src/lib/server/preprocessMessages.ts

import type { Conversation } from "$lib/types/Conversation";
import type { Message } from "$lib/types/Message";
import { format } from "date-fns";
import { downloadFile } from "./files/downloadFile";

export async function preprocessMessages(
	messages: Message[],
	multimodal: boolean,
	id: Conversation["_id"]
): Promise<Message[]> {
	return await Promise.all(
		messages.map(async (message, idx) => {
			// start by adding websearch to the last message
			if (idx === messages.length - 1 && message.webSearch && message.webSearch.context) {
				const lastUsrMsgIndex = messages.map((el) => el.from).lastIndexOf("user");
				const previousUserMessages = messages.filter((el) => el.from === "user").slice(0, -1);
				const previousQuestions =
					previousUserMessages.length > 0
						? `Previous questions: \n${previousUserMessages
								.map(({ content }) => `- ${content}`)
								.join("\n")}`
						: "";
				const currentDate = format(new Date(), "MMMM d, yyyy");

				message.content = `I searched the web using the query: ${message.webSearch.searchQuery}. Today is ${currentDate} and here are the results:
=====================
${message.webSearch.context}
=====================
${previousQuestions}
Answer the question: ${messages[lastUsrMsgIndex].content}`;
			}
			// handle files if model is multimodal
			if (multimodal) {
				if (message.files && message.files.length > 0) {
					const markdowns = await Promise.all(
						message.files.map(async (hash) => {
							try {
								const { content: image, mime } = await downloadFile(hash, id);
								const b64 = image.toString("base64");
								return `![](data:${mime};base64,${b64})})`;
							} catch (e) {
								console.error(e);
							}
						})
					);
					message.content += markdowns.join("\n ");
				} else {
					// if no image, append an empty white image
					message.content +=
						"\n![](data:image/png;base64,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)";
				}
			}

			return message;
		})
	);
}