breadcrumb-the-shire/web/js/components/app-lookup-field.js

/**
 * Generic autocomplete lookup field.
 *
 * Usage:
 *   <div data-app-lookup
 *        data-lookup-url="/helpdesk/debitor-lookup-data"
 *        data-lookup-min-chars="2"
 *        data-lookup-debounce="300"
 *        data-lookup-value-key="value"
 *        data-lookup-display-key="label"
 *        data-lookup-placeholder="Search...">
 *     <input type="hidden" name="debitor_no" data-lookup-value>
 *     <input type="hidden" name="debitor_name" data-lookup-display-value>
 *   </div>
 *
 * The component creates a visible text input, a dropdown, and indicator icons.
 * On selection, it sets the hidden input values and fires a 'lookup:select' CustomEvent.
 */

/** @param {HTMLElement} container */
export function initLookupField(container) {
  const url = container.dataset.lookupUrl || '';
  const minChars = parseInt(container.dataset.lookupMinChars || '2', 10);
  const debounceMs = parseInt(container.dataset.lookupDebounce || '300', 10);
  const valueKey = container.dataset.lookupValueKey || 'value';
  const displayKey = container.dataset.lookupDisplayKey || 'label';
  const placeholder = container.dataset.lookupPlaceholder || '';
  const initialDisplay = container.dataset.lookupInitialDisplay || '';
  const initialValue = container.dataset.lookupInitialValue || '';

  const hiddenValue = container.querySelector('[data-lookup-value]');
  const hiddenDisplay = container.querySelector('[data-lookup-display-value]');

  // Build DOM
  container.classList.add('app-lookup-field');

  const wrap = document.createElement('div');
  wrap.className = 'app-lookup-field-input-wrap';

  const input = document.createElement('input');
  input.type = 'text';
  input.className = 'app-lookup-field-input';
  input.placeholder = placeholder;
  input.setAttribute('role', 'combobox');
  input.setAttribute('aria-expanded', 'false');
  input.setAttribute('aria-autocomplete', 'list');
  input.setAttribute('autocomplete', 'off');

  const indicator = document.createElement('div');
  indicator.className = 'app-lookup-field-indicator';

  wrap.appendChild(input);
  wrap.appendChild(indicator);

  const dropdown = document.createElement('ul');
  dropdown.className = 'app-lookup-field-dropdown';
  dropdown.setAttribute('role', 'listbox');
  dropdown.hidden = true;

  container.appendChild(wrap);
  container.appendChild(dropdown);

  // State
  let results = [];
  let activeIndex = -1;
  let debounceTimer = null;
  let abortController = null;
  let selected = false;

  // Restore initial state
  if (initialValue && initialDisplay) {
    input.value = initialDisplay;
    selected = true;
    input.dataset.lookupSelected = '';
    showClear();
  }

  // ── Indicator helpers ──────────────────────────────────────────────

  function showSpinner() {
    clearElement(indicator);
    const spinner = document.createElement('div');
    spinner.className = 'app-lookup-field-spinner';
    indicator.appendChild(spinner);
  }

  function showClear() {
    clearElement(indicator);
    const button = document.createElement('button');
    button.type = 'button';
    button.className = 'app-lookup-field-clear';
    button.setAttribute('aria-label', 'Clear');
    button.addEventListener('click', clearSelection);
    const icon = document.createElement('i');
    icon.className = 'bi bi-x-lg';
    button.appendChild(icon);
    indicator.appendChild(button);
  }

  function hideIndicator() {
    clearElement(indicator);
  }

  // ── Dropdown helpers ───────────────────────────────────────────────

  function openDropdown() {
    dropdown.hidden = false;
    input.setAttribute('aria-expanded', 'true');
  }

  function closeDropdown() {
    dropdown.hidden = true;
    input.setAttribute('aria-expanded', 'false');
    activeIndex = -1;
  }

  function clearElement(el) {
    while (el.firstChild) el.removeChild(el.firstChild);
  }

  function renderResults(items) {
    results = items;
    activeIndex = -1;
    clearElement(dropdown);

    if (items.length === 0) {
      const msg = document.createElement('li');
      msg.className = 'app-lookup-field-message';
      msg.textContent = container.dataset.lookupEmptyText || 'No results';
      dropdown.appendChild(msg);
      openDropdown();
      return;
    }

    items.forEach((item, index) => {
      const li = document.createElement('li');
      li.className = 'app-lookup-field-option';
      li.setAttribute('role', 'option');
      li.setAttribute('aria-selected', 'false');
      li.dataset.index = index;

      const label = document.createElement('span');
      label.className = 'app-lookup-field-option-label';
      label.textContent = item[displayKey] || '';
      li.appendChild(label);

      if (item.meta) {
        const meta = document.createElement('span');
        meta.className = 'app-lookup-field-option-meta';
        meta.textContent = item.meta;
        li.appendChild(meta);
      }

      li.addEventListener('mousedown', (e) => {
        e.preventDefault();
        selectItem(index);
      });

      li.addEventListener('mouseenter', () => {
        setActive(index);
      });

      dropdown.appendChild(li);
    });

    openDropdown();
  }

  function renderError() {
    clearElement(dropdown);
    const msg = document.createElement('li');
    msg.className = 'app-lookup-field-message';
    msg.textContent = container.dataset.lookupErrorText || 'Search failed';
    dropdown.appendChild(msg);
    openDropdown();
  }

  function setActive(index) {
    const options = dropdown.querySelectorAll('.app-lookup-field-option');
    options.forEach((opt, i) => {
      opt.setAttribute('aria-selected', i === index ? 'true' : 'false');
    });
    activeIndex = index;

    // Scroll active into view
    const active = options[index];
    if (active) {
      active.scrollIntoView({ block: 'nearest' });
    }
  }

  // ── Selection ──────────────────────────────────────────────────────

  function selectItem(index) {
    const item = results[index];
    if (!item) return;

    input.value = item[displayKey] || '';
    input.dataset.lookupSelected = '';
    selected = true;

    if (hiddenValue) hiddenValue.value = item[valueKey] || '';
    if (hiddenDisplay) hiddenDisplay.value = item[displayKey] || '';

    closeDropdown();
    showClear();

    container.dispatchEvent(new CustomEvent('lookup:select', {
      detail: item,
      bubbles: true,
    }));
  }

  function clearSelection() {
    input.value = '';
    delete input.dataset.lookupSelected;
    selected = false;

    if (hiddenValue) hiddenValue.value = '';
    if (hiddenDisplay) hiddenDisplay.value = '';

    hideIndicator();
    input.focus();

    container.dispatchEvent(new CustomEvent('lookup:clear', { bubbles: true }));
  }

  // ── Fetch ──────────────────────────────────────────────────────────

  function fetchResults(query) {
    if (abortController) abortController.abort();
    abortController = new AbortController();

    showSpinner();

    const separator = url.includes('?') ? '&' : '?';
    fetch(url + separator + 'q=' + encodeURIComponent(query), {
      signal: abortController.signal,
      headers: { 'Accept': 'application/json' },
    })
      .then((res) => {
        if (!res.ok) throw new Error(res.statusText);
        return res.json();
      })
      .then((data) => {
        hideIndicator();
        const items = Array.isArray(data) ? data : (data.data || []);
        renderResults(items);
      })
      .catch((err) => {
        if (err.name === 'AbortError') return;
        hideIndicator();
        renderError();
      });
  }

  // ── Input events ───────────────────────────────────────────────────

  input.addEventListener('input', () => {
    if (selected) {
      selected = false;
      delete input.dataset.lookupSelected;
      if (hiddenValue) hiddenValue.value = '';
      if (hiddenDisplay) hiddenDisplay.value = '';
    }

    const query = input.value.trim();
    if (query.length < minChars) {
      closeDropdown();
      hideIndicator();
      return;
    }

    clearTimeout(debounceTimer);
    debounceTimer = setTimeout(() => fetchResults(query), debounceMs);
  });

  input.addEventListener('keydown', (e) => {
    if (dropdown.hidden) return;

    const options = dropdown.querySelectorAll('.app-lookup-field-option');
    if (!options.length) return;

    if (e.key === 'ArrowDown') {
      e.preventDefault();
      setActive(activeIndex < options.length - 1 ? activeIndex + 1 : 0);
    } else if (e.key === 'ArrowUp') {
      e.preventDefault();
      setActive(activeIndex > 0 ? activeIndex - 1 : options.length - 1);
    } else if (e.key === 'Enter') {
      e.preventDefault();
      if (activeIndex >= 0) {
        selectItem(activeIndex);
      }
    } else if (e.key === 'Escape') {
      e.preventDefault();
      closeDropdown();
    }
  });

  input.addEventListener('focus', () => {
    if (input.value.trim().length >= minChars && !selected && results.length > 0) {
      openDropdown();
    }
  });

  input.addEventListener('blur', () => {
    // Delay to allow mousedown on option to fire first
    setTimeout(() => closeDropdown(), 150);
  });

  return { input, clearSelection };
}

// ── Auto-init ──────────────────────────────────────────────────────

function initAll() {
  document.querySelectorAll('[data-app-lookup]').forEach((el) => {
    if (el.dataset.lookupInitialized) return;
    el.dataset.lookupInitialized = '1';
    initLookupField(el);
  });
}

if (document.readyState === 'loading') {
  document.addEventListener('DOMContentLoaded', initAll);
} else {
  initAll();
}