import { showError } from './toast';

const API_BASE = import.meta.env.DEV ? 'http://localhost:8080/api' : '/api';

// Helper function to handle API responses and show error toasts
async function handleResponse<T>(response: Response, errorMessage: string): Promise<T> {
	if (!response.ok) {
		let message = errorMessage;
		try {
			const errorData = await response.json();
			if (errorData.error) {
				message = errorData.error;
			}
		} catch (e) {
			// If we can't parse JSON, use the default message
		}
		showError(message);
		throw new Error(message);
	}
	return response.json();
}

export interface User {
  id: string;
  email: string;
  username: string;
}

export interface AuthResponse {
  token: string;
  user: User;
}

export interface Ebook {
  id: string;
  title: string;
  author: string | null;
  isbn: string | null;
  description: string | null;
  file_path: string;
  file_size: number | null;
  mime_type: string | null;
  cover_image_path: string | null;
  created_at: string;
  updated_at: string;
}

export interface ReadingProgress {
  ebook_id: string;
  user_id: string;
  current_page: number;
  total_pages: number | null;
  last_read_at: string;
}

// Get stored token
function getToken(): string | null {
  if (typeof window !== 'undefined') {
    return localStorage.getItem('auth_token');
  }
  return null;
}

// Create headers with auth
function createHeaders(): Record<string, string> {
  const headers: Record<string, string> = {
    'Content-Type': 'application/json',
  };

  const token = getToken();
  if (token) {
    headers['Authorization'] = `Bearer ${token}`;
  }

  return headers;
}

// Auth functions
export async function registerUser(email: string, username: string, password: string): Promise<AuthResponse> {
  const response = await fetch(`${API_BASE}/auth/register`, {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify({ email, username, password }),
  });
  return handleResponse<AuthResponse>(response, 'Registration failed');
}

export async function loginUser(login: string, password: string): Promise<AuthResponse> {
  const response = await fetch(`${API_BASE}/auth/login`, {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify({ login, password }),
  });
  return handleResponse<AuthResponse>(response, 'Login failed');
}

export async function getUserProfile(): Promise<User> {
  const response = await fetch(`${API_BASE}/auth/profile`, {
    headers: createHeaders(),
  });
  return handleResponse<User>(response, 'Failed to get profile');
}

export async function fetchEbooks(limit: number = 20, offset: number = 0): Promise<Ebook[]> {
  const response = await fetch(`${API_BASE}/ebooks?limit=${limit}&offset=${offset}`, {
    headers: createHeaders(),
  });
  return handleResponse<Ebook[]>(response, 'Failed to fetch ebooks');
}

export async function fetchEbook(id: string): Promise<Ebook> {
  const response = await fetch(`${API_BASE}/ebooks/${id}`, {
    headers: createHeaders(),
  });
  return handleResponse<Ebook>(response, 'Failed to fetch ebook');
}

export async function createEbook(data: Partial<Ebook>): Promise<Ebook> {
  const response = await fetch(`${API_BASE}/ebooks`, {
    method: 'POST',
    headers: createHeaders(),
    body: JSON.stringify(data),
  });
  return handleResponse<Ebook>(response, 'Failed to create ebook');
}

export async function updateEbook(id: string, data: Partial<Ebook>): Promise<Ebook> {
  const response = await fetch(`${API_BASE}/ebooks/${id}`, {
    method: 'PUT',
    headers: createHeaders(),
    body: JSON.stringify(data),
  });
  return handleResponse<Ebook>(response, 'Failed to update ebook');
}

export async function deleteEbook(id: string): Promise<void> {
  const response = await fetch(`${API_BASE}/ebooks/${id}`, {
    method: 'DELETE',
    headers: createHeaders(),
  });
  if (!response.ok) {
    let message = 'Failed to delete ebook';
    try {
      const errorData = await response.json();
      if (errorData.error) {
        message = errorData.error;
      }
    } catch (e) {
      // If we can't parse JSON, use the default message
    }
    showError(message);
    throw new Error(message);
  }
}

export async function fetchReadingProgress(ebookId: string): Promise<ReadingProgress> {
  const response = await fetch(`${API_BASE}/ebooks/${ebookId}/progress`, {
    headers: createHeaders(),
  });
  return handleResponse<ReadingProgress>(response, 'Failed to fetch reading progress');
}

export async function updateReadingProgress(ebookId: string, currentPage: number, totalPages?: number): Promise<ReadingProgress> {
  const response = await fetch(`${API_BASE}/ebooks/${ebookId}/progress`, {
    method: 'PUT',
    headers: createHeaders(),
    body: JSON.stringify({ current_page: currentPage, total_pages: totalPages }),
  });
  return handleResponse<ReadingProgress>(response, 'Failed to update reading progress');
}