fourth-wall-embed-wp/libs/settings.php

<?php

class fourthwall_settings {

	public function __construct() {

		add_action( 'admin_menu', array( $this, 'add_admin_menu' ) );
		add_action( 'admin_init', array( $this, 'init_settings'  ) );

	}

	public function add_admin_menu() {

		add_menu_page(
			esc_html__( 'Fourthwall Store Embed', 'fourthwall_text_domain' ),
			esc_html__( 'FourthWall Embed', 'fourthwall_text_domain' ),
			'manage_options',
			'fwembed',
			array( $this, 'fourthwall_page_layout' ),
			'dashicons-store',
			10
		);

	}

	public function init_settings() {

		register_setting(
			'fourthwall_settings_group',
			'fourthwall_settings_name'
		);

		add_settings_section(
			'fourthwall_settings_name_section',
			'',
			false,
			'fourthwall_settings_name'
		);

		add_settings_field(
			'fourth_url',
			__( 'Store URL', 'fourthwall_text_domain' ),
			array( $this, 'render_fourth_url_field' ),
			'fourthwall_settings_name',
			'fourthwall_settings_name_section'
		);

	}

	public function fourthwall_page_layout() {

		// Check required user capability
		if ( !current_user_can( 'manage_options' ) )  {
			wp_die( esc_html__( 'You do not have sufficient permissions to access this page.', 'fourthwall_text_domain' ) );
		}

		// Admin Page Layout
		echo '<div class="wrap">' . "\n";
		echo '	<h1>' . get_admin_page_title() . '</h1>' . "\n";
		echo '	<form action="options.php" method="post">' . "\n";

		settings_fields( 'fourthwall_settings_group' );
		do_settings_sections( 'fourthwall_settings_name' );
		submit_button();

		echo '	</form>' . "\n";
		echo ' <div><p>To use the fourthwall Embed, use the shortcode [fourthwall]</p></div>';
		echo '</div>' . "\n";

	}

	function render_fourth_url_field() {

		// Retrieve data from the database.
		$options = get_option( 'fourthwall_settings_name' );

		// Set default value.
		$value = isset( $options['fourth_url'] ) ? $options['fourth_url'] : '';

		// Field output.
		echo '<input type="url" name="fourthwall_settings_name[fourth_url]" class="regular-text fourth_url_field" placeholder="' . esc_attr__( 'https://some-shop.fourthwall.com', 'fourthwall_text_domain' ) . '" value="' . esc_attr( $value ) . '">';
		echo '<p class="description">' . __( 'The fourth wall URL', 'fourthwall_text_domain' ) . '</p>';

	}

}

new fourthwall_settings;