Initial commit

src/Subscriber.php

@@ -0,0 +1,74 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Nsq;
+
+use Generator;
+use LogicException;
+
+final class Subscriber
+{
+    private Reader $reader;
+
+    public function __construct(Reader $reader)
+    {
+        $this->reader = $reader;
+    }
+
+    /**
+     * @psalm-return Generator<int, Envelope|null, true|null, void>
+     */
+    public function subscribe(string $topic, string $channel, ?float $timeout = 0): Generator
+    {
+        $reader = $this->reader;
+        $reader->sub($topic, $channel);
+        $reader->rdy(1);
+
+        while (true) {
+            $message = $reader->consume($timeout);
+
+            if (null === $message) {
+                if (true === yield null) {
+                    break;
+                }
+
+                continue;
+            }
+
+            $finished = false;
+            $envelop = new Envelope(
+                $message,
+                static function () use ($reader, $message, &$finished): void {
+                    if ($finished) {
+                        throw new LogicException('Can\'t ack, message already finished.');
+                    }
+
+                    $finished = true;
+
+                    $reader->fin($message->id);
+                },
+                static function (int $timeout) use ($reader, $message, &$finished): void {
+                    if ($finished) {
+                        throw new LogicException('Can\'t retry, message already finished.');
+                    }
+
+                    $finished = true;
+
+                    $reader->req($message->id, $timeout);
+                },
+                static function () use ($reader, $message): void {
+                    $reader->touch($message->id);
+                },
+            );
+
+            if (true === yield $envelop) {
+                break;
+            }
+
+            $reader->rdy(1);
+        }
+
+        $reader->close();
+    }
+}