From 4fad1fa4f46c5bbc9c4ee68f8b099f1caded5966 Mon Sep 17 00:00:00 2001
From: Greg Marshall <greg@alley.co>
Date: Wed, 20 Dec 2023 19:17:41 -0600
Subject: [PATCH 01/10] WIP: issue-293


From f81286cfe41f170da0e0858990ddfbe1889bd453 Mon Sep 17 00:00:00 2001
From: Greg Marshall <greg@alley.co>
Date: Wed, 20 Dec 2023 20:35:12 -0600
Subject: [PATCH 02/10] add feature-manager

---
 plugin.php                    |  10 +++-
 src/class-feature-manager.php | 105 ++++++++++++++++++++++++++++++++++
 2 files changed, 114 insertions(+), 1 deletion(-)
 create mode 100644 src/class-feature-manager.php

diff --git a/plugin.php b/plugin.php
index 54efe700..7882d540 100644
--- a/plugin.php
+++ b/plugin.php
@@ -58,11 +58,19 @@ function () {
 // Load the plugin's main files.
 require_once __DIR__ . '/src/assets.php';
 require_once __DIR__ . '/src/meta.php';
+require_once __DIR__ . '/src/class-feature-manager.php';
 
 /**
  * Instantiate the plugin.
  */
 function main(): void {
-	// ...
+
+	$features =[
+		'Create_WordPress_Plugin\Features\Featured_Image_Caption' => [],
+	];
+	$features = apply_filters( 'create_wordpress_plugin_features', $features );
+
+	$feature_manager = new Feature_Manager( $features );
+	$feature_manager->boot();
 }
 main();
diff --git a/src/class-feature-manager.php b/src/class-feature-manager.php
new file mode 100644
index 00000000..bd857573
--- /dev/null
+++ b/src/class-feature-manager.php
@@ -0,0 +1,105 @@
+<?php
+/**
+ * Class to manage plugin features.
+ *
+ * @package create-wordpress-plugin
+ */
+
+namespace Create_WordPress_Plugin;
+
+use \Alley\WP\Types\Feature;
+
+class Feature_Manager implements Feature {
+	/**
+	 * Collected features.
+	 *
+	 * @var Feature[]
+	 */
+	private array $features;
+
+    /**
+     * Have the features been booted?
+     *
+     * @var bool $booted
+     */
+    private bool $booted = false;
+
+    /**
+	 * Set up.
+	 *
+	 * @param Feature ...$features Features.
+	 */
+	public function __construct( array $features_to_create = [] ) {
+        if ( empty( $this->features ) ) {
+            $this->features = [];
+        }
+        $this->autoload_features( CREATE_WORDPRESS_PLUGIN_DIR . '/features' );
+
+        foreach ( $features_to_create as $feature_class => $args ) {
+            $this->features[] = new $feature_class( ...$args );
+        }
+	}
+
+	/**
+	 * Boot the feature.
+	 */
+	public function boot(): void {
+        // if ( empty( $this->features ) ) {
+        //     $this->features = [];
+        // }
+		foreach ( $this->features as $feature ) {
+			$feature->boot();
+		}
+        $this->booted = true;
+	}
+
+    /**
+     * Return the plugin features.
+     *
+     * @return Feature[] The plugin features.
+     */
+    public function get_features() {
+        return $this->features;
+    }
+
+    /**
+     * Add a feature to the plugin.
+     *
+     * @param Feature $feature The new feature.
+     * @return void
+     */
+    public function add_feature( Feature $feature ) {
+        $this->features[] = $feature;
+        if ( $this->booted ) {
+            $feature->boot();
+        }
+    }
+
+    /**
+     * Get a feature by name.
+     *
+     * @param string $feature_name The name of the feature to get.
+     * @return Feature|null The feature or null if it doesn't exist.
+     */
+    public function get_feature( string $feature_name ) {
+        foreach ( $this->features as $feature ) {
+            if ( $feature->get_name() === $feature_name ) {
+                return $feature;
+            }
+        }
+        return null;
+    }
+
+    /**
+     * Autoload features from a directory.
+     *
+     * @param string $path The directory path.
+     * @return void
+     */
+    public function autoload_features( string $path ) {
+        $files = glob( $path . '/*.php' );
+        foreach ( $files as $file ) {
+            require_once $file;
+        }
+    }
+}

From 17627ee3cd87f5fcd54bac76b883f868e7f1c1ab Mon Sep 17 00:00:00 2001
From: Greg Marshall <greg@alley.co>
Date: Thu, 21 Dec 2023 08:34:07 -0600
Subject: [PATCH 03/10] add example

---
 features/class-hello.php      | 82 +++++++++++++++++++++++++++++++++++
 plugin.php                    | 40 ++++++++++++++++-
 src/class-feature-manager.php | 22 +++++-----
 3 files changed, 131 insertions(+), 13 deletions(-)
 create mode 100644 features/class-hello.php

diff --git a/features/class-hello.php b/features/class-hello.php
new file mode 100644
index 00000000..b18ddd05
--- /dev/null
+++ b/features/class-hello.php
@@ -0,0 +1,82 @@
+<?php
+/**
+ * Feature implementation of hello.php
+ *
+ * @package Create_WordPress_Plugin
+ */
+
+namespace Create_WordPress_Plugin\Features;
+
+use Alley\WP\Types\Feature;
+
+final class Hello implements Feature {
+	/**
+	 * Set up.
+	 *
+	 * @param string $lyrics The lyrics to Hello Dolly.
+	 */
+	public function __construct(
+		private readonly string $lyrics,
+	) {}
+
+	/**
+	 * Boot the feature.
+	 */
+	public function boot(): void {
+		add_action( 'admin_notices', [ $this, 'hello_dolly' ] );
+		add_action( 'admin_head', [ $this, 'dolly_css' ] );
+	}
+
+	public function hello_dolly_get_lyric() {
+		// Here we split the lyrics into lines.
+		$lyrics = explode( "\n", $this->lyrics );
+
+		// And then randomly choose a line.
+		return wptexturize( $lyrics[ mt_rand( 0, count( $lyrics ) - 1 ) ] );
+	}
+
+	// This just echoes the chosen line, we'll position it later.
+	public function hello_dolly() {
+		$chosen = $this->hello_dolly_get_lyric();
+		$lang   = '';
+		if ( 'en_' !== substr( get_user_locale(), 0, 3 ) ) {
+			$lang = ' lang="en"';
+		}
+
+		printf(
+			'<p id="dolly"><span class="screen-reader-text">%s </span><span dir="ltr"%s>%s</span></p>',
+			__( 'Quote from Hello Dolly song, by Jerry Herman:' ),
+			$lang,
+			$chosen
+		);
+	}
+
+	// We need some CSS to position the paragraph.
+	public function dolly_css() {
+		echo "
+		<style type='text/css'>
+		#dolly {
+			float: right;
+			padding: 5px 10px;
+			margin: 0;
+			font-size: 12px;
+			line-height: 1.6666;
+		}
+		.rtl #dolly {
+			float: left;
+		}
+		.block-editor-page #dolly {
+			display: none;
+		}
+		@media screen and (max-width: 782px) {
+			#dolly,
+			.rtl #dolly {
+				float: none;
+				padding-left: 0;
+				padding-right: 0;
+			}
+		}
+		</style>
+		";
+	}
+}
diff --git a/plugin.php b/plugin.php
index 7882d540..db43554e 100644
--- a/plugin.php
+++ b/plugin.php
@@ -64,13 +64,51 @@ function () {
  * Instantiate the plugin.
  */
 function main(): void {
+	$lyrics = "Hello, Dolly
+		Well, hello, Dolly
+		It's so nice to have you back where you belong
+		You're lookin' swell, Dolly
+		I can tell, Dolly
+		You're still glowin', you're still crowin'
+		You're still goin' strong
+		I feel the room swayin'
+		While the band's playin'
+		One of our old favorite songs from way back when
+		So, take her wrap, fellas
+		Dolly, never go away again
+		Hello, Dolly
+		Well, hello, Dolly
+		It's so nice to have you back where you belong
+		You're lookin' swell, Dolly
+		I can tell, Dolly
+		You're still glowin', you're still crowin'
+		You're still goin' strong
+		I feel the room swayin'
+		While the band's playin'
+		One of our old favorite songs from way back when
+		So, golly, gee, fellas
+		Have a little faith in me, fellas
+		Dolly, never go away
+		Promise, you'll never go away
+		Dolly'll never go away again";
 
+	// Add a feature using the filter.
+	// add_filter( 'create_wordpress_plugin_features', function ( array $features ) use ( $lyrics ): array {
+	// 	$features[ 'Create_WordPress_Plugin\Features\Hello' ] = [ 'lyrics' => $lyrics ];
+	// 	return $features;
+	// } );
+
+	// Add a feature using the array on construct.
 	$features =[
-		'Create_WordPress_Plugin\Features\Featured_Image_Caption' => [],
+		// 'Create_WordPress_Plugin\Features\Hello' => [ 'lyrics' => $lyrics ],
 	];
 	$features = apply_filters( 'create_wordpress_plugin_features', $features );
 
 	$feature_manager = new Feature_Manager( $features );
+	// Add a feature using the add_feature method.
+	// $feature_manager->add_feature( 'Create_WordPress_Plugin\Features\Hello', [ 'lyrics' => $lyrics ] );
 	$feature_manager->boot();
+	// Get the instance of the feature.
+	$hello_feature = $feature_manager->get_feature( 'Create_WordPress_Plugin\Features\Hello' );
 }
 main();
diff --git a/src/class-feature-manager.php b/src/class-feature-manager.php
index bd857573..bd2d3509 100644
--- a/src/class-feature-manager.php
+++ b/src/class-feature-manager.php
@@ -15,7 +15,7 @@ class Feature_Manager implements Feature {
 	 *
 	 * @var Feature[]
 	 */
-	private array $features;
+	private array $features = [];
 
     /**
      * Have the features been booted?
@@ -30,9 +30,6 @@ class Feature_Manager implements Feature {
 	 * @param Feature ...$features Features.
 	 */
 	public function __construct( array $features_to_create = [] ) {
-        if ( empty( $this->features ) ) {
-            $this->features = [];
-        }
         $this->autoload_features( CREATE_WORDPRESS_PLUGIN_DIR . '/features' );
 
         foreach ( $features_to_create as $feature_class => $args ) {
@@ -44,9 +41,6 @@ public function __construct( array $features_to_create = [] ) {
 	 * Boot the feature.
 	 */
 	public function boot(): void {
-        // if ( empty( $this->features ) ) {
-        //     $this->features = [];
-        // }
 		foreach ( $this->features as $feature ) {
 			$feature->boot();
 		}
@@ -65,25 +59,28 @@ public function get_features() {
     /**
      * Add a feature to the plugin.
      *
-     * @param Feature $feature The new feature.
-     * @return void
+     * @param string $feature_class The feature class to add.
+     * @param array  $args          The arguments to pass to the feature constructor.
+     * @return Feature The feature that was added.
      */
-    public function add_feature( Feature $feature ) {
+    public function add_feature( string $feature_class, array $args = [] ) {
+        $feature = new $feature_class( ...$args );
         $this->features[] = $feature;
         if ( $this->booted ) {
             $feature->boot();
         }
+        return $feature;
     }
 
     /**
-     * Get a feature by name.
+     * Get a feature by class name.
      *
      * @param string $feature_name The name of the feature to get.
      * @return Feature|null The feature or null if it doesn't exist.
      */
     public function get_feature( string $feature_name ) {
         foreach ( $this->features as $feature ) {
-            if ( $feature->get_name() === $feature_name ) {
+            if ( get_class( $feature ) === $feature_name ) {
                 return $feature;
             }
         }
@@ -92,6 +89,7 @@ public function get_feature( string $feature_name ) {
 
     /**
      * Autoload features from a directory.
+     * This only includes the files. It does not boot the features.
      *
      * @param string $path The directory path.
      * @return void

From 83bc11ea6de7853498ef893ba9675b6916229df2 Mon Sep 17 00:00:00 2001
From: Greg Marshall <greg@alley.co>
Date: Thu, 21 Dec 2023 09:24:20 -0600
Subject: [PATCH 04/10] phpcs and example of removing action

---
 features/class-hello.php | 24 ++++++++++++++++++------
 plugin.php               |  4 +++-
 2 files changed, 21 insertions(+), 7 deletions(-)

diff --git a/features/class-hello.php b/features/class-hello.php
index b18ddd05..720d9e82 100644
--- a/features/class-hello.php
+++ b/features/class-hello.php
@@ -9,6 +9,9 @@
 
 use Alley\WP\Types\Feature;
 
+/**
+ * Hello class file
+ */
 final class Hello implements Feature {
 	/**
 	 * Set up.
@@ -27,15 +30,22 @@ public function boot(): void {
 		add_action( 'admin_head', [ $this, 'dolly_css' ] );
 	}
 
+	/**
+	 * Gets a random lyric from the lyric string.
+	 *
+	 * @return void
+	 */
 	public function hello_dolly_get_lyric() {
 		// Here we split the lyrics into lines.
 		$lyrics = explode( "\n", $this->lyrics );
 
 		// And then randomly choose a line.
-		return wptexturize( $lyrics[ mt_rand( 0, count( $lyrics ) - 1 ) ] );
+		return wptexturize( $lyrics[ wp_rand( 0, count( $lyrics ) - 1 ) ] );
 	}
 
-	// This just echoes the chosen line, we'll position it later.
+	/**
+	 * Echos the chosen line.
+	 */
 	public function hello_dolly() {
 		$chosen = $this->hello_dolly_get_lyric();
 		$lang   = '';
@@ -45,13 +55,15 @@ public function hello_dolly() {
 
 		printf(
 			'<p id="dolly"><span class="screen-reader-text">%s </span><span dir="ltr"%s>%s</span></p>',
-			__( 'Quote from Hello Dolly song, by Jerry Herman:' ),
-			$lang,
-			$chosen
+			esc_html__( 'Quote from Hello Dolly song, by Jerry Herman:' ),
+			esc_attr( $lang ),
+			esc_html( $chosen )
 		);
 	}
 
-	// We need some CSS to position the paragraph.
+	/**
+	 * Output css to position the paragraph.
+	 */
 	public function dolly_css() {
 		echo "
 		<style type='text/css'>
diff --git a/plugin.php b/plugin.php
index db43554e..23baa975 100644
--- a/plugin.php
+++ b/plugin.php
@@ -106,9 +106,11 @@ function main(): void {
 
 	$feature_manager = new Feature_Manager( $features );
 	// Add a feature using the add_feature method.
-	// $feature_manager->add_feature( 'Create_WordPress_Plugin\Features\Hello', [ 'lyrics' => $lyrics ] );
+	$feature_manager->add_feature( 'Create_WordPress_Plugin\Features\Hello', [ 'lyrics' => $lyrics ] );
 	$feature_manager->boot();
 	// Get the instance of the feature.
 	$hello_feature = $feature_manager->get_feature( 'Create_WordPress_Plugin\Features\Hello' );
+	// Once we have the instance, we can remove hooks from inside the instance.
+	// remove_action( 'admin_head', [ $hello_feature, 'dolly_css' ] );
 }
 main();

From 3bd416ecb5035f0f44d27daa1ac516b0b9de58d2 Mon Sep 17 00:00:00 2001
From: Greg Marshall <greg@alley.co>
Date: Thu, 21 Dec 2023 15:06:40 -0600
Subject: [PATCH 05/10] change to static and rearrange

---
 plugin.php                                 | 49 ++----------------
 src/class-feature-manager.php              | 59 +++++-----------------
 src/features/README.md                     | 53 +++++++++++++++++++
 {features => src/features}/class-hello.php |  0
 4 files changed, 68 insertions(+), 93 deletions(-)
 create mode 100644 src/features/README.md
 rename {features => src/features}/class-hello.php (100%)

diff --git a/plugin.php b/plugin.php
index 23baa975..eea7bdf7 100644
--- a/plugin.php
+++ b/plugin.php
@@ -64,53 +64,10 @@ function () {
  * Instantiate the plugin.
  */
 function main(): void {
-	$lyrics = "Hello, Dolly
-		Well, hello, Dolly
-		It's so nice to have you back where you belong
-		You're lookin' swell, Dolly
-		I can tell, Dolly
-		You're still glowin', you're still crowin'
-		You're still goin' strong
-		I feel the room swayin'
-		While the band's playin'
-		One of our old favorite songs from way back when
-		So, take her wrap, fellas
-		Dolly, never go away again
-		Hello, Dolly
-		Well, hello, Dolly
-		It's so nice to have you back where you belong
-		You're lookin' swell, Dolly
-		I can tell, Dolly
-		You're still glowin', you're still crowin'
-		You're still goin' strong
-		I feel the room swayin'
-		While the band's playin'
-		One of our old favorite songs from way back when
-		So, golly, gee, fellas
-		Have a little faith in me, fellas
-		Dolly, never go away
-		Promise, you'll never go away
-		Dolly'll never go away again";
-
-	// Add a feature using the filter.
-	// add_filter( 'create_wordpress_plugin_features', function ( array $features ) use ( $lyrics ): array {
-	// 	$features[ 'Create_WordPress_Plugin\Features\Hello' ] = [ 'lyrics' => $lyrics ];
-	// 	return $features;
-	// } );
-
-	// Add a feature using the array on construct.
-	$features =[
-		// 'Create_WordPress_Plugin\Features\Hello' => [ 'lyrics' => $lyrics ],
+	$features = [
+		// Add initial features here.
 	];
 	$features = apply_filters( 'create_wordpress_plugin_features', $features );
-
-	$feature_manager = new Feature_Manager( $features );
-	// Add a feature using the add_feature method.
-	$feature_manager->add_feature( 'Create_WordPress_Plugin\Features\Hello', [ 'lyrics' => $lyrics ] );
-	$feature_manager->boot();
-	// Get the instance of the feature.
-	$hello_feature = $feature_manager->get_feature( 'Create_WordPress_Plugin\Features\Hello' );
-	// Once we have the instance, we can remove hooks from inside the instance.
-	// remove_action( 'admin_head', [ $hello_feature, 'dolly_css' ] );
+	Feature_Manager::add_features( $features );
 }
 main();
diff --git a/src/class-feature-manager.php b/src/class-feature-manager.php
index bd2d3509..1f7f705f 100644
--- a/src/class-feature-manager.php
+++ b/src/class-feature-manager.php
@@ -9,51 +9,32 @@
 
 use \Alley\WP\Types\Feature;
 
-class Feature_Manager implements Feature {
+class Feature_Manager {
 	/**
 	 * Collected features.
 	 *
 	 * @var Feature[]
 	 */
-	private array $features = [];
-
-    /**
-     * Have the features been booted?
-     *
-     * @var bool $booted
-     */
-    private bool $booted = false;
+	private static array $features = [];
 
     /**
 	 * Set up.
 	 *
-	 * @param Feature ...$features Features.
+	 * @param array ...$features_to_create Array of feature classnames and arguments.
 	 */
-	public function __construct( array $features_to_create = [] ) {
-        $this->autoload_features( CREATE_WORDPRESS_PLUGIN_DIR . '/features' );
-
+	public static function add_features( array $features_to_create = [] ) {
         foreach ( $features_to_create as $feature_class => $args ) {
-            $this->features[] = new $feature_class( ...$args );
+            self::add_feature( $feature_class, $args );
         }
 	}
 
-	/**
-	 * Boot the feature.
-	 */
-	public function boot(): void {
-		foreach ( $this->features as $feature ) {
-			$feature->boot();
-		}
-        $this->booted = true;
-	}
-
     /**
      * Return the plugin features.
      *
      * @return Feature[] The plugin features.
      */
-    public function get_features() {
-        return $this->features;
+    public static function get_features() {
+        return self::$features;
     }
 
     /**
@@ -63,12 +44,10 @@ public function get_features() {
      * @param array  $args          The arguments to pass to the feature constructor.
      * @return Feature The feature that was added.
      */
-    public function add_feature( string $feature_class, array $args = [] ) {
+    public static function add_feature( string $feature_class, array $args = [] ) {
         $feature = new $feature_class( ...$args );
-        $this->features[] = $feature;
-        if ( $this->booted ) {
-            $feature->boot();
-        }
+        self::$features[] = $feature;
+        $feature->boot();
         return $feature;
     }
 
@@ -78,26 +57,12 @@ public function add_feature( string $feature_class, array $args = [] ) {
      * @param string $feature_name The name of the feature to get.
      * @return Feature|null The feature or null if it doesn't exist.
      */
-    public function get_feature( string $feature_name ) {
-        foreach ( $this->features as $feature ) {
+    public static function get_feature( string $feature_name ) {
+        foreach ( self::$features as $feature ) {
             if ( get_class( $feature ) === $feature_name ) {
                 return $feature;
             }
         }
         return null;
     }
-
-    /**
-     * Autoload features from a directory.
-     * This only includes the files. It does not boot the features.
-     *
-     * @param string $path The directory path.
-     * @return void
-     */
-    public function autoload_features( string $path ) {
-        $files = glob( $path . '/*.php' );
-        foreach ( $files as $file ) {
-            require_once $file;
-        }
-    }
 }
diff --git a/src/features/README.md b/src/features/README.md
new file mode 100644
index 00000000..921673a6
--- /dev/null
+++ b/src/features/README.md
@@ -0,0 +1,53 @@
+# Features
+Features should be PHP classes that implement the [Alley\WP\Types\Feature interface](https://github.com/alleyinteractive/wp-type-extensions/blob/main/src/alley/wp/types/interface-feature.php).
+
+Features should be located in the `src/features` directory of the plugin and have namespace `Create_WordPress_Plugin\Features;`
+
+Files in the features directory will be autoloaded, but features will not be instantiated. Features are instantiated via the `Feature_Manager` static class.
+
+The following variable is passed to the `Class_Hello` feature in each of the following examples. This shows how we can remove any business logic from the feature and pass it in when the feature is added.
+
+```
+$lyrics = "Hello, Dolly
+    Well, hello, Dolly
+    It's so nice to have you back where you belong
+    You're lookin' swell, Dolly
+    I can tell, Dolly
+    You're still glowin', you're still crowin'
+    You're still goin' strong
+    I feel the room swayin'
+    While the band's playin'
+    One of our old favorite songs from way back when
+    So, take her wrap, fellas
+    Dolly, never go away again";
+```
+
+## There are three ways to add a feature:
+### Add a feature using the `create_wordpress_plugin_features` filter.
+```
+add_filter( 'create_wordpress_plugin_features', function ( array $features ) use ( $lyrics ): array {
+    $features[ 'Create_WordPress_Plugin\Features\Hello' ] = [ 'lyrics' => $lyrics ];
+    return $features;
+} );
+```
+### Add a feature using the add_features method
+```
+$features = [
+    'Create_WordPress_Plugin\Features\Hello' => [ 'lyrics' => $lyrics ],
+];
+$features = apply_filters( 'create_wordpress_plugin_features', $features );
+
+Feature_Manager::add_features( $features );
+```
+### Add a feature using the add_feature method
+```
+Feature_Manager::add_feature( 'Create_WordPress_Plugin\Features\Hello', [ 'lyrics' => $lyrics ] );
+```
+## Get the instance of an added feature
+```
+$hello_feature = Feature_Manager::get_feature( 'Create_WordPress_Plugin\Features\Hello' );
+```
+## Once we have the instance, we can remove hooks from inside the instance
+```
+remove_action( 'admin_head', [ $hello_feature, 'dolly_css' ] );
+```
\ No newline at end of file
diff --git a/features/class-hello.php b/src/features/class-hello.php
similarity index 100%
rename from features/class-hello.php
rename to src/features/class-hello.php

From 16c84731f2926926752070a337f9bcc5d17aff21 Mon Sep 17 00:00:00 2001
From: Greg Marshall <greg@alley.co>
Date: Thu, 21 Dec 2023 15:21:37 -0600
Subject: [PATCH 06/10] a little clean up

---
 plugin.php             | 2 +-
 src/features/README.md | 6 +++---
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/plugin.php b/plugin.php
index eea7bdf7..0417366a 100644
--- a/plugin.php
+++ b/plugin.php
@@ -58,12 +58,12 @@ function () {
 // Load the plugin's main files.
 require_once __DIR__ . '/src/assets.php';
 require_once __DIR__ . '/src/meta.php';
-require_once __DIR__ . '/src/class-feature-manager.php';
 
 /**
  * Instantiate the plugin.
  */
 function main(): void {
+	// This should be an array with keys set to feature classnames and arguments
 	$features = [
 		// Add initial features here.
 	];
diff --git a/src/features/README.md b/src/features/README.md
index 921673a6..641e9485 100644
--- a/src/features/README.md
+++ b/src/features/README.md
@@ -30,7 +30,7 @@ add_filter( 'create_wordpress_plugin_features', function ( array $features ) use
     return $features;
 } );
 ```
-### Add a feature using the add_features method
+### Add a feature using the `add_features` method
 ```
 $features = [
     'Create_WordPress_Plugin\Features\Hello' => [ 'lyrics' => $lyrics ],
@@ -39,11 +39,11 @@ $features = apply_filters( 'create_wordpress_plugin_features', $features );
 
 Feature_Manager::add_features( $features );
 ```
-### Add a feature using the add_feature method
+### Add a feature using the `add_feature` method
 ```
 Feature_Manager::add_feature( 'Create_WordPress_Plugin\Features\Hello', [ 'lyrics' => $lyrics ] );
 ```
-## Get the instance of an added feature
+## Get the instance of an added feature with the `get_feature` method
 ```
 $hello_feature = Feature_Manager::get_feature( 'Create_WordPress_Plugin\Features\Hello' );
 ```

From 212e6c91dd52c1989267f77cebff028ca361b5a0 Mon Sep 17 00:00:00 2001
From: Greg Marshall <greg@alley.co>
Date: Fri, 22 Dec 2023 09:03:08 -0600
Subject: [PATCH 07/10] phpcs and phpstan

---
 src/class-feature-manager.php | 91 +++++++++++++++++++----------------
 src/features/class-hello.php  |  8 +--
 2 files changed, 53 insertions(+), 46 deletions(-)

diff --git a/src/class-feature-manager.php b/src/class-feature-manager.php
index 1f7f705f..ce0ba451 100644
--- a/src/class-feature-manager.php
+++ b/src/class-feature-manager.php
@@ -13,56 +13,63 @@ class Feature_Manager {
 	/**
 	 * Collected features.
 	 *
-	 * @var Feature[]
+	 * @var object[]
 	 */
 	private static array $features = [];
 
-    /**
+	/**
 	 * Set up.
 	 *
-	 * @param array ...$features_to_create Array of feature classnames and arguments.
+	 * @param array $features_to_create Array of feature classnames and arguments.
+	 *
+	 * @phpstan-param array{string: array{string?: mixed}}|array{} $features_to_create
 	 */
-	public static function add_features( array $features_to_create = [] ) {
-        foreach ( $features_to_create as $feature_class => $args ) {
-            self::add_feature( $feature_class, $args );
-        }
+	public static function add_features( array $features_to_create = [] ): void {
+		foreach ( $features_to_create as $feature_class => $args ) {
+			self::add_feature( $feature_class, $args );
+		}
 	}
 
-    /**
-     * Return the plugin features.
-     *
-     * @return Feature[] The plugin features.
-     */
-    public static function get_features() {
-        return self::$features;
-    }
+	/**
+	 * Return the plugin features.
+	 *
+	 * @return object[] The plugin features.
+	 */
+	public static function get_features(): array {
+		return self::$features;
+	}
 
-    /**
-     * Add a feature to the plugin.
-     *
-     * @param string $feature_class The feature class to add.
-     * @param array  $args          The arguments to pass to the feature constructor.
-     * @return Feature The feature that was added.
-     */
-    public static function add_feature( string $feature_class, array $args = [] ) {
-        $feature = new $feature_class( ...$args );
-        self::$features[] = $feature;
-        $feature->boot();
-        return $feature;
-    }
+	/**
+	 * Add a feature to the plugin.
+	 *
+	 * @param string $feature_class The feature class to add.
+	 * @param array  $args          The arguments to pass to the feature constructor.
+	 *
+	 * @phpstan-param array{string?: mixed} $args
+	 * @return object The instatiated feature that was added.
+	 */
+	public static function add_feature( string $feature_class, array $args = [] ): object {
+		if ( ! in_array( Feature::class, class_implements( $feature_class ) ?: [], true ) ) {
+			throw new \Exception( 'Feature class must implement Feature interface.' );
+		}
+		$feature = new $feature_class( ...$args );
+		$feature->boot(); // @phpstan-ignore-line
+		self::$features[] = $feature;
+		return $feature;
+	}
 
-    /**
-     * Get a feature by class name.
-     *
-     * @param string $feature_name The name of the feature to get.
-     * @return Feature|null The feature or null if it doesn't exist.
-     */
-    public static function get_feature( string $feature_name ) {
-        foreach ( self::$features as $feature ) {
-            if ( get_class( $feature ) === $feature_name ) {
-                return $feature;
-            }
-        }
-        return null;
-    }
+	/**
+	 * Get a feature by class name.
+	 *
+	 * @param string $feature_name The name of the feature to get.
+	 * @return object|null The feature or null if it doesn't exist.
+	 */
+	public static function get_feature( string $feature_name ): ?object {
+		foreach ( self::$features as $feature ) {
+			if ( get_class( $feature ) === $feature_name ) {
+				return $feature;
+			}
+		}
+		return null;
+	}
 }
diff --git a/src/features/class-hello.php b/src/features/class-hello.php
index 720d9e82..a405713c 100644
--- a/src/features/class-hello.php
+++ b/src/features/class-hello.php
@@ -33,9 +33,9 @@ public function boot(): void {
 	/**
 	 * Gets a random lyric from the lyric string.
 	 *
-	 * @return void
+	 * @return string
 	 */
-	public function hello_dolly_get_lyric() {
+	public function hello_dolly_get_lyric(): string {
 		// Here we split the lyrics into lines.
 		$lyrics = explode( "\n", $this->lyrics );
 
@@ -46,7 +46,7 @@ public function hello_dolly_get_lyric() {
 	/**
 	 * Echos the chosen line.
 	 */
-	public function hello_dolly() {
+	public function hello_dolly(): void {
 		$chosen = $this->hello_dolly_get_lyric();
 		$lang   = '';
 		if ( 'en_' !== substr( get_user_locale(), 0, 3 ) ) {
@@ -64,7 +64,7 @@ public function hello_dolly() {
 	/**
 	 * Output css to position the paragraph.
 	 */
-	public function dolly_css() {
+	public function dolly_css(): void {
 		echo "
 		<style type='text/css'>
 		#dolly {

From 42555cc534b489c76e3c51a750af99131c95cbb6 Mon Sep 17 00:00:00 2001
From: Greg Marshall <greg@alley.co>
Date: Fri, 22 Dec 2023 09:11:44 -0600
Subject: [PATCH 08/10] phcps

---
 plugin.php                    | 2 +-
 src/class-feature-manager.php | 7 ++++++-
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/plugin.php b/plugin.php
index 0417366a..11793e97 100644
--- a/plugin.php
+++ b/plugin.php
@@ -63,7 +63,7 @@ function () {
  * Instantiate the plugin.
  */
 function main(): void {
-	// This should be an array with keys set to feature classnames and arguments
+	// This should be an array with keys set to feature classnames and arguments.
 	$features = [
 		// Add initial features here.
 	];
diff --git a/src/class-feature-manager.php b/src/class-feature-manager.php
index ce0ba451..3b1248b6 100644
--- a/src/class-feature-manager.php
+++ b/src/class-feature-manager.php
@@ -7,8 +7,11 @@
 
 namespace Create_WordPress_Plugin;
 
-use \Alley\WP\Types\Feature;
+use Alley\WP\Types\Feature;
 
+/**
+ * The Feature Manager class.
+ */
 class Feature_Manager {
 	/**
 	 * Collected features.
@@ -46,7 +49,9 @@ public static function get_features(): array {
 	 * @param array  $args          The arguments to pass to the feature constructor.
 	 *
 	 * @phpstan-param array{string?: mixed} $args
+	 *
 	 * @return object The instatiated feature that was added.
+	 * @throws \Exception If the feature class does not implement Feature.
 	 */
 	public static function add_feature( string $feature_class, array $args = [] ): object {
 		if ( ! in_array( Feature::class, class_implements( $feature_class ) ?: [], true ) ) {

From ea3b9240fa4b8e56dddf300e2e963ad9041a695a Mon Sep 17 00:00:00 2001
From: Greg Marshall <greg@alley.co>
Date: Fri, 22 Dec 2023 12:53:38 -0600
Subject: [PATCH 09/10] code review feedback

---
 src/features/README.md       | 112 ++++++++++++++++++++++++++++++++---
 src/features/class-hello.php |  94 -----------------------------
 2 files changed, 103 insertions(+), 103 deletions(-)
 delete mode 100644 src/features/class-hello.php

diff --git a/src/features/README.md b/src/features/README.md
index 641e9485..cbe4a573 100644
--- a/src/features/README.md
+++ b/src/features/README.md
@@ -22,23 +22,18 @@ $lyrics = "Hello, Dolly
     Dolly, never go away again";
 ```
 
-## There are three ways to add a feature:
-### Add a feature using the `create_wordpress_plugin_features` filter.
-```
-add_filter( 'create_wordpress_plugin_features', function ( array $features ) use ( $lyrics ): array {
-    $features[ 'Create_WordPress_Plugin\Features\Hello' ] = [ 'lyrics' => $lyrics ];
-    return $features;
-} );
-```
+## There are two ways to add a feature:
 ### Add a feature using the `add_features` method
 ```
 $features = [
     'Create_WordPress_Plugin\Features\Hello' => [ 'lyrics' => $lyrics ],
 ];
-$features = apply_filters( 'create_wordpress_plugin_features', $features );
 
 Feature_Manager::add_features( $features );
 ```
+
+> 💡 If you `apply_filters` to the features array before passing it to `add_features`, you can modify it with a filter.
+
 ### Add a feature using the `add_feature` method
 ```
 Feature_Manager::add_feature( 'Create_WordPress_Plugin\Features\Hello', [ 'lyrics' => $lyrics ] );
@@ -50,4 +45,103 @@ $hello_feature = Feature_Manager::get_feature( 'Create_WordPress_Plugin\Features
 ## Once we have the instance, we can remove hooks from inside the instance
 ```
 remove_action( 'admin_head', [ $hello_feature, 'dolly_css' ] );
+```
+
+## Example feature class:
+This is a port of the infamous WordPress `hello.php` plugin to a feature. The lyrics would be passed in when the feature was called, as shown above.
+```
+<?php
+/**
+ * Feature implementation of hello.php
+ *
+ * @package Create_WordPress_Plugin
+ */
+
+namespace Create_WordPress_Plugin\Features;
+
+use Alley\WP\Types\Feature;
+
+/**
+ * Hello class file
+ */
+final class Hello implements Feature {
+	/**
+	 * Set up.
+	 *
+	 * @param string $lyrics The lyrics to Hello Dolly.
+	 */
+	public function __construct(
+		private readonly string $lyrics,
+	) {}
+
+	/**
+	 * Boot the feature.
+	 */
+	public function boot(): void {
+		add_action( 'admin_notices', [ $this, 'hello_dolly' ] );
+		add_action( 'admin_head', [ $this, 'dolly_css' ] );
+	}
+
+	/**
+	 * Gets a random lyric from the lyric string.
+	 *
+	 * @return string
+	 */
+	public function hello_dolly_get_lyric(): string {
+		// Here we split the lyrics into lines.
+		$lyrics = explode( "\n", $this->lyrics );
+
+		// And then randomly choose a line.
+		return wptexturize( $lyrics[ wp_rand( 0, count( $lyrics ) - 1 ) ] );
+	}
+
+	/**
+	 * Echos the chosen line.
+	 */
+	public function hello_dolly(): void {
+		$chosen = $this->hello_dolly_get_lyric();
+		$lang   = '';
+		if ( 'en_' !== substr( get_user_locale(), 0, 3 ) ) {
+			$lang = ' lang="en"';
+		}
+
+		printf(
+			'<p id="dolly"><span class="screen-reader-text">%s </span><span dir="ltr"%s>%s</span></p>',
+			esc_html__( 'Quote from Hello Dolly song, by Jerry Herman:' ),
+			esc_attr( $lang ),
+			esc_html( $chosen )
+		);
+	}
+
+	/**
+	 * Output css to position the paragraph.
+	 */
+	public function dolly_css(): void {
+		echo "
+		<style type='text/css'>
+		#dolly {
+			float: right;
+			padding: 5px 10px;
+			margin: 0;
+			font-size: 12px;
+			line-height: 1.6666;
+		}
+		.rtl #dolly {
+			float: left;
+		}
+		.block-editor-page #dolly {
+			display: none;
+		}
+		@media screen and (max-width: 782px) {
+			#dolly,
+			.rtl #dolly {
+				float: none;
+				padding-left: 0;
+				padding-right: 0;
+			}
+		}
+		</style>
+		";
+	}
+}
 ```
\ No newline at end of file
diff --git a/src/features/class-hello.php b/src/features/class-hello.php
deleted file mode 100644
index a405713c..00000000
--- a/src/features/class-hello.php
+++ /dev/null
@@ -1,94 +0,0 @@
-<?php
-/**
- * Feature implementation of hello.php
- *
- * @package Create_WordPress_Plugin
- */
-
-namespace Create_WordPress_Plugin\Features;
-
-use Alley\WP\Types\Feature;
-
-/**
- * Hello class file
- */
-final class Hello implements Feature {
-	/**
-	 * Set up.
-	 *
-	 * @param string $lyrics The lyrics to Hello Dolly.
-	 */
-	public function __construct(
-		private readonly string $lyrics,
-	) {}
-
-	/**
-	 * Boot the feature.
-	 */
-	public function boot(): void {
-		add_action( 'admin_notices', [ $this, 'hello_dolly' ] );
-		add_action( 'admin_head', [ $this, 'dolly_css' ] );
-	}
-
-	/**
-	 * Gets a random lyric from the lyric string.
-	 *
-	 * @return string
-	 */
-	public function hello_dolly_get_lyric(): string {
-		// Here we split the lyrics into lines.
-		$lyrics = explode( "\n", $this->lyrics );
-
-		// And then randomly choose a line.
-		return wptexturize( $lyrics[ wp_rand( 0, count( $lyrics ) - 1 ) ] );
-	}
-
-	/**
-	 * Echos the chosen line.
-	 */
-	public function hello_dolly(): void {
-		$chosen = $this->hello_dolly_get_lyric();
-		$lang   = '';
-		if ( 'en_' !== substr( get_user_locale(), 0, 3 ) ) {
-			$lang = ' lang="en"';
-		}
-
-		printf(
-			'<p id="dolly"><span class="screen-reader-text">%s </span><span dir="ltr"%s>%s</span></p>',
-			esc_html__( 'Quote from Hello Dolly song, by Jerry Herman:' ),
-			esc_attr( $lang ),
-			esc_html( $chosen )
-		);
-	}
-
-	/**
-	 * Output css to position the paragraph.
-	 */
-	public function dolly_css(): void {
-		echo "
-		<style type='text/css'>
-		#dolly {
-			float: right;
-			padding: 5px 10px;
-			margin: 0;
-			font-size: 12px;
-			line-height: 1.6666;
-		}
-		.rtl #dolly {
-			float: left;
-		}
-		.block-editor-page #dolly {
-			display: none;
-		}
-		@media screen and (max-width: 782px) {
-			#dolly,
-			.rtl #dolly {
-				float: none;
-				padding-left: 0;
-				padding-right: 0;
-			}
-		}
-		</style>
-		";
-	}
-}

From b01c6ded423fe4e2a0ddc74c93c5e5b26bde4dd1 Mon Sep 17 00:00:00 2001
From: Greg Marshall <greg@alley.co>
Date: Fri, 22 Dec 2023 12:55:44 -0600
Subject: [PATCH 10/10] add example of filter

---
 src/features/README.md | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/features/README.md b/src/features/README.md
index cbe4a573..eeafb8bc 100644
--- a/src/features/README.md
+++ b/src/features/README.md
@@ -33,6 +33,9 @@ Feature_Manager::add_features( $features );
 ```
 
 > 💡 If you `apply_filters` to the features array before passing it to `add_features`, you can modify it with a filter.
+```
+$features = apply_filters( 'create_wordpress_plugin_features', $features );
+```
 
 ### Add a feature using the `add_feature` method
 ```