import { csrfTokenFor } from "../../src/lib/csrf.ts";
import { buildApp } from "../../src/server/app.ts";

const app = buildApp();

interface FetchOptions {
	cookie?: string;
	body?: FormData | string;
	contentType?: string;
}

function didFromCookie(cookie: string): string | null {
	const match = cookie.match(/(?:^|;\s*)did=([^;]+)/);
	return match?.[1] ? decodeURIComponent(match[1]) : null;
}

/** Send a Request through the app without binding a port. */
export function fetch(
	method: string,
	path: string,
	opts: FetchOptions = {},
): Promise<Response> {
	const headers: Record<string, string> = {};
	if (opts.cookie) headers["cookie"] = opts.cookie;
	if (opts.contentType) headers["content-type"] = opts.contentType;
	const m = method.toUpperCase();
	const unsafe = m === "POST" || m === "PUT" || m === "PATCH" || m === "DELETE";
	const did = opts.cookie ? didFromCookie(opts.cookie) : null;
	if (unsafe && did) {
		const token = csrfTokenFor(did);
		headers["x-csrf-token"] = token;
		if (opts.body instanceof FormData && !opts.body.has("_csrf")) {
			opts.body.append("_csrf", token);
		}
	}
	const init: RequestInit = { method, headers };
	if (opts.body !== undefined) init.body = opts.body;
	return app.handle(new Request(`http://localhost${path}`, init));
}

const cookieCache = new Map<string, string>();

/**
 * Exercise /dev/login/:handle and return the `did=...` cookie. Cached per handle
 * since the result is deterministic.
 */
export async function loginCookie(handle: string): Promise<string> {
	const cached = cookieCache.get(handle);
	if (cached) return cached;
	const res = await fetch("GET", `/dev/login/${handle}`);
	if (res.status !== 302) {
		throw new Error(`/dev/login/${handle} returned ${res.status}`);
	}
	const cookies = res.headers.getSetCookie();
	const didCookie = cookies.find((c) => c.startsWith("did="));
	if (!didCookie) {
		throw new Error(
			`No did cookie in /dev/login response: ${cookies.join(",")}`,
		);
	}
	const value = didCookie.split(";")[0];
	if (!value) {
		throw new Error(`Malformed cookie: ${didCookie}`);
	}
	cookieCache.set(handle, value);
	return value;
}

export function form(fields: Record<string, string>): FormData {
	const fd = new FormData();
	for (const [key, value] of Object.entries(fields)) {
		fd.append(key, value);
	}
	return fd;
}