import express from 'express';
import { readFile, writeFile } from 'fs/promises';
import { fileURLToPath } from 'url';
import { dirname, join } from 'path';

const router = express.Router();
const __dirname = dirname(fileURLToPath(import.meta.url));
const MODELS_PATH = join(__dirname, '../data/models.json');

async function loadModels() {
  const raw = await readFile(MODELS_PATH, 'utf-8');
  return JSON.parse(raw);
}

async function saveModels(models) {
  await writeFile(MODELS_PATH, JSON.stringify(models, null, 2));
}

router.get('/', async (req, res) => {
  try {
    const models = await loadModels();
    res.json(models);
  } catch (err) {
    res.status(500).json({ error: 'Failed to load models' });
  }
});

router.post('/', async (req, res) => {
  try {
    const { tag, displayName, owner, name, type, avatar, color, description, systemPromptParam, defaultInput } = req.body;
    if (!tag || !owner || !name || !displayName) {
      return res.status(400).json({ error: 'Missing required fields: tag, owner, name, displayName' });
    }
    const models = await loadModels();
    if (models.find(m => m.tag === tag)) {
      return res.status(409).json({ error: `Tag @${tag} already exists` });
    }
    const newModel = {
      id: `${owner}-${name}`.replace(/[^a-z0-9-]/gi, '-'),
      tag: tag.toLowerCase().replace(/[^a-z0-9]/g, ''),
      displayName,
      owner,
      name,
      type: type || 'text',
      avatar: avatar || '🤖',
      color: color || '#6B7280',
      description: description || '',
      systemPromptParam: systemPromptParam || null,
      defaultInput: defaultInput || {}
    };
    models.push(newModel);
    await saveModels(models);
    res.status(201).json(newModel);
  } catch (err) {
    res.status(500).json({ error: 'Failed to add model' });
  }
});

router.put('/:id', async (req, res) => {
  try {
    const models = await loadModels();
    const idx = models.findIndex(m => m.id === req.params.id);
    if (idx === -1) return res.status(404).json({ error: 'Model not found' });
    models[idx] = { ...models[idx], ...req.body, id: models[idx].id };
    await saveModels(models);
    res.json(models[idx]);
  } catch (err) {
    res.status(500).json({ error: 'Failed to update model' });
  }
});

router.delete('/:id', async (req, res) => {
  try {
    const models = await loadModels();
    const filtered = models.filter(m => m.id !== req.params.id);
    if (filtered.length === models.length) return res.status(404).json({ error: 'Model not found' });
    await saveModels(filtered);
    res.json({ success: true });
  } catch (err) {
    res.status(500).json({ error: 'Failed to delete model' });
  }
});

export { router as modelsRouter, loadModels };