/**
 * Schulkalender API client. Re-uses the same /api/school/* proxy + the JWT
 * helper from stundenplan so we don't fork the auth flow.
 */

import { getStundenplanToken } from '@/lib/stundenplan/api'
import type {
  PublicEvent, SchoolCalendarConfig, UpsertSchoolCalendarConfig,
} from '@/app/schulkalender/types'

async function apiFetch<T>(endpoint: string, options: RequestInit = {}): Promise<T> {
  const headers: Record<string, string> = {
    'Content-Type': 'application/json',
    ...(options.headers as Record<string, string> | undefined),
  }
  const token = getStundenplanToken()
  if (token) headers['Authorization'] = `Bearer ${token}`

  const res = await fetch(`/api/school${endpoint}`, { ...options, headers })
  if (!res.ok) {
    const err = await res.json().catch(() => ({ error: 'Unknown error' }))
    throw new Error(err.error || err.detail || `HTTP ${res.status}`)
  }
  if (res.status === 204) return undefined as T
  return res.json()
}

export const calendarApi = {
  listHolidays: (region: string, from: string, to: string) =>
    apiFetch<PublicEvent[]>(`/calendar/holidays?region=${encodeURIComponent(region)}&from=${from}&to=${to}`),
  getConfig: () => apiFetch<SchoolCalendarConfig | null>('/calendar/config'),
  upsertConfig: (data: UpsertSchoolCalendarConfig) =>
    apiFetch<SchoolCalendarConfig>('/calendar/config', { method: 'PUT', body: JSON.stringify(data) }),
}