import OpenAI from "openai";

export default async function handler(req, res) {
  if (req.method === "POST") {
    /// parse the request object
    const body = JSON.parse(req.body);

    const { similaritySearchResults, messages, userQuery } = body;

    // Set response headers for SSE
    res.setHeader("Content-Type", "text/event-stream");
    res.setHeader("Cache-Control", "no-cache");
    res.setHeader("Connection", "keep-alive");
    res.setHeader("Content-Encoding", "none");

    // Fetch the response from the OpenAI API
    const openai = new OpenAI({
      apiKey: process.env.NEXT_PUBLIC_OPENAI_KEY,
    });
    const stream = await openai.chat.completions.create({
      model: "gpt-3.5-turbo-16k",
      temperature: 0,
      top_p: 1,
      messages: [
        {
          role: "system",
          content: `Use the following pieces of context to answer the users question.
                  If you don't know the answer, just say that you don't know, don't try to make up an answer.
                  ----------------
                  context:
                  ${similaritySearchResults}
    
                  Answer user query and include images write respect to each line if available`,
        },
        ...messages,
        {
          role: "user",
          content: `
                    Strictly write all the response in html format with only raw text and img tags.
                    Answer user query and include images in response if available in the given context
    
                    query: ${userQuery}`,
        },
      ],
      stream: true,
    });
    for await (const part of stream) {
      res.write(part.choices[0]?.delta?.content || "");
    }

    res.end();
  }
}

 const responseFromBackend: any = await fetch(
            `${process.env.NEXT_PUBLIC_WEBSITE_URL}api/chat`,
            {
              method: "POST",
              body: JSON.stringify({
                similaritySearchResults,
                messages,
                userQuery,
              }),
              headers: {
                "Content-Type": "text/event-stream",
              },
            }
          );
          let resptext = "";

          const reader = responseFromBackend.body
            .pipeThrough(new TextDecoderStream())
            .getReader();
          while (true) {
            const { value, done } = await reader.read();
            if (done) {
              /// setting the response when completed
              setMessages((prev: any) => [
                ...prev,
                { role: "assistant", content: resptext },
              ]);
              /// store the chathistory
              setResponse("");
              setLoading(false);
              break;
            }

            resptext += value;
            setResponse(resptext);
          }