pressbooks-aldine/app/activation.php

<?php

namespace Aldine;

add_action('after_switch_theme', function () {
    $default_pages = [
        'about' => [
            'post_title' => __('About', 'aldine'),
            // @codingStandardsIgnoreStart
            'post_content' => apply_filters('pb_root_about_page_content', __('Pressbooks is simple book production software. You can use Pressbooks to publish textbooks, scholarly monographs, syllabi, fiction and non-fiction books, white papers, and more in multiple formats including:

<ul><li>MOBI (for Kindle ebooks)</li>
<li>EPUB (for all other ebookstores)</li>
<li>designed PDF (for print-on-demand and digital distribution)</li></ul>

Pressbooks is used by educational institutions around the world as well as authors and publishers.

For more information about Pressbooks, see <a href="https://pressbooks.com/about">here</a>.', 'aldine'))
            // @codingstandardsIgnoreEnd
        ],
        'help' => [
            'post_title' => __('Help', 'aldine'),
            // @codingStandardsIgnoreStart
            'post_content' => apply_filters('pb_root_help_page_content', __('The easiest way to get started with Pressbooks is to follow our <a href="https://pressbooks.com/how-to-make-a-book-with-pressbooks">4 Step Guide to Making a Book on Pressbooks</a>. Or, you can review our <a href="https://guide.pressbooks.com/">Guide to Using Pressbooks</a>.

If you require further assistance, please contact your network manager.', 'aldine'))
            // @codingstandardsIgnoreEnd
        ],
        'catalog' => [
            'post_title' => __('Catalog', 'aldine'),
            'post_content' => ''
        ],
        'home' => [
            'post_title' => __('Home', 'aldine'),
            'post_content' => ''
        ],
    ];

    if (! get_site_option('pb_aldine_activated')) {
        // Add our pages
        $pages = [];

        foreach ($default_pages as $slug => $page) {
            $check = get_page_by_path($slug);
            if (empty($check)) {
                $pages[$slug] = wp_insert_post(array_merge($page, ['post_type' => 'page', 'post_status' => 'publish']));
            } else {
                $pages[$slug] = $check->ID;
            }
        }

        // Set front page to Home
        update_option('show_on_front', 'page');
        update_option('page_on_front', $pages['home']);

        // Remove content generated by wp_install_defaults
        if (! wp_delete_post(1, true)) {
            return;
        }
        if (! wp_delete_post(2, true)) {
            return;
        }
        if (! wp_delete_comment(1, true)) {
            return;
        }

        // Add "pb_aldine_activated" site option to enable check above
        add_site_option('pb_aldine_activated', true);
    }
});