// Thin fetch wrapper. Redirects to login on 401.
async function req(method, url, body) {
  const opts = { method, headers: {} };
  if (body !== undefined) {
    opts.headers['Content-Type'] = 'application/json';
    opts.body = JSON.stringify(body);
  }
  const res = await fetch(url, opts);
  if (res.status === 401 && !url.endsWith('/api/login')) {
    location.href = '/login.html';
    throw new Error('Not authenticated');
  }
  const data = res.headers.get('content-type')?.includes('application/json')
    ? await res.json() : null;
  if (!res.ok) throw new Error((data && data.error) || `Request failed (${res.status})`);
  return data;
}

export const api = {
  login: (password) => req('POST', '/api/login', { password }),
  logout: () => req('POST', '/api/logout'),
  me: () => req('GET', '/api/me'),
  setPassword: (current, next) => req('POST', '/api/password', { current, next }),

  categories: (all = false) => req('GET', `/api/categories${all ? '?all=1' : ''}`),
  addCategory: (c) => req('POST', '/api/categories', c),
  updateCategory: (id, c) => req('PUT', `/api/categories/${id}`, c),
  addMetric: (catId, m) => req('POST', `/api/categories/${catId}/metrics`, m),
  updateMetric: (id, m) => req('PUT', `/api/metrics/${id}`, m),
  deleteMetric: (id) => req('DELETE', `/api/metrics/${id}`),

  day: (day) => req('GET', `/api/day/${day}`),
  logEntry: (e) => req('POST', '/api/entries', e),
  updateEntry: (id, e) => req('PUT', `/api/entries/${id}`, e),
  deleteEntry: (id) => req('DELETE', `/api/entries/${id}`),
  saveNotes: (day, notes) => req('PUT', `/api/day/${day}/notes`, { notes }),

  plans: (from, to) => req('GET', `/api/plans?from=${from}&to=${to}`),
  addPlan: (p) => req('POST', '/api/plans', p),
  deletePlan: (id) => req('DELETE', `/api/plans/${id}`),

  goals: () => req('GET', '/api/goals'),
  addGoal: (g) => req('POST', '/api/goals', g),
  updateGoal: (id, g) => req('PUT', `/api/goals/${id}`, g),
  deleteGoal: (id) => req('DELETE', `/api/goals/${id}`),

  stats: () => req('GET', '/api/stats'),
};