Prevent scheme generation from running when result is not used (#56)

stylix/hm/palette.nix

@@ -7,7 +7,14 @@ args:
   config = {
     xdg.configFile = {
       # See ../nixos/palette.nix for the rational behind these two options
-      "stylix/palette.json".source = config.stylix.generated.json;
+      "stylix/generated.json".source = config.lib.stylix.scheme {
+        template = builtins.readFile ../palette.json.mustache;
+        extension = ".json";
+      };
+      "stylix/palette.json".source = config.lib.stylix.colors {
+        template = builtins.readFile ../palette.json.mustache;
+        extension = ".json";
+      };
       "stylix/palette.html".source = config.lib.stylix.colors {
         template = builtins.readFile ../palette.html.mustache;
         extension = ".html";

stylix/nixos/palette.nix

@@ -10,7 +10,18 @@ args:
       # garbage collection, so future configurations can be evaluated without
       # having to generate the palette again. The generator is not kept, only
       # the palette which came from it, so this uses very little disk space.
-      "stylix/palette.json".source = config.stylix.generated.json;
+      # The extra indirection should prevent the palette generator from running
+      # when the theme is manually specified. generated.json is necessary in
+      # the presence of overrides.
+      "stylix/generated.json".source = config.lib.stylix.scheme {
+        template = builtins.readFile ../palette.json.mustache;
+        extension = ".json";
+      };
+
+      "stylix/palette.json".source = config.lib.stylix.colors {
+        template = builtins.readFile ../palette.json.mustache;
+        extension = ".json";
+      };
 
       # We also provide a HTML version which is useful for viewing the colors
       # during development.

stylix/palette.json.mustache

@@ -0,0 +1,21 @@
+{
+  "base00": "{{{base00}}}",
+  "base01": "{{{base01}}}",
+  "base02": "{{{base02}}}",
+  "base03": "{{{base03}}}",
+  "base04": "{{{base04}}}",
+  "base05": "{{{base05}}}",
+  "base06": "{{{base06}}}",
+  "base07": "{{{base07}}}",
+  "base08": "{{{base08}}}",
+  "base09": "{{{base09}}}",
+  "base0A": "{{{base0A}}}",
+  "base0B": "{{{base0B}}}",
+  "base0C": "{{{base0C}}}",
+  "base0D": "{{{base0D}}}",
+  "base0E": "{{{base0E}}}",
+  "base0F": "{{{base0F}}}",
+  "scheme": "Stylix",
+  "author": "Stylix",
+  "slug": "stylix"
+}

stylix/palette.nix

@@ -8,16 +8,18 @@ let
 
   cfg = config.stylix;
 
-  paletteJSON = pkgs.runCommand "palette.json" { } ''
-    ${palette-generator}/bin/palette-generator ${cfg.polarity} ${cfg.image} $out
-  '';
-  generatedPalette = importJSON paletteJSON;
-
-  generatedScheme = generatedPalette // {
-    author = "Stylix";
-    scheme = "Stylix";
-    slug = "stylix";
-  };
+  paletteJSON = let
+    generatedJSON = pkgs.runCommand "palette.json" { } ''
+      ${palette-generator}/bin/palette-generator ${cfg.polarity} ${cfg.image} $out
+    '';
+    palette = importJSON generatedJSON;
+    scheme = base16.mkSchemeAttrs palette;
+    json = scheme {
+      template = builtins.readFile ./palette.json.mustache;
+      extension = ".json";
+    };
+  in json;
+  generatedScheme = importJSON paletteJSON;
 
   override =
     (if cfg.base16Scheme == fromOs [ "base16Scheme" ] {}
@@ -84,7 +86,7 @@ in {
         description = "The imported json";
         readOnly = true;
         internal = true;
-        default = generatedPalette;
+        default = generatedScheme;
       };
     };
 
@@ -124,5 +126,6 @@ in {
     # This attrset can be used like a function too, see
     # https://github.com/SenchoPens/base16.nix#mktheme
     lib.stylix.colors = (base16.mkSchemeAttrs cfg.base16Scheme).override override;
+    lib.stylix.scheme = base16.mkSchemeAttrs cfg.base16Scheme;
   };
 }