const BASE = '/api';

export interface User {
	id: number;
	username: string;
	is_admin: boolean;
	created_at: string;
	updated_at: string;
}

export interface Image {
	id: number;
	filename: string;
	storage_path: string;
	thumbnail_path: string | null;
	uploaded_by: number;
	file_size: number;
	width: number;
	height: number;
	mime_type: string;
	created_at: string;
	updated_at: string;
	tags: string[];
}

export interface ImageList {
	images: Image[];
	total: number;
}

export interface Tag {
	tag: string;
	usage_count: number;
}

export interface ApiError {
	error: string;
}

async function request<T>(path: string, opts: RequestInit = {}): Promise<T> {
	const res = await fetch(BASE + path, {
		credentials: 'include',
		headers: opts.body instanceof FormData ? {} : { 'Content-Type': 'application/json' },
		...opts,
	});
	if (!res.ok) {
		const body = await res.json().catch(() => ({ error: res.statusText }));
		throw new Error((body as ApiError).error || `HTTP ${res.status}`);
	}
	return res.json();
}

export async function login(username: string, password: string): Promise<User> {
	return request<User>('/auth/login', {
		method: 'POST',
		body: JSON.stringify({ username, password }),
	});
}

export async function register(username: string, password: string): Promise<User> {
	return request<User>('/auth/register', {
		method: 'POST',
		body: JSON.stringify({ username, password }),
	});
}

export async function logout(): Promise<void> {
	await request('/auth/logout', { method: 'POST' });
}

export async function listImages(tags: string[] = [], page = 1, perPage = 50): Promise<ImageList> {
	const params = new URLSearchParams();
	params.set('page', String(page));
	params.set('per_page', String(perPage));
	for (const t of tags) {
		params.append('tags', t);
	}
	return request<ImageList>(`/images?${params}`);
}

export async function getImage(id: number): Promise<Image> {
	return request<Image>(`/images/${id}`);
}

export function imageDownloadUrl(id: number): string {
	return `${BASE}/images/${id}/download`;
}

export function thumbnailUrl(id: number): string {
	return `${BASE}/images/${id}/thumbnail`;
}

export async function uploadImage(file: File, tags: string[]): Promise<Image> {
	const fd = new FormData();
	fd.append('file', file);
	for (const t of tags) {
		fd.append('tags', t);
	}
	return request<Image>('/upload', { method: 'POST', body: fd });
}

export async function suggestTags(query: string): Promise<Tag[]> {
	return request<Tag[]>(`/tags/suggest?q=${encodeURIComponent(query)}`);
}