feat: Page Editor live preview

- Add POST /preview/page/{slug} and /preview/template/{cpt} endpoints
- Render full HTML using PageSSR for iframe preview
- Templates use sample post for dynamic placeholder resolution
- PageSettings iframe with debounced section updates (500ms)
- Desktop/Mobile toggle with scaled iframe view
- Show/Hide preview toggle button
- Refresh button for manual preview reload
- Preview indicator banner in iframe

admin-spa/src/routes/Appearance/Pages/components/PageSettings.tsx

@@ -1,4 +1,5 @@
-import React from 'react';
+import React, { useState, useEffect, useRef } from 'react';
+import { api } from '@/lib/api';
 import { __ } from '@/lib/i18n';
 import { Card, CardContent, CardHeader, CardTitle } from '@/components/ui/card';
 import { Label } from '@/components/ui/label';
@@ -13,7 +14,7 @@ import {
     SelectValue,
 } from '@/components/ui/select';
 import { Switch } from '@/components/ui/switch';
-import { Settings, Eye, Smartphone, Monitor, ExternalLink } from 'lucide-react';
+import { Settings, Eye, Smartphone, Monitor, ExternalLink, RefreshCw, Loader2 } from 'lucide-react';
 
 interface Section {
     id: string;
@@ -40,6 +41,7 @@ interface AvailableSource {
 interface PageSettingsProps {
     page: PageItem | null;
     section: Section | null;
+    sections: Section[]; // All sections for preview
     onSectionUpdate: (section: Section) => void;
     isTemplate?: boolean;
     availableSources?: AvailableSource[];
@@ -111,11 +113,84 @@ const COLOR_SCHEMES = [
 export function PageSettings({
     page,
     section,
+    sections,
     onSectionUpdate,
     isTemplate = false,
     availableSources = [],
 }: PageSettingsProps) {
-    const [previewMode, setPreviewMode] = React.useState<'desktop' | 'mobile'>('desktop');
+    const [previewMode, setPreviewMode] = useState<'desktop' | 'mobile'>('desktop');
+    const [previewHtml, setPreviewHtml] = useState<string | null>(null);
+    const [previewLoading, setPreviewLoading] = useState(false);
+    const [showPreview, setShowPreview] = useState(false);
+    const iframeRef = useRef<HTMLIFrameElement>(null);
+    const previewTimeoutRef = useRef<NodeJS.Timeout | null>(null);
+
+    // Debounced preview fetch
+    useEffect(() => {
+        if (!page || !showPreview) return;
+
+        // Clear existing timeout
+        if (previewTimeoutRef.current) {
+            clearTimeout(previewTimeoutRef.current);
+        }
+
+        // Debounce preview updates
+        previewTimeoutRef.current = setTimeout(async () => {
+            setPreviewLoading(true);
+            try {
+                const endpoint = page.type === 'page'
+                    ? `/preview/page/${page.slug}`
+                    : `/preview/template/${page.cpt}`;
+
+                const response = await api.post(endpoint, { sections });
+                if (response?.html) {
+                    setPreviewHtml(response.html);
+                }
+            } catch (error) {
+                console.error('Preview error:', error);
+            } finally {
+                setPreviewLoading(false);
+            }
+        }, 500);
+
+        return () => {
+            if (previewTimeoutRef.current) {
+                clearTimeout(previewTimeoutRef.current);
+            }
+        };
+    }, [page, sections, showPreview]);
+
+    // Update iframe when HTML changes
+    useEffect(() => {
+        if (iframeRef.current && previewHtml) {
+            const doc = iframeRef.current.contentDocument;
+            if (doc) {
+                doc.open();
+                doc.write(previewHtml);
+                doc.close();
+            }
+        }
+    }, [previewHtml]);
+
+    // Manual refresh
+    const handleRefreshPreview = async () => {
+        if (!page) return;
+        setPreviewLoading(true);
+        try {
+            const endpoint = page.type === 'page'
+                ? `/preview/page/${page.slug}`
+                : `/preview/template/${page.cpt}`;
+
+            const response = await api.post(endpoint, { sections });
+            if (response?.html) {
+                setPreviewHtml(response.html);
+            }
+        } catch (error) {
+            console.error('Preview error:', error);
+        } finally {
+            setPreviewLoading(false);
+        }
+    };
 
     // Update section prop
     const updateProp = (name: string, value: any, isDynamic?: boolean) => {
@@ -310,16 +385,30 @@ export function PageSettings({
                         </>
                     )}
 
-                    {/* Preview Toggle */}
+                    {/* Preview Panel */}
                     <Card>
                         <CardHeader className="pb-3">
-                            <CardTitle className="text-sm flex items-center gap-2">
-                                <Eye className="w-4 h-4" />
-                                {__('Preview')}
+                            <CardTitle className="text-sm flex items-center justify-between">
+                                <span className="flex items-center gap-2">
+                                    <Eye className="w-4 h-4" />
+                                    {__('Preview')}
+                                </span>
+                                {showPreview && (
+                                    <Button
+                                        variant="ghost"
+                                        size="icon"
+                                        className="h-6 w-6"
+                                        onClick={handleRefreshPreview}
+                                        disabled={previewLoading}
+                                    >
+                                        <RefreshCw className={`w-3 h-3 ${previewLoading ? 'animate-spin' : ''}`} />
+                                    </Button>
+                                )}
                             </CardTitle>
                         </CardHeader>
                         <CardContent>
-                            <div className="flex gap-2">
+                            {/* Preview Mode Toggle */}
+                            <div className="flex gap-2 mb-3">
                                 <Button
                                     variant={previewMode === 'desktop' ? 'default' : 'outline'}
                                     size="sm"
@@ -337,9 +426,57 @@ export function PageSettings({
                                     {__('Mobile')}
                                 </Button>
                             </div>
-                            <p className="text-xs text-gray-500 mt-3">
-                                {__('Live preview will be available after saving.')}
-                            </p>
+
+                            {/* Preview Toggle */}
+                            {!showPreview ? (
+                                <Button
+                                    variant="outline"
+                                    className="w-full"
+                                    onClick={() => setShowPreview(true)}
+                                    disabled={!page}
+                                >
+                                    <Eye className="w-4 h-4 mr-2" />
+                                    {__('Show Preview')}
+                                </Button>
+                            ) : (
+                                <div className="space-y-2">
+                                    {/* Preview Iframe Container */}
+                                    <div
+                                        className="relative bg-gray-100 rounded-lg overflow-hidden border"
+                                        style={{
+                                            height: '300px',
+                                            width: previewMode === 'mobile' ? '200px' : '100%',
+                                            margin: previewMode === 'mobile' ? '0 auto' : undefined,
+                                        }}
+                                    >
+                                        {previewLoading && (
+                                            <div className="absolute inset-0 bg-white/80 flex items-center justify-center z-10">
+                                                <Loader2 className="w-6 h-6 animate-spin text-primary" />
+                                            </div>
+                                        )}
+                                        <iframe
+                                            ref={iframeRef}
+                                            className="w-full h-full border-0"
+                                            title="Page Preview"
+                                            sandbox="allow-same-origin"
+                                            style={{
+                                                transform: previewMode === 'mobile' ? 'scale(0.5)' : 'scale(0.4)',
+                                                transformOrigin: 'top left',
+                                                width: previewMode === 'mobile' ? '400px' : '250%',
+                                                height: previewMode === 'mobile' ? '600px' : '750px',
+                                            }}
+                                        />
+                                    </div>
+                                    <Button
+                                        variant="ghost"
+                                        size="sm"
+                                        className="w-full text-xs"
+                                        onClick={() => setShowPreview(false)}
+                                    >
+                                        {__('Hide Preview')}
+                                    </Button>
+                                </div>
+                            )}
                         </CardContent>
                     </Card>
                 </div>

admin-spa/src/routes/Appearance/Pages/index.tsx

@@ -235,6 +235,7 @@ export default function AppearancePages() {
                 <PageSettings
                     page={selectedPage}
                     section={selectedSection}
+                    sections={structure?.sections || []}
                     onSectionUpdate={handleSectionUpdate}
                     isTemplate={selectedPage?.type === 'template'}
                     availableSources={pageData?.available_sources || []}

includes/Api/PagesController.php

@@ -68,6 +68,20 @@ class PagesController
             'callback' => [__CLASS__, 'create_page'],
             'permission_callback' => [__CLASS__, 'check_admin_permission'],
         ]);
+        
+        // Preview page (render HTML for iframe)
+        register_rest_route($namespace, '/preview/page/(?P<slug>[a-zA-Z0-9_-]+)', [
+            'methods' => 'POST',
+            'callback' => [__CLASS__, 'render_page_preview'],
+            'permission_callback' => [__CLASS__, 'check_admin_permission'],
+        ]);
+        
+        // Preview template (render HTML for iframe)
+        register_rest_route($namespace, '/preview/template/(?P<cpt>[a-zA-Z0-9_-]+)', [
+            'methods' => 'POST',
+            'callback' => [__CLASS__, 'render_template_preview'],
+            'permission_callback' => [__CLASS__, 'check_admin_permission'],
+        ]);
     }
     
     /**
@@ -470,4 +484,204 @@ class PagesController
         
         return $seo;
     }
+    
+    /**
+     * Render page preview HTML (for editor iframe)
+     */
+    public static function render_page_preview(WP_REST_Request $request)
+    {
+        $slug = $request->get_param('slug');
+        $body = $request->get_json_params();
+        
+        // Get sections from POST body (unsaved changes)
+        $sections = $body['sections'] ?? [];
+        
+        // Find page for title
+        $page = get_page_by_path($slug);
+        $title = $page ? $page->post_title : 'Preview';
+        
+        // Render HTML
+        $html = self::render_preview_html($title, $sections, 'page');
+        
+        // Return as HTML response
+        return new WP_REST_Response([
+            'html' => $html,
+        ], 200);
+    }
+    
+    /**
+     * Render template preview HTML (for editor iframe)
+     */
+    public static function render_template_preview(WP_REST_Request $request)
+    {
+        $cpt = $request->get_param('cpt');
+        $body = $request->get_json_params();
+        
+        // Get sections from POST body
+        $sections = $body['sections'] ?? [];
+        
+        // Get sample post for dynamic placeholders
+        $sample_post = null;
+        if ($cpt && $cpt !== 'page') {
+            $posts = get_posts([
+                'post_type' => $cpt,
+                'posts_per_page' => 1,
+                'post_status' => 'publish',
+            ]);
+            if (!empty($posts)) {
+                $sample_post = $posts[0];
+            }
+        }
+        
+        // Resolve placeholders if sample post exists
+        $resolved_sections = $sections;
+        if ($sample_post) {
+            $post_data = PlaceholderRenderer::build_post_data($sample_post);
+            $resolved_sections = [];
+            foreach ($sections as $section) {
+                $resolved_section = $section;
+                $resolved_section['props'] = PageSSR::resolve_props($section['props'] ?? [], $post_data);
+                $resolved_sections[] = $resolved_section;
+            }
+        }
+        
+        $cpt_obj = get_post_type_object($cpt);
+        $title = $cpt_obj ? $cpt_obj->labels->singular_name . ' Preview' : 'Template Preview';
+        
+        // Render HTML
+        $html = self::render_preview_html($title, $resolved_sections, 'template', $sample_post);
+        
+        return new WP_REST_Response([
+            'html' => $html,
+            'sample_post' => $sample_post ? [
+                'id' => $sample_post->ID,
+                'title' => $sample_post->post_title,
+            ] : null,
+        ], 200);
+    }
+    
+    /**
+     * Helper: Render preview HTML document
+     */
+    private static function render_preview_html($title, $sections, $type, $sample_post = null)
+    {
+        // Get site URL for assets
+        $plugin_url = plugins_url('', dirname(dirname(__FILE__)));
+        
+        // Start output buffering
+        ob_start();
+        ?>
+<!DOCTYPE html>
+<html <?php language_attributes(); ?>>
+<head>
+    <meta charset="<?php bloginfo('charset'); ?>">
+    <meta name="viewport" content="width=device-width, initial-scale=1">
+    <title><?php echo esc_html($title); ?> - Preview</title>
+    <style>
+        /* Reset and base styles */
+        *, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
+        body { 
+            font-family: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
+            line-height: 1.6;
+            color: #1f2937;
+            background: #fff;
+        }
+        img { max-width: 100%; height: auto; }
+        
+        /* Section base */
+        .wn-section { padding: 4rem 1rem; }
+        .wn-container { max-width: 1200px; margin: 0 auto; }
+        
+        /* Color schemes */
+        .wn-scheme-default { background: #fff; color: #1f2937; }
+        .wn-scheme-primary { background: #3b82f6; color: #fff; }
+        .wn-scheme-secondary { background: #1f2937; color: #fff; }
+        .wn-scheme-muted { background: #f3f4f6; color: #1f2937; }
+        .wn-scheme-gradient { 
+            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%); 
+            color: #fff; 
+        }
+        
+        /* Hero section */
+        .wn-hero { text-align: center; padding: 6rem 1rem; }
+        .wn-hero h1 { font-size: 2.5rem; font-weight: 800; margin-bottom: 1rem; }
+        .wn-hero p { font-size: 1.25rem; opacity: 0.9; margin-bottom: 2rem; }
+        .wn-hero .wn-btn { 
+            display: inline-block; padding: 0.75rem 1.5rem; 
+            background: currentColor; color: inherit;
+            border-radius: 0.5rem; text-decoration: none;
+            filter: invert(1); font-weight: 600;
+        }
+        
+        /* Content section */
+        .wn-content { padding: 3rem 1rem; }
+        .wn-content.wn-narrow .wn-container { max-width: 720px; }
+        .wn-content.wn-medium .wn-container { max-width: 960px; }
+        
+        /* Image + Text */
+        .wn-image-text { display: flex; gap: 3rem; align-items: center; flex-wrap: wrap; }
+        .wn-image-text .wn-image { flex: 1; min-width: 300px; }
+        .wn-image-text .wn-text { flex: 1; min-width: 300px; }
+        .wn-image-text.wn-image-right { flex-direction: row-reverse; }
+        
+        /* Feature grid */
+        .wn-features { display: grid; gap: 2rem; }
+        .wn-features.wn-grid-2 { grid-template-columns: repeat(2, 1fr); }
+        .wn-features.wn-grid-3 { grid-template-columns: repeat(3, 1fr); }
+        .wn-features.wn-grid-4 { grid-template-columns: repeat(4, 1fr); }
+        @media (max-width: 768px) {
+            .wn-features { grid-template-columns: 1fr; }
+        }
+        .wn-feature { text-align: center; padding: 1.5rem; }
+        .wn-feature-icon { font-size: 2rem; margin-bottom: 1rem; }
+        
+        /* CTA Banner */
+        .wn-cta { text-align: center; padding: 4rem 1rem; }
+        .wn-cta h2 { font-size: 2rem; margin-bottom: 1rem; }
+        
+        /* Contact form */
+        .wn-contact form { max-width: 500px; margin: 0 auto; }
+        .wn-contact input, .wn-contact textarea {
+            width: 100%; padding: 0.75rem; margin-bottom: 1rem;
+            border: 1px solid #d1d5db; border-radius: 0.375rem;
+        }
+        .wn-contact button {
+            width: 100%; padding: 0.75rem; background: #3b82f6;
+            color: #fff; border: none; border-radius: 0.375rem;
+            cursor: pointer; font-weight: 600;
+        }
+        
+        /* Preview indicator */
+        .wn-preview-indicator {
+            position: fixed; top: 0; left: 0; right: 0;
+            background: #f59e0b; color: #000; text-align: center;
+            padding: 0.5rem; font-size: 0.875rem; font-weight: 500;
+            z-index: 9999;
+        }
+    </style>
+</head>
+<body>
+    <div class="wn-preview-indicator">
+        🔍 Preview Mode <?php if ($sample_post): ?>(Using: <?php echo esc_html($sample_post->post_title); ?>)<?php endif; ?>
+    </div>
+    
+    <main style="padding-top: 2.5rem;">
+        <?php
+        foreach ($sections as $section) {
+            echo PageSSR::render_section($section, $sample_post ? PlaceholderRenderer::build_post_data($sample_post) : []);
+        }
+        
+        if (empty($sections)) {
+            echo '<div style="text-align:center; padding:4rem; color:#9ca3af;">';
+            echo '<p>No sections added yet.</p>';
+            echo '<p>Add sections in the editor to see preview.</p>';
+            echo '</div>';
+        }
+        ?>
+    </main>
+</body>
+</html>
+        <?php
+        return ob_get_clean();
+    }
 }