A solution for adding tags in Laravel

In a form, I have a Tags field, which is a just a standard text field. A user can type a Tag name and it is added to the article.

I already have three tables: tags, taggables and articles and they are linked via Eloquent relationship methods, given the setup in a previous question I asked.

This is my update method in my ArticleController

/**
 * Update the specified resource in storage.
 *
 * @param  \Illuminate\Http\Request  $request
 * @param  int  $id
 * @return \Illuminate\Http\Response
 */
public function update(Request $request, $id)
{
    $validatedData = $request->validate([
        'title' => 'required',
        'excerpt' => 'required',
    ]);

    $article = Article::find($id);

    $article->title = $request->get('title');
    $article->author = $request->get('author');
    $article->category = $request->get('category');
    $article->excerpt = $request->get('excerpt');
    $article->content = $request->get('content');
    $article->featuredImage = $request->get('featuredImage');
    $article->featuredVideo = $request->get('featuredVideo');
    $article->readingTime = $request->get('readingTime');
    $article->published = $request->get('published');

    $article->save();

    /**
     * Once the article has been saved, we deal with the tag logic.
     * Grab the tag or tags from the field, sync them with the article
     */
    $tags = $request->get('tags');
    $comma = ',';

    if (!empty($tags)) {
        if (strpos($tags, $comma) !== false) {
            $tagList = explode(",", $tags);

            // Loop through the tag array that we just created
            foreach ($tagList as $tags) {

                // Get any existing tags
                $tag = Tag::where('name', '=', $tags)->first();

                // If the tag exists, sync it, otherwise create it
                if ($tag != null) {
                    $article->tags()->sync($tag->id);
                } else {
                    $tag = new Tag();

                    $tag->name = $tags;
                    $tag->slug = str_slug($tags);

                    $tag->save();

                    $article->tags()->sync($tag->id);
                }
            }
        } else {
            // Only one tag
            $tag = Tag::where('name', '=', $tags)->first();

            if ($tag != null) {
                $article->tags()->sync($tag->id);
            } else {
                $tag = new Tag();

                $tag->name = $tags;
                $tag->slug = str_slug($tags);

                $tag->save();

                $article->tags()->sync($tag->id);
            }
        }
    }

    return back();
    return redirect()->back();
}

In the section of this method that looks for tags, I do the following things:

1. Check if the field is not empty
2. Check if the string sent contains a comma
3. If there is a comma, I use explode() to convert the string into an array
4. Loop through the array to see if the given tag within the string already exists
5. If it doesn't exist, I create it and then sync it with the Article, otherwise I just sync it

This approach feels very messy, however, is there any way I could make this cleaner?

via Chebli Mohamed