first draft

app/lib/pagelib.py

@@ -0,0 +1,54 @@
+from typing import Any
+from app.serializers.album import serialize_for_card
+from app.serializers.artist import serialize_for_card as serialize_artist
+from app.store.albums import AlbumStore
+from app.store.artists import ArtistStore
+
+
+def validate_page_items(items: list[dict[str, str]]):
+    """
+    Validate the items in a page before adding them to the database.
+    """
+    validated: list[dict[str, str]] = []
+
+    for item in items:
+        if item["type"] == "album":
+            album = AlbumStore.albummap.get(item["hash"])
+
+            if album is not None:
+                validated.append(item)
+        elif item["type"] == "artist":
+            artist = ArtistStore.artistmap.get(item["hash"])
+
+            if artist is not None:
+                validated.append(item)
+        else:
+            raise ValueError(f"Invalid item type: {item['type']}")
+
+    return validated
+
+
+def recover_page_items(items: list[dict[str, str]]):
+    """
+    Recover the items in a page.
+    """
+    recovered: list[dict[str, Any]] = []
+
+    for item in items:
+        if item["type"] == "album":
+            album = AlbumStore.albummap.get(item["hash"])
+
+            if album is not None:
+                recovered.append(
+                    {"item": serialize_for_card(album.album), "type": "album"}
+                )
+        elif item["type"] == "artist":
+            artist = ArtistStore.artistmap.get(item["hash"])
+
+            if artist is not None:
+                recovered.append(
+                    {"item": serialize_artist(artist.artist), "type": "artist"}
+                )
+
+    recovered.reverse()
+    return recovered