provide mobilizonPatchLogos as a nix flake library function

flake.nix

@@ -59,5 +59,123 @@
         inherit (self.packages.x86_64-linux) mobilizon update;
       };
 
+      lib = {
+        # Patch the logos in a built Mobilizon package, so we don't have to do it in the source tree.
+        mobilizonPatchLogos = pkg: icons:
+          let
+            inherit (icons) logo favicon;
+            faviconDir = "./lib/mobilizon-${pkg.version}/priv/static";
+            iconDir = "${faviconDir}/img/icons";
+          in
+          pkgs.stdenvNoCC.mkDerivation {
+            inherit (pkg) name pname version;
+            src = pkg;
+            nativeBuildInputs = [ pkgs.imagemagick ];
+            patchPhase = ''
+              magick convert \
+                -resize x16 \
+                -gravity center \
+                -crop 16x16+0+0 \
+                -flatten \
+                -colors 256 \
+                '${favicon}' \
+                ${iconDir}/favicon-16x16.png
+
+              magick convert \
+                -resize x32 \
+                -gravity center \
+                -crop 32x32+0+0 \
+                -flatten \
+                -colors 256 \
+                '${favicon}' \
+                ${iconDir}/favicon-32x32.png
+
+
+              magick convert \
+                -resize x16 \
+                -gravity center \
+                -crop 16x16+0+0 \
+                -flatten \
+                -colors 256 \
+                '${favicon}' \
+                favicon-16x16.ico
+
+              magick convert \
+                -resize x32 \
+                -gravity center \
+                -crop 32x32+0+0 \
+                -flatten \
+                -colors 256 \
+                '${favicon}' \
+                favicon-32x32.ico
+
+              magick convert \
+                -resize x48 \
+                -gravity center \
+                -crop 48x48+0+0 \
+                -flatten \
+                -colors 256 \
+                '${favicon}' \
+                favicon-48x48.ico
+
+              magick convert favicon-16x16.ico favicon-32x32.ico favicon-48x48.ico ${faviconDir}/favicon.ico
+              rm favicon-16x16.ico favicon-32x32.ico favicon-48x48.ico
+
+              cp '${favicon}' ${iconDir}/favicon.svg
+              cp '${favicon}' ${iconDir}/safari-pinned-tab.svg
+
+              magick convert \
+                '${favicon}' \
+                -gravity center \
+                -extent 630x350 \
+                ${faviconDir}/img/mobilizon_default_card.png
+
+              magick convert \
+                -background '#e08c96' \
+                '${logo}' \
+                -resize 366x108 \
+                ${faviconDir}/img/mobilizon_logo.png
+
+            '' + nixpkgs.lib.concatMapStrings
+              ({ resize, filename }: ''
+                magick convert \
+                  -resize x${resize} \
+                  '${favicon}' \
+                  ${iconDir}/${filename}
+
+              '')
+              [
+                { resize = "180"; filename = "apple-touch-icon.png"; }
+                { resize = "180"; filename = "apple-touch-icon-180x180.png"; }
+                { resize = "152"; filename = "apple-touch-icon-152x152.png"; }
+                { resize = "120"; filename = "apple-touch-icon-120x120.png"; }
+                { resize = "76"; filename = "apple-touch-icon-76x76.png"; }
+                { resize = "60"; filename = "apple-touch-icon-60x60.png"; }
+                { resize = "192"; filename = "android-chrome-192x192.png"; }
+                { resize = "512"; filename = "android-chrome-512x512.png"; }
+                { resize = "192"; filename = "android-chrome-maskable-192x192.png"; }
+                { resize = "512"; filename = "android-chrome-maskable-512x512.png"; }
+                { resize = "128"; filename = "badge-128x128.png"; }
+                { resize = "144"; filename = "icon-144x144.png"; }
+                { resize = "168"; filename = "icon-168x168.png"; }
+                { resize = "256"; filename = "icon-256x256.png"; }
+                { resize = "48"; filename = "icon-48x48.png"; }
+                { resize = "72"; filename = "icon-72x72.png"; }
+                { resize = "96"; filename = "icon-96x96.png"; }
+                { resize = "144"; filename = "msapplication-icon-144x144.png"; }
+                { resize = "150"; filename = "mstile-150x150.png"; }
+                { resize = "192"; filename = "android-chrome-192x192.png"; }
+                { resize = "512"; filename = "android-chrome-512x512.png"; }
+                { resize = "192"; filename = "android-chrome-maskable-192x192.png"; }
+                { resize = "512"; filename = "android-chrome-maskable-512x512.png"; }
+              ];
+
+
+            installPhase = "cp -R ./ $out";
+          };
+
+      };
+
+
     };
 }