"""
Validation functions for the Flask job application system.
"""
import re
from flask import current_app


def validate_email(email):
    """Validate email format"""
    pattern = r'^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$'
    return re.match(pattern, email) is not None


def validate_phone(phone):
    """Validate international phone format"""
    # Accepts formats like: +41 79 123 45 67, +41791234567, etc.
    # Remove spaces and check if it matches the pattern
    pattern = r'^\+\d{1,3}[\s\d]{1,20}$'
    if not re.match(pattern, phone):
        return False
    # Ensure there are at least some digits after the country code
    digits_only = re.sub(r'\s', '', phone)
    return len(digits_only) >= 5  # At least +XX XXX format


def validate_year(year):
    """Validate birth year"""
    try:
        year_int = int(year)
        return (current_app.config['MIN_BIRTH_YEAR'] <= year_int <= current_app.config['MAX_BIRTH_YEAR']
                and len(str(year)) == 4)
    except ValueError:
        return False


def validate_zip(zip_code):
    """Validate ZIP code"""
    try:
        zip_int = int(zip_code)
        return len(str(zip_code)) <= current_app.config['MAX_ZIP_DIGITS']
    except ValueError:
        return False


def allowed_file(filename):
    """Check if file extension is allowed"""
    return '.' in filename and \
           filename.rsplit('.', 1)[1].lower() in current_app.config['ALLOWED_EXTENSIONS']