How to avoid adding an event that conflicts with another event schedule?

For my project I am using laravel and also used fullcalendar to display the events I made I have already made the code to add and update event details.

What I want to know is how can I add an event and also make sure that that specific timeslot is available and it won't cause conflict with another event?

My EventController.php

public function ajaxget(){


        $ev = event::select('id as id', 'event_name as title', 'event_start as start', 'event_finish as end', 'event_dow as dow')->where('user_id', Auth::user()->id)->get();
        // Return as json
        return response()->json($ev);
}

public function store(Request $request)
{

     //dd($request);

     $this->validate($request, [
        'event_name' => 'required|string|min:2|max:255',
        'daterange' => 'required',
    ]);


     $tempDate = $request->input('daterange');
     $temp2 = str_replace('-', null, $tempDate);
     $temp2 = str_replace('/', '-', $temp2);
     $temp3 = explode('  ', $temp2);

     $date1 = date_create_from_format('m-d-Y', $temp3[0]);
     $date2 = date_create_from_format('m-d-Y', $temp3[1]);
     $tempdate1 = date_format($date1, 'Y-m-d');
     $tempdate2 = date_format($date2, 'Y-m-d');

     $time_start = $request->input('start_time');
     $time_end = $request->input('end_time');

     $combinedDT1 = date('Y-m-d H:i:s', strtotime("$tempdate1 $time_start"));
     $combinedDT2 = date('Y-m-d H:i:s', strtotime("$tempdate2 $time_end"));

    $event_dow = [];

     if($request->has('monCheck'))
     {
        $event_dow[] = (int)$request->monCheck;
    };

    if($request->has('tueCheck'))
    {
        $event_dow[] = (int)$request->tueCheck;
    };

    if($request->has('wedCheck'))
    {
        $event_dow[] = (int)$request->wedCheck;
    };

    if($request->has('thurCheck'))
    {
        $event_dow[] = (int)$request->thurCheck;
    };

    if($request->has('friCheck'))
    {
        $event_dow[] = (int)$request->friCheck;
    };

    if($request->has('satCheck'))
    {
        $event_dow[] = (int)$request->satCheck;
    };

    if($request->has('sunCheck'))
    {
        $event_dow[] = (int)$request->sunCheck;
    };

    //$eventDow = implode(',', $event_dow);

    $event = new event([
        'event_name' => $request->input('event_name'),
        'event_desc' => $request->input('event_desc'),
        'event_venue' => $request->input('event_venue'),
        'event_start' => $combinedDT1,
        'event_finish' => $combinedDT2,


        'event_dow' => $event_dow, //days of week
        'evcat_id' => $request->input('evcat_id'),
        'user_id' => $request->input('user_id')


        ]);

    $event->save();
    Session::flash('success', 'Event Created Successfully');
    return redirect()->route('event.sched');

}

My calendar view

I want to avoid instances such as these that have 2 events that clash with each others schedules.

via Chebli Mohamed