I feared so 🙂
This requires a lot of custom code.
It requires a bit less if creating the terms only in the Taxonomy Edit Screen, but in the post edit, you'd have to hook into save_post, from there get the attached term, it's meta field and updates that with the date.
The only toolset related thing is that the Meta field will be with a prefix wpcf-, that's basically all. The rest will depend on WordPress and PHP, independently from Toolset altogether.
If you are not experienced with Custom code at this point I'd suggest contacting a contractor https://toolset.com/contractors/, because in the Support we cannot provide this complete.
I can give you the path to this, along with examples.
Let's assume we work on the save_post, hence when editing a post.
You'd use the save_post hook of WordPress:
https://codex.wordpress.org/Plugin_API/Action_Reference/save_post
This allows you to fire your Custom Code at the right moment, so you'd put your custom code in a custom function, and then fire that function with above hook on save_post:
function custom_function( $post_id ) {
//All your custom code, like getting and updated terms and term fields
}
add_action( 'save_post', 'custom_function' );
I suggest studying the Codex above for a better understanding of the hook and how you can create a custom function for it.
Then, in/with that function we need to:
- determine if the post is new or edited (we do not want to work it when we edit the post...)
- get the term saved for the post,
- determine the date to use
- update that term field with the date
You can determine if the post is new or not within the save_post hook itself:
(this is related to the save_post hook, see here how to determine that: https://wordpress.stackexchange.com/questions/48678/check-for-update-vs-new-post-on-save-post-action/185991)
After this, you can concentrate on the "//All your custom code, like getting and updated terms and term fields" part.
There you can get the term saved for the post with code as described here: https://wordpress.stackexchange.com/questions/74017/get-terms-on-save-post-hook (Using $_POST[])
Example:
$term_addeed_to_post = $_POST['tax_input']['your_custom_tax']
You can now use the data from $_POST to get/update the Term Meta with the WordPress API get_term_meta() and update_term_meta():
https://codex.wordpress.org/Function_Reference/get_term_by
https://developer.wordpress.org/reference/functions/update_term_meta/
Example n(we use $term_addeed_to_post from previous code sample) :
update_term_meta( $term_addeed_to_post, 'wpcf-your-term-field', '$date_timestamp' );
Notice the $date_timestamp, this is the date you want to update for the field, it should be a Timestamp, this could be generated for example using date() PHP native function:
hidden link
You'd use the "U" format (Timestamp)
That's basically it, after above code, you'd close the function and when saving a new post it'd get the term added and update its meta with a timestamp.
Note that my code samples do not include safety checks like wether we deal with arrays, empty values or non existing values, this would require more custom work on it, but the outline should allow you to proceed (not without any PHP knowledge, but I am limited in what I can provide for support here in the forum, unfortunately).
Please let me know if something's not clear.
