import { json } from '@sveltejs/kit';
import { PROXY_URL } from '$app/env/public';
import type { RequestEvent } from '@sveltejs/kit';

const HONO_URL = PROXY_URL;

type Body = {
	action: 'send' | 'typing';
	famId?: string;
	content?: string;
	clientId?: string;
	typing?: boolean;
};

export async function POST(event: RequestEvent) {
	const body = (await event.request.json().catch(() => null)) as Body | null;
	if (!body || !body.action) return json({ error: 'missing action' }, 400);

	const session = event.locals.session;
	const deviceToken = event.cookies.get('device_token') || '';

	const headers: Record<string, string> = { 'Content-Type': 'application/json' };
	let famId = body.famId || '';

	if (session?.famId && session?.userId) {
		// Admin (parent) — trust the verified session server-side.
		headers['x-session-famid'] = session.famId;
		headers['x-session-userid'] = session.userId;
		famId = session.famId;
	} else if (deviceToken) {
		// Member (child) — forward the device token; the proxy re-validates.
		headers['x-device-token'] = deviceToken;
		headers['x-device-famid'] = famId;
	} else {
		return json({ error: 'Unauthorized' }, 401);
	}

	if (!famId) return json({ error: 'famId required' }, 400);

	const path = body.action === 'typing' ? `/api/chat/${famId}/typing` : `/api/chat/${famId}/messages`;
	const payload =
		body.action === 'typing'
			? { typing: Boolean(body.typing) }
			: { content: body.content || '', clientId: body.clientId || '' };

	try {
		const res = await fetch(`${HONO_URL}${path}`, {
			method: 'POST',
			headers,
			body: JSON.stringify(payload),
		});
		const data = await res.json().catch(() => ({}));
		if (!res.ok) return json({ error: data.error || 'chat request failed' }, res.status);
		return json(data);
	} catch {
		return json({ error: 'chat request failed' }, 502);
	}
}