#!/usr/bin/env python3
"""
Sync Manager - Automatically backs up PostgreSQL to HuggingFace Xet Dataset
"""

import os
import sys
import time
import subprocess
import tempfile
import signal
from datetime import datetime
from pathlib import Path

# Configuration
SYNC_INTERVAL = int(os.environ.get('SYNC_INTERVAL', 300))  # 5 minutes
HF_TOKEN = os.environ.get('HF_TOKEN', '')
XET_DATASET = os.environ.get('XET_DATASET', 'your-username/postgres-backup')
POSTGRES_HOST = 'localhost'
POSTGRES_PORT = 5432
POSTGRES_USER = 'postgres'
POSTGRES_DB = 'appdb'
PGPASSWORD = os.environ.get('POSTGRES_PASSWORD', 'postgres123')

# Global flag for graceful shutdown
running = True


def log(message: str):
    """Print timestamped log message."""
    timestamp = datetime.now().strftime('%Y-%m-%d %H:%M:%S')
    print(f"[{timestamp}] {message}", flush=True)


def wait_for_postgres(max_retries: int = 30) -> bool:
    """Wait for PostgreSQL to be ready."""
    import psycopg2
    
    for i in range(max_retries):
        try:
            conn = psycopg2.connect(
                host=POSTGRES_HOST,
                port=POSTGRES_PORT,
                user=POSTGRES_USER,
                password=PGPASSWORD,
                database='postgres'
            )
            conn.close()
            log("✅ PostgreSQL is ready")
            return True
        except psycopg2.OperationalError:
            log(f"⏳ Waiting for PostgreSQL... ({i+1}/{max_retries})")
            time.sleep(2)
    
    log("❌ PostgreSQL did not become ready")
    return False


def create_backup() -> str | None:
    """Create a PostgreSQL backup using pg_dump."""
    try:
        backup_dir = Path('/data/backup')
        backup_dir.mkdir(parents=True, exist_ok=True)
        
        backup_file = backup_dir / 'pg_backup.sql'
        
        env = os.environ.copy()
        env['PGPASSWORD'] = PGPASSWORD
        
        # Create backup
        result = subprocess.run(
            [
                'pg_dump',
                '-h', POSTGRES_HOST,
                '-p', str(POSTGRES_PORT),
                '-U', POSTGRES_USER,
                '-d', POSTGRES_DB,
                '--clean',
                '--if-exists',
                '-f', str(backup_file)
            ],
            env=env,
            capture_output=True,
            text=True
        )
        
        if result.returncode == 0:
            size = backup_file.stat().st_size
            log(f"✅ Backup created: {backup_file} ({size} bytes)")
            return str(backup_file)
        else:
            log(f"❌ Backup failed: {result.stderr}")
            return None
            
    except Exception as e:
        log(f"❌ Backup error: {e}")
        return None


def upload_to_xet(backup_file: str) -> bool:
    """Upload backup to HuggingFace Xet dataset."""
    if not HF_TOKEN:
        log("⚠️  No HF_TOKEN set, skipping upload")
        return False
    
    try:
        from huggingface_hub import HfApi, create_repo
        
        api = HfApi(token=HF_TOKEN)
        
        # Create dataset repo if it doesn't exist
        try:
            create_repo(
                repo_id=XET_DATASET,
                repo_type="dataset",
                private=True,
                token=HF_TOKEN,
                exist_ok=True
            )
        except Exception as e:
            log(f"ℹ️  Repo creation note: {e}")
        
        # Upload backup file
        api.upload_file(
            path_or_fileobj=backup_file,
            path_in_repo="backup/pg_backup.sql",
            repo_id=XET_DATASET,
            repo_type="dataset",
            token=HF_TOKEN,
            commit_message=f"PostgreSQL backup - {datetime.now().isoformat()}"
        )
        
        log(f"✅ Backup uploaded to {XET_DATASET}")
        return True
        
    except Exception as e:
        log(f"❌ Upload failed: {e}")
        return False


def sync_once():
    """Perform one sync cycle."""
    log("🔄 Starting sync cycle...")
    
    backup_file = create_backup()
    if backup_file:
        upload_to_xet(backup_file)
    
    log("✅ Sync cycle complete")


def signal_handler(signum, frame):
    """Handle shutdown signals."""
    global running
    log("🛑 Shutdown signal received, performing final backup...")
    running = False
    sync_once()
    log("👋 Sync manager shutting down")
    sys.exit(0)


def main():
    """Main sync loop."""
    log("🚀 Sync Manager starting...")
    log(f"📦 Target dataset: {XET_DATASET}")
    log(f"⏰ Sync interval: {SYNC_INTERVAL} seconds")
    
    # Set up signal handlers
    signal.signal(signal.SIGTERM, signal_handler)
    signal.signal(signal.SIGINT, signal_handler)
    
    # Wait for PostgreSQL
    if not wait_for_postgres():
        log("❌ Cannot start without PostgreSQL")
        return
    
    # Initial delay
    time.sleep(30)
    
    # Main loop
    while running:
        try:
            sync_once()
        except Exception as e:
            log(f"❌ Sync error: {e}")
        
        # Sleep with interrupt handling
        for _ in range(SYNC_INTERVAL):
            if not running:
                break
            time.sleep(1)


if __name__ == '__main__':
    main()