Restrict one post per author

Question

I'm trying to create an events plugin and so far, I'm through with the following:

1. A short-code that displays a form on the front-end to the user.
2. The event display page that renders the output.
3. 'Events' as custom post type and several custom-fields for additional event information.

Problems:

1. I want to restrict the users from submitting more than one event.

2. If the user has already published an event, he/she should be presented with a form that has their earlier values (aka values of custom fields) prefilled. They can edit these values and save to update the event display page.

If they haven't published any event before, show a blank form with regular placeholders.

I'm unable to think about any approach to address this issue. Would really appreciate if you could point me in the right direction.

Thank you for your time and I look forward to getting response.

Answer 1

Answer from comments:

First, create a conditional to check if the user has already 'published' a post. If yes, simply redirect them.

One can use update_post_meta with the post ID without any problem. Simply use that information to populate the fields.

Answer 2

Check the current user info, then query for posts by that user, depending on query (has posts?), output the data/form you need.

<?php
    // Retrieve current user info
    $current_user = wp_get_current_user();                      

    // Prepare the query for posts by that author
    $args = array(
        'author' =>  $current_user->ID, 
    );
    $author_posts = new WP_Query( $args );

    // Depending on query results, output what you need
    if($author_posts->have_posts()) {
       // display the edit form
    } else {
       // display the new post form
    }

?>