import type { Post, SiteConfig, Asset, ContactSubmission, Message } from './types';

async function apiFetch<T>(path: string, options: RequestInit = {}): Promise<T> {
  const headers: Record<string, string> = {
    ...(options.headers as Record<string, string> || {}),
  };

  if (!(options.body instanceof FormData)) {
    headers['Content-Type'] = headers['Content-Type'] || 'application/json';
  }

  const res = await fetch(`/api${path}`, {
    ...options,
    headers,
    credentials: 'same-origin',
  });

  if (!res.ok) {
    const body = await res.json().catch(() => ({}));
    throw new ApiError(res.status, body.error || res.statusText);
  }

  const text = await res.text();
  return text ? JSON.parse(text) : (undefined as T);
}

export class ApiError extends Error {
  constructor(public status: number, message: string) {
    super(message);
    this.name = 'ApiError';
  }
}

// Auth
export const login = (token: string) =>
  apiFetch<void>('/auth/login', { method: 'POST', body: JSON.stringify({ token }) });
export const logout = () => apiFetch<void>('/auth/logout', { method: 'POST' });
export const checkSession = () => apiFetch<void>('/auth/me');

// Posts
export const getPosts = () => apiFetch<Post[]>('/posts');
export const getPost = (slug: string) => apiFetch<Post>(`/posts/${encodeURIComponent(slug)}`);
export const savePost = (data: {
  slug: string;
  old_slug?: string | null;
  title?: string | null;
  date?: string;
  summary?: string | null;
  tags?: string[];
  draft?: boolean;
  content: string;
}) => apiFetch<Post>('/posts', { method: 'POST', body: JSON.stringify(data) });
export const deletePost = (slug: string) =>
  apiFetch<void>(`/posts/${encodeURIComponent(slug)}`, { method: 'DELETE' });

// Config
export const getConfig = () => apiFetch<SiteConfig>('/config');
export const updateConfig = (data: Partial<SiteConfig>) =>
  apiFetch<SiteConfig>('/config', { method: 'POST', body: JSON.stringify(data) });

// Assets
export const getAssets = () => apiFetch<Asset[]>('/uploads');
export const uploadAsset = (file: File) => {
  const form = new FormData();
  form.append('file', file);
  return apiFetch<Asset>('/upload', { method: 'POST', body: form });
};
export const deleteAsset = (name: string) =>
  apiFetch<void>(`/uploads/${encodeURIComponent(name)}`, { method: 'DELETE' });

// Contact
export const submitContact = (data: ContactSubmission) =>
  apiFetch<{ ok: boolean }>('/contact', { method: 'POST', body: JSON.stringify(data) });
export const listMessages = () => apiFetch<Message[]>('/messages');
export const deleteMessage = (id: string) =>
  apiFetch<{ ok: boolean }>(`/messages/${encodeURIComponent(id)}`, { method: 'DELETE' });