public function confirm(HTTPRequest $request)
    {
        if ($this->EmailType !== 'Confirmation' &&
            $this->EmailType !== 'Validation') {
            return $this->httpError(400, 'No confirmation required.');
        }

        $currentMember = Member::currentUser();
        $id = (int)$request->param('ID');
        $key = $request->getVar('key');

        if ($currentMember) {
            if ($currentMember->ID == $id) {
                return Security::permissionFailure($this, _t(
                    'MemberProfiles.ALREADYCONFIRMED',
                    'Your account is already confirmed.'
                ));
            }
            return Security::permissionFailure($this, _t(
                'MemberProfiles.CANNOTCONFIRMLOGGEDIN',
                'You cannot confirm account while you are logged in.'
            ));
        }

        if (!$id ||
            !$key) {
            return $this->httpError(404);
        }

        $confirmationTitle = $this->data()->dbObject('ConfirmationTitle');

        /**
         * @var Member|null $member
         */
        $member = DataObject::get_by_id(Member::class, $id);
        if (!$member) {
            return $this->invalidRequest('Member #'.$id.' does not exist.');
        }
        if (!$member->NeedsValidation) {
            // NOTE(Jake): 2018-05-03
            //
            // You might be hitting this if you set your MemberProfilePage to use
            // Email Setting 'Confirmation' rather than 'Validation' and you didn't
            // edit the original Email template to not include the copy about confirmation.
            //
            return $this->invalidRequest('Member #'.$id.' does not need validation.');
        }
        if (!$member->ValidationKey) {
            return $this->invalidRequest('Member #'.$id.' does not have a validation key.');
        }
        if ($member->ValidationKey !== $key) {
            return $this->invalidRequest('Validation key does not match.');
        }

        // Allow member to login
        $member->NeedsValidation = false;
        $member->ValidationKey = null;

        $validationResult = $member->validateCanLogin();
        if (!$validationResult->isValid()) {
            $this->getResponse()->setStatusCode(500);
            $validationMessages = $validationResult->getMessages();
            return [
                'Title'   => $confirmationTitle,
                'Content' => $validationMessages ? $validationMessages[0]['message'] : _t('MemberProfiles.ERRORCONFIRMATION', 'An unexpected error occurred.'),
            ];
        }
        $member->write();

        $this->extend('onConfirm', $member);

        if ($member->canLogin()) {
            Injector::inst()->get(IdentityStore::class)->logIn($member);
        } else {
            throw new Exception('Permission issue occurred. Was the "$member->validateCanLogin" check above this code block removed?');
        }

        return [
            'Title'   => $this->data()->dbObject('ConfirmationTitle'),
            'Content' => $this->data()->dbObject('ConfirmationContent')
        ];
    }