feat: Implement version switching functionality in plugin settings

src/css/settings.scss

@@ -1,6 +1,6 @@
 @use 'common/codemirror';
 
-$sections: general, editor, debug;
+$sections: general, editor, debug, version-switch;
 
 p.submit {
 	display: flex;
@@ -127,3 +127,85 @@ body.js {
 .cloud-settings tbody tr:nth-child(n+5) {
 	display: none;
 }
+
+// Version Switch Styles
+.code-snippets-version-switch {
+	.current-version {
+		font-family: monospace;
+		font-size: 1.1em;
+		font-weight: bold;
+		color: #0073aa;
+		background: #f0f6fc;
+		padding: 2px 8px;
+		border-radius: 3px;
+		border: 1px solid #c3c4c7;
+	}
+
+	#target_version {
+		min-width: 200px;
+		margin-inline-start: 8px;
+	}
+
+	#switch-version-btn {
+		&[disabled] {
+			opacity: 0.6;
+			cursor: not-allowed;
+			background-color: #f0f0f1 !important;
+			color: #a7aaad !important;
+			border-color: #dcdcde !important;
+		}
+	}
+
+	// Warning box styling
+	#version-switch-warning {
+		margin-top: 20px !important;
+		padding: 12px 16px;
+		border-left: 4px solid #dba617;
+		background: #fff8e5;
+		border-radius: 4px;
+
+		p {
+			margin: 0;
+			color: #8f6914;
+
+			strong {
+				color: #8f6914;
+			}
+		}
+	}
+
+	#version-switch-result {
+		margin-block-start: 12px;
+
+		&.notice {
+			padding: 8px 12px;
+			border-radius: 4px;
+		}
+	}
+
+	.notice {
+		&.notice-success {
+			border-left-color: #00a32a;
+		}
+
+		&.notice-error {
+			border-left-color: #d63638;
+		}
+
+		&.notice-warning {
+			border-left-color: #dba617;
+		}
+
+		&.notice-info {
+			border-left-color: #72aee6;
+		}
+	}
+}
+
+.version-switch-settings {
+	.form-table {
+		th {
+			width: 180px;
+		}
+	}
+}

src/php/class-plugin.php

@@ -125,6 +125,7 @@ public function load_plugin() {
 		// Settings component.
 		require_once $includes_path . '/settings/settings-fields.php';
 		require_once $includes_path . '/settings/editor-preview.php';
+		require_once $includes_path . '/settings/version-switch.php';
 		require_once $includes_path . '/settings/settings.php';
 
 		// Cloud List Table shared functions.

src/php/settings/class-setting-field.php

@@ -117,7 +117,11 @@ public function render() {
 	 * Render a callback field.
 	 */
 	public function render_callback_field() {
-		call_user_func( $this->render_callback );
+		if ( ! is_callable( $this->render_callback ) ) {
+			return;
+		}
+
+		call_user_func( $this->render_callback, $this->args );
 	}
 
 	/**

src/php/settings/settings-fields.php

@@ -46,6 +46,9 @@ function get_default_settings(): array {
 			'keymap'                      => 'default',
 			'theme'                       => 'default',
 		],
+		'version-switch' => [
+			'selected_version'  => '',
+		],
 	];
 
 	$defaults = apply_filters( 'code_snippets_settings_defaults', $defaults );
@@ -81,6 +84,24 @@ function get_settings_fields(): array {
 		],
 	];
 
+	$fields['version-switch'] = [
+		'version_switcher'  => [
+			'name' => __( 'Switch Version', 'code-snippets' ),
+			'type' => 'callback',
+			'render_callback' => 'Code_Snippets\Settings\VersionSwitch\render_version_switch_field',
+		],
+		'refresh_versions'  => [
+			'name' => __( 'Refresh Versions', 'code-snippets' ),
+			'type' => 'callback',
+			'render_callback' => 'Code_Snippets\Settings\VersionSwitch\render_refresh_versions_field',
+		],
+		'version_warning'   => [
+			'name' => '',
+			'type' => 'callback',
+			'render_callback' => 'Code_Snippets\Settings\VersionSwitch\render_version_switch_warning',
+		],
+	];
+
 	$fields['general'] = [
 		'activate_by_default' => [
 			'name'  => __( 'Activate by Default', 'code-snippets' ),

src/php/settings/settings.php

@@ -136,9 +136,10 @@ function update_setting( string $section, string $field, $new_value ): bool {
  */
 function get_settings_sections(): array {
 	$sections = array(
-		'general' => __( 'General', 'code-snippets' ),
-		'editor'  => __( 'Code Editor', 'code-snippets' ),
-		'debug'   => __( 'Debug', 'code-snippets' ),
+		'general'        => __( 'General', 'code-snippets' ),
+		'editor'         => __( 'Code Editor', 'code-snippets' ),
+		'debug'          => __( 'Debug', 'code-snippets' ),
+		'version-switch' => __( 'Version', 'code-snippets' ),
 	);
 
 	return apply_filters( 'code_snippets_settings_sections', $sections );