function authHeaders(extra) {
  // The app's global getAuthHeaders includes Content-Type: application/json;
  // without it, Express never parses JSON bodies (empty message, etc.).
  var base;
  if (typeof window !== 'undefined' && typeof window.getAuthHeaders === 'function') {
    base = window.getAuthHeaders();
  } else {
    var token = typeof localStorage === 'undefined' ? null : localStorage.getItem('auth_token');
    base = token ? { Authorization: 'Bearer ' + token } : {};
  }
  if (extra) Object.assign(base, extra);
  return base;
}

function parseJsonWithStatus(response) {
  return response.json().catch(function () { return {}; }).then(function(data) {
    data._status = response.status;
    return data;
  });
}

export function fetchAssistantStatus() {
  return fetch('/api/clinical-assistant/status', { headers: authHeaders(), credentials: 'same-origin' })
    .then(function(r) { return r.json(); });
}

export function fetchAssistantExamples() {
  return fetch('/api/clinical-assistant/examples', { headers: authHeaders(), credentials: 'same-origin' })
    .then(function(r) { return r.json(); });
}

export function openAssistantStream(payload, options) {
  options = options || {};
  return fetch('/api/clinical-assistant/chat/stream', {
    method: 'POST',
    headers: authHeaders(),
    credentials: 'same-origin',
    signal: options.signal,
    body: JSON.stringify(payload)
  });
}

export function fetchAssistantChat(payload, options) {
  options = options || {};
  return fetch('/api/clinical-assistant/chat', {
    method: 'POST',
    headers: authHeaders(),
    credentials: 'same-origin',
    signal: options.signal,
    body: JSON.stringify(payload)
  }).then(parseJsonWithStatus);
}

export function requestAssistantImage(prompt) {
  return fetch('/api/clinical-assistant/image', {
    method: 'POST',
    headers: authHeaders(),
    credentials: 'same-origin',
    body: JSON.stringify({ prompt: prompt })
  }).then(function(r) { return r.json(); });
}

export function translateAssistantMessage(message, target, provider, format) {
  return fetch('/api/clinical-assistant/translate', {
    method: 'POST',
    headers: authHeaders(),
    credentials: 'same-origin',
    body: JSON.stringify({ message: message, target: target, provider: provider, format: format || 'text' })
  }).then(parseJsonWithStatus);
}

var imageDraft = null;
export function startAssistantImageJob(prompt, history, imageModel) {
  const input = { prompt, ...(history === undefined ? {} : { history }), ...(imageModel ? { imageModel } : {}) };
  const identity = JSON.stringify(input);
  if (!imageDraft || imageDraft.identity !== identity) imageDraft = { identity, body: { ...input, idempotencyKey: crypto.randomUUID() } };
  return fetch('/api/clinical-assistant/image/jobs', {
    method: 'POST',
    headers: authHeaders(),
    credentials: 'same-origin',
    body: JSON.stringify(imageDraft.body)
  }).then(function(r) { return r.json(); });
}

export function fetchAssistantImageJob(jobId) {
  return fetch('/api/clinical-assistant/image/jobs/' + encodeURIComponent(jobId), {
    headers: authHeaders(),
    credentials: 'same-origin'
  }).then(function(r) { return r.json(); });
}

export function saveAssistantChat(payload) {
  return fetch('/api/clinical-assistant/chats', {
    method: 'POST',
    headers: authHeaders(),
    credentials: 'same-origin',
    body: JSON.stringify(payload)
  }).then(parseJsonWithStatus);
}

export function fetchSavedAssistantChats() {
  return fetch('/api/clinical-assistant/chats', { headers: authHeaders(), credentials: 'same-origin' })
    .then(function(r) { return r.json(); });
}

export function fetchSavedAssistantChat(id) {
  return fetch('/api/clinical-assistant/chats/' + encodeURIComponent(id), { headers: authHeaders(), credentials: 'same-origin' })
    .then(parseJsonWithStatus);
}

export function deleteSavedAssistantChat(id) {
  return fetch('/api/clinical-assistant/chats/' + encodeURIComponent(id), {
    method: 'DELETE',
    headers: authHeaders(),
    credentials: 'same-origin'
  }).then(function(r) { return r.json(); });
}

// Image attachments ride the outgoing clinical question payload for inference.
// Once a question is sent, its attachments persist with the saved chat. The
// server enforces the same limits authoritatively; these mirror them for early
// feedback.
export var assistantAttachmentLimits = Object.freeze({
  mimeTypes: ['image/png', 'image/jpeg', 'image/webp'],
  maxImages: 4,
  maxImageBytes: 5 * 1024 * 1024,
  maxTotalBytes: 10 * 1024 * 1024
});

export function assistantAttachmentPayload(attachments) {
  return (Array.isArray(attachments) ? attachments : []).map(function(attachment) {
    return { dataBase64: attachment.dataBase64, mimeType: attachment.mimeType };
  });
}

export function fetchAssistantImageJobs() {
  return fetch('/api/clinical-assistant/image/jobs?limit=24', { headers: authHeaders(), credentials: 'same-origin' })
    .then(parseJsonWithStatus);
}

export function renameSavedAssistantChat(id, title) {
  return fetch('/api/clinical-assistant/chats/' + encodeURIComponent(id), {
    method: 'PATCH',
    headers: authHeaders(Object.assign({ 'Content-Type': 'application/json' })),
    credentials: 'same-origin',
    body: JSON.stringify({ title: title })
  }).then(parseJsonWithStatus);
}