ET-VISA/database/seeders/AppointmentTableSeeder.php

<?php

namespace Database\Seeders;

use Illuminate\Database\Console\Seeds\WithoutModelEvents;
use Illuminate\Database\Seeder;
use App\Models\Appointment;
use Carbon\Carbon;
use Carbon\CarbonInterval;
use Illuminate\Support\Facades\DB;


class AppointmentTableSeeder extends Seeder
{
    /**
     * Run the database seeds.
     *
     * @return void
     */
    public function run()
    {
        
        $latestAppointment = DB::table('appointments')->latest('date')->first();
        $startDate = $latestAppointment ? Carbon::parse($latestAppointment->date)->addDay() : Carbon::now();

        $startTime = Carbon::parse("9:00 AM");
        $endTime = Carbon::parse("5:00 PM");
        
        foreach(config('custom.service_type') as $key => $value){

            for ($i = 0; $i < 7; $i++) {
                $date = $startDate->copy()->addDays($i);
                for ($j = 0; $j <= ((($endTime->diffInMinutes($startTime)) / 30)-1); $j++) {

                    $currentTime = $startTime->copy()->addMinutes(30 * $j);
                    $currentEndTime = $startTime->copy()->addMinutes(30 * $j + 30);

                    DB::table('appointments')->insert([
                        'date' => $date,
                        'start_time' => $currentTime->format("H:i A"),  
                        'end_time' => $currentEndTime->format("H:i A"),
                        'service_type' => $key
                    ]);
                }
            }
        }

    }
}