"""PowerPoint to PDF converter using LibreOffice."""
import os
import subprocess
import time
import logging
from typing import Optional

logger = logging.getLogger(__name__)


def cleanup_libreoffice_processes() -> None:
    """Clean up any hanging LibreOffice processes."""
    try:
        subprocess.run(['pkill', '-f', 'soffice'], capture_output=True, timeout=10)
        time.sleep(1)  # Give processes time to terminate
    except Exception as e:
        logger.warning(f"Failed to cleanup LibreOffice processes: {e}")


def pptx_to_pdf_libreoffice(pptx_path: str, output_dir: str) -> Optional[str]:
    """Convert PPTX to PDF using LibreOffice for highest quality.
    
    This function is the core component of the PPTX processing workflow:
    PPTX → PDF (this function) → JPG images (handled in uploads.py)
    
    Args:
        pptx_path: Path to the PPTX file
        output_dir: Directory to save the PDF
    
    Returns:
        Path to the generated PDF file, or None if conversion failed
    """
    try:
        # Clean up any existing LibreOffice processes
        cleanup_libreoffice_processes()
        
        # Ensure output directory exists
        os.makedirs(output_dir, exist_ok=True)
        
        # Use LibreOffice to convert PPTX to PDF
        cmd = [
            'libreoffice',
            '--headless',
            '--convert-to', 'pdf',
            '--outdir', output_dir,
            '--invisible',
            '--nodefault',
            pptx_path
        ]
        
        logger.info(f"Converting PPTX to PDF using LibreOffice: {pptx_path}")
        
        # Increase timeout to 300 seconds (5 minutes) for large presentations
        result = subprocess.run(cmd, capture_output=True, text=True, timeout=300)
        
        if result.returncode != 0:
            logger.error(f"LibreOffice conversion failed: {result.stderr}")
            logger.error(f"LibreOffice stdout: {result.stdout}")
            cleanup_libreoffice_processes()
            return None
        
        # Find the generated PDF file
        base_name = os.path.splitext(os.path.basename(pptx_path))[0]
        pdf_path = os.path.join(output_dir, f"{base_name}.pdf")
        
        if os.path.exists(pdf_path):
            logger.info(f"PDF conversion successful: {pdf_path}")
            cleanup_libreoffice_processes()
            return pdf_path
        else:
            logger.error(f"PDF file not found after conversion: {pdf_path}")
            cleanup_libreoffice_processes()
            return None
            
    except subprocess.TimeoutExpired:
        logger.error("LibreOffice conversion timed out (300s)")
        cleanup_libreoffice_processes()
        return None
        
    except Exception as e:
        logger.error(f"Error in PPTX to PDF conversion: {e}")
        cleanup_libreoffice_processes()
        return None


def validate_pptx_file(filepath: str) -> bool:
    """Validate if file is a valid PowerPoint file.
    
    Args:
        filepath: Path to file to validate
        
    Returns:
        True if valid PPTX file, False otherwise
    """
    if not os.path.exists(filepath):
        return False
    
    # Check file extension
    if not filepath.lower().endswith(('.ppt', '.pptx')):
        return False
    
    # Check file size (must be > 0)
    if os.path.getsize(filepath) == 0:
        return False
    
    return True