import { json, type RequestHandler } from '@sveltejs/kit';
import { StatusCodes } from 'http-status-codes';
import { getFbpFbcFromCookies } from '../metapixel/fbc.ts';
import type { CAPIConnector } from './connector.ts';
import { getRequestIP } from '../util/ip.ts';
import * as v from 'valibot';
import { CAPIEvent, MetaServerEventParamsSchema, type CAPICustomerInfoParams } from './event.ts';

export const capiRequestBodySchema = v.object({
	events: v.array(MetaServerEventParamsSchema)
});

/** Request body for conversion events */
export type CAPIRequestBody = v.InferOutput<typeof capiRequestBodySchema>;

export const capiErrorBodySchema = v.object({
	error: v.string()
});

/** Returned by the conversion request handler in case of an error */
export type CAPIErrorBody = v.InferOutput<typeof capiErrorBodySchema>;

export const capiResponseBodySchema = v.object({
	pixelID: v.string(),
	fbTraceID: v.string(),
	receivedEvents: v.number(),
	processedEvents: v.number(),
	messages: v.array(v.string())
});

/** Returned by the conversion request handler in case of a successful response */
export type CAPIResponseBody = v.InferOutput<typeof capiResponseBodySchema>;

/**
 * Creates a SvelteKit request handler for processing conversion events.
 *
 * @param connector - The CAPIConnector instance to send events through.
 * @returns A SvelteKit RequestHandler function.
 */
export const createCAPIHandler: (connector: CAPIConnector) => RequestHandler = (connector) => {
	const handle: RequestHandler = async ({ request, getClientAddress, cookies }) => {
		try {
			const json = await request.json();
			const parsed = v.parse(capiRequestBodySchema, json);

			// Build enriched user data with IP, user agent, and fbp/fbc from cookies
			const ip = getRequestIP(request, getClientAddress);
			const ua = request.headers.get('user-agent') ?? undefined;
			const { fbp, fbc } = getFbpFbcFromCookies(cookies);

			const enrichedUserData: Partial<CAPICustomerInfoParams> = {
				clientIP: ip,
				clientUserAgent: ua,
				fbp,
				fbc
			};

			// Enrich each event's user data
			const events: CAPIEvent[] = parsed.events.map((eventParams) => {
				const event = CAPIEvent.fromObject(eventParams);
				event.enrichUserData(enrichedUserData);
				return event;
			});

			// Send the event via the control
			const response = await connector.sendEvents(events);
			return json(response, { status: StatusCodes.OK });
		} catch (e) {
			const response: CAPIErrorBody = { error: e instanceof Error ? e.message : String(e) };
			return json(response, {
				status: StatusCodes.INTERNAL_SERVER_ERROR
			});
		}
	};
	return handle;
};