const { Router } = require('express');
const memory = require('../services/memory');
const { EPISODIC } = require('@nexusai/shared');

const router = Router();

router.get('/:sessionId/history', async (req, res) => {
  const { sessionId } = req.params;
  const { limit = EPISODIC.DEFAULT_PAGE_SIZE, offset = EPISODIC.DEFAULT_OFFSET } = req.query;

  try {
    const session = await memory.getSessionByExternalId(sessionId);
    if (!session) return res.status(404).json({ error: 'Session not found' });

    const history = await memory.getSessionHistory(session.id, Number(limit), Number(offset));
    res.json({ sessionId, episodes: history });
  } catch (err) {
    res.status(500).json({ error: 'Failed to fetch session history', detail: err.message });
  }
});

router.get('/', async (req, res) => {
  const { limit = EPISODIC.DEFAULT_PAGE_SIZE, offset = EPISODIC.DEFAULT_OFFSET, projectId } = req.query;
  const parsedProjectId = projectId && projectId !== 'null' ? projectId : null;
  try {
    const sessions = await memory.getSessions(Number(limit), Number(offset), parsedProjectId);
    res.json(sessions);
  } catch (err) {
    res.status(500).json({ error: 'Failed to fetch sessions', detail: err.message });
  }
});

router.patch('/:sessionId', async (req, res) => {
  const { name, projectId } = req.body;
  
  // Allow patch with just projectId, or just name, or both
  if (!name?.trim() && projectId === undefined) {
    return res.status(400).json({ error: 'name or projectId is required' });
  }

  try {
    const session = await memory.updateSession(req.params.sessionId, { 
      name: name?.trim() || undefined, 
      projectId 
    });
    res.json(session);
  } catch (err) {
    res.status(500).json({ error: 'Failed to update session', detail: err.message });
  }
});

router.delete('/:sessionId', async (req, res) => {
    try {
        await memory.deleteSession(req.params.sessionId);
        res.status(204).send();
    } catch (err) {
        res.status(500).json({ error: 'Failed to delete session', detail: err.message });
    }
});

module.exports = router;