How to Add IF statement around Shortcodes (Echo'd) in PHP? (Hide / Show Tabs)

[admin]

I have inserted a set of tabs to my php wordpress template using the following shortcodes

    <?php echo do_shortcode('[tabs style="boxed"]
            [tab title="1"][some content here][/tab]
            [tab title="2"]' . get_the_excerpt() . '[/tab]
            [/tabs]');  ?>

This works fine.

I have created 2 x custom checkbox fields called 'tab_contact_1' and 'tab_contact_2' in a custom post.

I would like to add conditional logic to the tabs so that if the checkbox is true/checked the tab shows. If not it hides. (This is due to some posts having this content available and some not)

I have similar logic working for other custom fields on the site, but not using tabs and was thinking I can apply the same mindset. I took a go at the code (see below) but the page is not loading. I am doing something wrong but can't figure it out. Was hoping for some guidance.

thanks a lot

<?php echo do_shortcode('[tabs style="boxed"]
' . if ( get_post_meta($post->ID, 'tab_contact_1', true)) { . '
[tab title="1"][some content here][/tab]
'. } .'
' . if ( get_post_meta($post->ID, 'tab_contact_2', true)) { . '
[tab title="2"]' . get_the_excerpt() . '[/tab]
'. } .'
[/tabs]');  ?>