Adicionar atributo ao cupom de regra de preço do carrinho de compras

Existe alguma maneira de adicionar um atributo a uma regra de preço do carrinho de compras no Magento? Preciso adicionar um campo chamado "em destaque" para cada regra de preço do carrinho de compras e, depois disso, poder filtrar as regras por esse atributo.

Acabei usando a resposta musicliftsme . Aqui está o código completo com um instalador para atualizar a tabela da regra de vendas.

Módulo disponível aqui.

app / code / local / MB / Attributes / Block / Adminhtml / Edit / Tab / Main.php

<?php
/**
 * Magento Enterprise Edition
 *
 * NOTICE OF LICENSE
 *
 * This source file is subject to the Magento Enterprise Edition License
 * that is bundled with this package in the file LICENSE_EE.txt.
 * It is also available through the world-wide-web at this URL:
 * http://www.magentocommerce.com/license/enterprise-edition
 * If you did not receive a copy of the license and are unable to
 * obtain it through the world-wide-web, please send an email
 * to license@magentocommerce.com so we can send you a copy immediately.
 *
 * DISCLAIMER
 *
 * Do not edit or add to this file if you wish to upgrade Magento to newer
 * versions in the future. If you wish to customize Magento for your
 * needs please refer to http://www.magentocommerce.com for more information.
 *
 * @category    Mage
 * @package     Mage_Adminhtml
 * @copyright   Copyright (c) 2013 Magento Inc. (http://www.magentocommerce.com)
 * @license     http://www.magentocommerce.com/license/enterprise-edition
 */

/**
 * Shopping Cart Price Rule General Information Tab
 *
 * @category Mage
 * @package Mage_Adminhtml
 * @author Magento Core Team <core@magentocommerce.com>
 */
class MB_Attributes_Block_Adminhtml_Edit_Tab_Main
    extends Mage_Adminhtml_Block_Widget_Form
    implements Mage_Adminhtml_Block_Widget_Tab_Interface
{
    /**
     * Prepare content for tab
     *
     * @return string
     */
    public function getTabLabel()
    {
        return Mage::helper('salesrule')->__('Rule Information');
    }

    /**
     * Prepare title for tab
     *
     * @return string
     */
    public function getTabTitle()
    {
        return Mage::helper('salesrule')->__('Rule Information');
    }

    /**
     * Returns status flag about this tab can be showed or not
     *
     * @return true
     */
    public function canShowTab()
    {
        return true;
    }

    /**
     * Returns status flag about this tab hidden or not
     *
     * @return true
     */
    public function isHidden()
    {
        return false;
    }

    protected function _prepareForm()
    {
        $model = Mage::registry('current_promo_quote_rule');

        $form = new Varien_Data_Form();
        $form->setHtmlIdPrefix('rule_');

        $fieldset = $form->addFieldset('base_fieldset',
            array('legend' => Mage::helper('salesrule')->__('General Information'))
        );

        if ($model->getId()) {
            $fieldset->addField('rule_id', 'hidden', array(
                'name' => 'rule_id',
            ));
        }

        $fieldset->addField('product_ids', 'hidden', array(
            'name' => 'product_ids',
        ));

        $fieldset->addField('name', 'text', array(
            'name' => 'name',
            'label' => Mage::helper('salesrule')->__('Rule Name'),
            'title' => Mage::helper('salesrule')->__('Rule Name'),
            'required' => true,
        ));

        $fieldset->addField('description', 'textarea', array(
            'name' => 'description',
            'label' => Mage::helper('salesrule')->__('Description'),
            'title' => Mage::helper('salesrule')->__('Description'),
            'style' => 'height: 100px;',
        ));

        $fieldset->addField('is_active', 'select', array(
            'label'     => Mage::helper('salesrule')->__('Status'),
            'title'     => Mage::helper('salesrule')->__('Status'),
            'name'      => 'is_active',
            'required' => true,
            'options'    => array(
                '1' => Mage::helper('salesrule')->__('Active'),
                '0' => Mage::helper('salesrule')->__('Inactive'),
            ),
        ));

        if (!$model->getId()) {
            $model->setData('is_active', '1');
        }

        if (Mage::app()->isSingleStoreMode()) {
            $websiteId = Mage::app()->getStore(true)->getWebsiteId();
            $fieldset->addField('website_ids', 'hidden', array(
                'name'     => 'website_ids[]',
                'value'    => $websiteId
            ));
            $model->setWebsiteIds($websiteId);
        } else {
            $field = $fieldset->addField('website_ids', 'multiselect', array(
                'name'     => 'website_ids[]',
                'label'     => Mage::helper('salesrule')->__('Websites'),
                'title'     => Mage::helper('salesrule')->__('Websites'),
                'required' => true,
                'values'   => Mage::getSingleton('adminhtml/system_store')->getWebsiteValuesForForm()
            ));
            $renderer = $this->getLayout()->createBlock('adminhtml/store_switcher_form_renderer_fieldset_element');
            $field->setRenderer($renderer);
        }

        $customerGroups = Mage::getResourceModel('customer/group_collection')->load()->toOptionArray();
        $found = false;

        foreach ($customerGroups as $group) {
            if ($group['value']==0) {
                $found = true;
            }
        }
        if (!$found) {
            array_unshift($customerGroups, array(
                'value' => 0,
                'label' => Mage::helper('salesrule')->__('NOT LOGGED IN'))
            );
        }

        $fieldset->addField('customer_group_ids', 'multiselect', array(
            'name'      => 'customer_group_ids[]',
            'label'     => Mage::helper('salesrule')->__('Customer Groups'),
            'title'     => Mage::helper('salesrule')->__('Customer Groups'),
            'required'  => true,
            'values'    => Mage::getResourceModel('customer/group_collection')->toOptionArray(),
        ));

        $couponTypeFiled = $fieldset->addField('coupon_type', 'select', array(
            'name'       => 'coupon_type',
            'label'      => Mage::helper('salesrule')->__('Coupon'),
            'required'   => true,
            'options'    => Mage::getModel('salesrule/rule')->getCouponTypes(),
        ));

        $couponCodeFiled = $fieldset->addField('coupon_code', 'text', array(
            'name' => 'coupon_code',
            'label' => Mage::helper('salesrule')->__('Coupon Code'),
            'required' => true,
        ));

        $autoGenerationCheckbox = $fieldset->addField('use_auto_generation', 'checkbox', array(
            'name'  => 'use_auto_generation',
            'label' => Mage::helper('salesrule')->__('Use Auto Generation'),
            'note'  => Mage::helper('salesrule')->__('If you select and save the rule you will be able to generate multiple coupon codes.'),
            'onclick' => 'handleCouponsTabContentActivity()',
            'checked' => (int)$model->getUseAutoGeneration() > 0 ? 'checked' : ''
        ));

        $autoGenerationCheckbox->setRenderer(
            $this->getLayout()->createBlock('adminhtml/promo_quote_edit_tab_main_renderer_checkbox')
        );

        $usesPerCouponFiled = $fieldset->addField('uses_per_coupon', 'text', array(
            'name' => 'uses_per_coupon',
            'label' => Mage::helper('salesrule')->__('Uses per Coupon'),
        ));

        $fieldset->addField('uses_per_customer', 'text', array(
            'name' => 'uses_per_customer',
            'label' => Mage::helper('salesrule')->__('Uses per Customer'),
        ));

        $dateFormatIso = Mage::app()->getLocale()->getDateFormat(Mage_Core_Model_Locale::FORMAT_TYPE_SHORT);
        $fieldset->addField('from_date', 'date', array(
            'name'   => 'from_date',
            'label'  => Mage::helper('salesrule')->__('From Date'),
            'title'  => Mage::helper('salesrule')->__('From Date'),
            'image'  => $this->getSkinUrl('images/grid-cal.gif'),
            'input_format' => Varien_Date::DATE_INTERNAL_FORMAT,
            'format'       => $dateFormatIso
        ));
        $fieldset->addField('to_date', 'date', array(
            'name'   => 'to_date',
            'label'  => Mage::helper('salesrule')->__('To Date'),
            'title'  => Mage::helper('salesrule')->__('To Date'),
            'image'  => $this->getSkinUrl('images/grid-cal.gif'),
            'input_format' => Varien_Date::DATE_INTERNAL_FORMAT,
            'format'       => $dateFormatIso
        ));

        $fieldset->addField('sort_order', 'text', array(
            'name' => 'sort_order',
            'label' => Mage::helper('salesrule')->__('Priority'),
        ));


        $fieldset->addField('featured', 'select', array(
            'label'     => Mage::helper('salesrule')->__('Featured'),
            'title'     => Mage::helper('salesrule')->__('Featured'),
            'name'      => 'featured',
            'options'   => array(
                '1' => Mage::helper('salesrule')->__('Yes'),
                '0' => Mage::helper('salesrule')->__('No'),
            ),
        ));


        $fieldset->addField('is_rss', 'select', array(
            'label'     => Mage::helper('salesrule')->__('Public In RSS Feed'),
            'title'     => Mage::helper('salesrule')->__('Public In RSS Feed'),
            'name'      => 'is_rss',
            'options'   => array(
                '1' => Mage::helper('salesrule')->__('Yes'),
                '0' => Mage::helper('salesrule')->__('No'),
            ),
        ));

        if(!$model->getId()){
            //set the default value for is_rss feed to yes for new promotion
            $model->setIsRss(1);
        }

        $form->setValues($model->getData());

        $autoGenerationCheckbox->setValue(1);

        if ($model->isReadonly()) {
            foreach ($fieldset->getElements() as $element) {
                $element->setReadonly(true, true);
            }
        }

        //$form->setUseContainer(true);

        $this->setForm($form);

        // field dependencies
        $this->setChild('form_after', $this->getLayout()->createBlock('adminhtml/widget_form_element_dependence')
            ->addFieldMap($couponTypeFiled->getHtmlId(), $couponTypeFiled->getName())
            ->addFieldMap($couponCodeFiled->getHtmlId(), $couponCodeFiled->getName())
            ->addFieldMap($autoGenerationCheckbox->getHtmlId(), $autoGenerationCheckbox->getName())
            ->addFieldMap($usesPerCouponFiled->getHtmlId(), $usesPerCouponFiled->getName())
            ->addFieldDependence(
                $couponCodeFiled->getName(),
                $couponTypeFiled->getName(),
                Mage_SalesRule_Model_Rule::COUPON_TYPE_SPECIFIC)
            ->addFieldDependence(
                $autoGenerationCheckbox->getName(),
                $couponTypeFiled->getName(),
                Mage_SalesRule_Model_Rule::COUPON_TYPE_SPECIFIC)
            ->addFieldDependence(
                $usesPerCouponFiled->getName(),
                $couponTypeFiled->getName(),
                Mage_SalesRule_Model_Rule::COUPON_TYPE_SPECIFIC)
        );

        Mage::dispatchEvent('adminhtml_promo_quote_edit_tab_main_prepare_form', array('form' => $form));

        return parent::_prepareForm();
    }
}

app / code / local / MB / Attributes / etc / config.xml

<?xml version="1.0"?>
<config>
    <modules>
        <MB_Attributes>
            <version>0.1.1</version>
        </MB_Attributes>
    </modules>
    <global>
        <blocks>
            <adminhtml>
                <rewrite>
                    <promo_quote_edit_tab_main>MB_Attributes_Block_Adminhtml_Edit_Tab_Main</promo_quote_edit_tab_main>
                </rewrite>
            </adminhtml>
        </blocks>
        <resources> 
            <mbattributes_setup>
                <setup>
                    <module>MB_Attributes</module>
                </setup>
                <connection>
                    <use>core_setup</use>
                </connection>
            </mbattributes_setup>
        </resources>
    </global>
</config>

app / code / local / MB / Attributes / sql / mbattributes_setup / mysql4-install-0.1.1.php

<?php

$installer = $this;
$installer->startSetup();

$installer->getConnection()
    ->addColumn($installer->getTable('salesrule'),
        'featured',
        array(
            'type' => Varien_Db_Ddl_Table::TYPE_SMALLINT,
            'length' => 6,
            'nullable' => false,
            'default' => 0,
            'comment' => 'Is featured'
        )
    );

$installer->endSetup();

app / etc / modules / MB_Attributes.xml

<?xml version="1.0"?>
<config>
    <modules>
        <MB_Attributes>
            <active>true</active>
            <codePool>local</codePool>
        </MB_Attributes>
    </modules>
</config>

Informações adicionais: Quando tentei remover alguns dos métodos de MB_Attributes_Block_Adminhtml_Edit_Tab_Main, obtive

[Mon May 18 15:26:34.805303 2015] [:error] [pid 19354] [client 127.0.0.1:37117] PHP Fatal error:  Class MB_Attributes_Block_Adminhtml_Edit_Tab_Main contains 4 abstract methods and must therefore be declared abstract or implement the remaining methods (Mage_Adminhtml_Block_Widget_Tab_Interface::getTabLabel, Mage_Adminhtml_Block_Widget_Tab_Interface::getTabTitle, Mage_Adminhtml_Block_Widget_Tab_Interface::canShowTab, ...) in /var/www/wa/app/code/local/MB/Attributes/Block/Adminhtml/Edit/Tab/Main.php on line 252, referer: http://wa-dev.com/index.php/admin/promo_quote/index/key/ee3695e7425bea8ad8bef471e3262e74ee161ff8c10f8132cea80280496abe15/

1. Instale uma nova coluna featuredna tabela salesrule.

2. Reescreva as Mage_Adminhtml_Block_Promo*classes para atualizar a interface do administrador para esta nova moda.

Depois de fazer isso, você pode filtrar por sua nova coluna.

No administrador, vá para Catalog > Attributes > Manage Attributese abra seu atributo. Em Frontend Properties, defina Use for Promo Rule Conditionscomo Yes. Isso permitirá que você use seu atributo nas regras de preço do carrinho de compras.