const API_URL = import.meta.env.VITE_API_URL || '/api/v1';
const SESSION_KEY = 'compor_hub_session';

export type ApiRole = 'student' | 'instructor' | 'admin';

export interface ApiUser {
  id: string;
  email: string;
  name: string;
  role: ApiRole;
}

export interface ManagedUser {
  id: string;
  email: string;
  name: string;
  role: ApiRole;
  isActive: boolean;
  createdAt: string;
}
export interface ManagedUserDetail extends ManagedUser {
  completedLessons: number;
  lastLearningAt: string | null;
}
export interface PlatformAnalytics { totalUsers: number; activeUsers: number; publishedCourses: number; completedLessons: number; comments: number; }
export interface InstructorAnalytics { courses: number; lessons: number; learners: number; completedLessons: number; comments: number; }
export interface AuditEntry { id: string; action: string; subjectType: string; subjectId: string | null; metadata: Record<string, unknown>; createdAt: string; actorName: string; }
export interface BunnyVideo { id: string; title: string; status: 'processing' | 'ready' | 'failed'; providerStatus: number; encodeProgress: number; durationSeconds: number | null; }
export interface LessonPlayback { provider: string; kind: 'embed' | 'video'; embedUrl?: string; source?: string; expiresAt?: string; }

interface Session {
  token: string;
  user: ApiUser;
}

export class ApiError extends Error {
  constructor(message: string, public status: number) {
    super(message);
  }
}

export function getSession(): Session | null {
  const value = localStorage.getItem(SESSION_KEY);
  if (!value) return null;
  try {
    return JSON.parse(value) as Session;
  } catch {
    localStorage.removeItem(SESSION_KEY);
    return null;
  }
}

export function saveSession(session: Session) {
  localStorage.setItem(SESSION_KEY, JSON.stringify(session));
}

export function clearSession() {
  localStorage.removeItem(SESSION_KEY);
}

export async function apiRequest<T>(path: string, options: RequestInit = {}): Promise<T> {
  const session = getSession();
  const headers = new Headers(options.headers);
  if (options.body) headers.set('Content-Type', 'application/json');
  if (session) headers.set('Authorization', `Bearer ${session.token}`);

  const response = await fetch(`${API_URL}${path}`, { ...options, headers });
  if (response.status === 204) return undefined as T;

  const body = await response.json().catch(() => ({}));
  if (!response.ok) {
    throw new ApiError(body.error || 'The request could not be completed', response.status);
  }
  return body as T;
}

async function uploadRequest<T>(path: string, file: File): Promise<T> {
  const session = getSession();
  const headers = new Headers({ 'Content-Type': file.type || 'application/octet-stream' });
  if (session) headers.set('Authorization', `Bearer ${session.token}`);
  const response = await fetch(`${API_URL}${path}`, { method: 'PUT', headers, body: file });
  const body = await response.json().catch(() => ({}));
  if (!response.ok) throw new ApiError(body.error || 'The video upload could not be completed', response.status);
  return body as T;
}

export const authApi = {
  async login(email: string, password: string) {
    return apiRequest<Session>('/auth/login', { method: 'POST', body: JSON.stringify({ email, password }) });
  },
  async register(name: string, email: string, password: string) {
    return apiRequest<Session>('/auth/register', { method: 'POST', body: JSON.stringify({ name, email, password }) });
  },
  async me() {
    return apiRequest<{ user: ApiUser }>('/auth/me');
  },
  async acceptInvitation(token: string, name: string, password: string) {
    return apiRequest<Session>('/auth/accept-invitation', { method: 'POST', body: JSON.stringify({ token, name, password }) });
  },
  async resetPassword(token: string, password: string) {
    return apiRequest<void>('/auth/reset-password', { method: 'POST', body: JSON.stringify({ token, password }) });
  },
};

export const adminApi = {
  async dashboard() { return apiRequest<{ data: PlatformAnalytics }>('/admin/dashboard'); },
  async listUsers() {
    return apiRequest<{ data: ManagedUser[] }>('/admin/users');
  },
  async updateUser(userId: string, update: Partial<Pick<ManagedUser, 'role' | 'isActive'>>) {
    return apiRequest<{ data: ManagedUser }>(`/admin/users/${userId}`, {
      method: 'PATCH',
      body: JSON.stringify(update),
    });
  },
  async invite(email: string, role: 'student' | 'instructor') {
    return apiRequest<{ data: { inviteUrl: string } }>('/admin/invitations', { method: 'POST', body: JSON.stringify({ email, role }) });
  },
  async passwordReset(userId: string) {
    return apiRequest<{ data: { resetUrl: string } }>(`/admin/users/${userId}/password-reset`, { method: 'POST' });
  },
  async userDetail(userId: string) { return apiRequest<{ data: ManagedUserDetail }>(`/admin/users/${userId}`); },
  async auditLog() { return apiRequest<{ data: AuditEntry[] }>('/admin/audit-log'); },
  async categories() { return apiRequest<{ data: Array<{ id: string; name: string; position: number; isActive: boolean }> }>('/admin/categories'); },
  async createCategory(name: string) { return apiRequest<{ data: { id: string; name: string; position: number; isActive: boolean } }>('/admin/categories', { method: 'POST', body: JSON.stringify({ name }) }); },
  async updateCategory(categoryId: string, update: { name: string; isActive?: boolean; position?: number }) { return apiRequest<{ data: { id: string; name: string; position: number; isActive: boolean } }>(`/admin/categories/${categoryId}`, { method: 'PATCH', body: JSON.stringify(update) }); },
  async homeConfiguration() { return apiRequest<{ data: { featuredCourseId: string | null; courseOrder: string[]; defaultCoverImageUrl: string | null; courses: Array<{ id: string; title: string; status: string }> } }>('/admin/home-configuration'); },
  async updateHomeConfiguration(input: { featuredCourseId: string | null; courseOrder: string[]; defaultCoverImageUrl: string | null }) { return apiRequest<{ data: typeof input }>('/admin/home-configuration', { method: 'PUT', body: JSON.stringify(input) }); },
};

export const instructorApi = {
  async analytics() { return apiRequest<{ data: InstructorAnalytics }>('/manage/courses/analytics'); },
  async bunnyConfiguration() { return apiRequest<{ data: { configured: boolean; maxUploadBytes: number } }>('/manage/media/bunny/config'); },
  async createBunnyVideo(title: string) {
    return apiRequest<{ data: BunnyVideo }>('/manage/media/bunny/videos', { method: 'POST', body: JSON.stringify({ title }) });
  },
  async uploadBunnyVideo(videoId: string, file: File) {
    return uploadRequest<{ data: BunnyVideo }>(`/manage/media/bunny/videos/${videoId}/upload`, file);
  },
  async bunnyVideoStatus(videoId: string) {
    return apiRequest<{ data: BunnyVideo }>(`/manage/media/bunny/videos/${videoId}`);
  },
};

export const courseApi = {
  async categories() { return apiRequest<{ data: string[] }>('/courses/categories'); },
  async playback(courseId: string, lessonId: string) {
    return apiRequest<{ data: LessonPlayback }>(`/courses/${courseId}/lessons/${lessonId}/playback`);
  },
};