/**
 * 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,
  SchoolEvent, CreateSchoolEvent, SchoolYearRolloverResult,
  ParentInviteListItem, InviteParentRequest, InviteParentResponse,
} 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) }),

  // School events
  listEvents: (from: string, to: string) =>
    apiFetch<SchoolEvent[]>(`/calendar/events?from=${from}&to=${to}`),
  createEvent: (data: CreateSchoolEvent) =>
    apiFetch<SchoolEvent>('/calendar/events', { method: 'POST', body: JSON.stringify(data) }),
  deleteEvent: (id: string) =>
    apiFetch<void>(`/calendar/events/${id}`, { method: 'DELETE' }),

  rolloverSchoolYear: (newYearStart?: string, newYearEnd?: string) =>
    apiFetch<SchoolYearRolloverResult>('/calendar/school-year-rollover', {
      method: 'POST',
      body: JSON.stringify({
        new_year_start: newYearStart,
        new_year_end: newYearEnd,
      }),
    }),

  // Phase 9c: parent invitations
  listParents: () => apiFetch<ParentInviteListItem[]>('/calendar/parents'),
  inviteParent: (data: InviteParentRequest) =>
    apiFetch<InviteParentResponse>('/calendar/parents/invite', { method: 'POST', body: JSON.stringify(data) }),
  deleteParentChild: (childId: string) =>
    apiFetch<void>(`/calendar/parents/children/${childId}`, { method: 'DELETE' }),
}