import fitz
from PIL import Image
import io
import os
from datetime import datetime, timezone, timedelta

def convert_pdf_to_image(pdf_path, page_number=0, dpi=150):
    """
    Convert a PDF page to PIL Image for preview
    """
    try:
        # Open PDF document
        pdf_document = fitz.open(pdf_path)
        
        # Get the specified page (default: first page)
        if page_number >= len(pdf_document):
            page_number = 0
            
        page = pdf_document.load_page(page_number)
        
        # Convert page to image
        # Increase DPI for better quality (default 72, we use 150)
        mat = fitz.Matrix(dpi/72, dpi/72)
        pix = page.get_pixmap(matrix=mat)
        
        # Convert to PIL Image
        img_data = pix.tobytes("ppm")
        img = Image.open(io.BytesIO(img_data))
        
        pdf_document.close()
        return img
        
    except Exception as e:
        print(f"Error converting PDF to image: {e}")
        return None

def get_pdf_info(pdf_path):
    """
    Get basic information about the PDF
    """
    try:
        pdf_document = fitz.open(pdf_path)
        page_count = len(pdf_document)
        pdf_document.close()
        return page_count
    except Exception as e:
        print(f"Error getting PDF info: {e}")
        return 0


def get_file_type(file_path):
    """
    Determine the file type based on extension
    """
    if file_path.lower().endswith('.pdf'):
        return 'pdf'
    elif file_path.lower().endswith(('.png', '.jpg', '.jpeg')):
        return 'image'
    elif file_path.lower().endswith('.txt'):
        return 'txt'
    else:
        return 'unknown'
    

def get_recent_file_id(files, minutes=5):
        now = datetime.now(timezone.utc)
        for file in sorted(files, key=lambda x: x.get('createdAt', ''), reverse=True):
            created_at_str = file.get('createdAt')
            if created_at_str:
                created_at = datetime.fromisoformat(created_at_str.replace('Z', '+00:00'))
                if now - created_at <= timedelta(minutes=minutes):
                    return file['fileId']
        return None