Query Taxonomy and Show terms into post and pages Plugin (Add this inside another folder)

tax_query.php

<?php
/*
Plugin Name: Tax Query
Plugin URI:
Description: Prints Taxonomies into post or pages
Version: 1.0
Author: Juan Pablo De la torre
Author URI:
License: GPL2
licence URI: https://www.gnu.org/licenses/gpl2-.0.html
*/

function show_taxonomies(){
  add_meta_box('ga-metaboxes', 'Show Taxonomies', 'taxonomies_container', array('post', 'page'), 'normal', 'high', null);
}
add_action('add_meta_boxes', 'show_taxonomies');

function taxonomies_container($post) {
  wp_nonce_field(basename(__FILE__), "meta-box-nonce" );
  ?>
  
  Mood:
  
<?php 
    $terms = get_terms( 'mood', array(
        'hide_empty' => false,
    ) );
   ?>
 
 <select name="mood">
   <?php foreach($terms as $key => $term): 
         if($term->term_taxonomy_id == get_post_meta($post->ID, "mood", true )) {
           echo '<option selected>' . $term->name . '</option>';
           
         } else {
           echo '<option value="' . $term->term_taxonomy_id . '">' . $term->name . '</option>';
         }
         
    endforeach; ?>
 </select>

<?php  
 
}

add_action('save_post', 'tax_save_post');
function tax_save_post($post_id, $post, $update){
   if (!isset($_POST["meta-box-nonce"]) || !wp_verify_nonce($_POST["meta-box-nonce"], basename(__FILE__)))
       return $post_id;

   if(!current_user_can("edit_post", $post_id))
       return $post_id;

   if(defined("DOING_AUTOSAVE") && DOING_AUTOSAVE)
       return $post_id;

    $input_metabox ='';
    $textarea_metabox ='';
    $dropdown_metabox = '';
    $mood = '';

    if(isset($_POST["mood"])) {
      $mood = $_POST["mood"];
    }
    update_post_meta($post_id, "mood", $mood );
    
}