import { Router } from "express";
import { z } from "zod";
import { answerWithContext, answerWithContextStream } from "../../chat/chatChain.js";
import { addMessage } from "../services/conversationsService.js";

export const chatRouter = Router();

const chatBodySchema = z.object({
  message: z.string().min(1),
  conversationId: z.coerce.number().int().positive().optional(),
  sessionId: z.string().min(1).optional(),
  model: z.string().min(1).optional(),
  options: z
    .object({
      temperature: z.number().min(0).max(2).optional(),
      top_p: z.number().min(0).max(1).optional()
    })
    .optional()
});

chatRouter.post("/", async (req, res, next) => {
  try {
    const body = chatBodySchema.parse(req.body);
    const result = await answerWithContext({
      message: body.message,
      conversationId: body.conversationId,
      options: body.options
    });

    const userId = req.user?.sub;
    if (userId && body.conversationId) {
      try {
        await Promise.all([
          addMessage(body.conversationId, { role: "user", content: body.message }),
          addMessage(body.conversationId, { role: "assistant", content: result.answer, sources: result.sources })
        ]);
      } catch (err) {
        console.error("[chat] falha ao salvar mensagem:", err);
      }
    }

    res.json(result);
  } catch (err) {
    next(err);
  }
});

chatRouter.post("/stream", async (req, res, next) => {
  let abortController;
  try {
    const body = chatBodySchema.parse(req.body);

    res.setHeader("Content-Type", "text/event-stream");
    res.setHeader("Cache-Control", "no-cache");
    res.setHeader("Connection", "keep-alive");
    res.setHeader("X-Accel-Buffering", "no");
    res.flushHeaders();

    abortController = new AbortController();
    res.on("close", () => abortController.abort());

    const result = await answerWithContextStream({
      message: body.message,
      conversationId: body.conversationId,
      options: body.options,
      signal: abortController.signal,
      onChunk: (delta) => {
        res.write(`data: ${JSON.stringify({ type: "delta", delta })}\n\n`);
      }
    });

    res.write(`data: ${JSON.stringify({ type: "sources", sources: result.sources })}\n\n`);
    res.write("data: [DONE]\n\n");
    res.end();

    const userId = req.user?.sub;
    if (userId && body.conversationId) {
      Promise.all([
        addMessage(body.conversationId, { role: "user", content: body.message }),
        addMessage(body.conversationId, { role: "assistant", content: result.answer, sources: result.sources })
      ]).catch((err) => console.error("[chat] falha ao salvar mensagem:", err));
    }
  } catch (err) {
    if (!res.headersSent) {
      next(err);
    } else if (err.name !== "AbortError") {
      res.write(`data: ${JSON.stringify({ type: "error", error: err.message })}\n\n`);
      res.end();
    }
  }
});