61 lines
1.7 KiB
PHP
61 lines
1.7 KiB
PHP
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<?php
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namespace Modules\Booking\Services;
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use Modules\Booking\Models\Booking;
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class BookingRefGenerator
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{
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private const PREFIX = 'EVB';
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private const CHARS = '123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ';
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/**
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* Must be called inside the same DB::transaction() as the booking insert
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* — the row lock on the latest booking is what keeps concurrent callers
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* from generating the same ref, and it only holds for the transaction's
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* lifetime.
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*/
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public function generate(): string
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{
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// Lock the latest row so concurrent transactions can't read the same ref.
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$latest = Booking::lockForUpdate()->orderByDesc('id')->value('booking_ref');
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// If the latest ref doesn't match the expected format, start the sequence fresh.
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if ($latest && preg_match('/^[A-Z]+-[A-Z0-9]+$/', $latest)) {
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return $this->incrementRef($latest);
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}
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return self::PREFIX.'-AAAAA1';
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}
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private function incrementRef(string $ref): string
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{
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preg_match('/^(.*)-([A-Z0-9]+)$/', $ref, $matches);
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$prefix = $matches[1];
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$suffix = str_split($matches[2]);
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$base = strlen(self::CHARS);
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$i = count($suffix) - 1;
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$carry = true;
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while ($i >= 0 && $carry) {
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$idx = strpos(self::CHARS, $suffix[$i]);
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if ($idx + 1 < $base) {
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$suffix[$i] = self::CHARS[$idx + 1];
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$carry = false;
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} else {
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$suffix[$i] = self::CHARS[0];
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}
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$i--;
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}
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if ($carry) {
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array_unshift($suffix, self::CHARS[0]);
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}
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return $prefix.'-'.implode('', $suffix);
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}
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}
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