const BASE = '/admin-api/learning';

export interface PaginatedResponse<T> {
  items: T[];
  total: number;
}

interface AnomalyData {
  deltaOutliers: unknown[];
  futureEvents: unknown[];
}

async function getApi<T>(path: string, params?: Record<string, any>): Promise<T> {
  let url = `${BASE}${path}`;
  if (params) {
    const qs = Object.entries(params)
      .filter(([, v]) => v !== undefined && v !== '')
      .map(([k, v]) => `${k}=${encodeURIComponent(v)}`)
      .join('&');
    if (qs) url += `?${qs}`;
  }
  const res = await fetch(url, { headers: { 'Content-Type': 'application/json', Authorization: `Bearer ${localStorage.getItem('admin_access_token') || ''}` } });
  if (!res.ok) throw new Error(`HTTP ${res.status}`);
  const json = await res.json();
  return json.data ?? json;
}

async function postApi<T>(path: string, body?: any): Promise<T> {
  const res = await fetch(`${BASE}${path}`, {
    method: 'POST',
    headers: { 'Content-Type': 'application/json', Authorization: `Bearer ${localStorage.getItem('admin_access_token') || ''}` },
    body: body ? JSON.stringify(body) : undefined,
  });
  if (!res.ok) throw new Error(`HTTP ${res.status}`);
  const json = await res.json();
  return json.data ?? json;
}

export interface DashboardData {
  overview: { totalEvents: number; todayEvents: number; failedEvents: number; duplicateEvents: number; warningEvents: number; totalActiveSeconds: number };
  sessions: { active: number; interrupted: number; completed: number; total: number };
  users: { activeToday: number; totalWithEvents: number };
  materials: { totalRead: number; totalMarkedRead: number };
  recentAnomalies: Array<{ eventId: string; userId: string; materialId: string; eventType: string; errorCode?: string; occurredAt: string }>;
}

export const learningAdminAPI = {
  getDashboard: (params?: { knowledgeBaseId?: string; startDate?: string; endDate?: string }) =>
    getApi<DashboardData>('/dashboard', params),
  getKnowledgeBases: () => getApi<Array<{ id: string; name: string }>>('/knowledge-bases'),
  getReadingEvents: (params?: Record<string, any>) => getApi<PaginatedResponse<unknown>>('/reading-events', params),
  getReadingEventDetail: (id: string) => getApi<any>(`/reading-events/${id}`),
  getFailedEvents: (params?: Record<string, any>) => getApi<PaginatedResponse<unknown>>('/reading-events/failed', params),
  getSessions: (params?: Record<string, any>) => getApi<PaginatedResponse<unknown>>('/sessions', params),
  getSessionDetail: (id: string) => getApi<any>(`/sessions/${id}`),
  getProgress: (params?: Record<string, any>) => getApi<PaginatedResponse<unknown>>('/progress', params),
  getDailyActivities: (params?: Record<string, any>) => getApi<PaginatedResponse<unknown>>('/daily-activities', params),
  getRecords: (params?: Record<string, any>) => getApi<PaginatedResponse<unknown>>('/records', params),
  getUserTimeline: (userId: string) => getApi<unknown>('/user-timeline', { userId }),
  getUserDiagnose: (userId: string) => getApi<unknown>('/user-diagnose', { userId }),
  getMaterialDiagnose: (materialId: string) => getApi<unknown>('/material-diagnose', { materialId }),
  getAnomalies: () => getApi<AnomalyData>('/anomalies'),
  getTemporaryMaterials: (params?: Record<string, any>) => getApi<PaginatedResponse<unknown>>('/temporary-materials', params),
  recalculate: () => postApi<unknown>('/recalculate'),
  replayEvent: (eventId: string) => postApi<{ success: boolean; message: string }>(`/reading-events/${eventId}/replay`),
  replayEventsBatch: (params: { userId?: string; materialId?: string; startDate?: string; endDate?: string; eventType?: string }) =>
    postApi<{ replayed: number; failed: number }>('/reading-events/replay-batch', params),
  exportData: (type: string) => getApi<unknown>('/export', { type }),
};