Laravel - project update with revision

projectController.php

<?php 

public function update(Request $request, $id)
{
    $this->validate($request, [
        'number'      => 'required',
        'client_id'   => 'required',
        'location_id' => 'required',
        'priority_id' => 'required',
        'status_id'   => 'required',
        'date'        => 'required',
    ], [
        'client_id.required'   => 'The client field is required.',
        'location_id.required' => 'The location field is required.',
        'priority_id.required' => 'The priority field is required.',
        'status_id.required'   => 'The status field is required.',
    ]);

    $tenant  = getCurrentTenant();
    $project = $tenant->projects()->where('id', $id)->first();
    
    //Using array diff to remove unwanted columns. 
    $before                = array_diff_key($project->toArray(), array_flip(['created_at', 'updated_at', 'status_id', 'priority_id', 'client_id']));
    $before['inventories'] = $project->inventories()->with(['material' => function ($query) { $query->select('id', 'type'); }])->get()->toArray();
    $before['tags']        = $project->tags()->pluck('tag')->toArray();
    $before['managers']    = $project->managers()->pluck('name')->toArray();
    $before['locations']   = $project->locations()->pluck('location')->toArray();
    $before['status']      = $project->status->status;
    $before['priority']    = $project->priority->priority;
    $before['client']      = $project->client->name;

    $projectNum = $request->input('number');
    if ($projectNum != $project->number) {
        $projectNum = getUniqueNumber('App\Project', $projectNum);
        $request->offsetSet('number', $projectNum);
    }

    $project->update($request->all());

    $project->locations()->sync([$request->input('location_id')]);

    if (! empty($request->input('manager_id'))) {
        $project->managers()->sync([$request->input('manager_id')]);
    } else {
        $project->managers()->detach();
    }

    if (! empty($request->input('tag_id'))) {
        $project->tags()->sync($request->input('tag_id'));
    } else {
        $project->tags()->detach();
    }

    $project->inventories()->delete();
    $inventoryRows = count($request->input('inventory')['material_id']);
    $inventories   = [];

    for ($i = 0; $i < $inventoryRows; $i++) {
        $row              = 'row-'.($i + 1);
        $materialId       = $request->input('inventory')['material_id'][$row][0];
        $dateOrdered      = $this->normalizeDate($request->input('inventory')['date_ordered'][$row][0]);
        $estimatedArrival = $this->normalizeDate($request->input('inventory')['estimated_arrival'][$row][0]);
        $isArrived        = $request->input('inventory')['is_arrived'][$row][0] ?? 0;

        if ($materialId) {
            $inventories[] = [
                'company_id'        => $tenant->id,
                'project_id'        => $project->id,
                'material_id'       => $materialId,
                'date_ordered'      => $dateOrdered,
                'estimated_arrival' => $estimatedArrival,
                'is_arrived'        => $isArrived
            ];
        }
    }

    if (count($inventories)) {
        DB::table('inventories')->insert($inventories);
    }

    $after                = array_diff_key($project->toArray(), array_flip(['created_at', 'updated_at', 'status_id', 'priority_id', 'client_id']));
    $after['inventories'] = $project->fresh()->inventories()->with(['material' => function ($query) { $query->select('id', 'type'); }])->get()->toArray();
    $after['tags']        = $project->tags()->pluck('tag')->toArray();
    $after['managers']    = $project->managers()->pluck('name')->toArray();
    $after['locations']   = $project->locations()->pluck('location')->toArray();
    $after['status']      = $project->fresh()->status->status;
    $after['priority']    = $project->fresh()->priority->priority;
    $after['client']      = $project->fresh()->client->name;

    $changes = getChanges($before, $after);

    if (count($changes)) {
        $project->revisions()->create([
            'company_id'        => $tenant->id,
            'user_id'           => Auth::id(),
            'revisionable_id'   => $project->id,
            'revisionable_type' => get_class($this),
            'before'            => $before,
            'changes'           => $changes,
            'after'             => $after,
        ]);
    }

    \Session::flash('flash_message', 'Project has been updated successfully');
    return redirect()->route('projects.show', [$id]);
}