/**
 * Stundenplan API client. All requests go through /api/school/* which proxies
 * to the school-service Gin server (port 8084). Auth token, if available, is
 * passed via Authorization: Bearer; for now no token = upstream 401.
 */

import type {
  TimetableClass, TimetablePeriod, TimetableRoom, TimetableSubject,
  TimetableTeacher, TimetableCurriculum, TimetableAssignment,
  CreateTimetableClass, CreateTimetablePeriod, CreateTimetableRoom,
  CreateTimetableSubject, CreateTimetableTeacher,
  CreateTimetableCurriculum, CreateTimetableAssignment,
  TeacherUnavailableDay, TeacherUnavailableWindow, TeacherMaxHoursDay,
  TeacherMaxHoursWeek, TeacherExcludedSubject, TeacherExcludedRoom,
  SubjectMinDayGap, SubjectMaxConsecutive, SubjectContiguousWhenRepeated,
  SubjectPreferredPeriod, SubjectDoubleLesson,
  ClassMaxHoursDay, ClassNoGaps,
  RoomRequiresType, RoomUnavailable,
  TimetableSolution, TimetableLesson, CreateTimetableSolution,
} from '@/app/stundenplan/types'

const TOKEN_KEY = 'bp_stundenplan_jwt'

export function setStundenplanToken(token: string): void {
  if (typeof window !== 'undefined') localStorage.setItem(TOKEN_KEY, token)
}

export function getStundenplanToken(): string {
  if (typeof window === 'undefined') return ''
  return localStorage.getItem(TOKEN_KEY) || ''
}

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 errData = await res.json().catch(() => ({ error: 'Unknown error' }))
    throw new Error(errData.error || errData.detail || `HTTP ${res.status}`)
  }
  if (res.status === 204) return undefined as T
  return res.json()
}

// ---------- Stammdaten ----------

export const classesApi = {
  list: () => apiFetch<TimetableClass[]>('/timetable/classes'),
  create: (data: CreateTimetableClass) =>
    apiFetch<TimetableClass>('/timetable/classes', { method: 'POST', body: JSON.stringify(data) }),
  remove: (id: string) =>
    apiFetch<void>(`/timetable/classes/${id}`, { method: 'DELETE' }),
}

export const periodsApi = {
  list: () => apiFetch<TimetablePeriod[]>('/timetable/periods'),
  create: (data: CreateTimetablePeriod) =>
    apiFetch<TimetablePeriod>('/timetable/periods', { method: 'POST', body: JSON.stringify(data) }),
  remove: (id: string) =>
    apiFetch<void>(`/timetable/periods/${id}`, { method: 'DELETE' }),
}

export const roomsApi = {
  list: () => apiFetch<TimetableRoom[]>('/timetable/rooms'),
  create: (data: CreateTimetableRoom) =>
    apiFetch<TimetableRoom>('/timetable/rooms', { method: 'POST', body: JSON.stringify(data) }),
  remove: (id: string) =>
    apiFetch<void>(`/timetable/rooms/${id}`, { method: 'DELETE' }),
}

export const subjectsApi = {
  list: () => apiFetch<TimetableSubject[]>('/timetable/subjects'),
  create: (data: CreateTimetableSubject) =>
    apiFetch<TimetableSubject>('/timetable/subjects', { method: 'POST', body: JSON.stringify(data) }),
  remove: (id: string) =>
    apiFetch<void>(`/timetable/subjects/${id}`, { method: 'DELETE' }),
}

export const teachersApi = {
  list: () => apiFetch<TimetableTeacher[]>('/timetable/teachers'),
  create: (data: CreateTimetableTeacher) =>
    apiFetch<TimetableTeacher>('/timetable/teachers', { method: 'POST', body: JSON.stringify(data) }),
  remove: (id: string) =>
    apiFetch<void>(`/timetable/teachers/${id}`, { method: 'DELETE' }),
}

export const curriculumApi = {
  list: () => apiFetch<TimetableCurriculum[]>('/timetable/curriculum'),
  create: (data: CreateTimetableCurriculum) =>
    apiFetch<TimetableCurriculum>('/timetable/curriculum', { method: 'POST', body: JSON.stringify(data) }),
  remove: (id: string) =>
    apiFetch<void>(`/timetable/curriculum/${id}`, { method: 'DELETE' }),
}

export const assignmentsApi = {
  list: () => apiFetch<TimetableAssignment[]>('/timetable/assignments'),
  create: (data: CreateTimetableAssignment) =>
    apiFetch<TimetableAssignment>('/timetable/assignments', { method: 'POST', body: JSON.stringify(data) }),
  remove: (id: string) =>
    apiFetch<void>(`/timetable/assignments/${id}`, { method: 'DELETE' }),
}

// ---------- Constraints ----------

/**
 * Factory that builds a list/create/remove triple for a constraint endpoint.
 * The 15 constraint tables share the same CRUD shape; only TItem differs.
 */
function constraintApi<TItem, TCreate>(path: string) {
  return {
    list: () => apiFetch<TItem[]>(`/timetable/constraints/${path}`),
    create: (data: TCreate) =>
      apiFetch<TItem>(`/timetable/constraints/${path}`, { method: 'POST', body: JSON.stringify(data) }),
    remove: (id: string) =>
      apiFetch<void>(`/timetable/constraints/${path}/${id}`, { method: 'DELETE' }),
  }
}

export const teacherUnavailableDayApi = constraintApi<TeacherUnavailableDay, Omit<TeacherUnavailableDay, 'id' | 'created_by_user_id' | 'created_at'>>('teacher/unavailable-day')
export const teacherUnavailableWindowApi = constraintApi<TeacherUnavailableWindow, Omit<TeacherUnavailableWindow, 'id' | 'created_by_user_id' | 'created_at'>>('teacher/unavailable-window')
export const teacherMaxHoursDayApi = constraintApi<TeacherMaxHoursDay, Omit<TeacherMaxHoursDay, 'id' | 'created_by_user_id' | 'created_at'>>('teacher/max-hours-day')
export const teacherMaxHoursWeekApi = constraintApi<TeacherMaxHoursWeek, Omit<TeacherMaxHoursWeek, 'id' | 'created_by_user_id' | 'created_at'>>('teacher/max-hours-week')
export const teacherExcludedSubjectApi = constraintApi<TeacherExcludedSubject, Omit<TeacherExcludedSubject, 'id' | 'created_by_user_id' | 'created_at'>>('teacher/excluded-subject')
export const teacherExcludedRoomApi = constraintApi<TeacherExcludedRoom, Omit<TeacherExcludedRoom, 'id' | 'created_by_user_id' | 'created_at'>>('teacher/excluded-room')

export const subjectMinDayGapApi = constraintApi<SubjectMinDayGap, Omit<SubjectMinDayGap, 'id' | 'created_by_user_id' | 'created_at'>>('subject/min-day-gap')
export const subjectMaxConsecutiveApi = constraintApi<SubjectMaxConsecutive, Omit<SubjectMaxConsecutive, 'id' | 'created_by_user_id' | 'created_at'>>('subject/max-consecutive')
export const subjectContiguousWhenRepeatedApi = constraintApi<SubjectContiguousWhenRepeated, Omit<SubjectContiguousWhenRepeated, 'id' | 'created_by_user_id' | 'created_at'>>('subject/contiguous-when-repeated')
export const subjectPreferredPeriodApi = constraintApi<SubjectPreferredPeriod, Omit<SubjectPreferredPeriod, 'id' | 'created_by_user_id' | 'created_at'>>('subject/preferred-period')
export const subjectDoubleLessonApi = constraintApi<SubjectDoubleLesson, Omit<SubjectDoubleLesson, 'id' | 'created_by_user_id' | 'created_at'>>('subject/double-lesson')

export const classMaxHoursDayApi = constraintApi<ClassMaxHoursDay, Omit<ClassMaxHoursDay, 'id' | 'created_by_user_id' | 'created_at'>>('class/max-hours-day')
export const classNoGapsApi = constraintApi<ClassNoGaps, Omit<ClassNoGaps, 'id' | 'created_by_user_id' | 'created_at'>>('class/no-gaps')

export const roomRequiresTypeApi = constraintApi<RoomRequiresType, Omit<RoomRequiresType, 'id' | 'created_by_user_id' | 'created_at'>>('room/requires-type')
export const roomUnavailableApi = constraintApi<RoomUnavailable, Omit<RoomUnavailable, 'id' | 'created_by_user_id' | 'created_at'>>('room/unavailable')

// ---------- Solutions ----------

export const solutionsApi = {
  list: () => apiFetch<TimetableSolution[]>('/timetable/solutions'),
  get: (id: string) => apiFetch<TimetableSolution>(`/timetable/solutions/${id}`),
  create: (data: CreateTimetableSolution) =>
    apiFetch<TimetableSolution>('/timetable/solutions', { method: 'POST', body: JSON.stringify(data) }),
  remove: (id: string) =>
    apiFetch<void>(`/timetable/solutions/${id}`, { method: 'DELETE' }),
  lessons: (id: string) =>
    apiFetch<TimetableLesson[]>(`/timetable/solutions/${id}/lessons`),
}

export const lessonsApi = {
  pin: (id: string, pinned: boolean) =>
    apiFetch<{ message: string; pinned: boolean }>(`/timetable/lessons/${id}/pin`, {
      method: 'PUT',
      body: JSON.stringify({ pinned }),
    }),
}