feat: fetch-novel builds an EPUB from any plugin; Kavita TOC fix

- scripts/load-plugins.js: shared plugin loader for the novel CLI scripts
- scripts/fetch-novel.js: download a novel via its plugin into a clean EPUB 3
- find-novel prints the plugin id/path for each match
- kavita 1.0.1: innermost TOC entry names the chapter

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

scripts/fetch-novel.js

@@ -0,0 +1,178 @@
+// Download a whole novel through its plugin and write it as an EPUB 3 file.
+// Usage: node scripts/fetch-novel.js <plugin-id> <novel-path> <out-dir>
+// Prints the written file path as the last stdout line.
+import JSZip from 'jszip';
+import { load } from 'cheerio';
+import fs from 'fs';
+import path from 'path';
+import { loadPlugins, print, ROOT } from './load-plugins.js';
+
+// Be gentle with the source site: few parallel requests, retries with backoff.
+const CONCURRENCY = 3;
+const RETRIES = 4;
+
+const [pluginId, novelPath, outDir] = process.argv.slice(2);
+if (!pluginId || !novelPath || !outDir) {
+  console.error(
+    'Usage: node scripts/fetch-novel.js <plugin-id> <novel-path> <out-dir>',
+  );
+  process.exit(2);
+}
+
+const langs = fs
+  .readdirSync(path.join(ROOT, 'plugins'), { withFileTypes: true })
+  .filter(d => d.isDirectory() && d.name !== 'multisrc')
+  .map(d => d.name);
+const plugin = (await loadPlugins(langs)).find(p => p.id === pluginId);
+if (!plugin) throw new Error(`No plugin with id "${pluginId}"`);
+
+const retry = async (label, fn) => {
+  for (let attempt = 1; ; attempt++) {
+    try {
+      return await fn();
+    } catch (e) {
+      if (attempt >= RETRIES) throw new Error(`${label}: ${e.message}`);
+      await new Promise(r => setTimeout(r, 1000 * 2 ** attempt));
+    }
+  }
+};
+
+const novel = await retry('novel', () => plugin.parseNovel(novelPath));
+const chapters = novel.chapters || [];
+if (!chapters.length) throw new Error('Novel has no chapters');
+process.stderr.write(
+  `${novel.name}: ${chapters.length} chapters from ${plugin.name}\n`,
+);
+
+const esc = s =>
+  String(s ?? '').replace(
+    /[&<>"]/g,
+    c => ({ '&': '&amp;', '<': '&lt;', '>': '&gt;', '"': '&quot;' })[c],
+  );
+
+// Chapter HTML is tag soup; re-serialise it as well-formed XHTML without
+// scripts or remote resources (an EPUB must be self-contained).
+const toXhtml = html => {
+  const $ = load(html, null, false);
+  $('script, style, iframe, link, meta, img, video, audio, source').remove();
+  return $.xml();
+};
+
+const bodies = new Array(chapters.length);
+let done = 0;
+const queue = chapters.map((c, i) => i);
+await Promise.all(
+  Array.from({ length: CONCURRENCY }, async () => {
+    for (let i; (i = queue.shift()) !== undefined;) {
+      const html = await retry(chapters[i].name, () =>
+        plugin.parseChapter(chapters[i].path),
+      );
+      bodies[i] = toXhtml(html);
+      if (++done % 50 === 0 || done === chapters.length) {
+        process.stderr.write(`  ${done}/${chapters.length}\n`);
+      }
+    }
+  }),
+);
+
+const zip = new JSZip();
+zip.file('mimetype', 'application/epub+zip', { compression: 'STORE' });
+zip.file(
+  'META-INF/container.xml',
+  `<?xml version="1.0" encoding="UTF-8"?>
+<container version="1.0" xmlns="urn:oasis:names:tc:opendocument:xmlns:container">
+  <rootfiles><rootfile full-path="OEBPS/content.opf" media-type="application/oebps-package+xml"/></rootfiles>
+</container>`,
+);
+
+const page = (title, body) => `<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE html>
+<html xmlns="http://www.w3.org/1999/xhtml" xmlns:epub="http://www.idpf.org/2007/ops" lang="en" xml:lang="en">
+<head><meta charset="UTF-8"/><title>${esc(title)}</title></head>
+<body>${body}</body>
+</html>`;
+
+const ids = chapters.map((_, i) => `ch${String(i + 1).padStart(4, '0')}`);
+chapters.forEach((c, i) => {
+  zip.file(
+    `OEBPS/${ids[i]}.xhtml`,
+    page(c.name, `<h2>${esc(c.name)}</h2>\n${bodies[i]}`),
+  );
+});
+
+const toc = chapters
+  .map((c, i) => `<li><a href="${ids[i]}.xhtml">${esc(c.name)}</a></li>`)
+  .join('\n');
+zip.file(
+  'OEBPS/nav.xhtml',
+  page('Contents', `<nav epub:type="toc"><ol>\n${toc}\n</ol></nav>`),
+);
+
+let cover = '';
+if (novel.cover && /^https?:/.test(novel.cover)) {
+  try {
+    const res = await fetch(novel.cover, { headers: { Referer: plugin.site } });
+    const type = (res.headers.get('content-type') || '').split(';')[0];
+    const ext = {
+      'image/jpeg': 'jpg',
+      'image/png': 'png',
+      'image/webp': 'webp',
+      'image/gif': 'gif',
+    }[type];
+    if (res.ok && ext) {
+      zip.file(`OEBPS/cover.${ext}`, Buffer.from(await res.arrayBuffer()));
+      cover = `<item id="cover" href="cover.${ext}" media-type="${type}" properties="cover-image"/>`;
+    }
+  } catch {
+    // A missing cover is not worth failing the book for.
+  }
+}
+
+const uid = `urn:lnreader:${plugin.id}:${novelPath}`;
+const subjects = (novel.genres || '')
+  .split(',')
+  .map(g => g.trim())
+  .filter(Boolean)
+  .map(g => `<dc:subject>${esc(g)}</dc:subject>`)
+  .join('\n    ');
+zip.file(
+  'OEBPS/content.opf',
+  `<?xml version="1.0" encoding="UTF-8"?>
+<package xmlns="http://www.idpf.org/2007/opf" version="3.0" unique-identifier="uid">
+  <metadata xmlns:dc="http://purl.org/dc/elements/1.1/">
+    <dc:identifier id="uid">${esc(uid)}</dc:identifier>
+    <dc:title>${esc(novel.name)}</dc:title>
+    <dc:language>en</dc:language>
+    ${novel.author ? `<dc:creator>${esc(novel.author)}</dc:creator>` : ''}
+    ${novel.summary ? `<dc:description>${esc(novel.summary)}</dc:description>` : ''}
+    <dc:publisher>${esc(plugin.name)}</dc:publisher>
+    <dc:source>${esc(plugin.resolveUrl ? plugin.resolveUrl(novelPath, true) : plugin.site)}</dc:source>
+    ${subjects}
+    <meta property="dcterms:modified">${new Date().toISOString().replace(/\.\d+Z$/, 'Z')}</meta>
+  </metadata>
+  <manifest>
+    <item id="nav" href="nav.xhtml" media-type="application/xhtml+xml" properties="nav"/>
+    ${cover}
+    ${ids.map(id => `<item id="${id}" href="${id}.xhtml" media-type="application/xhtml+xml"/>`).join('\n    ')}
+  </manifest>
+  <spine>
+    ${ids.map(id => `<itemref idref="${id}"/>`).join('\n    ')}
+  </spine>
+</package>`,
+);
+
+fs.mkdirSync(outDir, { recursive: true });
+const file = path.join(
+  outDir,
+  `${novel.name.replace(/[/\\:*?"<>|]/g, '-')}.epub`,
+);
+fs.writeFileSync(
+  file,
+  await zip.generateAsync({
+    type: 'nodebuffer',
+    compression: 'DEFLATE',
+    mimeType: 'application/epub+zip',
+  }),
+);
+print(file);
+process.exit(0);