const express = require('express');
const { spawn } = require('child_process');
const cors = require('cors');
const path = require('path');
const fs = require('fs');

const VERSION = "1.2.0"; // Added for debugging and tracking

const app = express();
const port = 3005;

// --- DATABASE INITIALIZATION ---
// Initialize the SQLite database on startup to ensure the 'gtm_projects' table exists.
const dbScript = path.join(__dirname, 'gtm_db_manager.py');
console.log(`[Init] Initializing database via ${dbScript}...`);
const initProcess = spawn('python3', [dbScript, 'init']);

initProcess.stdout.on('data', (data) => console.log(`[DB Init] ${data.toString().trim()}`));
initProcess.stderr.on('data', (data) => console.error(`[DB Init Error] ${data.toString().trim()}`));
initProcess.on('close', (code) => {
    if (code === 0) {
        console.log('[DB Init] Database initialization completed successfully.');
    } else {
        console.error(`[DB Init] Database initialization failed with code ${code}.`);
    }
});
// -------------------------------

// Enable CORS for all routes
app.use(cors());

// Serve static files from the 'dist' directory
const staticPath = path.join(__dirname, 'dist');
if (fs.existsSync(staticPath)) {
  app.use(express.static(staticPath));
} else {
  console.warn(`Static path not found: ${staticPath}. The frontend might not be served correctly. Make sure to build the frontend first.`);
}


app.use(express.json({ limit: '50mb' }));

// API endpoint to run the Python script
app.post('/api/run', (req, res) => {
  const { mode, ...payload } = req.body;

  if (!mode) {
    return res.status(400).json({ error: 'Mode is required' });
  }

  // E2BIG FIX: Write payload to a temporary file instead of passing via command line args
  const tmpDir = path.join(__dirname, 'tmp');
  if (!fs.existsSync(tmpDir)) {
      fs.mkdirSync(tmpDir);
  }
  const payloadFilePath = path.join(tmpDir, `payload_${Date.now()}_${Math.random().toString(36).substring(7)}.json`);
  
  try {
      fs.writeFileSync(payloadFilePath, JSON.stringify(payload));
  } catch (err) {
      console.error("Failed to write payload file:", err);
      return res.status(500).json({ error: "Failed to process request payload." });
  }

  const pythonScriptPath = path.join(__dirname, 'gtm_architect_orchestrator.py');
  const pythonProcess = spawn('python3', [
    pythonScriptPath,
    '--mode', mode,
    '--payload_file', payloadFilePath // Use file path instead of base64 string
  ]);

  let stdoutData = '';
  let stderrData = '';

  // STREAMING LOGS: Output Python logs immediately to Docker console
  pythonProcess.stdout.on('data', (data) => {
    const str = data.toString();
    console.log(`[Python stdout] ${str.trim()}`);
    stdoutData += str;
  });

  pythonProcess.stderr.on('data', (data) => {
    const str = data.toString();
    console.error(`[Python stderr] ${str.trim()}`);
    stderrData += str;
  });

  pythonProcess.on('close', (code) => {
    // Cleanup temp file
    try {
        if (fs.existsSync(payloadFilePath)) fs.unlinkSync(payloadFilePath);
    } catch (e) {
        console.error("Failed to delete temp payload file:", e);
    }

    if (code !== 0) {
      console.error(`Python script exited with code ${code}`);
      console.error('Stderr:', stderrData);
      return res.status(500).json({
        error: 'Python script execution failed.',
        stderr: stderrData,
      });
    }

    try {
      // The Python script is expected to print JSON to stdout
      const result = JSON.parse(stdoutData);
      res.json(result);
    } catch (e) {
      console.error('Failed to parse JSON from Python script stdout:', e);
      console.error('Stdout:', stdoutData);
      res.status(500).json({
        error: 'Failed to parse response from Python script.',
        stdout: stdoutData,
      });
    }
  });
});

// Serve the main index.html for any other GET request to support client-side routing
if (fs.existsSync(staticPath)) {
    app.get('*', (req, res) => {
        res.sendFile(path.join(staticPath, 'index.html'));
      });
}


const server = app.listen(port, () => {
  console.log(`Server listening on port ${port} (Version: ${VERSION})`);
});
server.setTimeout(600000); // 10 minutes
server.keepAliveTimeout = 610000;
server.headersTimeout = 620000;