const db = require('./db');

function startQueueWorker(io) {
    console.log('Starting SMS Queue Worker...');
    
    setInterval(() => {
        // Check if there are any connected devices (we'll broadcast to the 'devices' room)
        // For simplicity, we just fetch one pending message and emit it.
        // If the app is connected, it will process it.
        
        db.get(`SELECT * FROM sms_queue WHERE status = 'pending' ORDER BY created_at ASC LIMIT 1`, (err, row) => {
            if (err) {
                console.error('Queue Worker Error:', err);
                return;
            }

            if (row) {
                console.log(`Processing SMS ID: ${row.id} for ${row.phone}`);
                
                // Mark as processing
                db.run(`UPDATE sms_queue SET status = 'processing', updated_at = CURRENT_TIMESTAMP WHERE id = ?`, [row.id], (updateErr) => {
                    if (updateErr) {
                        console.error('Error updating status to processing:', updateErr);
                        return;
                    }

                    // Emit to authenticated devices
                    io.to('devices').emit('send_sms', {
                        id: row.id,
                        phone: row.phone,
                        message: row.message
                    });
                    
                    // Note: If no device is connected, it stays in 'processing' state.
                    // A robust system would have a timeout to revert 'processing' back to 'pending'.
                    // We will add a simple timeout mechanism.
                    setTimeout(() => {
                        db.get(`SELECT status FROM sms_queue WHERE id = ?`, [row.id], (checkErr, checkRow) => {
                            if (checkRow && checkRow.status === 'processing') {
                                console.log(`SMS ID: ${row.id} timed out. Reverting to pending.`);
                                db.run(`UPDATE sms_queue SET status = 'pending' WHERE id = ?`, [row.id]);
                            }
                        });
                    }, 30000); // 30 seconds timeout
                });
            }
        });
    }, 5000); // Check every 5 seconds
}

module.exports = startQueueWorker;