feat: nav progress bar, chapter list polling, live chapter fallback, and jump to current page

ui/src/routes/api/chapter-text-preview/[slug]/[n]/+server.ts

@@ -0,0 +1,46 @@
+import { error } from '@sveltejs/kit';
+import type { RequestHandler } from './$types';
+import { env } from '$env/dynamic/private';
+import { log } from '$lib/server/logger';
+
+const SCRAPER_URL = env.SCRAPER_API_URL ?? 'http://localhost:8080';
+
+/**
+ * GET /api/chapter-text-preview/[slug]/[n]
+ * Proxies to the scraper's /api/chapter-text-preview endpoint.
+ * Used client-side when the normal chapter path returns no content
+ * (chapter indexed but not yet scraped to MinIO).
+ */
+export const GET: RequestHandler = async ({ params, url }) => {
+	const { slug, n } = params;
+	const chapter = parseInt(n, 10);
+	if (!slug || !chapter || chapter < 1) {
+		error(400, 'Invalid slug or chapter number');
+	}
+
+	// Forward optional query params (chapter_url, title) if present
+	const qs = new URLSearchParams();
+	const chapterUrl = url.searchParams.get('chapter_url');
+	const title = url.searchParams.get('title');
+	if (chapterUrl) qs.set('chapter_url', chapterUrl);
+	if (title) qs.set('title', title);
+
+	const scraperRes = await fetch(
+		`${SCRAPER_URL}/api/chapter-text-preview/${encodeURIComponent(slug)}/${chapter}?${qs.toString()}`
+	).catch((e) => {
+		log.error('chapter-preview', 'scraper fetch failed', { slug, chapter, err: String(e) });
+		return null;
+	});
+
+	if (!scraperRes || !scraperRes.ok) {
+		const status = scraperRes?.status ?? 502;
+		log.error('chapter-preview', 'scraper returned error', { slug, chapter, status });
+		error(status as Parameters<typeof error>[0], 'Chapter preview not available');
+	}
+
+	const data = await scraperRes.json();
+
+	return new Response(JSON.stringify(data), {
+		headers: { 'Content-Type': 'application/json' }
+	});
+};