require ('dotenv').config();
const express = require('express');
const {getEnv} = require('@nexusai/shared');
const { getDB } = require('./db');
const episodic = require('./episodic');
const semantic = require('./semantic');
const entities = require('./entities');

const app = express();
app.use(express.json());

const  PORT = getEnv('PORT', '3002');  // Default to 3002 if PORT is not set

//initialize database on startup
const db = getDB();

semantic.initCollections()
    .then(() => console.log(`QDrant collections ready`))
    .catch(err => console.error(`QDrant initialization error:`, err.message));

// Health check endpoint
app.get('/health', (req, res) => {
    res.json({ service: 'Memory Service', status: 'healthy' });
});

/************************************ */
/********** Session Routes ********** */
/************************************ */

// Creates a new session with an external ID and optional metadata
app.post('/sessions', (req, res) => {
    const {externalId, metadata} = req.body;
    if (!externalId) {
        return res.status(400).json({ error: 'externalId is required' });
    }
    try {
        const session = episodic.createSession(externalId, metadata);
        res.status(201).json(session);
    } catch (err) {
        res.status(409).json({ error: 'Session already exists', detail: err.message });
    }
});

// Retrieves a session by its internal ID
app.get('/sessions/:id', (req, res) => {
  const session = episodic.getSession(req.params.id);
  if (!session) return res.status(404).json({ error: 'Session not found' });
  res.json(session);
});

// Retrieves a session by its external ID
app.get('/sessions/by-external/:externalId', (req, res) => {
  const session = episodic.getSessionByExternalId(req.params.externalId);
  if (!session) return res.status(404).json({ error: 'Session not found' });
  res.json(session);
});


// Updates the session's updated_at timestamp to now
app.delete('/sessions/:id', (req, res) => {
  episodic.deleteSession(req.params.id);
  res.status(204).send();
});


/************************************* */
/********** Episodic Routes ********** */
/************************************* */

app.post('/episodes', async (req, res) => {
  const { sessionId, userMessage, aiResponse, tokenCount, metadata } = req.body;
  if (!sessionId || !userMessage || !aiResponse) {
    return res.status(400).json({ error: 'sessionId, userMessage and aiResponse are required' });
  }
  const episode = await episodic.createEpisode(sessionId, userMessage, aiResponse, tokenCount, metadata);
  res.status(201).json(episode);
});

// Search MUST come before /:id — otherwise 'search' gets captured as an id
app.get('/episodes/search', (req, res) => {
  const { q, limit = 10 } = req.query;
  if (!q) return res.status(400).json({ error: 'q (query) parameter is required' });
  const results = episodic.searchEpisodes(q, Number(limit));
  res.json(results);
});

app.get('/episodes/:id', (req, res) => {
  const episode = episodic.getEpisode(req.params.id);
  if (!episode) return res.status(404).json({ error: 'Episode not found' });
  res.json(episode);
});

app.delete('/episodes/:id', (req, res) => {
  episodic.deleteEpisode(req.params.id);
  res.status(204).send();
});

/*********************************** */
/********** Entity Routes ********** */
/*********************************** */
//Upsert an entity, creates or updates if already exists
app.post('/entities', (req, res) => {
  const {name, type, notes, metadata} = req.body;
  if (!name || !type) {
    return res.status(400).json({ error: 'name and type are required' });
  }
  const entity = entities.upsertEntity(name, type, notes, metadata);
  res.status(201).json(entity);
});

// Get an entity by ID
app.get('/entities/:id', (req, res) => {
  const entity = entities.getEntity(req.params.id);
  if (!entity) return res.status(404).json({ error: 'Entity not found' });
  res.json(entity);
});

// Get all entities of a given type
app.get('/entities/by-type/:type', (req, res) => {
  res.json(entities.getEntitiesByType(req.params.type));
});

// Delete an entity by ID
app.delete('/entities/:id', (req, res) => {
  entities.deleteEntity(req.params.id);
  res.status(204).send();
});

/***************************************** */
/********** Relationship Routes ********** */
/***************************************** */

// Upsert a relationship between two entities
app.post('/relationships', (req, res) => {
  const {fromId, toId, label, metadata } = req.body;
  if (!fromId || !toId || !label) {
    return res.status(400).json({ error: 'fromId, toId and label are required' });
  }
  const relationship = entities.upsertRelationship(fromId, toId, label, metadata);
  res.status(201).json(relationship);
});

// Get all relationships for a given entity ID
app.get('/entities/:id/relationships', (req, res) => {
  res.json(entities.getRelationshipsByEntity(req.params.id));
});

// Delete a specific relationship
app.delete('/relationships', (req, res) => {
  const {fromId, toId, label} = req.body;
  if (!fromId || !toId || !label) {
    return res.status(400).json({ error: 'fromId, toId and label are required' });
  }
  entities.deleteRelationship(fromId, toId, label);
  res.status(204).send();
})



/********************************** */
/********** Start Server ********** */
/********************************** */
app.listen(PORT, () => {
    console.log(`Memory Service is running on port ${PORT}`);
});