feat: add user centric features

lib/source-reference.ts

@@ -247,6 +247,128 @@ export function getSourceReference(): {
   return null;
 }
 
+/**
+ * URL-only variant of getSourceReference — pure function, safe on server.
+ *
+ * For `/books/...` paths we can derive a clean citation (e.g.
+ * "Bhagavad-gītā As It Is — Chapter 1, Verse 1") from the path alone.
+ * Mirrors the logic in `lib/og.ts`'s `ogForVerse` so post cards display
+ * the same reference the OG image carries.
+ *
+ * For non-book paths the title lives in the page DOM (h1) which we don't
+ * have at card-render time, so we return null — callers should fall back
+ * to whatever `source_title` was saved at compose time.
+ */
+export function referenceFromUrl(
+  sourceUrl: string,
+): { title: string; detail: string | null } | null {
+  if (!sourceUrl) return null;
+  let path: string;
+  try {
+    if (sourceUrl.startsWith("/")) {
+      path = sourceUrl.split("?")[0];
+    } else {
+      const u = new URL(sourceUrl);
+      path = u.pathname;
+    }
+  } catch {
+    return null;
+  }
+
+  const parts = path.split("/").filter(Boolean);
+  if (parts[0] !== "books" || parts.length < 2) return null;
+
+  const code = parts[1];
+  const bookName = BOOK_NAMES[code] || code.toUpperCase();
+
+  // Verse-based: /books/bg/[chapter]/[verse]
+  if (code === "bg" && parts.length >= 4) {
+    return {
+      title: bookName,
+      detail: `Chapter ${parts[2]}, Verse ${parts[3]}`,
+    };
+  }
+  // SB: /books/sb/[canto]/[chapter]/[verse]
+  if (code === "sb" && parts.length >= 5) {
+    return {
+      title: bookName,
+      detail: `Canto ${parts[2]}, Chapter ${parts[3]}, Verse ${parts[4]}`,
+    };
+  }
+  // CC: /books/cc/[lila]/[chapter]/[verse]
+  if (code === "cc" && parts.length >= 5) {
+    const lila = CC_LILAS[parts[2]] || parts[2];
+    return {
+      title: bookName,
+      detail: `${lila}, Chapter ${parts[3]}, Verse ${parts[4]}`,
+    };
+  }
+  // CC lila index: /books/cc/[lila]
+  if (code === "cc" && parts.length === 3) {
+    const lila = CC_LILAS[parts[2]] || parts[2];
+    return { title: bookName, detail: lila };
+  }
+  // SB1962: /books/sb1962/[chapter]/[verse]
+  if (code === "sb1962" && parts.length >= 4) {
+    return {
+      title: bookName,
+      detail: `Chapter ${parts[2]}, Verse ${parts[3]}`,
+    };
+  }
+  // ISO / NOI: /books/{code}/[mantra]
+  if ((code === "iso" || code === "noi") && parts.length >= 3) {
+    const num = parts[2];
+    const label = code === "iso" ? "Mantra" : "Text";
+    return { title: bookName, detail: `${label} ${num}` };
+  }
+  // BS/MM/NBS verse: /books/{code}/[chapter]/[verse]
+  if (
+    (code === "bs" || code === "mm" || code === "nbs") &&
+    parts.length >= 4
+  ) {
+    return {
+      title: bookName,
+      detail: `Chapter ${parts[2]}, Verse ${parts[3]}`,
+    };
+  }
+  // KB: /books/kb/[volume]/[slug]
+  if (code === "kb" && parts.length >= 4) {
+    return {
+      title: bookName,
+      detail: `Volume ${parts[2]}, Chapter ${parts[3]}`,
+    };
+  }
+  // Generic prose: /books/{code}/[chapter]
+  if (parts.length >= 3) {
+    const chSlug = parts[2];
+    const chNum = parseInt(chSlug, 10);
+    const detail = isNaN(chNum)
+      ? chSlug.replace(/-/g, " ")
+      : `Chapter ${chNum}`;
+    return { title: bookName, detail };
+  }
+  // Book index
+  return { title: bookName, detail: null };
+}
+
+/**
+ * Render a one-line citation string for a post/bookmark card.
+ *
+ * For book URLs we always prefer the URL-derived reference (canonical
+ * format, no stale data). For non-book content (letters, essays, etc.)
+ * the saved `source_title` is the source of truth.
+ */
+export function displaySourceLabel(
+  sourceUrl: string,
+  storedTitle?: string | null,
+): string {
+  const ref = referenceFromUrl(sourceUrl);
+  if (ref) {
+    return ref.detail ? `${ref.title} — ${ref.detail}` : ref.title;
+  }
+  return storedTitle?.trim() || "Source";
+}
+
 /**
  * Format selected text with source attribution appended.
  */