Grab first sentence of from Instagram and make it a post title. Available for multiple categories with personal excerpts and create single WordPress posts without a plugin

instagram.php

add_action( 'save_post', 'save_post_wpse_87921', 10, 2 );

function strposa($haystack, $needles=array(), $offset=0) {
        $chr = array();
        foreach($needles as $needle) {
                $res = strpos($haystack, $needle, $offset);
                if ($res !== false) {
            $chr[$needle] = $res;
        }
    }
    if(empty($chr)) {
        return false;
    }
    return min($chr);
}

function save_post_wpse_87921( $post_id, $post_object ){

    if (defined('DOING_AUTOSAVE') && DOING_AUTOSAVE) {
        return $post_id;
    }

    if(has_excerpt($post_id)){
                return;
            }

	$title_delimiters = array('.', '!', '?');
	$new_title = substr($post_object->post_title, 0, strposa($post_object->post_title, $title_delimiters)+1);

    remove_action( 'save_post', 'save_post_wpse_87921' );

    // Call wp_update_post update, which calls save_post again.
    if ( in_category( 'category-1', $post_id )&& has_tag('instagram', $post_id)) {
            // Update post
            $my_post = array(
                'ID' => $post_id,
                'post_title' => $new_title,
                'post_name' => '',
                'post_excerpt' => 'This is the personal excerpt for Category 1. Change this into whatever you'd like.' );

            // Update the post into the database
            wp_update_post( $my_post );
        //    set_post_format($post_id, 'image');
        }

        if ( in_category( 'category-2', $post_id )&& has_tag('instagram', $post_id)) {
            // Update post
            $my_post = array(
                'ID' => $post_id,
                'post_title' => $new_title,
                'post_name' => '',
                'post_excerpt' => 'This is the custom excerpt for the second category. You can change this into whatever you'd like.' );

            // Update the post into the database
            wp_update_post( $my_post );
        //    set_post_format($post_id, 'image');
        }

		if ( in_category( 'category-3', $post_id )&& has_tag('instagram', $post_id)) {
            // Update post
            $my_post = array(
                'ID' => $post_id,
                'post_title' => $new_title,
                'post_name' => '',
                'post_excerpt' => 'This is the custom excerpt for the third category. Change this into whatever you'd like as an excerpt.' );

            // Update the post into the database
            wp_update_post( $my_post );
        //    set_post_format($post_id, 'image');
        }

    add_action( 'save_post', 'save_post_wpse_87921', 10, 2 );
}