Initialize Nest events library.

.gitignore

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+# IDEA
+.idea/
+*.iml
+
+# Composer
+vendor/

composer.json

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+{
+	"version": "1.0",
+	"name": "nest/events",
+	"description": "Nest events implementation.",
+	"type": "library",
+	"authors": [
+		{
+			"name": "Madeorsk",
+			"email": "madeorsk@protonmail.com"
+		}
+	],
+	"autoload": {
+		"psr-4": {
+			"Nest\\Events\\": "src/"
+		}
+	},
+	"repositories": [
+		{
+			"type": "vcs",
+			"url": "https://code.zeptotech.net/Nest/Core"
+		}
+	],
+	"require": {
+		"php": "^8.3",
+		"nest/core": "dev-main"
+	}
+}

composer.lock

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+{
+    "_readme": [
+        "This file locks the dependencies of your project to a known state",
+        "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#installing-dependencies",
+        "This file is @generated automatically"
+    ],
+    "content-hash": "4185bcac56ba1943814494a50cebd442",
+    "packages": [
+        {
+            "name": "nest/core",
+            "version": "dev-main",
+            "source": {
+                "type": "git",
+                "url": "https://code.zeptotech.net/Nest/Core",
+                "reference": "22296b8d7c8b528089189a8d9500395424cb6468"
+            },
+            "require": {
+                "php": "^8.3"
+            },
+            "default-branch": true,
+            "type": "library",
+            "autoload": {
+                "psr-4": {
+                    "Nest\\": "src/"
+                },
+                "files": [
+                    "src/Utils/Array.php",
+                    "src/Utils/Paths.php",
+                    "src/Utils/Reflection.php",
+                    "src/Utils/String.php"
+                ]
+            },
+            "authors": [
+                {
+                    "name": "Madeorsk",
+                    "email": "madeorsk@protonmail.com"
+                }
+            ],
+            "description": "Nest framework core.",
+            "time": "2024-11-08T11:12:38+00:00"
+        }
+    ],
+    "packages-dev": [],
+    "aliases": [],
+    "minimum-stability": "stable",
+    "stability-flags": {
+        "nest/core": 20
+    },
+    "prefer-stable": false,
+    "prefer-lowest": false,
+    "platform": {
+        "php": "^8.3"
+    },
+    "platform-dev": {},
+    "plugin-api-version": "2.6.0"
+}

src/Event.php

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+<?php
+
+namespace Nest\Events;
+
+abstract class Event
+{
+}

src/EventsManager.php

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+<?php
+
+namespace Nest\Events;
+
+use Nest\Exceptions\InvalidTypeException;
+use function Nest\Utils\expect_type;
+use function Nest\Utils\get_all_classes;
+
+/**
+ * Events manager class.
+ */
+class EventsManager
+{
+	/**
+	 * Events listeners.
+	 * If false is returned, stop event propagation.
+	 * @var array<class-string, (callable(Event $event): (void|bool))[]>
+	 */
+	protected array $listeners = [];
+
+	/**
+	 * Add an event listener to the listeners list.
+	 * @template T of Event
+	 * @param class-string<T> $eventType The event type class to listen for.
+	 * @param callable(T $event): (void|bool) $listener The event listener to add. If false is returned, stop event propagation.
+	 * @return void
+	 * @throws InvalidTypeException
+	 */
+	public function addListener(string $eventType, callable $listener): void
+	{
+		expect_type($eventType, Event::class);
+
+		// Initialize the listeners list if it's empty.
+		if (empty($this->listeners[$eventType])) $this->listeners[$eventType] = [];
+		// Add the listener.
+		$this->listeners[$eventType][] = $listener;
+	}
+
+	/**
+	 * Remove the given listener from the listeners list.
+	 * @template T of Event
+	 * @param class-string<T> $eventType The event type class.
+	 * @param callable(T $event): (void|bool) $listener The listener to remove.
+	 * @return void
+	 * @throws InvalidTypeException
+	 */
+	public function removeListener(string $eventType, callable $listener): void
+	{
+		expect_type($eventType, Event::class);
+
+		if (!empty($this->listeners[$eventType]))
+		{
+			foreach ($this->listeners[$eventType] as $key => $currentListener)
+			{ // For each listeners, if it's matching the given one, remove it.
+				if ($currentListener == $listener) unset($this->listeners[$eventType][$key]);
+			}
+		}
+	}
+
+	/**
+	 * Fire an event.
+	 * @param Event $event The event to fire.
+	 * @return void
+	 */
+	public function fire(Event $event): void
+	{
+		foreach (get_all_classes($event) as $className)
+		{ // For each class, from the most specific to the least specific.
+			if (!empty($this->listeners[$className]))
+			{ // If there are listeners for the current class.
+				foreach ($this->listeners[$className] as $listener)
+				{ // Call each listener.
+					$result = $listener($event);
+					if ($result === false)
+						// If the result is false, stop firing.
+						return;
+				}
+			}
+		}
+	}
+}

src/HasEvents.php

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+<?php
+
+namespace Nest\Events;
+
+use Nest\Exceptions\InvalidTypeException;
+
+trait HasEvents
+{
+	/**
+	 * Events manager instance.
+	 * @var EventsManager
+	 */
+	private EventsManager $eventsManager;
+
+	/**
+	 * Get the current instance of the events manager.
+	 * @return EventsManager - The events manager.
+	 */
+	protected function getEventsManager(): EventsManager
+	{
+		// If there is no instance, initializing one.
+		if (empty($this->eventsManager)) $this->eventsManager = new EventsManager();
+
+		return $this->eventsManager;
+	}
+
+	/**
+	 * Add a listener for the given event type.
+	 * @template T of Event
+	 * @param class-string<T> $eventType The event type class to listen for.
+	 * @param callable(T $event): (void|bool) $eventListener The event listener. If false is returned, stop event propagation.
+	 * @return void
+	 * @throws InvalidTypeException
+	 */
+	public function listen(string $eventType, callable $eventListener): void
+	{
+		$this->getEventsManager()->addListener($eventType, $eventListener);
+	}
+}