import os
import pandas as pd
from typing import List, Optional

def validate_phone_number(number: str) -> bool:
    """Validate if number contains only digits and has appropriate length."""
    cleaned = ''.join(filter(str.isdigit, str(number)))
    return len(cleaned) >= 10 and cleaned.isdigit()

def create_vcf_contacts(excel_path: str, group_name: str = "Contacts") -> Optional[str]:
    """Create VCF file from Excel containing phone numbers."""
    try:
        # Check if file exists
        if not os.path.exists(excel_path):
            raise FileNotFoundError(f"Excel file not found: {excel_path}")

        # Read phone numbers from first column of Excel file
        df = pd.read_excel(excel_path)
        if df.empty:
            raise ValueError("Excel file is empty")

        numbers = df.iloc[:, 0].astype(str).tolist()
        filename = f"{group_name}_contacts.vcf"

        valid_numbers = 0
        skipped_numbers = 0

        with open(filename, 'w') as f:
            for i, number in enumerate(numbers, start=1):
                if not validate_phone_number(number) or not number.isdigit():
                    skipped_numbers += 1
                    continue

                try:
                    f.write("BEGIN:VCARD\n")
                    f.write("VERSION:3.0\n")
                    f.write(f"N:{group_name}_{i:03d};;;\n")
                    f.write(f"FN:{group_name}_{i:03d}\n")
                    f.write(f"TEL;TYPE=CELL:+91{number}\n")
                    f.write(f"X-WhatsApp-Group:{group_name}\n")
                    f.write("END:VCARD\n\n")
                    valid_numbers += 1
                except IOError:
                    raise

        return filename

    except pd.errors.EmptyDataError:
        raise
    except Exception:
        raise

if __name__ == "__main__":
    try:
        created_file = create_vcf_contacts('numbers.xlsx')
    except Exception as e:
        print(f"Failed to create contacts file: {str(e)}")