topnotch_website/app/Models/InvoiceReport.php

<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Factories\HasFactory;
use Illuminate\Database\Eloquent\Model;
use Illuminate\Database\Eloquent\Relations\BelongsTo;
use Illuminate\Database\Eloquent\Relations\BelongsToMany;
use Illuminate\Database\Eloquent\Relations\HasManyThrough;

class InvoiceReport extends Model
{
    use HasFactory;

    protected $fillable = [
        'internal_id',
        'customer_id',
        'date_start',
        'date_end',
        'filter_paid',
        'subtotal',
        'pst',
        'gst',
        'total',
    ];

    public static function boot(): void
    {
        parent::boot();

        static::created(function ($model) {
            $model->attributes['internal_id'] = 'TN-INR-'.$model->id;

            $invoices = Invoice::whereBetween('date', [$model->date_start, $model->date_end])
                ->where('customer_id', $model->customer_id)->get()->pluck('id')->toArray();

            $model->invoices()->sync($invoices);

            $model->save();
        });

        // todo: sync all invoices within time and customer constraints

    }

    public function customer(): BelongsTo
    {
        return $this->belongsTo(Customer::class);
    }

    public function invoices(): BelongsToMany
    {
        return $this->BelongsToMany(Invoice::class);
    }

    public function orders(): HasManyThrough
    {
        return $this->hasManyThrough(Order::class, Invoice::class);
    }
}