ||
            labelText.startsWith('email') ||
            labelText.startsWith('e-mail')
          ) {
            return true;
          }
        }

        if (nameAttr.includes('username')) {
          return true;
        }

        if (nameAttr.includes('email')) {
          return true;
        }

        if (nameAttr.includes('name')) {
          return true;
        }
      });

      usernameField = contenders[0];

      loginForms.push({
        password: field,
        username: usernameField,
        form: closestForm,
      });
    });

    if (loginForms.length) {
      chrome.runtime.sendMessage({
        message: 'login_forms',
        payload: loginForms.map((stringify) => ({
          form: generateQuerySelector(stringify.form),
          password: generateQuerySelector(stringify.password),
          passwordAgain: stringify.passwordAgain
            ? generateQuerySelector(stringify.passwordAgain)
            : null,
          username: stringify.username
            ? generateQuerySelector(stringify.username)
            : null,
        })),
      });
    }

    return loginForms;
  }

  function createOptionsSelect(commitAutofill) {
    const select = document.createElement('select');
    const unopt = document.createElement('option');
    unopt.innerText = 'Select autofill...';
    select.appendChild(unopt);

    Object.assign(select.style, {
      pointerEvents: 'all',
    });

    currentPageMatches.forEach((match) => {
      const option = document.createElement('option');
      option.value = match;
      option.innerText = match;
      select.appendChild(option);
    });

    select.addEventListener('change', function () {
      const val = select.value;
      if (val) {
        commitAutofill(val);
      }
    });
    return select;
  }

  function attachLoginFormHighlight(info) {
    successfulAttachment = true;
    const autoFillContainer = document.createElement('div');
    Object.assign(autoFillContainer.style, {
      position: 'absolute',
      outline: '10px solid rgb(0 170 255 / 60%)',
      boxSizing: 'border-box',
      pointerEvents: 'none',
      borderRadius: '10px',
      zIndex: '10000000',
    });
    document.body.appendChild(autoFillContainer);

    function reposition() {
      const boundingBox = info.form.getBoundingClientRect();
      Object.assign(autoFillContainer.style, {
        top: `${boundingBox.y - 10 + window.scrollY}px`,
        left: `${boundingBox.x - 10}px`,
        width: `${boundingBox.width + 20}px`,
        height: `${boundingBox.height + 20}px`,
      });
    }

    window.addEventListener('resize', reposition);
    window.addEventListener('scroll', reposition);
    reposition();

    const select = createOptionsSelect((password) => {
      currentForm = info;
      chrome.runtime.sendMessage({
        message: 'autofill',
        payload: password,
      });
    });
    autoFillContainer.appendChild(select);
  }

  function init() {
    const forms = lookForLoginForms();
    if (forms.length) {
      forms.forEach((form) => attachLoginFormHighlight(form));
    }
  }

  function fakeTriggers(input, value) {
    const inputEvt = new Event('input');
    const changeEvt = new Event('change');
    input.focus();
    input.value = value;
    input.setAttribute('value', value);
    input.dispatchEvent(inputEvt);
    input.dispatchEvent(changeEvt);
    input.blur();
  }

  chrome.runtime.onMessage.addListener(function (
    request,
    sender,
    sendResponse
  ) {
    if (request.message === 'has_entries') {
      currentPageMatches = request.payload;
      init();
      sendResponse(true);
    }

    if (request.message === 'fill_password') {
      if (request && request.payload.password) {
        if (currentForm) {
          fakeTriggers(currentForm.password, request.payload.password);

          if (currentForm.username && request.payload.username) {
            fakeTriggers(currentForm.username, request.payload.username);
          }

          setTimeout(() => currentForm.password.focus(), 100);
        } else if (focusedField) {
          fakeTriggers(focusedField, request.payload.password);
        }
      }

      sendResponse(true);
    }
  });

  document.addEventListener('click', function (e) {
    if (!currentPageMatches) {
      return;
    }

    focusedField = e.target;

    if (successfulAttachment) {
      return;
    }

    if (e.target && e.target.tagName === 'INPUT') {
      init();
    }
  });
})();