adds viewdataprovider

Author: ljonesfl

src/Mvc/Views/ViewDataProvider.php

@@ -0,0 +1,214 @@
+<?php
+
+namespace Neuron\Mvc\Views;
+
+use Neuron\Patterns\Registry;
+
+/**
+ * Global view data provider for the MVC framework.
+ *
+ * This class manages globally-shared view data that should be automatically
+ * injected into all views. It eliminates the need for views to directly access
+ * the Registry and provides a centralized place to configure view-level globals.
+ *
+ * 1. Register in an Initializer during application bootstrap
+ * 2. Share data using share() method with static values or callables
+ * 3. Data automatically injected into all views via Base::injectHelpers()
+ *
+ * @package Neuron\Mvc\Views
+ *
+ * @example
+ * ```php
+ * // In an Initializer:
+ * $provider = ViewDataProvider::getInstance();
+ *
+ * // Static values
+ * $provider->share('siteName', 'My Website');
+ *
+ * // Lazy evaluation (callable executed on each request)
+ * $provider->share('currentUser', function() {
+ *     return Registry::getInstance()->get('Auth.User');
+ * });
+ *
+ * // Multiple values at once
+ * $provider->shareMultiple([
+ *     'theme' => 'default',
+ *     'year' => fn() => date('Y')
+ * ]);
+ * ```
+ */
+class ViewDataProvider
+{
+	private array $_data = [];
+	private static ?ViewDataProvider $_instance = null;
+
+	/**
+	 * Private constructor to enforce singleton pattern
+	 */
+	private function __construct()
+	{}
+
+	/**
+	 * Get the singleton instance of ViewDataProvider.
+	 *
+	 * Creates and registers the instance in Registry if it doesn't exist.
+	 *
+	 * @return ViewDataProvider
+	 */
+	public static function getInstance(): ViewDataProvider
+	{
+		if( self::$_instance === null )
+		{
+			self::$_instance = new self();
+			Registry::getInstance()->set( 'ViewDataProvider', self::$_instance );
+		}
+
+		return self::$_instance;
+	}
+
+	/**
+	 * Share a value globally with all views.
+	 *
+	 * The value can be a static value or a callable. If a callable is provided,
+	 * it will be executed each time the view data is resolved, allowing for
+	 * dynamic values that change per request.
+	 *
+	 * @param string $key The key to store the data under
+	 * @param mixed $value The value to share (can be callable for lazy evaluation)
+	 * @return ViewDataProvider Fluent interface
+	 *
+	 * @example
+	 * ```php
+	 * $provider->share('siteName', 'My Website');
+	 * $provider->share('currentUser', fn() => Auth::user());
+	 * ```
+	 */
+	public function share( string $key, mixed $value ): ViewDataProvider
+	{
+		$this->_data[ $key ] = $value;
+		return $this;
+	}
+
+	/**
+	 * Share multiple values at once.
+	 *
+	 * @param array $data Associative array of key-value pairs
+	 * @return ViewDataProvider Fluent interface
+	 *
+	 * @example
+	 * ```php
+	 * $provider->shareMultiple([
+	 *     'siteName' => 'My Website',
+	 *     'theme' => 'dark',
+	 *     'currentYear' => fn() => date('Y')
+	 * ]);
+	 * ```
+	 */
+	public function shareMultiple( array $data ): ViewDataProvider
+	{
+		foreach( $data as $key => $value )
+		{
+			$this->share( $key, $value );
+		}
+		return $this;
+	}
+
+	/**
+	 * Get a shared value by key.
+	 *
+	 * If the value is a callable, it will be executed and the result returned.
+	 * If the key doesn't exist, returns the default value.
+	 *
+	 * @param string $key The key to retrieve
+	 * @param mixed $default Default value if key doesn't exist
+	 * @return mixed The resolved value
+	 */
+	public function get( string $key, mixed $default = null ): mixed
+	{
+		if( !$this->has( $key ) )
+		{
+			return $default;
+		}
+
+		$value = $this->_data[ $key ];
+
+		// If value is callable, execute it and return result
+		if( is_callable( $value ) )
+		{
+			return $value();
+		}
+
+		return $value;
+	}
+
+	/**
+	 * Check if a key exists in the shared data.
+	 *
+	 * @param string $key The key to check
+	 * @return bool True if key exists, false otherwise
+	 */
+	public function has( string $key ): bool
+	{
+		return array_key_exists( $key, $this->_data );
+	}
+
+	/**
+	 * Get all shared data with callables resolved.
+	 *
+	 * This resolves all callables before returning, so the returned array
+	 * contains only static values ready for view rendering.
+	 *
+	 * @return array Associative array of all shared data with resolved values
+	 */
+	public function all(): array
+	{
+		$resolved = [];
+
+		foreach( $this->_data as $key => $value )
+		{
+			if( is_callable( $value ) )
+			{
+				$resolved[ $key ] = $value();
+			}
+			else
+			{
+				$resolved[ $key ] = $value;
+			}
+		}
+
+		return $resolved;
+	}
+
+	/**
+	 * Remove a shared value.
+	 *
+	 * @param string $key The key to remove
+	 * @return ViewDataProvider Fluent interface
+	 */
+	public function remove( string $key ): ViewDataProvider
+	{
+		unset( $this->_data[ $key ] );
+		return $this;
+	}
+
+	/**
+	 * Clear all shared data.
+	 *
+	 * @return ViewDataProvider Fluent interface
+	 */
+	public function clear(): ViewDataProvider
+	{
+		$this->_data = [];
+		return $this;
+	}
+
+	/**
+	 * Get count of shared data items.
+	 *
+	 * @return int Number of shared items
+	 */
+	public function count(): int
+	{
+		return count( $this->_data );
+	}
+}