src/routes/conversation/[id]/summarize/+server.ts

import { RATE_LIMIT } from "$env/static/private";
import { buildPrompt } from "$lib/buildPrompt";
import { authCondition } from "$lib/server/auth";
import { collections } from "$lib/server/database";
import { generateFromDefaultEndpoint } from "$lib/server/generateFromDefaultEndpoint";
import { defaultModel } from "$lib/server/models";
import { ERROR_MESSAGES } from "$lib/stores/errors.js";
import { error } from "@sveltejs/kit";
import { ObjectId } from "mongodb";

export async function POST({ params, locals, getClientAddress }) {
	const convId = new ObjectId(params.id);

	const conversation = await collections.conversations.findOne({
		_id: convId,
		...authCondition(locals),
	});

	if (!conversation) {
		throw error(404, "Conversation not found");
	}

	const userId = locals.user?._id ?? locals.sessionId;

	await collections.messageEvents.insertOne({
		userId: userId,
		createdAt: new Date(),
		ip: getClientAddress(),
	});

	const nEvents = Math.max(
		await collections.messageEvents.countDocuments({ userId }),
		await collections.messageEvents.countDocuments({ ip: getClientAddress() })
	);

	if (RATE_LIMIT != "" && nEvents > parseInt(RATE_LIMIT)) {
		throw error(429, ERROR_MESSAGES.rateLimited);
	}

	const firstMessage = conversation.messages.find((m) => m.from === "user");

	const userPrompt =
		`Please summarize the following message as a single sentence of less than 5 words:\n` +
		firstMessage?.content;

	const prompt = await buildPrompt({
		messages: [{ from: "user", content: userPrompt }],
		model: defaultModel,
	});
	const generated_text = await generateFromDefaultEndpoint(prompt);

	if (generated_text) {
		await collections.conversations.updateOne(
			{
				_id: convId,
				...authCondition(locals),
			},
			{
				$set: { title: generated_text },
			}
		);
	}

	return new Response(
		JSON.stringify(
			generated_text
				? {
						title: generated_text,
				  }
				: {}
		),
		{ headers: { "Content-Type": "application/json" } }
	);
}