(() => {
  const PANEL_SELECTOR = '[data-refresh-url="data/fabrication.php"]';
  const TABLE_SELECTOR = '[data-boiler-section]';
  const STORAGE_KEY = 'lasuca.boilerPanels';

  const loadState = () => {
    try {
      const stored = window.localStorage.getItem(STORAGE_KEY);
      if (!stored) {
        return {};
      }
      const parsed = JSON.parse(stored);
      return typeof parsed === 'object' && parsed !== null ? parsed : {};
    } catch (error) {
      console.warn('Unable to load boiler panel state from storage.', error);
      return {};
    }
  };

  const saveState = (state) => {
    try {
      window.localStorage.setItem(STORAGE_KEY, JSON.stringify(state));
    } catch (error) {
      console.warn('Unable to persist boiler panel state.', error);
    }
  };

  const applyCollapsedState = (table, collapsed) => {
    const rows = Array.from(table.rows).slice(1);
    rows.forEach((row) => {
      row.style.display = collapsed ? 'none' : '';
    });
    table.classList.toggle('is-collapsed', collapsed);
  };

  const formatSummary = (value, units) => {
    if (value === undefined || value === null || value === '') {
      return '';
    }

    const numeric = Number(value);
    const formatted = Number.isFinite(numeric)
      ? numeric.toLocaleString(undefined, { maximumFractionDigits: 1 })
      : value;

    const unitPart = units ? ` ${units}` : '';
    return `Steam Flow: ${formatted}${unitPart}`;
  };

  const initialiseTable = (table, state) => {
    const id = table.dataset.boilerSection;
    if (!id) {
      return;
    }

    const headerRow = table.querySelector('tr');
    const headerCell = headerRow ? headerRow.querySelector('td, th') : null;
    if (!headerCell) {
      return;
    }

    const title = (table.dataset.boilerTitle || headerCell.textContent || '').trim() || 'Boiler';
    const steamValue = table.dataset.steamValue || '';
    const steamUnits = table.dataset.steamUnits || '';

    const targetId = table.id || `${id}-table`;
    table.id = targetId;

    let headerWrapper = headerCell.querySelector('.boiler-panel__header');
    let toggleButton;
    let summary;

    if (!headerWrapper) {
      headerWrapper = document.createElement('div');
      headerWrapper.className = 'boiler-panel__header';

      toggleButton = document.createElement('button');
      toggleButton.type = 'button';
      toggleButton.className = 'boiler-panel__toggle';
      toggleButton.setAttribute('data-boiler-toggle', id);
      toggleButton.setAttribute('aria-controls', targetId);
      toggleButton.innerHTML = `
        <span class="boiler-panel__title">${title}</span>
        <span class="boiler-panel__indicator" aria-hidden="true"></span>
      `;

      summary = document.createElement('span');
      summary.className = 'boiler-panel__summary';
      summary.setAttribute('data-boiler-summary', '');
      summary.textContent = formatSummary(steamValue, steamUnits);

      headerWrapper.appendChild(toggleButton);
      headerWrapper.appendChild(summary);

      headerCell.innerHTML = '';
      headerCell.appendChild(headerWrapper);

      toggleButton.addEventListener('click', () => {
        const nextCollapsed = !table.classList.contains('is-collapsed');
        applyCollapsedState(table, nextCollapsed);
        toggleButton.setAttribute('aria-expanded', (!nextCollapsed).toString());
        state[id] = nextCollapsed;
        saveState(state);
      });

      table.dataset.boilerInitialised = 'true';
    } else {
      toggleButton = headerWrapper.querySelector('.boiler-panel__toggle');
      summary = headerWrapper.querySelector('[data-boiler-summary]');
    }

    if (toggleButton) {
      toggleButton.setAttribute('aria-controls', targetId);
    }

    if (summary) {
      summary.textContent = formatSummary(steamValue, steamUnits);
    }

    const collapsed = state[id] === true;
    applyCollapsedState(table, collapsed);
    if (toggleButton) {
      toggleButton.setAttribute('aria-expanded', (!collapsed).toString());
    }
  };

  const initialisePanel = (panel) => {
    const state = loadState();
    const tables = panel.querySelectorAll(TABLE_SELECTOR);
    tables.forEach((table) => initialiseTable(table, state));
  };

  const handlePanelUpdate = (event) => {
    if (!event || !event.currentTarget) {
      return;
    }
    initialisePanel(event.currentTarget);
  };

  const setup = () => {
    const panel = document.querySelector(PANEL_SELECTOR);
    if (!panel) {
      return;
    }

    panel.addEventListener('livepanel:updated', handlePanelUpdate);

    if (panel.innerHTML.trim().length) {
      initialisePanel(panel);
    }
  };

  if (document.readyState === 'loading') {
    document.addEventListener('DOMContentLoaded', setup, { once: true });
  } else {
    setup();
  }
})();