Migrate image of the post meta to featured image

meta-to-featured-image.php

<?php

namespace MetaToFeaturedImage;

/**
 * Plugin Name:       Meta to featured image
 * Description:       Migrate image of the post meta to featured image
 * Version:           0.0.1
 * Requires at least: 5.8
 * Requires PHP:      7.0
 * Author:            The WordPress Contributors
 * License:           GPL-2.0-or-later
 * License URI:       https://www.gnu.org/licenses/gpl-2.0.html
 */

add_action( 'admin_menu', 'MetaToFeaturedImage\\add_admin_menu' );
add_action( 'admin_init', 'MetaToFeaturedImage\\settings_menu' );

function add_admin_menu() {
    add_options_page(
        __( 'Meta to featured image', 'meta-to-featured-image' ),
        __( 'Meta to featured image', 'meta-to-featured-image' ),
        'manage_options',
        'meta_featured_image',
        'MetaToFeaturedImage\\settings_page_render'
    );
}
 
function settings_menu() {
    register_setting( 'meta_featured_image', 'meta_featured_image_settings' );

    add_settings_section(
        'meta_featured_image_section',
        __( 'Informações', 'meta-to-featured-image' ),
        'MetaToFeaturedImage\\settings_section_callback',
        'meta_featured_image'
    );

    add_settings_field(
        'post_type',
        __( 'Post type', 'meta-to-featured-image' ),
        'MetaToFeaturedImage\\settings_post_type_render',
        'meta_featured_image',
        'meta_featured_image_section'
    );

    add_settings_field(
        'post_meta',
        __( 'Post meta', 'meta-to-featured-image' ),
        'MetaToFeaturedImage\\settings_post_meta_render',
        'meta_featured_image',
        'meta_featured_image_section'
    );
}

function settings_section_callback() {
    echo '';
}

function settings_post_type_render() {
    $options = get_option( 'meta_featured_image_settings' );
    $value = isset( $options['post_type'] ) ? $options['post_type'] : '';
    ?>
        <input type='text' name='meta_featured_image_settings[post_type]' value='<?php echo $value; ?>'>
    <?php
}

function settings_post_meta_render() {
    $options = get_option( 'meta_featured_image_settings' );
    $value = isset( $options['post_meta'] ) ? $options['post_meta'] : '';
    ?>
        <input type='text' name='meta_featured_image_settings[post_meta]' value='<?php echo $value; ?>'>
    <?php
}

/**
 * Render the settings page
*/
function settings_page_render() {

    if ( isset( $_GET['page'] ) && $_GET['page'] === 'meta_featured_image' ) {
        if ( isset( $_GET['settings-updated'] ) && $_GET['settings-updated'] === "true" ) {
            migrate_data();
        }
    }

    ?>
    <form action='options.php' method='post'>
        <input type="hidden" name="action" value="meta_featured_image_save">
        <?php
        settings_fields( 'meta_featured_image' );
        do_settings_sections( 'meta_featured_image' );
        submit_button();
        ?>
    </form>
    <?php
}

function migrate_data() {
    $options = get_option( 'meta_featured_image_settings' );
    $post_type = isset( $options['post_type'] ) ? $options['post_type'] : '';
    $post_meta = isset( $options['post_meta'] ) ? $options['post_meta'] : '';

    if ( $post_type && $post_meta ) {
        $args = [
            'post_type'      => sanitize_title( $post_type ),
            'posts_per_page' => -1,
            'post_status'    => 'publish'
        ];
    }

    $get_posts = get_posts( $args );

    foreach ( $get_posts as $post ) {
        $imagem_id = get_post_meta( $post->ID, $post_meta, true );

        if ( ! empty( $imagem_id ) ) {
            $set_post_thumbnail = set_post_thumbnail( $post->ID, $imagem_id );

            if ( $set_post_thumbnail ) {
                do_action( 'logger', ["Meta to featured image => Imagem destacada ($imagem_id), definida com sucesso no post ($post->ID)" ] );
            }
        }
    }
}