anki: add withAddons

`anki.withAddons` creates a wrapped version of Anki with
all the addons provided to the function installed.

pkgs/games/anki/addons/anki-utils.nix

@@ -0,0 +1,126 @@
+{
+  lib,
+  stdenv,
+  symlinkJoin,
+  lndir,
+  formats,
+  runCommand,
+}:
+{
+  buildAnkiAddon = lib.extendMkDerivation {
+    constructDrv = stdenv.mkDerivation;
+    extendDrvArgs =
+      finalAttrs:
+      {
+        pname,
+        version,
+        src,
+        sourceRoot ? "",
+        configurePhase ? ''
+          runHook preConfigure
+          runHook postConfigure
+        '',
+        buildPhase ? ''
+          runHook preBuild
+          runHook postBuild
+        '',
+        dontPatchELF ? true,
+        dontStrip ? true,
+        nativeBuildInputs ? [ ],
+        passthru ? { },
+        meta ? { },
+        # Script run after "user_files" folder is populated.
+        # Used when an add-on needs to process and change "user_files" based
+        # on what the user added to it.
+        processUserFiles ? "",
+        ...
+      }:
+      {
+        inherit
+          version
+          src
+          sourceRoot
+          configurePhase
+          buildPhase
+          dontPatchELF
+          dontStrip
+          nativeBuildInputs
+          ;
+
+        pname = "anki-addon-${pname}";
+
+        installPrefix = "share/anki/addons/${pname}";
+
+        installPhase = ''
+          runHook preInstall
+
+          mkdir -p "$out/$installPrefix"
+          find . -mindepth 1 -maxdepth 1 | xargs -d'\n' mv -t "$out/$installPrefix/"
+
+          runHook postInstall
+        '';
+
+        passthru = {
+          withConfig =
+            {
+              # JSON add-on config. The available options for an add-on are in its
+              # config.json file.
+              # See https://addon-docs.ankiweb.net/addon-config.html#config-json
+              config ? { },
+              # Path to a folder to be merged with the add-on "user_files" folder.
+              # See https://addon-docs.ankiweb.net/addon-config.html#user-files.
+              userFiles ? null,
+            }:
+            let
+              metaConfigFormat = formats.json { };
+              addonMetaConfig = metaConfigFormat.generate "meta.json" { inherit config; };
+            in
+            symlinkJoin {
+              pname = "${finalAttrs.pname}-with-config";
+              inherit (finalAttrs) version meta;
+
+              paths = [
+                finalAttrs.finalPackage
+              ];
+
+              postBuild = ''
+                cd $out/${finalAttrs.installPrefix}
+
+                rm -f meta.json
+                ln -s ${addonMetaConfig} meta.json
+
+                mkdir -p user_files
+                ${
+                  if (userFiles != null) then
+                    ''
+                      ${lndir}/bin/lndir -silent "${userFiles}" user_files
+                    ''
+                  else
+                    ""
+                }
+
+                ${processUserFiles}
+              '';
+            };
+        } // passthru;
+
+        meta = {
+          platforms = lib.platforms.all;
+        } // meta;
+      };
+  };
+
+  buildAnkiAddonsDir =
+    addonPackages:
+    let
+      addonDirs = map (pkg: "${pkg}/share/anki/addons") addonPackages;
+      addons = lib.concatMapStringsSep " " (p: "${p}/*") addonDirs;
+    in
+    runCommand "anki-addons" { } ''
+      mkdir $out
+      [[ '${addons}' ]] || exit 0
+      for addon in ${addons}; do
+        ln -s "$addon" $out/
+      done
+    '';
+}

pkgs/games/anki/addons/default.nix

@@ -0,0 +1,6 @@
+{
+  callPackage,
+}:
+{
+
+}

pkgs/games/anki/default.nix

@@ -10,6 +10,7 @@
   lame,
   mpv-unwrapped,
   ninja,
+  callPackage,
   nixosTests,
   nodejs,
   nodejs-slim,
@@ -129,6 +130,8 @@ python3.pkgs.buildPythonApplication {
     ./patches/disable-auto-update.patch
     ./patches/remove-the-gl-library-workaround.patch
     ./patches/skip-formatting-python-code.patch
+    # Used in with-addons.nix
+    ./patches/allow-setting-addons-folder.patch
   ];
 
   inherit cargoDeps yarnOfflineCache;
@@ -301,6 +304,7 @@ python3.pkgs.buildPythonApplication {
   '';
 
   passthru = {
+    withAddons = ankiAddons: callPackage ./with-addons.nix { inherit ankiAddons; };
     tests.anki-sync-server = nixosTests.anki-sync-server;
   };
 
@@ -324,6 +328,7 @@ python3.pkgs.buildPythonApplication {
     inherit (mesa.meta) platforms;
     maintainers = with maintainers; [
       euank
+      junestepp
       oxij
     ];
     # Reported to crash at launch on darwin (as of 2.1.65)

pkgs/games/anki/patches/allow-setting-addons-folder.patch

@@ -0,0 +1,15 @@
+diff --git a/qt/aqt/profiles.py b/qt/aqt/profiles.py
+index 469908c1b2..34612d6e08 100644
+--- a/qt/aqt/profiles.py
++++ b/qt/aqt/profiles.py
+@@ -310,7 +310,9 @@ def profileFolder(self, create: bool = True) -> str:
+         return path
+ 
+     def addonFolder(self) -> str:
+-        return self._ensureExists(os.path.join(self.base, "addons21"))
++        path = Path(os.environ.get("ANKI_ADDONS") or Path(self.base) / "addons21")
++        path.mkdir(parents=True, exist_ok=True)
++        return str(path.resolve())
+ 
+     def backupFolder(self) -> str:
+         return self._ensureExists(os.path.join(self.profileFolder(), "backups"))

pkgs/games/anki/with-addons.nix

@@ -0,0 +1,107 @@
+{
+  lib,
+  symlinkJoin,
+  makeWrapper,
+  anki,
+  anki-utils,
+  writeTextDir,
+  ankiAddons ? [ ],
+}:
+/*
+  `ankiAddons`
+   :  A set of Anki add-ons to be installed. Here's a an example:
+
+      ~~~
+      pkgs.anki.withAddons [
+        # When the add-on is already available in nixpkgs
+        pkgs.ankiAddons.anki-connect
+
+        # When the add-on is not available in nixpkgs
+        (pkgs.anki-utils.buildAnkiAddon (finalAttrs: {
+          pname = "recolor";
+          version = "3.1";
+          src = pkgs.fetchFromGitHub {
+            owner = "AnKing-VIP";
+            repo = "AnkiRecolor";
+            rev = finalAttrs.version;
+            sparseCheckout = [ "src/addon" ];
+            hash = "sha256-28DJq2l9DP8O6OsbNQCZ0pm4S6CQ3Yz0Vfvlj+iQw8Y=";
+          };
+          sourceRoot = "source/src/addon";
+        }))
+
+        # When the add-on needs to be configured
+        pkgs.ankiAddons.passfail2.withConfig {
+          config = {
+            again_button_name = "not quite";
+            good_button_name = "excellent";
+          };
+
+          user_files = ./dir-to-be-merged-into-addon-user-files-dir;
+        };
+      ]
+      ~~~
+
+      The original `anki` executable will be wrapped so that it uses the addons from
+      `ankiAddons`.
+
+      This only works with Anki versions patched to support the `ANKI_ADDONS` environment
+      variable. `pkgs.anki` has this, but `pkgs.anki-bin` does not.
+*/
+let
+  defaultAddons = [
+    (anki-utils.buildAnkiAddon {
+      pname = "nixos";
+      version = "1.0";
+      src = writeTextDir "__init__.py" ''
+        import aqt
+        from aqt.qt import QMessageBox
+        import json
+
+        def addons_dialog_will_show(dialog: aqt.addons.AddonsDialog) -> None:
+          dialog.setEnabled(False)
+          QMessageBox.information(
+            dialog,
+            "NixOS Info",
+            ("These add-ons are managed by NixOS.<br>"
+             "See <a href='https://github.com/NixOS/nixpkgs/tree/master/pkgs/games/anki/with-addons.nix'>"
+             "github.com/NixOS/nixpkgs/tree/master/pkgs/games/anki/with-addons.nix</a>")
+          )
+
+        def addon_tried_to_write_config(module: str, conf: dict) -> None:
+          message_box = QMessageBox(
+            QMessageBox.Icon.Warning,
+            "NixOS Info",
+            (f"The add-on module: \"{module}\" tried to update its config.<br>"
+              "See <a href='https://github.com/NixOS/nixpkgs/tree/master/pkgs/games/anki/with-addons.nix'>"
+              "github.com/NixOS/nixpkgs/tree/master/pkgs/games/anki/with-addons.nix</a>"
+              " for how to configure add-ons managed by NixOS.")
+          )
+          message_box.setDetailedText(json.dumps(conf))
+          message_box.exec()
+
+        aqt.gui_hooks.addons_dialog_will_show.append(addons_dialog_will_show)
+        aqt.mw.addonManager.writeConfig = addon_tried_to_write_config
+      '';
+      meta.maintainers = with lib.maintainers; [ junestepp ];
+    })
+  ];
+in
+symlinkJoin {
+  inherit (anki) version;
+  pname = "${anki.pname}-with-addons";
+
+  paths = [ anki ];
+
+  nativeBuildInputs = [ makeWrapper ];
+  postBuild = ''
+    wrapProgram $out/bin/anki \
+      --set ANKI_ADDONS "${anki-utils.buildAnkiAddonsDir (ankiAddons ++ defaultAddons)}"
+  '';
+
+  meta = builtins.removeAttrs anki.meta [
+    "name"
+    "outputsToInstall"
+    "position"
+  ];
+}

pkgs/top-level/all-packages.nix

@@ -14902,6 +14902,8 @@ with pkgs;
   amoeba-data = callPackage ../games/amoeba/data.nix { };
 
   anki = callPackage ../games/anki { };
+  anki-utils = callPackage ../games/anki/addons/anki-utils.nix { };
+  ankiAddons = recurseIntoAttrs (callPackage ../games/anki/addons { });
   anki-bin = callPackage ../games/anki/bin.nix { };
   anki-sync-server = callPackage ../games/anki/sync-server.nix { };