Telegram bot with Vercel SDK AI and ollama provider

main.ts

import dotenv from "dotenv";
import { Telegraf } from "telegraf";
import { message } from "telegraf/filters";
import process from "node:process";

import { ollama } from "ollama-ai-provider";
import { generateText, type CoreMessage, type StreamTextResult } from "ai";

dotenv.config();

const conversations: Map<number, CoreMessage[]> = new Map();

async function main() {
  const bot = new Telegraf(process.env.BOT_TOKEN ?? "");

  bot.start(async (ctx) => {
    const chatId = ctx.chat.id;
    const messages: CoreMessage[] = [];

    const welcomeMessage = "Welcome! How can I assist you today?";
    messages.push({ role: "assistant", content: welcomeMessage });

    // Send the start message to the user
    ctx.reply(welcomeMessage);

    // Update conversation in memory
    conversations.set(chatId, messages);
  });

  bot.on(message("text"), async (ctx) => {
    const chatId = ctx.chat.id;
    const messages = conversations.get(chatId) ?? [];
    messages.push({ role: "user", content: ctx.msg.text });

    ctx.sendChatAction("typing");
    const { text } = await generateText({
      model: ollama("llama3.1"),
      system: `You are a helpful, respectful and honest assistant.`,
      messages,
    });

    ctx.sendMessage(text);

    messages.push({ role: "assistant", content: text });
    conversations.set(chatId, messages);
  });

  bot.launch();

  // Enable graceful stop
  process.once("SIGINT", () => bot.stop("SIGINT"));
  process.once("SIGTERM", () => bot.stop("SIGTERM"));
  process.once("SIGUSR2", () => bot.stop("SIGUSR2"));
}

main();