/**
 * WordPress 修改更新文章后邮件通知评论过那篇文章的用户 - 龙笑天下
 * https://www.ilxtx.com/notify-comment-authors-when-the-post-is-updated.html
 */
//修改更新文章时邮件通知评论用户
add_action( 'submitpost_box', 'lxtx_fo_submit_box');
function lxtx_fo_submit_box( ){
echo '<div id="fo_side-sortables" class="meta-box-sortables ui-sortable">';
echo '<div id="fo_submit_box" class="postbox ">';
echo '<div class="handlediv" title="点击以切换"><br></div>';
echo '<h3 class="hndle"><span>邮件通知</span></h3>';
echo '<div class="inside"><div class="submitbox">';
echo ' <div style="padding: 10px 10px 0;text-align: left;"><label class="selectit" title="慎用此功能，重要文章才勾选嘛，以免引起读者反感哈"><input type="checkbox" name="FO_emaill_report_user" value="true" title="勾选此项，将邮件通知本文所有评论者"/>邮通知本文所有评论者</label></div>';
echo '</div></div>';
echo '</div>';
echo '</div>';
}
//开始
add_action( 'publish_post', 'lxtx_fo_emaill_report_users' );
function lxtx_fo_emaill_report_users($post_ID)
{
//如果未勾选保存，不进行任何操作
if($_POST['FO_emaill_report_user'] != 'true'){
return;
}

//修订版本不通知，以免滥用
if( wp_is_post_revision($post_ID) ){
return;
}

//获取 wp 数据操作类
global $wpdb,$post;
// 读数据库，获取文章的所有用户的 email 并且不重复
$emailauthor != '你自己的邮箱';
$wp_user_emails = $wpdb->get_results("SELECT DISTINCT comment_author, comment_author_email FROM $wpdb->comments WHERE TRIM(comment_author_email) IS NOT NULL AND TRIM(comment_author_email) != '' AND TRIM(comment_author_email) != '$emailauthor' AND comment_post_ID = $post->ID");

// 获取博客名称
$blogname = wp_specialchars_decode(get_option('blogname'), ENT_QUOTES);
// 获取博客 URL
$blogurl = get_bloginfo("siteurl");

//文章链接
$post_link = get_permalink($post_ID);
//文章标题$post -> post_title
$post_title = strip_tags($_POST['post_title']);
//文章内容$post->post_content
$post_content = strip_tags($_POST['post_content']);
//文章摘要
$output = preg_replace('/^(?:[x00-x7F]|[xC0-xFF][x80-xBF]+){0,0}((?:[x00-x7F]|[xC0-xFF][x80-xBF]+){0,200}).*/s','1',$post_content).'......';

//邮件头，以免乱码
$message_headers = "Content-Type: text/html; charset="utf-8"n";
// 邮件标题
$subject = '您曾经来访过的《'.$post_title.'》文章更新通知。';

foreach ( $wp_user_emails as $wp_user_email )
{
// 邮件内容
$message = '
<div style="MARGIN-RIGHT: auto; MARGIN-LEFT: auto;">
<strong style="line-height: 1.5; font-family:Microsoft YaHei;">
亲爱的'.$wp_user_email->comment_author.'：
</strong>
<p style="FONT-SIZE: 14px; PADDING-TOP: 6px">
您曾经来访过的《'.$post_title.'》有更新，博主觉得有必要通知您，希望不会骚扰到您。
</p>
<p style="FONT-SIZE: 14px; PADDING-TOP: 6px">
文章标题：<a title="'.$post_title.'" href="'.$post_link.'" target="_top">'.$post_title.'</a>
<br/>
文章摘要：'.$output.'
</p>
<p style="FONT-SIZE: 14px; PADDING-TOP: 6px">
您可以点击链接
<a href="'.$blogurl.'" style="line-height: 1.5;">'.$blogname.'</a>
>
<a title="'.$post_title.'" href="'.$post_link.'" target="_top">'.$post_title.'</a>
详细查看
</p>
<p style="font-size: 14px; padding-top: 6px; text-align: left;">
<span style="line-height: 1.5; color: rgb(153, 153, 153);">
来自：
</span>
<a href="'.$blogurl.'" style="line-height: 1.5;">'.$blogname.'</a>
</p>
<div style="font-size: 12px; border-top-color: rgb(204, 204, 204); border-top-width: 1px; border-top-style: solid; height: 35px; width: 500px; color: rgb(102, 102, 102); line-height: 35px; background-color: rgb(245, 245, 245);">
该邮件为系统发送邮件，请勿直接回复！如有打扰，请向博主留言反映。灰常感谢您的阅读！
</div>
</div>';
wp_mail($wp_user_email->comment_author_email, $subject, $message, $message_headers);
}
}