require ('dotenv').config();
const express = require('express');
const {getEnv, OLLAMA, PORTS, logger} = require('@nexusai/shared');

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

const PORT          = getEnv('PORT',            PORTS.EMBEDDING);  
const OLLAMA_URL    = getEnv('OLLAMA_URL',      OLLAMA.DEFAULT_URL); 
const EMBED_MODEL   = getEnv('EMBEDDING_MODEL', OLLAMA.EMBED_MODEL); 

//OLLAMA embedding helper function
async function embedText(text) {
    const res = await fetch(`${OLLAMA_URL}/api/embed`, {
        method: 'POST',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify({ model: EMBED_MODEL, input: text })
    });

    if (!res.ok) {
        throw new Error(`Ollama error: ${res.status} ${res.statusText}`);
    }

    const data = await res.json();
    return data.embeddings[0];  
}


/**** ROUTES ***** */

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

// Single text embedding
app.post('/embed', async (req, res) => {
    const { text } = req.body;
    if (!text || typeof text !== 'string' || text.trim() === '') {
        return res.status(400).json({ error: 'text is required and must be empty' });
    }

    try {
        const embedding = await embedText(text.trim());
        res.json({ 
            embedding, 
            model: EMBED_MODEL, 
            dimensions: embedding.length 
        });
    } catch (err) {
        res.status(502).json({ error: 'Embedding failed', detail: err.message });
    }
});

// Batch embedding endpoint
app.post('/embed/batch', async (req, res) => {
    const { texts } = req.body;
    if (!Array.isArray(texts) || texts.length ===0 ) {
        return res.status(400).json({ error: 'texts array must not be empty' });
    }

    try {
        //sequential embedding for now, Ollama doesn't natively parallize embeddings
        const embeddings = [];
        for (const text of texts) {
            embeddings.push(await embedText(text.trim()));
        }
        res.json ({
            embeddings,
            model: EMBED_MODEL,
            dimensions: embeddings[0].length,
            count: embeddings.length
        })
    } catch (err) {
        res.status(502).json({ error: 'Batch embedding failed', detail: err.message });
    }
})

/******* Start Server ********/
app.listen(PORT, () => {
    logger.info(`Embedding Service listening on port ${PORT}`);
});