administraCursos/app/Semester.php

<?php

namespace App;

use Exception;
use Illuminate\Database\Eloquent\Model;

class Semester extends Model
{
    public $primaryKey = 'code';
    public $incrementing = false;
    public $timestamps = false;

    protected $keyType = 'string';
    protected $fillable = [
        'code',
        'alpha'
    ];


    public function courses() {
        return $this->belongsToMany(Course::class, 'sections');
    }

    public function sections() {
        return $this->hasMany(Section::class);
    }

    public function professors() {
        return $this->belongsToMany(Professor::class)->withPivot('admin_load', 'investigative_load');
    }

    public function getIsFutureAttribute() {
        return Semester::orderBy('code', 'desc')->take(6)->get()->contains('code', $this->code);
    }

    /**
     * Returns a clone of this semester with the provided code and alpha.
     * This functions also copies every section and professor_section
     *
     * @param string $newSemCode
     * @param string $newSemAlpha
     *
     * @return Semester
     */
    public function clone(string $newSemCode, string $newSemAlpha) {
        if (Semester::find($newSemCode)) {
            throw new Exception('A semester with code ' . $newSemCode . ' already exists');
        }
        $newSem = Semester::create([
            'code'  => $newSemCode,
            'alpha' => $newSemAlpha,
        ]);

        // Copy all sections to new semester
        foreach($this->sections as $section) {
            $sectionClone = $section->replicate();
            $sectionClone->semester_code = $newSem->code;
            $sectionClone->save();

            foreach($section->professors as $professor) {
                $sectionClone->professors()->attach($professor, ['percent' => $professor->pivot->percent]);
            }

            foreach($section->schedules as $schedule) {
                $sectionClone->schedules()->save($schedule);
            }
        }

        return $newSem;
    }

}