Method getPriceHistoryChartById

public static function getPriceHistoryChartById($productId)
{
    $data = array();
    $dataX = $dataY = array();
    $history = self::getPriceHistoryById($productId);
    if (!empty($history)) {
        foreach ($history as $k => $v) {
            $dataY[] = '\'' . $v['price'] . '\'';
            $dataX[] = '\'' . HTMLHelper::_('date', $v['date'], Text::_('DATE_FORMAT_LC3')) . '\'';
        }
    }
    $data['x'] = '';
    if (!empty($dataX)) {
        $data['x'] = implode(',', $dataX);
    }
    $data['y'] = '';
    if (!empty($dataY)) {
        $data['y'] = implode(',', $dataY);
    }
    if (!empty($data['x']) && !empty($data['y'])) {
        $s = new PhocacartStatistics();
        $s->renderChartJsLine2('phChartAreaLine', $data['y'], Text::_('COM_PHOCACART_PRICE'), $data['x']);
        $s->setFunction('phChartAreaLine', 'Line');
        $s->renderFunctions();
        return true;
    }
    return false;
}