from rest_framework.permissions import BasePermission, SAFE_METHODS


class IsActiveUser(BasePermission):

    def has_permission(self, request, view):
        return request.user and request.user.is_active 


class IsSuperAdmin(BasePermission):
    """
    Allows access only to super admins and staff admins.
    """
    def has_permission(self, request, view):
        return (
            request.user and
            request.user.is_authenticated and
            request.user.is_active and
            (request.user.is_superuser or request.user.user_type in ['super_admin', 'admin'])
        )


class IsPanelUser(BasePermission):
    """
    Allows access to all administrative panel roles: super admins, admins, and professors.
    """
    def has_permission(self, request, view):
        return (
            request.user and
            request.user.is_authenticated and
            request.user.is_active and
            (request.user.is_superuser or request.user.user_type in ['super_admin', 'admin', 'professor'])
        )


class IsSuperAdminOrReadOnlyForProfessor(BasePermission):
    """
    Allows full read-write access to super admins/admins, 
    but only read-only (GET, HEAD, OPTIONS) access to professors.
    """
    def has_permission(self, request, view):
        if not request.user or not request.user.is_authenticated or not request.user.is_active:
            return False
        
        # Super admin / Admin can do everything
        if request.user.is_superuser or request.user.user_type in ['super_admin', 'admin']:
            return True
            
        # Professor has read-only access
        if request.user.user_type == 'professor':
            return request.method in SAFE_METHODS
            
        return False