Creating a shortcode in WordPress

Hello I’m trying to turn a function into a shortcode. I’ve read how to create a shortcode however, when I turn my function into a shortcode I get a different output.

Basically whenever you click on an area of focus all teachers associated with that area will show .

The code below works perfectly.

`<?php $schools = $post->ID; // the current post id ?>

<?php
$args = array(
‘post_type’ => ‘teacher’,
‘meta_query’ => array(
array(
‘key’ => ‘areas_of_focus’,
‘value’ => $schools,
‘compare’ => ‘LIKE’,
),
),
);

$schools_data_query = new WP_Query($args);

?>

<?php

if ( $schools_data_query->have_posts() ) {
echo ‘<ul>’;
while ( $schools_data_query->have_posts() ) {
$schools_data_query->the_post();
//echo ‘<li>’ . get_the_title() . ‘</li>’;
//echo ‘<li>’ . get_permalink() . ‘</li>’; ?>
<li><a href=”<?php the_permalink(); ?>” title=”<?php the_title_attribute(); ?>”><?php the_title(); ?></a></li>

<?php
}
echo ‘</ul>’;
} else {
// no posts found
}`

Now I want to turn it into a shortcode. Here is what I have so far

` function gm_list_teacher_shortcode($atts){
$args = array(
‘post_type’ => ‘teacher’,
‘meta_query’ => array(
array(
‘key’ => ‘areas_of_focus’,
‘value’ => $schools,
‘compare’ => ‘LIKE’,
),
),
);

$schools_data_query = new WP_Query($args);

global $post;
$schools = $post->ID;

$content = ”;
$content .= ‘<ul>’;

while($schools_data_query->have_posts()) : $schools_data_query->the_post();

$content .= ‘<li><a href=”‘.get_permalink().'”>’.get_the_title().'</a></li>’;

endwhile;

$content .= ‘</ul>’;

wp_reset_query();

return $content;
}

add_shortcode(‘gm_list_teacher’, ‘gm_list_teacher_shortcode’);`

However when I use this shortcode no matter what area of focus I click on the same teachers show. I believe when creating the shortcode I’m no addressing the following line correctly

$schools = $post->ID;

Any help would be really appreciated. I’m in no way a great programmer. Thank you