src/routes/chat.ts

import express from "express";
import { generateContent, generateContentStream } from "../utils/geminiClient";

const router = express.Router();

/**
 * @openapi
 * /api/chat:
 *   post:
 *     summary: Fashion chat without wardrobe (using Gemini AI)
 *     tags: [Chat]
 *     requestBody:
 *       required: true
 *       content:
 *         application/json:
 *           schema:
 *             type: object
 *             required:
 *               - message
 *             properties:
 *               message:
 *                 type: string
 *                 description: User's fashion question
 *               session_id:
 *                 type: string
 *                 description: Session ID for conversation context (not used with Gemini, but kept for compatibility)
 *               images:
 *                 type: array
 *                 items:
 *                   type: string
 *                 description: Optional array of image URLs or base64 images
 *     responses:
 *       200:
 *         description: Chat response from Gemini AI
 *       400:
 *         description: Bad request
 *       500:
 *         description: Server error
 */
router.post("/", async (req, res) => {
  try {
    const { message, session_id, images } = req.body;

    if (!message) {
      return res.status(400).json({ success: false, error: "message is required" });
    }

    console.log(`[Chat] Sending request to Gemini AI`);

    const systemInstruction = "You are a helpful fashion and style assistant. Provide friendly, practical fashion advice and answer questions about clothing, style, trends, and outfit coordination.";

    const result = await generateContent(
      message,
      systemInstruction,
      images && Array.isArray(images) && images.length > 0 ? images : undefined
    );

    res.json({ 
      success: true, 
      response: result.text,
      session_id: session_id || "default"
    });
  } catch (error: any) {
    console.error("Chat error:", error.message);
    res.status(500).json({ success: false, error: error.message || "Chat failed" });
  }
});

/**
 * @openapi
 * /api/chat/stream:
 *   post:
 *     summary: Fashion chat with streaming response (using Gemini AI)
 *     tags: [Chat]
 *     requestBody:
 *       required: true
 *       content:
 *         application/json:
 *           schema:
 *             type: object
 *             required:
 *               - message
 *             properties:
 *               message:
 *                 type: string
 *                 description: User's fashion question
 *               session_id:
 *                 type: string
 *                 description: Session ID for conversation context (not used with Gemini, but kept for compatibility)
 *               images:
 *                 type: array
 *                 items:
 *                   type: string
 *                 description: Optional array of image URLs or base64 images
 *     responses:
 *       200:
 *         description: Server-Sent Events stream
 *         content:
 *           text/event-stream:
 *             schema:
 *               type: string
 *       400:
 *         description: Bad request
 *       500:
 *         description: Server error
 */
router.post("/stream", async (req, res) => {
  try {
    const { message, session_id, images } = req.body;

    if (!message) {
      return res.status(400).json({ success: false, error: "message is required" });
    }

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

    console.log(`[Chat Stream] Sending streaming request to Gemini AI`);

    const systemInstruction = "You are a helpful fashion and style assistant. Provide friendly, practical fashion advice and answer questions about clothing, style, trends, and outfit coordination.";

    try {
      const stream = generateContentStream(
        message,
        systemInstruction,
        images && Array.isArray(images) && images.length > 0 ? images : undefined
      );

      for await (const chunk of stream) {
        if (chunk.text) {
          res.write(`data: ${JSON.stringify({ type: "chunk", content: chunk.text })}\n\n`);
        }
        if (chunk.done) {
          break;
        }
      }

      res.write(`data: ${JSON.stringify({ type: "done" })}\n\n`);
      res.end();
    } catch (streamError: any) {
      console.error('[Chat Stream] Stream error:', streamError);
      res.write(`data: ${JSON.stringify({ type: "error", message: streamError.message || "Streaming failed" })}\n\n`);
      res.end();
    }

    req.on('close', () => {
      console.log('[Chat Stream] Client disconnected');
    });

  } catch (error: any) {
    console.error("Chat stream error:", error.message);
    res.write(`data: ${JSON.stringify({ type: "error", message: error.message || "Streaming failed" })}\n\n`);
    res.end();
  }
});

export default router;