ISMAIL MASSERAN
97 lines
2.3 KiB
PHP
97 lines
2.3 KiB
PHP
<?php
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namespace App\Services;
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class PhysicalAttendanceGateCode
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{
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/** @var string */
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protected $secret;
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/** @var int */
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protected $period;
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public function __construct()
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{
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$this->secret = (string) config('physical_attendance_gate.secret');
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$this->period = max(30, (int) config('physical_attendance_gate.period_seconds', 60));
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}
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public function isConfigured()
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{
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return $this->secret !== '';
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}
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/**
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* Current code and countdown for the counter display.
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*
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* @param int $electionId
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* @return array{code:string,seconds_remaining:int,period_seconds:int}
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*/
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public function currentPayload($electionId)
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{
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$slot = $this->currentSlot();
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$code = $this->codeForSlot((int) $electionId, $slot);
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$expiresAt = ($slot + 1) * $this->period;
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$secondsRemaining = max(0, $expiresAt - time());
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return [
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'code' => $code,
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'seconds_remaining' => $secondsRemaining,
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'period_seconds' => $this->period,
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];
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}
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/**
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* Accept current, previous, or next slot to tolerate minor clock skew.
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*
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* @param int $electionId
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* @param string $input
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* @return bool
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*/
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public function validates($electionId, $input)
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{
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if (!$this->isConfigured()) {
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return false;
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}
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$normalized = strtoupper(preg_replace('/\s+/', '', (string) $input));
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if (strlen($normalized) < 4) {
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return false;
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}
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$slot = $this->currentSlot();
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foreach ([$slot - 1, $slot, $slot + 1] as $s) {
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if ($s < 0) {
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continue;
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}
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if (hash_equals($this->codeForSlot((int) $electionId, $s), $normalized)) {
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return true;
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}
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}
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return false;
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}
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protected function currentSlot()
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{
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return intdiv(time(), $this->period);
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}
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/**
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* Deterministic code for one election and time slot.
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*
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* @param int $electionId
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* @param int $slot
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* @return string
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*/
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protected function codeForSlot($electionId, $slot)
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{
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$material = (string) $electionId.'|'.(string) $slot;
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$hex = hash_hmac('sha256', $material, $this->secret);
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return strtoupper(substr($hex, 0, 8));
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}
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}
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