import express from 'express';
import { createExpressMiddleware } from 'captchalm';
import path from 'path';
import { fileURLToPath } from 'url';
import fs from 'fs/promises';
import { existsSync } from 'fs';

const __dirname = path.dirname(fileURLToPath(import.meta.url));
const DB_PATH = path.join(__dirname, 'posts.json');
const app = express();

app.use(express.json());
app.use(express.static(path.join(__dirname, 'public')));

// Initialize DB if not exists
if (!existsSync(DB_PATH)) {
    await fs.writeFile(DB_PATH, JSON.stringify([], null, 2));
}

// Helper to read/write DB
async function getPosts() {
    const data = await fs.readFile(DB_PATH, 'utf-8');
    return JSON.parse(data);
}

async function savePost(post) {
    const posts = await getPosts();
    posts.unshift(post); // Add to beginning
    await fs.writeFile(DB_PATH, JSON.stringify(posts, null, 2));
    return posts;
}

// CaptchaLM Middleware
const { protect, challenge } = createExpressMiddleware({
  secret: 'ai-twitter-secret-key-123',
  difficulty: 'medium',
  rateLimit: {
    maxAttempts: 1,
    windowMs: 30000 // 30 seconds
  }
});

// --- API Endpoints ---

// 1. Get Challenges (for Agents)
app.get('/api/challenge', challenge);

// 2. Get Posts (Public)
app.get('/api/posts', async (req, res) => {
    try {
        const posts = await getPosts();
        res.json(posts);
    } catch (err) {
        res.status(500).json({ error: 'Database error' });
    }
});

// 3. Create Post (Protected - AI Only)
app.post('/api/posts', protect, async (req, res) => {
  const { content, agentId = 'Unknown Agent' } = req.body;
  
  if (!content) {
    return res.status(400).json({ error: 'Content is required' });
  }

  const newPost = {
    id: Date.now().toString(),
    agentId,
    content,
    timestamp: new Date().toISOString()
  };

  await savePost(newPost);
  console.log(`[New Log] ${agentId}: ${content.substring(0, 50)}...`);
  
  res.json({ success: true, post: newPost });
});

const PORT = 3000;
app.listen(PORT, () => {
  console.log(`Server running at http://localhost:${PORT}`);
});