import { log, timedExecution } from '$lib';
import { validate, v7 as uuidv7 } from 'uuid';

const requestIdHeader = 'x-request-id';

/** @type {import('@sveltejs/kit').Handle} */
export async function handle({ event, resolve }) {
	// use incomming requestId, if it is a valid uuid, else generate one
	const reqIdFromRequest = event.request.headers.get(requestIdHeader);
	const { requestId, fromRequest } =
		reqIdFromRequest && validate(reqIdFromRequest)
			? { requestId: reqIdFromRequest, fromRequest: true }
			: { requestId: uuidv7(), fromRequest: false };

	var context = {
		requestId,
		route: event.route.id,
		method: event.request.method,
		userAgent: event.request.headers.get('user-agent'),
		clientIP: event.getClientAddress(),
	};
	if (fromRequest) {
		log.trace(context, 'using incomming request-id');
	}

	// make requestId available to handlers
	event.locals.requestId = requestId;

	const { executionTime, result: response } = await timedExecution(async () => {
		return await resolve(event);
	});
	response.headers.set(requestIdHeader, requestId);

	log.info(
		{
			executionTime: `${executionTime}ms`,
			status: response.status,
			size: response.headers.get('content-length'),
			...context,
		},
		'finished request'
	);

	return response;
}