Constructeur de module d’emails dont les contenus sont administrables dans ACF

mail-acf-fields.php

<?php
add_action( 'admin_menu', 'register_option_page', 10 );
function register_option_page() {
	if( function_exists( 'acf_add_options_page' ) ) {
		acf_add_options_page( array(
		'page_title'  => 'Réglages des emails',
		'menu_title'  => 'Réglages',
		'menu_slug'   => 'emails-settings',
		'capability'  => 'manage_options',
		'redirect'    => false,
		) );
	}
}

add_action( 'admin_init', 'load_acf_fields', 9 );
add_action( 'init', 'load_acf_fields', 9 );
function load_acf_fields() {
	if ( function_exists('acf_add_local_field_group') ):
		$format = array(
			// ici on peut créer de nouveaux mails
			array(
				'title' => 'Exemple de mail',
				'slug' => 'email_user_demo',
				'placeholders' => array( 
					'%accueil%',
					'%user_id%',
					'%display_name%',
					'%prenom%',
					'%email%',
					'%login%',
				),
				'to' => true,
			),
		);
	
		// Plus touche à la suite
		$fields_emails = array();
		foreach ( $format as $k => $args ) {
			$fields_emails[] = array (
				'key' => 'field_' . substr( md5( $args['slug'] . 'tab' ), 0, 13 ),
				'label' => ucfirst( $args['title'] ),
				'name' => '',
				'type' => 'tab',
				'instructions' => '',
				'required' => 0,
				'conditional_logic' => 0,
				'wrapper' => array (
					'width' => '',
					'class' => '',
					'id' => '',
				),
				'placement' => 'top',
				'endpoint' => 0,
			);
			if ( ! empty( $args['to'] ) ) {
				$fields_emails[] = array (
					'key' => 'field_' . substr( md5( $args['slug'] . 'dest' ), 0, 13 ),
					'label' => 'Destinataire de l’email de ' . $args['title'],
					'name' => $args['slug'] . '_destinataire',
					'type' => 'email',
					'instructions' => '',
					'required' => 0,
					'conditional_logic' => 0,
					'wrapper' => array (
						'width' => '50',
						'class' => '',
						'id' => '',
					),
					'default_value' => '',
					'placeholder' => '',
					'prepend' => '',
					'append' => '',
					'maxlength' => '',
				);
			}
			$fields_emails[] = array (
				'key' => 'field_' . substr( md5( $args['slug'] . 'title' ), 0, 13 ),
				'label' => 'Titre de l’email de ' . $args['title'],
				'name' => $args['slug'] . '_title',
				'type' => 'text',
				'instructions' => '',
				'required' => 0,
				'conditional_logic' => 0,
				'wrapper' => array (
					'width' => ! empty( $args['to'] ) ? '50' : '100',
					'class' => '',
					'id' => '',
				),
				'default_value' => '',
				'placeholder' => '',
				'prepend' => '',
				'append' => '',
				'maxlength' => '',
			);
			$fields_emails[] = array (
				'key' => 'field_' . substr( md5( $args['slug'] . 'from_name' ), 0, 13 ),
				'label' => 'Nom de l’expéditeur',
				'name' => $args['slug'] . '_from_name',
				'type' => 'text',
				'instructions' => '',
				'required' => 0,
				'conditional_logic' => 0,
				'wrapper' => array (
					'width' => '50',
					'class' => '',
					'id' => '',
				),
				'default_value' => '',
				'placeholder' => '',
				'prepend' => '',
				'append' => '',
				'maxlength' => '',
			);
			$fields_emails[] = array (
				'key' => 'field_' . substr( md5( $args['slug'] . 'from_email' ), 0, 13 ),
				'label' => 'Addresse email de l’expéditeur',
				'name' => $args['slug'] . '_from_email',
				'type' => 'email',
				'instructions' => '',
				'required' => 0,
				'conditional_logic' => 0,
				'wrapper' => array (
					'width' => '50',
					'class' => '',
					'id' => '',
				),
				'default_value' => '',
				'placeholder' => '',
				'prepend' => '',
				'append' => '',
				'maxlength' => '',
			);
			$fields_emails[] = array (
				'key' => 'field_' . substr( md5( $args['slug'] ), 0, 13 ),
				'label' => 'Email de ' . $args['title'],
				'name' => $args['slug'],
				'type' => 'textarea',
				'instructions' => wp_sprintf( __( 'Vous pouvez utiliser les tags %l dans le corps du message.', 'w-espace-client' ), array_map( function ($el) {
					return "<code>{$el}</code>";
				} , $args['placeholders'] ) ),
				'required' => 0,
				'conditional_logic' => 0,
				'wrapper' => array (
					'width' => '',
					'class' => '',
					'id' => '',
				),
				'default_value' => '',
				'rows' => 20,
				'tabs' => 'all',
				'toolbar' => 'full',
				'media_upload' => 1,
				'delay' => 1,
			);
		}

		acf_add_local_field_group(array (
			'key' => 'group_5956912dbe16c',
			'title' => 'Formats d’emails',
			'fields' => $fields_emails,
			'location' => array (
				array (
					array (
						'param' => 'options_page',
						'operator' => '==',
						'value' => 'emails-settings',
					),
				),
			),
			'menu_order' => 10,
			'position' => 'normal',
			'style' => 'default',
			'label_placement' => 'top',
			'instruction_placement' => 'label',
			'hide_on_screen' => '',
			'active' => 1,
			'description' => '',
		));
	endif;
}

mail-functions.php

<?php

// Cette fonction peut être appelée quand on veut dans le template
function send_user_email_demo( $user_id ) {
	$wrapper_title = 'options_email_user_demo';
	if ( $email_inscription = get_option( $wrapper_title, '' ) ) {
		$email_inscription = base64_decode( $email_inscription );
	}
	$email_subject  = get_option( "{$wrapper_title}_from_name", sprintf( __( 'Nouveau message de %s', 'w-espace-client' ), get_bloginfo( 'name' ) ) );
	$user           = new WP_User( $user_id );
	$email          = get_option( "{$wrapper_title}_destinataire", $user->user_email );
	$emetteur_name  = sanitize_text_field( get_option( "{$wrapper_title}_from_name", get_bloginfo( 'name' ) ) );
	$emetteur_email = sanitize_email( get_option( "{$wrapper_title}_from_email", get_option( 'admin_email' ) ) );
	$emetteur       = "{$emetteur_name} <{$emetteur_email}>";
	
	// les tags doivent matcher ceux proposés dans les champs ACF
	$replace = array(
		'%accueil%'      => get_permalink( get_option( 'page_on_front' ) ),
		'%user_id%'      => $user->ID,
		'%display_name%' => $user->display_name,
		'%prenom%'       => $user->first_name,
		'%email%'        => $user->email,
		'%login%'        => $user->user_login,
	);
	
	$mail = str_ireplace( array_keys( $replace ), array_values( $replace ), $email_inscription );
	$email_subject = str_ireplace( array_keys( $replace ), array_values( $replace ), $email_subject );
	wp_mail( $email, $email_subject, $mail, array(
		"From: {$emetteur}",
		"Reply-To: {$emetteur}",
		'Content-type: text/html',
	) );
}

mail-sanitize-acf-fields.php

<?php

// on base_encode le contenu du mail par défaut (pour eviter tout formattage via ACF)
function is_special_mail_textarea( $name ) {
	$mails = array(
		'options_email_user_demo',
	);
	return in_array( $name, $mails );
}

add_filter( 'acf/update_value/type=textarea', 'need_sanitize_mail' , 10, 3);
function need_sanitize_mail( $value, $post_id, $field ) {
	if ( $post_id === 'options' && is_special_mail_textarea( $field['name'] ) ) {
		$value = base64_encode( stripslashes( $value ) );
	}
	return $value;
}

add_filter( 'acf/load_value/type=textarea', 'need_unsanitize_mail' , 10, 3);
function need_unsanitize_mail( $value, $post_id, $field ) {
	if ( $post_id === 'options' && is_special_mail_textarea( $field['name'] ) ) {
		$value = base64_decode( $value );
	}
	return $value;
}