fix(app): meta null guard, deduplicate previewChords, env API URL, always show add card

app/.env.example

@@ -0,0 +1 @@
+VITE_API_URL=http://localhost:8000

app/app/components/add-song-sheet.tsx

@@ -9,6 +9,7 @@ import {
 import { Input } from "~/components/ui/input";
 import { Button } from "~/components/ui/button";
 import type { Song, SongSummary } from "~/lib/types";
+import { previewChords } from "~/lib/mock";
 
 interface Props {
   open: boolean;
@@ -16,23 +17,6 @@ interface Props {
   onSongAdded: (summary: SongSummary) => void;
 }
 
-function previewChords(song: Song): string[] {
-  const seen = new Set<string>();
-  const result: string[] = [];
-  for (const section of song.sections) {
-    for (const line of section.lines) {
-      for (const cp of line.chords) {
-        if (!seen.has(cp.chord)) {
-          seen.add(cp.chord);
-          result.push(cp.chord);
-        }
-      }
-    }
-    if (result.length >= 5) break;
-  }
-  return result.slice(0, 5);
-}
-
 export function AddSongSheet({ open, onOpenChange, onSongAdded }: Props) {
   const navigate = useNavigate();
   const [url, setUrl] = useState("");
@@ -58,7 +42,8 @@ export function AddSongSheet({ open, onOpenChange, onSongAdded }: Props) {
         throw new Error("File upload requires running the app locally with direct file paths. Use a URL instead.");
       }
 
-      const resp = await fetch("http://localhost:8000/tabs/parse", {
+      const apiBase = import.meta.env.VITE_API_URL ?? "http://localhost:8000";
+      const resp = await fetch(`${apiBase}/tabs/parse`, {
         method: "POST",
         headers: { "Content-Type": "application/json" },
         body: JSON.stringify({ source: url.trim() }),

app/app/lib/mock.ts

@@ -114,7 +114,7 @@ const SONGS_MAP: Record<string, Song> = {
   "song-naked": NAKED,
 };
 
-function previewChords(song: Song): string[] {
+export function previewChords(song: Song): string[] {
   const seen = new Set<string>();
   const result: string[] = [];
   for (const section of song.sections) {

app/app/routes/home.tsx

@@ -58,26 +58,25 @@ export default function Home({ loaderData }: Route.ComponentProps) {
 
       {/* Grid */}
       <div className="flex-1 overflow-y-auto px-4 pb-4">
-        {filtered.length === 0 ? (
+        {filtered.length === 0 && (
-          <p className="text-sm text-muted-foreground text-center pt-12">
+          <p className="text-sm text-muted-foreground text-center pt-8 pb-4">
             {query ? "No songs match your search." : "No songs yet. Tap Add to get started."}
           </p>
-        ) : (
-          <div className="grid grid-cols-2 gap-3">
-            {filtered.map((song) => (
-              <SongCard key={song.id} song={song} />
-            ))}
-            {/* Add card */}
-            <Card
-              className="h-full border-dashed cursor-pointer hover:bg-accent transition-colors"
-              onClick={() => setSheetOpen(true)}
-            >
-              <CardContent className="p-3 flex items-center justify-center h-full min-h-[80px]">
-                <Plus className="w-6 h-6 text-muted-foreground" />
-              </CardContent>
-            </Card>
-          </div>
         )}
+        <div className="grid grid-cols-2 gap-3">
+          {filtered.map((song) => (
+            <SongCard key={song.id} song={song} />
+          ))}
+          {/* Add card */}
+          <Card
+            className="h-full border-dashed cursor-pointer hover:bg-accent transition-colors"
+            onClick={() => setSheetOpen(true)}
+          >
+            <CardContent className="p-3 flex items-center justify-center h-full min-h-[80px]">
+              <Plus className="w-6 h-6 text-muted-foreground" />
+            </CardContent>
+          </Card>
+        </div>
       </div>
 
       <AddSongSheet

app/app/routes/songs.$id.tsx

@@ -8,10 +8,10 @@ import { getMockSong } from "~/lib/mock";
 import type { Song } from "~/lib/types";
 
 export function meta({ data }: Route.MetaArgs) {
-  if (!data) return [{ title: "Song not found" }];
+  if (!data?.song) return [{ title: "PocketChords" }];
   return [
     { title: `${data.song.meta.title} — PocketChords` },
-    { name: "description", content: `${data.song.meta.artist}` },
+    { name: "description", content: data.song.meta.artist },
   ];
 }
 
@@ -34,7 +34,7 @@ export default function SongDetail({ loaderData }: Route.ComponentProps) {
   const { tempId } = loaderData;
 
   // Resolve song — either from loader or from sessionStorage (temp songs)
-  const [song] = useState<Song>(() => {
+  const [song] = useState<Song | null>(() => {
     if (loaderData.song) return loaderData.song;
     if (tempId && typeof window !== "undefined") {
       const stored = sessionStorage.getItem(tempId);