from flask_login import current_user
from models import RoomMemberPermission
from datetime import datetime, timezone

def user_has_permission(room, perm_name):
    """
    Check if the current user has a specific permission in a room.
    
    Args:
        room: Room object
        perm_name: Name of the permission to check (e.g., 'can_view', 'can_upload')
    
    Returns:
        bool: True if user has permission, False otherwise
    """
    # Admin users have all permissions
    if current_user.is_admin:
        return True
    
    # Check if user is a member of the room
    if current_user not in room.members:
        return False
    
    # Get user's permissions for this room
    permission = RoomMemberPermission.query.filter_by(
        room_id=room.id,
        user_id=current_user.id
    ).first()
    
    # If no specific permissions are set, user only has view access
    if not permission:
        return perm_name == 'can_view'
    
    # Check the specific permission
    return getattr(permission, perm_name, False)

def clean_path(path):
    """
    Clean a file path by removing leading/trailing slashes and normalizing separators.
    
    Args:
        path: Path string to clean
    
    Returns:
        str: Cleaned path
    """
    if not path:
        return ''
    return path.strip('/\\')

def timeago(date):
    """Convert a datetime to a human-readable time ago string."""
    if not date:
        return ''
    
    # Convert naive datetime to UTC if it's naive
    if date.tzinfo is None:
        date = date.replace(tzinfo=timezone.utc)
    
    now = datetime.now(timezone.utc)
    diff = now - date
    
    if diff.days > 365:
        years = diff.days // 365
        return f'{years} year{"s" if years != 1 else ""} ago'
    elif diff.days > 30:
        months = diff.days // 30
        return f'{months} month{"s" if months != 1 else ""} ago'
    elif diff.days > 0:
        return f'{diff.days} day{"s" if diff.days != 1 else ""} ago'
    elif diff.seconds > 3600:
        hours = diff.seconds // 3600
        return f'{hours} hour{"s" if hours != 1 else ""} ago'
    elif diff.seconds > 60:
        minutes = diff.seconds // 60
        return f'{minutes} minute{"s" if minutes != 1 else ""} ago'
    else:
        return 'just now'