michaelschiemer/src/Framework/LiveComponents/Rendering/FragmentRenderer.php

<?php

declare(strict_types=1);

namespace App\Framework\LiveComponents\Rendering;

use App\Framework\LiveComponents\Contracts\LiveComponentContract;
use App\Framework\LiveComponents\ValueObjects\FragmentCollection;
use App\Framework\View\LiveComponentRenderer;

/**
 * Fragment Renderer
 *
 * Handles partial rendering of LiveComponents by extracting specific
 * fragments from the full component HTML.
 *
 * Workflow:
 * 1. Render full component HTML using LiveComponentRenderer
 * 2. Extract requested fragments using FragmentExtractor
 * 3. Return FragmentCollection with extracted fragments
 * 4. Fallback to full render if fragments not found
 *
 * Benefits:
 * - Reduces bandwidth by sending only changed fragments
 * - Improves perceived performance with targeted updates
 * - Maintains full HTML structure for graceful degradation
 */
final readonly class FragmentRenderer
{
    public function __construct(
        private LiveComponentRenderer $componentRenderer,
        private FragmentExtractor $fragmentExtractor
    ) {
    }

    /**
     * Render specific fragments of a component
     *
     * If no fragments are specified or found, returns empty collection.
     * Client should fallback to full re-render in that case.
     *
     * @param LiveComponentContract $component Component to render
     * @param array<string> $fragmentNames Fragment names to extract (e.g., ['user-stats', 'recent-activity'])
     * @return FragmentCollection Collection of extracted fragments
     */
    public function renderFragments(
        LiveComponentContract $component,
        array $fragmentNames
    ): FragmentCollection {
        if (empty($fragmentNames)) {
            return FragmentCollection::empty();
        }

        // Render full component HTML
        $renderData = $component->getRenderData();

        $fullHtml = $this->componentRenderer->render(
            templatePath: $renderData->templatePath,
            data: $renderData->data,
            componentId: $component->id->toString()
        );

        // Extract requested fragments
        return $this->fragmentExtractor->extract($fullHtml, $fragmentNames);
    }

    /**
     * Check if component has specific fragment
     *
     * Useful for validating fragment names before attempting to render.
     *
     * @param LiveComponentContract $component Component to check
     * @param string $fragmentName Fragment name to look for
     * @return bool True if fragment exists in component template
     */
    public function hasFragment(LiveComponentContract $component, string $fragmentName): bool
    {
        $renderData = $component->getRenderData();

        $fullHtml = $this->componentRenderer->render(
            templatePath: $renderData->templatePath,
            data: $renderData->data,
            componentId: $component->id->toString()
        );

        return $this->fragmentExtractor->hasFragment($fullHtml, $fragmentName);
    }

    /**
     * Get all available fragment names from component
     *
     * Useful for debugging and introspection.
     *
     * @param LiveComponentContract $component Component to analyze
     * @return array<string> Available fragment names
     */
    public function getAvailableFragments(LiveComponentContract $component): array
    {
        $renderData = $component->getRenderData();

        $fullHtml = $this->componentRenderer->render(
            templatePath: $renderData->templatePath,
            data: $renderData->data,
            componentId: $component->id->toString()
        );

        return $this->fragmentExtractor->getFragmentNames($fullHtml);
    }
}