"""
PPTX to PDF converter using LibreOffice for high-quality conversion
This module provides the essential function to convert PowerPoint presentations to PDF
using LibreOffice headless mode for professional-grade quality.

The converted PDF is then processed by the main upload workflow for 4K image generation.
"""

import os
import subprocess
import logging

# Set up logging
logging.basicConfig(level=logging.INFO)
logger = logging.getLogger(__name__)


def pptx_to_pdf_libreoffice(pptx_path, output_dir):
    """
    Convert PPTX to PDF using LibreOffice for highest quality.
    
    This function is the core component of the PPTX processing workflow:
    PPTX → PDF (this function) → 4K JPG images (handled in uploads.py)
    
    Args:
        pptx_path (str): Path to the PPTX file
        output_dir (str): Directory to save the PDF
    
    Returns:
        str: Path to the generated PDF file, or None if conversion failed
    """
    try:
        # 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,
            pptx_path
        ]
        
        logger.info(f"Converting PPTX to PDF using LibreOffice: {pptx_path}")
        result = subprocess.run(cmd, capture_output=True, text=True, timeout=120)
        
        if result.returncode != 0:
            logger.error(f"LibreOffice conversion failed: {result.stderr}")
            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}")
            return pdf_path
        else:
            logger.error(f"PDF file not found after conversion: {pdf_path}")
            return None
            
    except subprocess.TimeoutExpired:
        logger.error("LibreOffice conversion timed out (120s)")
        return None
    except Exception as e:
        logger.error(f"Error in PPTX to PDF conversion: {e}")
        return None


if __name__ == "__main__":
    # Test the converter
    import sys
    if len(sys.argv) > 1:
        test_pptx = sys.argv[1]
        if os.path.exists(test_pptx):
            output_dir = "test_output"
            pdf_result = pptx_to_pdf_libreoffice(test_pptx, output_dir)
            if pdf_result:
                print(f"Successfully converted PPTX to PDF: {pdf_result}")
            else:
                print("PPTX to PDF conversion failed")
        else:
            print(f"File not found: {test_pptx}")
    else:
        print("Usage: python pptx_converter.py <pptx_file>")