From 963da0b5d0b88fe1793f5f157cd3f14266de82e2 Mon Sep 17 00:00:00 2001
From: Keith Edmunds <kae@tiger-computing.co.uk>
Date: Sat, 8 Mar 2025 21:30:37 +0000
Subject: [PATCH] No db calls when servicing data() except for caching

---
 app/models.py        |  8 ++++----
 app/music_manager.py |  6 ++++++
 app/playlistmodel.py | 41 ++++++++++++++++++++++-------------------
 3 files changed, 32 insertions(+), 23 deletions(-)

diff --git a/app/models.py b/app/models.py
index 66f8c73..cec667d 100644
--- a/app/models.py
+++ b/app/models.py
@@ -109,7 +109,7 @@ class NoteColours(dbtables.NoteColoursTable):
     @staticmethod
     def get_colour(
         session: Session, text: str, foreground: bool = False
-    ) -> Optional[str]:
+    ) -> str:
         """
         Parse text and return background (foreground if foreground==True) colour
         string if matched, else None
@@ -117,7 +117,7 @@ class NoteColours(dbtables.NoteColoursTable):
         """
 
         if not text:
-            return None
+            return ""
 
         match = False
         for rec in NoteColours.get_all(session):
@@ -138,10 +138,10 @@ class NoteColours(dbtables.NoteColoursTable):
 
             if match:
                 if foreground:
-                    return rec.foreground
+                    return rec.foreground or ""
                 else:
                     return rec.colour
-        return None
+        return ""
 
     def invalidate_cache(self) -> None:
         """Invalidate dogpile cache"""
diff --git a/app/music_manager.py b/app/music_manager.py
index 565f0dc..9ae6147 100644
--- a/app/music_manager.py
+++ b/app/music_manager.py
@@ -439,6 +439,12 @@ class RowAndTrack:
         self.row_number = playlist_row.row_number
         self.track_id = playlist_row.track_id
 
+        # Playlist display data
+        self.row_fg: Optional[str] = None
+        self.row_bg: Optional[str] = None
+        self.note_fg: Optional[str] = None
+        self.note_bg: Optional[str] = None
+
         # Collect track data if there's a track
         if playlist_row.track_id:
             self.artist = playlist_row.track.artist
diff --git a/app/playlistmodel.py b/app/playlistmodel.py
index 4663275..04205a5 100644
--- a/app/playlistmodel.py
+++ b/app/playlistmodel.py
@@ -70,8 +70,11 @@ class PlaylistModel(QAbstractTableModel):
     database.
     """
 
-    def __init__(self, playlist_id: int, is_template: bool,) -> None:
-
+    def __init__(
+        self,
+        playlist_id: int,
+        is_template: bool,
+    ) -> None:
         super().__init__()
 
         log.debug("PlaylistModel.__init__()")
@@ -182,12 +185,13 @@ class PlaylistModel(QAbstractTableModel):
         # Header row
         if self.is_header_row(row):
             # Check for specific header colouring
-            with db.Session() as session:
-                note_background = NoteColours.get_colour(session, rat.note)
-                if note_background:
-                    return QBrush(QColor(note_background))
-                else:
-                    return QBrush(QColor(Config.COLOUR_NOTES_PLAYLIST))
+            if rat.row_bg is None:
+                with db.Session() as session:
+                    rat.row_bg = NoteColours.get_colour(session, rat.note)
+            if rat.row_bg:
+                return QBrush(QColor(rat.row_bg))
+            else:
+                return QBrush(QColor(Config.COLOUR_NOTES_PLAYLIST))
         # Unreadable track file
         if file_is_unreadable(rat.path):
             return QBrush(QColor(Config.COLOUR_UNREADABLE))
@@ -219,10 +223,11 @@ class PlaylistModel(QAbstractTableModel):
                 return QBrush(QColor(Config.COLOUR_BITRATE_OK))
         if column == Col.NOTE.value:
             if rat.note:
-                with db.Session() as session:
-                    note_background = NoteColours.get_colour(session, rat.note)
-                    if note_background:
-                        return QBrush(QColor(note_background))
+                if rat.note_bg is None:
+                    with db.Session() as session:
+                        rat.note_bg = NoteColours.get_colour(session, rat.note)
+                if rat.note_bg:
+                    return QBrush(QColor(rat.note_bg))
 
         return QBrush()
 
@@ -1575,13 +1580,11 @@ class PlaylistModel(QAbstractTableModel):
             if not track_id:
                 return ""
             playdates = Playdates.last_playdates(session, track_id)
-            return (
-                "<br>".join(
-                    [
-                        a.lastplayed.strftime(Config.LAST_PLAYED_TOOLTIP_DATE_FORMAT)
-                        for a in playdates
-                    ]
-                )
+            return "<br>".join(
+                [
+                    a.lastplayed.strftime(Config.LAST_PLAYED_TOOLTIP_DATE_FORMAT)
+                    for a in playdates
+                ]
             )
 
     def update_or_insert(self, track_id: int, row_number: int) -> None: