feat(latest): parse comix SSR state and kagane API for latest chapter

backend/internal/latest/sites.go

@@ -25,6 +25,15 @@ var asuraSlugRe = regexp.MustCompile(`/comics/([^/?#]+)`)
 // through. Both the raw "&" and the HTML-escaped "&" forms occur.
 var demonicChapterRe = regexp.MustCompile(`chaptered\.php\?manga=\d+&(?:amp;)?chapter=([0-9.]+)`)
 
+// comixSlugRe pulls the "<id>-<slug>" segment out of a stored series_url.
+// Only the id prefix is stable; the slug tail follows the title.
+var comixSlugRe = regexp.MustCompile(`/title/([^/?#]+)`)
+
+// kaganeChapterRe matches the chapter numbers in a kagane API response. This
+// branch is fed by the browser fetcher, so the body is JSON rather than HTML —
+// there are no anchors to scan.
+var kaganeChapterRe = regexp.MustCompile(`"chapter_no":"([0-9.]+)"`)
+
 // latestChapterFrom returns the highest chapter number body advertises for this
 // series. ok is false when the body yields nothing usable — an unknown site, an
 // empty body, a Cloudflare challenge page, and a site redesign all land here,
@@ -61,6 +70,22 @@ func latestChapterFrom(site, seriesURL, body string) (latestChapter, bool) {
 		re = regexp.MustCompile(`/comics/` + regexp.QuoteMeta(slug) + `(?:-[0-9a-f]{8})?/chapter/([0-9.]+)`)
 	case "demonic":
 		re = demonicChapterRe
+	case "comix":
+		m := comixSlugRe.FindStringSubmatch(seriesURL)
+		if m == nil {
+			return latestChapter{}, false
+		}
+		// comix ships an SPA: the served HTML carries a JSON state blob instead
+		// of chapter anchors, and latestChapterUrl is the only place the newest
+		// chapter appears. Scoping to this series' id prefix keeps a
+		// "recommended" strip's entries from winning the maximum.
+		id := m[1]
+		if i := strings.Index(id, "-"); i != -1 {
+			id = id[:i]
+		}
+		re = regexp.MustCompile(`"latestChapterUrl":"/title/` + regexp.QuoteMeta(id) + `-[^"]*-chapter-([0-9.]+)"`)
+	case "kagane":
+		re = kaganeChapterRe
 	default:
 		return latestChapter{}, false
 	}