(function () {
  'use strict';

  let savedConfig = {};
  let pendingChanges = {};

  function setSavedConfig(config) {
    savedConfig = config;
  }

  function populateFields(config) {
    document.querySelectorAll('[data-key]').forEach(el => {
      const key = el.dataset.key;
      const value = config[key] || '';
      if (el.type === 'checkbox') {
        el.checked = value === 'true' || value === true;
      } else if (el.type === 'color') {
        const num = parseInt(value) || 0;
        el.value = '#' + num.toString(16).padStart(6, '0');
      } else {
        el.value = value;
      }
      el.addEventListener('change', () => handleFieldChange(el, key));
      el.addEventListener('input', () => {
        if (el.type === 'text' || el.type === 'number' || el.type === 'password' || el.tagName === 'TEXTAREA') {
          handleFieldChange(el, key);
        }
      });
    });
  }

  function handleFieldChange(el, key) {
    let value;
    if (el.type === 'checkbox') {
      value = el.checked ? 'true' : 'false';
    } else if (el.type === 'color') {
      value = '0x' + el.value.slice(1).toUpperCase();
    } else {
      value = el.value;
    }
    markChanged(key, value);
    el.classList.toggle('changed', key in pendingChanges);
  }

  function initSmartSelects(config) {
    document.querySelectorAll('[data-smart]').forEach(el => {
      const key = el.dataset.key;
      const type = el.dataset.smart;
      const value = config[key] || '';
      if (type === 'channel') DiscordFields.renderChannelSelect(el, value);
      else if (type === 'category') DiscordFields.renderCategorySelect(el, value);
      else if (type === 'role') DiscordFields.renderRoleSelect(el, value);
      else if (type === 'member') DiscordFields.renderMemberSelect(el, value);
      else if (type === 'multi-member') DiscordFields.renderMultiMemberSelect(el, value);
    });
  }

  function markChanged(key, value) {
    if (String(value) === String(savedConfig[key] || '')) {
      delete pendingChanges[key];
    } else {
      pendingChanges[key] = value;
    }
    updateSaveBar();
  }

  function isChanged(key) {
    return key in pendingChanges;
  }

  function updateSaveBar() {
    const bar = document.getElementById('save-bar');
    const count = Object.keys(pendingChanges).length;
    bar.classList.toggle('visible', count > 0);
    document.getElementById('change-count').textContent =
      `${count} unsaved change${count !== 1 ? 's' : ''}`;
  }

  function setupSaveBar() {
    updateSaveBar();
  }

  async function saveConfig(mode) {
    const buttons = document.querySelectorAll('#save-bar button');
    buttons.forEach(b => b.disabled = true);
    try {
      if (mode === 'restart' && !confirm('Save changes and restart the bot now?')) {
        return;
      }
      const res = await fetch('/api/config', {
        method: 'POST',
        credentials: 'same-origin',
        headers: Util.csrfHeaders({ 'Content-Type': 'application/json' }),
        body: JSON.stringify(pendingChanges)
      });
      const data = await res.json();
      if (data.applied) {
        for (const key of data.applied) savedConfig[key] = pendingChanges[key];
        pendingChanges = {};
        updateSaveBar();
        document.querySelectorAll('.changed').forEach(el => el.classList.remove('changed'));
        Util.showToast(`${data.applied.length} settings saved.`, 'success');
      }
      const hasErrors = data.errors && data.errors.length > 0;
      if (hasErrors) {
        Util.showToast(`Errors: ${data.errors.join(', ')}`, 'error');
      }
      if (mode === 'restart' && !hasErrors) {
        await fetch('/api/restart', {
          method: 'POST',
          credentials: 'same-origin',
          headers: Util.csrfHeaders({ 'Content-Type': 'application/json' }),
          body: JSON.stringify({ mode: 'immediate' })
        });
        Util.showToast('Restart initiated.', 'warning');
      } else if (mode === 'restart' && hasErrors) {
        Util.showToast(`Restart cancelled — save returned errors: ${data.errors.join(', ')}`, 'warning');
      }
    } catch (e) {
      Util.showToast('Failed to save. Bot may be unreachable.', 'error');
    } finally {
      buttons.forEach(b => b.disabled = false);
    }
  }

  window.Fields = {
    setSavedConfig,
    populateFields,
    handleFieldChange,
    initSmartSelects,
    markChanged,
    isChanged,
    updateSaveBar,
    setupSaveBar,
    saveConfig
  };
})();