const express = require('express');
const router = express.Router();
const fs = require('fs');
const path = require('path');
const appSettings = require('../config/settings');

const { getEnv, LLAMACPP, logger } = require('@nexusai/shared');
const LLAMA_URL = getEnv('LLAMA_SERVER_URL', LLAMACPP.DEFAULT_URL);

router.get('/', (req, res) => {
  const { modelsFolderPath } = appSettings.load();

  try {
    // Try scanning folder for .gguf files
    const files = fs.readdirSync(modelsFolderPath)
      .filter(f => f.endsWith('.gguf'));

    // Try loading models.json for richer metadata (label, description)
    let manifest = {};
    try {
      const manifestPath = path.join(modelsFolderPath, 'models.json');
      const raw = fs.readFileSync(manifestPath, 'utf8');
      // Index manifest by filename for quick lookup
      const list = JSON.parse(raw);
      for (const m of list) {
        manifest[m.value] = m;
      }
    } catch {
      // No manifest — scan only, that's fine
    }

    const models = files.map(filename => ({
      value:       filename,
      label:       manifest[filename]?.label ?? filename.replace('.gguf', ''),
      description: manifest[filename]?.description ?? null,
      size:        getFileSizeMB(path.join(modelsFolderPath, filename)),
    }));

    res.json(models);
  } catch (err) {
    logger.error('[models] Failed to scan folder:', err.message);
    res.status(500).json({ error: `Could not read models folder: ${modelsFolderPath}` });
  }
});

router.get('/props', async (req, res) => {
  try {
    const response = await fetch(`${LLAMA_URL}/props`);
    if (!response.ok) throw new Error(`llama-server error: ${response.status}`);
    const data = await response.json();
    res.json({
      contextWindow: data.default_generation_settings?.n_ctx ?? null,
      modelAlias: data.model_alias,
    });
  } catch (err) {
    logger.error('[models/props]', err.message);
    res.status(503).json({ error: 'Could not reach llama-server' });
  }
});

function getFileSizeMB(filepath) {
  try {
    const bytes = fs.statSync(filepath).size;
    return (bytes / (1024 ** 3)).toFixed(1) + ' GB'; // models are big — show GB
  } catch {
    return null;
  }
}

module.exports = router;