Hardcode php from interactivity API

src/Interactivity/directives/attributes/woo-bind.php

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+<?php
+
+require_once __DIR__ . '/../utils.php';
+
+function process_woo_bind( $tags, $context ) {
+	if ( $tags->is_tag_closer() ) {
+		return;
+	}
+
+	$prefixed_attributes = $tags->get_attribute_names_with_prefix( 'woo-bind:' );
+
+	foreach ( $prefixed_attributes as $attr ) {
+		list( , $bound_attr ) = explode( ':', $attr );
+		if ( empty( $bound_attr ) ) {
+			continue;
+		}
+
+		$expr  = $tags->get_attribute( $attr );
+		$value = evaluate( $expr, $context->get_context() );
+		$tags->set_attribute( $bound_attr, $value );
+	}
+}

src/Interactivity/directives/attributes/woo-class.php

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+<?php
+
+require_once __DIR__ . '/../utils.php';
+
+function process_woo_class( $tags, $context ) {
+	if ( $tags->is_tag_closer() ) {
+		return;
+	}
+
+	$prefixed_attributes = $tags->get_attribute_names_with_prefix( 'woo-class:' );
+
+	foreach ( $prefixed_attributes as $attr ) {
+		list( , $class_name ) = explode( ':', $attr );
+		if ( empty( $class_name ) ) {
+			continue;
+		}
+
+		$expr      = $tags->get_attribute( $attr );
+		$add_class = evaluate( $expr, $context->get_context() );
+		if ( $add_class ) {
+			$tags->add_class( $class_name );
+		} else {
+			$tags->remove_class( $class_name );
+		}
+	}
+}

src/Interactivity/directives/attributes/woo-context.php

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+<?php
+
+function process_woo_context_attribute( $tags, $context ) {
+	if ( $tags->is_tag_closer() ) {
+		$context->rewind_context();
+		return;
+	}
+
+	$value = $tags->get_attribute( 'woo-context' );
+	if ( null === $value ) {
+		// No woo-context directive.
+		return;
+	}
+
+	$new_context = json_decode( $value, true );
+	// TODO: Error handling.
+
+	$context->set_context( $new_context );
+}

src/Interactivity/directives/attributes/woo-style.php

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+<?php
+
+require_once __DIR__ . '/../utils.php';
+
+function process_woo_style( $tags, $context ) {
+	if ( $tags->is_tag_closer() ) {
+		return;
+	}
+
+	$prefixed_attributes = $tags->get_attribute_names_with_prefix( 'woo-style:' );
+
+	foreach ( $prefixed_attributes as $attr ) {
+		list( , $style_name ) = explode( ':', $attr );
+		if ( empty( $style_name ) ) {
+			continue;
+		}
+
+		$expr        = $tags->get_attribute( $attr );
+		$style_value = evaluate( $expr, $context->get_context() );
+		if ( $style_value ) {
+			$style_attr = $tags->get_attribute( 'style' );
+			$style_attr = set_style( $style_attr, $style_name, $style_value );
+			$tags->set_attribute( 'style', $style_attr );
+		} else {
+			// TODO: Do we want to unset styles if they're null?
+			// $tags->remove_class( $style_name );
+		}
+	}
+}
+

src/Interactivity/directives/class-woo-directive-context.php

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+<?php
+/**
+ * Context data implementation.
+ *
+ * @package block-hydration-experiments
+ */
+
+/**
+ * This is a data structure to hold the current context.
+ *
+ * Whenever encountering a `woo-context` directive, we need to update
+ * the context with the data found in that directive. Conversely,
+ * when "leaving" that context (by encountering a closing tag), we
+ * need to reset the context to its previous state. This means that
+ * we actually need sort of a stack to keep track of all nested contexts.
+ *
+ * Example:
+ *
+ * <woo-context data='{ "foo": 123 }'>
+ *     <!-- foo should be 123 here. -->
+ *     <woo-context data='{ "foo": 456 }'>
+ *         <!-- foo should be 456 here. -->
+ *     </woo-context>
+ *     <!-- foo should be reset to 123 here. -->
+ * </woo-context>
+ */
+class Woo_Directive_Context {
+	/**
+	 * The stack used to store contexts internally.
+	 *
+	 * @var array An array of contexts.
+	 */
+	protected $stack = array( array() );
+
+	/**
+	 * Constructor.
+	 *
+	 * Accepts a context as an argument to initialize this with.
+	 *
+	 * @param array $context A context.
+	 */
+	function __construct( $context = array() ) {
+		$this->set_context( $context );
+	}
+
+	/**
+	 * Return the current context.
+	 *
+	 * @return array The current context.
+	 */
+	public function get_context() {
+		return end( $this->stack );
+	}
+
+	/**
+	 * Set the current context.
+	 *
+	 * @param array $context The context to be set.
+	 * @return void
+	 */
+	public function set_context( $context ) {
+		array_push( $this->stack, array_replace_recursive( $this->get_context(), $context ) );
+	}
+
+	/**
+	 * Reset the context to its previous state.
+	 *
+	 * @return void
+	 */
+	public function rewind_context() {
+		array_pop( $this->stack );
+	}
+}

src/Interactivity/directives/class-woo-directive-store.php

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+<?php
+
+class Woo_Directive_Store {
+	private static array $store = array();
+
+	static function get_data() {
+		return self::$store;
+	}
+
+	static function merge_data( $data ) {
+		self::$store = array_replace_recursive( self::$store, $data );
+	}
+
+	static function serialize() {
+		return json_encode( self::$store );
+	}
+
+	static function reset() {
+		self::$store = array();
+	}
+
+	static function render() {
+		if ( empty( self::$store ) ) {
+			return;
+		}
+
+		// TODO: find a better ID for the script tag.
+		$id    = 'store';
+		$store = self::serialize();
+		echo "<script id=\"$id\" type=\"application/json\">$store</script>";
+	}
+}

src/Interactivity/directives/tags/woo-context.php

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+<?php
+
+function process_woo_context_tag( $tags, $context ) {
+	if ( $tags->is_tag_closer() ) {
+		$context->rewind_context();
+		return;
+	}
+
+	$value = $tags->get_attribute( 'data' );
+	if ( null === $value ) {
+		// No woo-context directive.
+		return;
+	}
+
+	$new_context = json_decode( $value, true );
+	// TODO: Error handling.
+
+	$context->set_context( $new_context );
+}

src/Interactivity/directives/utils.php

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+<?php
+
+require_once  __DIR__ . '/class-woo-directive-store.php';
+
+function store( $data ) {
+	Woo_Directive_Store::merge_data( $data );
+}
+
+// TODO: Implement evaluation of complex logical expressions.
+function evaluate( string $path, array $context = array() ) {
+	$current = array_merge(
+		Woo_Directive_Store::get_data(),
+		array( 'context' => $context )
+	);
+
+	$array = explode( '.', $path );
+	foreach ( $array as $p ) {
+		if ( isset( $current[ $p ] ) ) {
+			$current = $current[ $p ];
+		} else {
+			return null;
+		}
+	}
+	return $current;
+}
+
+function set_style( $style, $name, $value ) {
+	$style_assignments = explode( ';', $style );
+	$modified          = false;
+	foreach ( $style_assignments as $style_assignment ) {
+		list( $style_name ) = explode( ':', $style_assignment );
+		if ( trim( $style_name ) === $name ) {
+			// TODO: Retain surrounding whitespace from $style_value, if any.
+			$style_assignment = $style_name . ': ' . $value;
+			$modified         = true;
+			break;
+		}
+	}
+
+	if ( ! $modified ) {
+		$new_style_assignment = $name . ': ' . $value;
+		// If the last element is empty or whitespace-only, we insert
+		// the new "key: value" pair before it.
+		if ( empty( trim( end( $style_assignments ) ) ) ) {
+			array_splice( $style_assignments, - 1, 0, $new_style_assignment );
+		} else {
+			array_push( $style_assignments, $new_style_assignment );
+		}
+	}
+	return implode( ';', $style_assignments );
+}