Perplexica/src/routes/suggestions.ts

import express from "express";
import generateSuggestions from "../agents/suggestionGeneratorAgent";
import { BaseChatModel } from "@langchain/core/language_models/chat_models";
import { getAvailableChatModelProviders } from "../lib/providers";
import { HumanMessage, AIMessage } from "@langchain/core/messages";
import logger from "../utils/logger";

const router = express.Router();

router.post("/", async (req, res) => {
  try {
    const { chat_history: raw_chat_history, chat_model, chat_model_provider } = req.body;

    // eslint-disable-next-line @typescript-eslint/no-explicit-any
    const chat_history = raw_chat_history.map((msg: any) => {
      if (msg.role === "user") {
        return new HumanMessage(msg.content);
      } else if (msg.role === "assistant") {
        return new AIMessage(msg.content);
      }
    });

    const chatModels = await getAvailableChatModelProviders();
    const provider = chat_model_provider ?? Object.keys(chatModels)[0];
    const chatModel = chat_model ?? Object.keys(chatModels[provider])[0];

    let llm: BaseChatModel | undefined;

    if (chatModels[provider] && chatModels[provider][chatModel]) {
      llm = chatModels[provider][chatModel] as BaseChatModel | undefined;
    }

    if (!llm) {
      res.status(500).json({ message: "Invalid LLM model selected" });
      return;
    }

    const suggestions = await generateSuggestions({ chat_history }, llm);

    res.status(200).json({ suggestions: suggestions });
  } catch (err) {
    res.status(500).json({ message: "An error has occurred." });
    logger.error(`Error in generating suggestions: ${err.message}`);
  }
});

export default router;