/**
 * Korrektur Core API - Base functions and CRUD operations
 *
 * Split from api.ts. This module contains the base fetch wrapper
 * and all core Klausur/Student/Annotation/Fairness operations.
 */

import type {
  Klausur, StudentWork, CriteriaScores, Annotation,
  AnnotationPosition, AnnotationType, FairnessAnalysis,
  EHSuggestion, GradeInfo, CreateKlausurData,
} from '@/app/korrektur/types'

export const getApiBase = (): string => {
  if (typeof window === 'undefined') return 'http://localhost:8086'
  const { hostname } = window.location
  return hostname === 'localhost' ? 'http://localhost:8086' : '/klausur-api'
}

export async function apiFetch<T>(endpoint: string, options: RequestInit = {}): Promise<T> {
  const url = `${getApiBase()}${endpoint}`
  const response = await fetch(url, { ...options, headers: { 'Content-Type': 'application/json', ...options.headers } })
  if (!response.ok) {
    const errorData = await response.json().catch(() => ({ detail: 'Unknown error' }))
    throw new Error(errorData.detail || `HTTP ${response.status}`)
  }
  return response.json()
}

// Klausuren
export async function getKlausuren(): Promise<Klausur[]> {
  const data = await apiFetch<{ klausuren: Klausur[] }>('/api/v1/klausuren')
  return data.klausuren || []
}

export async function getKlausur(id: string): Promise<Klausur> {
  return apiFetch<Klausur>(`/api/v1/klausuren/${id}`)
}

export async function createKlausur(data: CreateKlausurData): Promise<Klausur> {
  return apiFetch<Klausur>('/api/v1/klausuren', { method: 'POST', body: JSON.stringify(data) })
}

export async function deleteKlausur(id: string): Promise<void> {
  await apiFetch(`/api/v1/klausuren/${id}`, { method: 'DELETE' })
}

// Students
export async function getStudents(klausurId: string): Promise<StudentWork[]> {
  const data = await apiFetch<{ students: StudentWork[] }>(`/api/v1/klausuren/${klausurId}/students`)
  return data.students || []
}

export async function getStudent(studentId: string): Promise<StudentWork> {
  return apiFetch<StudentWork>(`/api/v1/students/${studentId}`)
}

export async function uploadStudentWork(klausurId: string, file: File, anonymId: string): Promise<StudentWork> {
  const formData = new FormData()
  formData.append('file', file)
  formData.append('anonym_id', anonymId)
  const response = await fetch(`${getApiBase()}/api/v1/klausuren/${klausurId}/students`, { method: 'POST', body: formData })
  if (!response.ok) {
    const errorData = await response.json().catch(() => ({ detail: 'Upload failed' }))
    throw new Error(errorData.detail || `HTTP ${response.status}`)
  }
  return response.json()
}

export async function deleteStudent(studentId: string): Promise<void> {
  await apiFetch(`/api/v1/students/${studentId}`, { method: 'DELETE' })
}

// Criteria & Gutachten
export async function updateCriteria(studentId: string, criteria: CriteriaScores): Promise<StudentWork> {
  return apiFetch<StudentWork>(`/api/v1/students/${studentId}/criteria`, { method: 'PUT', body: JSON.stringify({ criteria_scores: criteria }) })
}

export async function updateGutachten(studentId: string, gutachten: string): Promise<StudentWork> {
  return apiFetch<StudentWork>(`/api/v1/students/${studentId}/gutachten`, { method: 'PUT', body: JSON.stringify({ gutachten }) })
}

export async function generateGutachten(studentId: string): Promise<{ gutachten: string }> {
  return apiFetch<{ gutachten: string }>(`/api/v1/students/${studentId}/gutachten/generate`, { method: 'POST' })
}

// Annotations
export async function getAnnotations(studentId: string): Promise<Annotation[]> {
  const data = await apiFetch<{ annotations: Annotation[] }>(`/api/v1/students/${studentId}/annotations`)
  return data.annotations || []
}

export async function createAnnotation(studentId: string, annotation: { page: number; position: AnnotationPosition; type: AnnotationType; text: string; severity?: 'minor' | 'major' | 'critical'; suggestion?: string; linked_criterion?: string }): Promise<Annotation> {
  return apiFetch<Annotation>(`/api/v1/students/${studentId}/annotations`, { method: 'POST', body: JSON.stringify(annotation) })
}

export async function updateAnnotation(annotationId: string, updates: Partial<{ text: string; severity: 'minor' | 'major' | 'critical'; suggestion: string }>): Promise<Annotation> {
  return apiFetch<Annotation>(`/api/v1/annotations/${annotationId}`, { method: 'PUT', body: JSON.stringify(updates) })
}

export async function deleteAnnotation(annotationId: string): Promise<void> {
  await apiFetch(`/api/v1/annotations/${annotationId}`, { method: 'DELETE' })
}

// EH/RAG
export async function getEHSuggestions(studentId: string, criterion?: string): Promise<EHSuggestion[]> {
  const data = await apiFetch<{ suggestions: EHSuggestion[] }>(`/api/v1/students/${studentId}/eh-suggestions`, { method: 'POST', body: JSON.stringify({ criterion }) })
  return data.suggestions || []
}

export async function queryRAG(query: string, topK: number = 5): Promise<{ results: Array<{ text: string; score: number; metadata: any }> }> {
  return apiFetch('/api/v1/eh/rag-query', { method: 'POST', body: JSON.stringify({ query, top_k: topK }) })
}

export async function uploadEH(file: File): Promise<{ id: string; name: string }> {
  const formData = new FormData()
  formData.append('file', file)
  const response = await fetch(`${getApiBase()}/api/v1/eh/upload`, { method: 'POST', body: formData })
  if (!response.ok) {
    const errorData = await response.json().catch(() => ({ detail: 'EH Upload failed' }))
    throw new Error(errorData.detail || `HTTP ${response.status}`)
  }
  return response.json()
}

// Fairness & Export
export async function getFairnessAnalysis(klausurId: string): Promise<FairnessAnalysis> {
  return apiFetch<FairnessAnalysis>(`/api/v1/klausuren/${klausurId}/fairness`)
}

export async function getGradeInfo(): Promise<GradeInfo> {
  return apiFetch<GradeInfo>('/api/v1/grade-info')
}

export function getGutachtenExportUrl(studentId: string): string { return `${getApiBase()}/api/v1/students/${studentId}/export/gutachten` }
export function getAnnotationsExportUrl(studentId: string): string { return `${getApiBase()}/api/v1/students/${studentId}/export/annotations` }
export function getOverviewExportUrl(klausurId: string): string { return `${getApiBase()}/api/v1/klausuren/${klausurId}/export/overview` }
export function getAllGutachtenExportUrl(klausurId: string): string { return `${getApiBase()}/api/v1/klausuren/${klausurId}/export/all-gutachten` }
export function getStudentFileUrl(studentId: string): string { return `${getApiBase()}/api/v1/students/${studentId}/file` }