function assistantBudgetMeta(budget, savedOverride) {
  var limit = budget && Number.isInteger(budget.limit) ? budget.limit.toLocaleString() : null;
  if (savedOverride) {
    return 'Saved override in use. Clear this field to fall back to CLINICAL_ASSISTANT_CONVERSATION_CHARS' +
      (limit ? ' (' + limit + ' UTF-16 code units).' : '.');
  }
  if (!limit) return 'UTF-16 code units. Leave empty to use CLINICAL_ASSISTANT_CONVERSATION_CHARS.';
  // conversationBudget() reports 'default' when the env var is unset, so naming
  // the env var alone would be wrong in the most common deployment.
  return budget.source === 'environment'
    ? 'Currently ' + limit + ' UTF-16 code units from CLINICAL_ASSISTANT_CONVERSATION_CHARS. Set a value here to override it.'
    : 'Currently the built-in default of ' + limit + ' UTF-16 code units (CLINICAL_ASSISTANT_CONVERSATION_CHARS is unset). Set a value here to override it.';
}

export function initClinicalAssistantAdmin(adminEscapeHtml) {
  let configState = 'idle';
  // Image models an admin added from the Image Generation card. The list below
  // offers these, plus anything already allowed or configured so a saved choice
  // never drops out of view.
  let imageRosterSaved = [];
  let savedChatAllowed = [];
  let savedImageAllowed = [];
  let chatRoster = [];
  let imageRoster = [];

  function parseAssistantList(value) {
    return String(value || '').split(',').map(function(s) { return s.trim(); }).filter(Boolean);
  }
  function renderAssistantCheckboxList(containerId, candidates, saved, emptyText) {
    var container = document.getElementById(containerId);
    if (!container) return;
    var ids = candidates.slice();
    saved.forEach(function(id) { if (ids.indexOf(id) === -1) ids.push(id); });
    ids = ids.filter(Boolean).filter(function(id, i, all) { return all.indexOf(id) === i; }).sort();
    container.innerHTML = '';
    if (!ids.length) {
      var empty = document.createElement('p');
      empty.style.cssText = 'margin:0;font-size:12px;color:var(--g500);';
      empty.textContent = emptyText || 'No models available. Add or enable models first.';
      container.appendChild(empty);
      return;
    }
    ids.forEach(function(id) {
      var row = document.createElement('label');
      row.style.cssText = 'display:flex;align-items:center;gap:6px;font-size:12px;padding:2px 0;';
      var box = document.createElement('input');
      box.type = 'checkbox';
      box.value = id;
      box.checked = saved.indexOf(id) !== -1;
      var span = document.createElement('span');
      span.textContent = id;
      row.appendChild(box);
      row.appendChild(span);
      container.appendChild(row);
    });
  }
  function checkedAssistantModels(containerId) {
    var container = document.getElementById(containerId);
    if (!container) return [];
    return Array.prototype.map.call(container.querySelectorAll('input[type="checkbox"]:checked'), function(box) { return box.value; });
  }
  // Built from the admin's roster, not from discovery: the gateway advertises
  // dozens of image models, and this used to wait on a dropdown that no longer
  // exists, so only four hard-coded fallbacks ever appeared.
  function renderAssistantImageModelCheckboxes() {
    imageRoster = imageRosterSaved.concat([window._assistantImageModelValue]);
    renderAssistantCheckboxList('assistant-allowed-image-models', imageRoster, savedImageAllowed,
      'No image models added yet. Add them under Image Generation below, then tick them here.');
  }
  // Adding or removing in the Image Generation card updates this list at once,
  // keeping any ticks made here that have not been saved yet.
  document.addEventListener('assistant-image-roster-changed', function(e) {
    imageRosterSaved = (e.detail && Array.isArray(e.detail.roster)) ? e.detail.roster.slice() : imageRosterSaved;
    if (configState !== 'ready') return;
    savedImageAllowed = checkedAssistantModels('assistant-allowed-image-models');
    renderAssistantImageModelCheckboxes();
  });

  document.addEventListener('tabChanged', function(e) {
    if (e.detail && e.detail.tab === 'admin') loadAssistantAdmin();
  });

  document.addEventListener('click', function(e) {
    if (e.target.closest('#btn-save-assistant-config')) saveAssistantAdmin();
    if (e.target.closest('#btn-retry-assistant-config')) loadAssistantAdmin();
    if (e.target.closest('#btn-test-assistant-chat-model')) testAssistantChatModel();
    if (e.target.closest('#btn-regenerate-assistant-prompt-pool')) regenerateAssistantPromptPool();
    if (e.target.closest('#btn-restore-assistant-prompt-pool')) restoreAssistantPromptPool();
    if (e.target.closest('#btn-save-review-model')) saveReviewModel();
  });

  // ── Slide review ────────────────────────────────────────────────────
  // Its own control rather than part of Save model & retrieval settings: it is
  // the one setting that spends money on every generation without a user having
  // asked for anything, so turning it on should be a deliberate act.
  function saveReviewModel() {
    var select = document.getElementById('mr-review-model');
    var status = document.getElementById('mr-review-status');
    if (!select) return;
    if (status) { status.textContent = 'Saving...'; status.style.color = 'var(--g500)'; }
    putAssistantConfig('my_resources.review_model', select.value || '')
      .then(function() {
        if (!status) return;
        status.textContent = select.value ? 'Decks will be reviewed by ' + select.value : 'Slide review is off';
        status.style.color = 'var(--green)';
      })
      .catch(function(err) {
        if (!status) return;
        status.textContent = err.message;
        status.style.color = 'var(--red)';
      });
  }

  // Any chat model the gateway offers. Whether it can actually see an image is
  // not something the model list says, so the choice is the administrator's —
  // a deck reviewed by a text-only model is discarded rather than applied.
  function renderReviewModel(models, saved) {
    var select = document.getElementById('mr-review-model');
    if (!select) return;
    select.innerHTML = '';
    var off = document.createElement('option');
    off.value = '';
    off.textContent = 'Off — do not review decks';
    select.appendChild(off);
    (Array.isArray(models) ? models : []).filter(function(m) { return m && m.id; }).forEach(function(m) {
      var opt = document.createElement('option');
      opt.value = m.id;
      opt.textContent = m.name || m.id;
      select.appendChild(opt);
    });
    if (saved && !Array.prototype.some.call(select.options, function(o) { return o.value === saved; })) {
      var kept = document.createElement('option');
      kept.value = saved;
      kept.textContent = saved + ' (saved/custom)';
      select.appendChild(kept);
    }
    select.value = saved || '';
  }

  function updateAssistantLoadState() {
    var save = document.getElementById('btn-save-assistant-config');
    if (save) save.disabled = configState !== 'ready';
    // The retry lives inside an error message rather than sitting beside Save
    // looking like an ordinary control, which is how it read before.
    var errorBox = document.getElementById('assistant-config-error');
    if (errorBox) errorBox.hidden = configState !== 'failed';
    var status = document.getElementById('assistant-admin-status');
    // The failure case is spelled out in the error box above, so repeating it
    // here would only be noise.
    if (status && configState !== 'ready') {
      status.textContent = configState === 'failed' ? '' : 'Loading settings...';
    } else if (status && !/^Saved |^Not saved/.test(status.textContent)) {
      status.textContent = 'Settings loaded. Unsaved changes are kept until you press Save.';
    }
  }

  function loadAssistantAdmin() {
    if (configState === 'loading' || configState === 'ready') return;
    configState = 'loading';
    updateAssistantLoadState();
    Promise.all([
      fetch('/api/models', { headers: getAuthHeaders() }).then(function(r) {
        if (!r.ok) throw new Error('Model discovery failed');
        return r.json();
      }).catch(function() { return {}; }),
      fetch('/api/admin/config', { headers: getAuthHeaders() }).then(function(r) {
        if (!r.ok) throw new Error('Settings request failed');
        return r.json();
      })
    ]).then(function(results) {
      var modelsData = results[0] || {};
      var configData = results[1];
      var budget = configData && configData.conversationBudget;
      var validBudget = budget && Number.isInteger(budget.limit) && budget.limit >= 1000 && budget.limit <= 1000000 &&
        budget.unit === 'characters' && budget.measure === 'UTF-16 code units' &&
        budget.env === 'CLINICAL_ASSISTANT_CONVERSATION_CHARS' && ['environment', 'default'].includes(budget.source);
      // Validate the entire response before touching any setting or draft.
      if (!configData || configData.success !== true || !Array.isArray(configData.config) ||
          !configData.config.every(function(row) { return row && typeof row.key === 'string' && row.key && typeof row.value === 'string'; }) ||
          !validBudget) throw new Error('Invalid settings response');
      var cfg = Object.create(null);
      configData.config.forEach(function(row) { cfg[row.key] = row.value; });

      var chatSelect = document.getElementById('assistant-chat-model');
      if (chatSelect) {
        var savedChatModel = cfg['clinical_assistant.chat_model'] || '';
        var defaultLabel = modelsData.defaultModel ? ('Use global default (' + modelsData.defaultModel + ')') : 'Use global default';
        chatSelect.innerHTML = '';
        var defaultOpt = document.createElement('option');
        defaultOpt.value = '';
        defaultOpt.textContent = defaultLabel;
        chatSelect.appendChild(defaultOpt);
        (Array.isArray(modelsData.models) ? modelsData.models : []).filter(function(m) { return m && typeof m.id === 'string' && m.id; }).forEach(function(m) {
          var opt = document.createElement('option');
          opt.value = m.id;
          opt.textContent = m.name || m.id;
          chatSelect.appendChild(opt);
        });
        if (savedChatModel && !Array.prototype.some.call(chatSelect.options, function(o) { return o.value === savedChatModel; })) {
          var saved = document.createElement('option');
          saved.value = savedChatModel;
          saved.textContent = savedChatModel + ' (saved/custom)';
          chatSelect.appendChild(saved);
        }
        chatSelect.value = savedChatModel;
      }
      renderReviewModel(modelsData.models, cfg['my_resources.review_model'] || '');
      window._assistantImageModelValue = cfg['clinical_assistant.image_model'] || '';
      savedChatAllowed = parseAssistantList(cfg['clinical_assistant.allowed_models']);
      savedImageAllowed = parseAssistantList(cfg['clinical_assistant.allowed_image_models']);
      imageRosterSaved = parseAssistantList(cfg['clinical_assistant.image_model_roster']);
      window._assistantImageRoster = imageRosterSaved.slice();
      // Only a nudge for the Image Generation card's buttons: it must never be
      // able to fail the settings load itself.
      try { document.dispatchEvent(new CustomEvent('assistant-image-roster', { detail: { roster: imageRosterSaved.slice() } })); } catch (e) {}
      chatRoster = chatOptions().map(function(o) { return o.value; }).filter(Boolean).concat([cfg['clinical_assistant.chat_model'] || '']);
      renderAssistantCheckboxList('assistant-allowed-chat-models', chatRoster, savedChatAllowed);
      renderAssistantImageModelCheckboxes();
      setValue('assistant-search-limit', cfg['clinical_assistant.search_limit'] || '8');
      setValue('assistant-context-chars', cfg['clinical_assistant.context_chars'] || '1400');
      setValue('assistant-translate-provider', 'libretranslate'); // the only provider the server accepts
      var sourcesBox = document.getElementById('assistant-show-sources');
      if (sourcesBox) {
        var saved = cfg['clinical_assistant.show_sources'];
        if (saved === undefined || saved === '') saved = cfg['clinical_assistant.citations_enabled']; // legacy key
        sourcesBox.checked = String(saved) !== 'false';
      }
      var budgetInput = document.getElementById('assistant-conversation-budget');
      var cfgBudget = cfg['clinical_assistant.conversation_chars'];
      if (budgetInput) {
        // Empty means "no override". Prefilling the environment value here would
        // turn the next Save into an accidental override, making the documented
        // "leave empty to use the environment" path unreachable.
        budgetInput.value = cfgBudget ? String(cfgBudget) : '';
        if (budget && Number.isInteger(budget.limit)) budgetInput.placeholder = String(budget.limit);
      }
      var budgetMeta = document.getElementById('assistant-conversation-budget-meta');
      if (budgetMeta) budgetMeta.textContent = assistantBudgetMeta(budget, cfgBudget);
      configState = 'ready';
      updateAssistantLoadState();
      loadAssistantPromptPoolStatus();
    }).catch(function() {
      configState = 'failed';
      updateAssistantLoadState();
      var budgetMetaFailed = document.getElementById('assistant-conversation-budget-meta');
      if (budgetMetaFailed) budgetMetaFailed.textContent = 'Conversation budget unavailable. Check server environment configuration; no fallback limit is assumed.';
    });
  }

  function testAssistantChatModel() {
    var model = getValue('assistant-chat-model');
    var result = document.getElementById('assistant-chat-test-result');
    if (!model) {
      var select = document.getElementById('assistant-chat-model');
      var selected = select && select.options[select.selectedIndex] ? select.options[select.selectedIndex].textContent : 'global default';
      if (result) result.textContent = 'Testing ' + selected + '...';
    } else if (result) {
      result.textContent = 'Testing ' + model + '...';
    }
    fetch('/api/admin/config/models/test', {
      method: 'POST', headers: getAuthHeaders(), body: JSON.stringify({ modelId: model || getGlobalDefaultFromAssistantSelect() })
    }).then(function(r) { return r.json(); }).then(function(data) {
      if (!data.success) throw new Error(data.error || 'Chat model test failed');
      if (result) result.textContent = 'Chat model OK (' + data.duration + ' ms): ' + (data.response || '').trim();
      showToast('Chat model works', 'success');
    }).catch(function(err) {
      if (result) result.textContent = err.message;
      showToast(err.message, 'error');
    });
  }

  function getGlobalDefaultFromAssistantSelect() {
    var select = document.getElementById('assistant-chat-model');
    if (!select || !select.options[0]) return '';
    var match = select.options[0].textContent.match(/\((.+)\)$/);
    return match ? match[1] : '';
  }

  function loadAssistantPromptPoolStatus() {
    var result = document.getElementById('assistant-prompt-pool-status');
    if (result) result.textContent = 'Checking prompt pool...';
    fetch('/api/admin/clinical-assistant/prompt-pool', { headers: getAuthHeaders() })
      .then(function(r) { return r.json(); })
      .then(function(data) {
        if (!data.success) throw new Error(data.error || 'Prompt pool status failed');
        renderAssistantPromptPoolStatus(data.meta);
        renderAssistantPromptPoolSnapshots(data.snapshots || []);
      })
      .catch(function(err) {
        if (result) result.textContent = err.message;
      });
  }

  function regenerateAssistantPromptPool() {
    var result = document.getElementById('assistant-prompt-pool-status');
    var btn = document.getElementById('btn-regenerate-assistant-prompt-pool');
    if (btn) btn.disabled = true;
    if (result) result.textContent = 'Regenerating prompt pool. This can take several minutes...';
    fetch('/api/admin/clinical-assistant/prompt-pool/regenerate', {
      method: 'POST', headers: getAuthHeaders(), body: JSON.stringify({})
    }).then(function(r) { return r.json(); }).then(function(data) {
      if (!data.success) throw new Error(data.error || 'Prompt pool regeneration failed');
      renderAssistantPromptPoolStatus(data.meta || { count: data.count, generatedAt: Date.now() });
      renderAssistantPromptPoolSnapshots(data.snapshots || []);
      showToast('Prompt pool regenerated', 'success');
    }).catch(function(err) {
      if (result) result.textContent = err.message;
      showToast(err.message, 'error');
    }).finally(function() {
      if (btn) btn.disabled = false;
    });
  }

  function renderAssistantPromptPoolStatus(meta) {
    var result = document.getElementById('assistant-prompt-pool-status');
    if (!result) return;
    if (!meta) {
      result.textContent = 'No generated pool found. The assistant will use indexed-topic fallback until you generate one.';
      return;
    }
    var generated = meta.generatedAt ? new Date(meta.generatedAt).toLocaleString() : 'unknown time';
    result.textContent = 'Generated pool: ' + (meta.count || 0) + ' prompts, target ' + (meta.target || '?') + ', generated ' + generated + (meta.restoredFrom ? ', restored from snapshot #' + meta.restoredFrom : '') + '.';
  }

  function renderAssistantPromptPoolSnapshots(snapshots) {
    var select = document.getElementById('assistant-prompt-pool-snapshots');
    if (!select) return;
    select.innerHTML = '';
    if (!snapshots.length) {
      var empty = document.createElement('option');
      empty.value = '';
      empty.textContent = 'No saved snapshots';
      select.appendChild(empty);
      return;
    }
    snapshots.forEach(function(s) {
      var opt = document.createElement('option');
      opt.value = s.id;
      var date = s.created_at ? new Date(s.created_at).toLocaleString() : 'unknown time';
      opt.textContent = '#' + s.id + ' - ' + (s.count || 0) + ' prompts - ' + date + (s.restored_from ? ' (restored from #' + s.restored_from + ')' : '');
      select.appendChild(opt);
    });
  }

  function restoreAssistantPromptPool() {
    var select = document.getElementById('assistant-prompt-pool-snapshots');
    var id = select ? select.value : '';
    var result = document.getElementById('assistant-prompt-pool-status');
    if (!id) { showToast('Select a prompt pool snapshot', 'error'); return; }
    if (result) result.textContent = 'Restoring prompt pool snapshot #' + id + '...';
    fetch('/api/admin/clinical-assistant/prompt-pool/restore', {
      method: 'POST', headers: getAuthHeaders(), body: JSON.stringify({ id: Number(id) })
    }).then(function(r) { return r.json(); }).then(function(data) {
      if (!data.success) throw new Error(data.error || 'Prompt pool restore failed');
      renderAssistantPromptPoolStatus(data.meta || { count: data.count, generatedAt: Date.now(), restoredFrom: id });
      renderAssistantPromptPoolSnapshots(data.snapshots || []);
      showToast('Prompt pool restored', 'success');
    }).catch(function(err) {
      if (result) result.textContent = err.message;
      showToast(err.message, 'error');
    });
  }

  function saveAssistantAdmin() {
    if (configState !== 'ready') return;
    var chat = document.getElementById('assistant-chat-model');
    if (!chat || chat.selectedIndex < 0) return;
    var status = document.getElementById('assistant-admin-status');
    if (status) status.textContent = 'Saving...';
    Promise.all([
      putAssistantConfig('clinical_assistant.chat_model', getValue('assistant-chat-model')),
      putAssistantConfig('clinical_assistant.conversation_chars', getValue('assistant-conversation-budget')),
      putAssistantConfig('clinical_assistant.search_limit', getValue('assistant-search-limit') || '8'),
      putAssistantConfig('clinical_assistant.context_chars', getValue('assistant-context-chars') || '1400'),
      putAssistantConfig('clinical_assistant.translate_provider', getValue('assistant-translate-provider') || 'libretranslate'),
      putAssistantConfig('clinical_assistant.show_sources',
        (document.getElementById('assistant-show-sources') || {}).checked === false ? 'false' : 'true'),

      putAssistantConfig('clinical_assistant.allowed_models', checkedAssistantModels('assistant-allowed-chat-models').join(',')),
      putAssistantConfig('clinical_assistant.allowed_image_models', checkedAssistantModels('assistant-allowed-image-models').join(','))
    ]).then(function() {
      // A toast is gone in three seconds. Whether these settings are saved is
      // exactly the question an admin has when they come back to this page, so
      // the answer stays on the page.
      if (status) status.textContent = 'Saved ' + new Date().toLocaleTimeString() + '.';
      showToast('Assistant settings saved', 'success');
    }).catch(function(err) {
      if (status) status.textContent = 'Not saved. Nothing was changed.';
      showToast(err.message || 'Save failed', 'error');
    });
  }

  function putAssistantConfig(key, value) {
    return fetch('/api/admin/config/' + encodeURIComponent(key), {
      method: 'PUT', headers: getAuthHeaders(), body: JSON.stringify({ value: value })
    }).then(function(r) { return r.json(); }).then(function(data) {
      if (!data.success) throw new Error(data.error || 'Save failed');
      return data;
    });
  }
  function chatOptions() {
    var chat = document.getElementById('assistant-chat-model');
    var out = [];
    if (chat) Array.prototype.forEach.call(chat.options, function(o) { out.push({ value: o.value }); });
    return out;
  }
  function getValue(id) { var el = document.getElementById(id); return el ? el.value.trim() : ''; }
  function setValue(id, value) { var el = document.getElementById(id); if (el) el.value = value; }
  const escAssistant = adminEscapeHtml;

  // Catch-up: when the admin tab is already active and loaded at module init
  // (e.g. restored tab before this module evaluated), tabChanged may never fire
  // again. The loader's own state guards make this idempotent with tabChanged.
  var adminTab = document.getElementById('admin-tab');
  if (adminTab && adminTab.classList.contains('active') && adminTab.dataset.loaded === '1') loadAssistantAdmin();
}