<?php

namespace App\Support;

use App\Enums\Invoice\InvoiceStatus;
use App\Models\Invoice;
use App\Models\Setting;
use Illuminate\Support\Facades\DB;

class VatNumbering
{
    public static function settle(Invoice $invoice): Invoice
    {
        VatCalculator::refresh($invoice);

        return self::issueIfAuto($invoice);
    }

    public static function issueIfAuto(Invoice $invoice): Invoice
    {
        if (!$invoice->vat_number
            && (int) $invoice->status === InvoiceStatus::PAID->value
            && (int) $invoice->total > 0
            && VatSettings::numbering()['auto_issue']) {
            return self::issue($invoice);
        }

        return $invoice;
    }

    public static function issue(Invoice $invoice): Invoice
    {
        return DB::transaction(function () use ($invoice) {
            $locked = Invoice::query()->with('customer')->lockForUpdate()->findOrFail($invoice->id);

            if ($locked->vat_number) {
                return $locked;
            }

            Setting::query()->firstOrCreate(['key' => VatSettings::NUMBERING_KEY], ['value' => json_encode(VatSettings::numbering())]);
            Setting::query()->where('key', VatSettings::NUMBERING_KEY)->lockForUpdate()->first();

            $config = VatSettings::numbering();
            VatCalculator::refresh($locked);

            $next = $config['next_number'];
            while (Invoice::query()->where('vat_serial', $config['serial'])->where('vat_number', self::format($next, $config['padding']))->exists()) {
                $next++;
            }

            $locked->fill([
                'vat_serial' => $config['serial'],
                'vat_number' => self::format($next, $config['padding']),
                'vat_issued_at' => now()->toDateString(),
                'buyer_snapshot' => InvoiceBuyer::fromCustomer($locked->customer),
            ])->save();

            VatSettings::saveNumbering([...$config, 'next_number' => $next + 1]);

            return $locked;
        });
    }

    private static function format(int $number, int $padding): string
    {
        return str_pad((string) $number, $padding, '0', STR_PAD_LEFT);
    }
}