from rest_framework.permissions import BasePermission
from django.utils.translation import gettext_lazy as _


class CanCreateDynamicForm(BasePermission):
    """
    Permission to create dynamic forms:
    1. User must be authenticated and active.
    2. Platform staff, superusers, or regional admins are permitted.
    3. Regular users must have an associated institution AND
       the 'can_create_forms' permission flag (toggled via role or user custom_permissions in panel admin).
    """
    message = _("Only users affiliated with an institution and granted form creation permissions can create dynamic forms.")

    def has_permission(self, request, view):
        user = request.user
        if not user or not user.is_authenticated or not user.is_active:
            return False

        if user.is_staff or getattr(user, 'is_super_admin', False) or getattr(user, 'is_regional_admin', False) or user.is_superuser:
            return True

        # Check if user has an associated institution
        has_institution = bool(
            (hasattr(user, 'institution_memberships') and user.institution_memberships.exists()) or
            (hasattr(user, 'created_institutions') and user.created_institutions.exists()) or
            bool(getattr(user, 'institution_name', None))
        )
        if not has_institution:
            self.message = _("Only users affiliated with an institution can create dynamic forms.")
            return False

        # Check togglable permission flag from panel admin (Role or custom_permissions)
        has_permission_flag = user.has_perm_flag('can_create_forms') if hasattr(user, 'has_perm_flag') else False
        if not has_permission_flag:
            self.message = _("You do not have permission to create dynamic forms. Please contact an administrator.")
            return False

        return True