build: replace flake with npins, add Nix packages for web and desktop

- npins pins nixpkgs-unstable + Inter font tarball; shell.nix replaces the flake devshell
- nix/bun-deps.nix: fixed-output bun install of the workspace (hash tied to bun.lock)
- nix/web.nix: static Next.js export; next/font/google patched to local Inter for offline builds
- nix/desktop.nix: tsc-built Electron app embedding the web export, wrapped with nixpkgs electron; ffmpeg-static satisfied by nixpkgs ffmpeg

11 files changed, 499 insertions, 62 deletions

diff --git a/AGENTS.md b/AGENTS.md
index 6c61e44e..6093ab29 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -46,7 +46,7 @@ Domain folders also include `animation/`, `effects/`, `masks/`, `params/`, `prev
 
 ## Development Commands
 
-Run from repo root unless noted. `flake.nix` provides a devshell (`nix develop`) with bun (1.3.x) + nodejs (24) + just; the pinned bun 1.2.18 works but so does 1.3.x. The root `justfile` wraps the common commands below (`just` lists them; e.g. `just dev`, `just test <path>`).
+Run from repo root unless noted. `shell.nix` provides a devshell (`nix-shell`, nixpkgs pinned via npins in `npins/`) with bun (1.3.x) + nodejs (24) + just; the pinned bun 1.2.18 works but so does 1.3.x. The root `justfile` wraps the common commands below (`just` lists them; e.g. `just dev`, `just test <path>`). Nix packages (npins-pinned): `nix-build -A packages.web` (static Next.js export) and `nix-build -A packages.desktop` (Electron app, `result/bin/opencut`).
 
 ```bash
 bun install
diff --git a/default.nix b/default.nix
new file mode 100644
index 00000000..5dc1a157
--- /dev/null
+++ b/default.nix
@@ -0,0 +1,9 @@
+let
+  sources = import ./npins;
+  pkgs = import sources.nixpkgs { };
+in
+rec {
+  packages.web = pkgs.callPackage ./nix/web.nix { inherit sources; };
+  packages.desktop = pkgs.callPackage ./nix/desktop.nix { inherit sources; };
+  packages.default = packages.desktop;
+}
diff --git a/flake.lock b/flake.lock
deleted file mode 100644
index 0b9301e2..00000000
--- a/flake.lock
+++ /dev/null
@@ -1,27 +0,0 @@
-{
-  "nodes": {
-    "nixpkgs": {
-      "locked": {
-        "lastModified": 1784796856,
-        "narHash": "sha256-wWFrV5/Qbm+lyt5x20E/bSbfJiGKMo4RCxZV8cl/WZI=",
-        "owner": "NixOS",
-        "repo": "nixpkgs",
-        "rev": "e2587caef70cea85dd97d7daab492899902dbf5d",
-        "type": "github"
-      },
-      "original": {
-        "owner": "NixOS",
-        "ref": "nixos-unstable",
-        "repo": "nixpkgs",
-        "type": "github"
-      }
-    },
-    "root": {
-      "inputs": {
-        "nixpkgs": "nixpkgs"
-      }
-    }
-  },
-  "root": "root",
-  "version": 7
-}
diff --git a/flake.nix b/flake.nix
deleted file mode 100644
index fab10705..00000000
--- a/flake.nix
+++ /dev/null
@@ -1,33 +0,0 @@
-{
-  description = "OpenCut Classic development shell";
-
-  inputs.nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
-
-  outputs =
-    { nixpkgs, ... }:
-    let
-      systems = [
-        "x86_64-linux"
-        "aarch64-linux"
-        "aarch64-darwin"
-      ];
-      forEachSystem = nixpkgs.lib.genAttrs systems;
-    in
-    {
-      devShells = forEachSystem (
-        system:
-        let
-          pkgs = import nixpkgs { inherit system; };
-        in
-        {
-          default = pkgs.mkShell {
-            packages = with pkgs; [
-              bun
-              just
-              nodejs
-            ];
-          };
-        }
-      );
-    };
-}
diff --git a/justfile b/justfile
index eea359d2..67d2ef19 100644
--- a/justfile
+++ b/justfile
@@ -1,4 +1,4 @@
-# Common commands for the OpenCut fork. Run inside the devshell (`nix develop`)
+# Common commands for the OpenCut fork. Run inside the devshell (`nix-shell`)
 # or anywhere bun + node are on PATH. `just` lists all recipes.
 
 default:
diff --git a/nix/bun-deps.nix b/nix/bun-deps.nix
new file mode 100644
index 00000000..646a91d7
--- /dev/null
+++ b/nix/bun-deps.nix
@@ -0,0 +1,49 @@
+# Fixed-output derivation: workspace node_modules from bun.lock.
+# Only re-runs when the lockfile or manifests change; the hash covers the
+# installed dependency tree, so it must be updated whenever bun.lock changes
+# (set outputHash = lib.fakeHash, build once, paste the reported hash).
+{
+  lib,
+  runCommand,
+  bun,
+  cacert,
+}:
+
+let
+  minimalSrc = runCommand "opencut-bun-src" { } ''
+    mkdir -p $out/apps/web $out/apps/desktop
+    cp ${../package.json} $out/package.json
+    cp ${../bun.lock} $out/bun.lock
+    cp ${../bunfig.toml} $out/bunfig.toml
+    cp ${../.npmrc} $out/.npmrc
+    cp ${../apps/web/package.json} $out/apps/web/package.json
+    cp ${../apps/desktop/package.json} $out/apps/desktop/package.json
+  '';
+in
+runCommand "opencut-bun-deps"
+  {
+    nativeBuildInputs = [
+      bun
+      cacert
+    ];
+    outputHashMode = "recursive";
+    outputHashAlgo = "sha256";
+    outputHash = "sha256-+zRGGTHFoM9d4wjP999J3JdcRgNksTTVOb+nceyvNak=";
+  }
+  ''
+    cp -r ${minimalSrc} src
+    chmod -R u+w src
+    cd src
+
+    export HOME=$TMPDIR
+    export BUN_INSTALL_CACHE_DIR=$TMPDIR/bun-cache
+    # The electron binary is unused; nixpkgs electron is used at runtime.
+    export ELECTRON_SKIP_BINARY_DOWNLOAD=1
+
+    bun install --frozen-lockfile
+
+    mkdir -p $out/apps/web $out/apps/desktop
+    cp -r node_modules $out/node_modules
+    cp -r apps/web/node_modules $out/apps/web/node_modules
+    cp -r apps/desktop/node_modules $out/apps/desktop/node_modules
+  ''
diff --git a/nix/desktop.nix b/nix/desktop.nix
new file mode 100644
index 00000000..de2c8660
--- /dev/null
+++ b/nix/desktop.nix
@@ -0,0 +1,86 @@
+# Electron desktop app: tsc-compiled main process + the static web export,
+# wrapped with nixpkgs electron (no electron-builder, no asar).
+# ffmpeg-static is satisfied by nixpkgs ffmpeg.
+{
+  lib,
+  stdenvNoCC,
+  bun,
+  nodejs,
+  callPackage,
+  electron,
+  ffmpeg,
+  makeWrapper,
+  sources ? import ../npins,
+}:
+
+let
+  bunDeps = callPackage ./bun-deps.nix { };
+  web = callPackage ./web.nix { inherit sources; };
+  desktopPkg = builtins.fromJSON (builtins.readFile ../apps/desktop/package.json);
+in
+stdenvNoCC.mkDerivation {
+  pname = "opencut-desktop";
+  version = desktopPkg.version;
+  src = lib.cleanSource ../.;
+
+  nativeBuildInputs = [
+    bun
+    nodejs
+    makeWrapper
+  ];
+
+  configurePhase = ''
+    runHook preConfigure
+    cp -r ${bunDeps}/node_modules node_modules
+    cp -r ${bunDeps}/apps/desktop/node_modules apps/desktop/node_modules
+    chmod -R u+w node_modules apps/desktop/node_modules
+    patchShebangs node_modules apps/desktop/node_modules
+    runHook postConfigure
+  '';
+
+  buildPhase = ''
+    runHook preBuild
+    export HOME=$TMPDIR
+    cd apps/desktop
+    bun run build
+    cd $NIX_BUILD_TOP/source
+    runHook postBuild
+  '';
+
+  installPhase = ''
+    runHook preInstall
+
+    appdir=$out/share/opencut
+    mkdir -p $appdir/node_modules/ffmpeg-static
+    cp apps/desktop/package.json $appdir/package.json
+    cp -r apps/desktop/dist $appdir/dist
+    cp -r ${web} $appdir/web
+
+    # main.js resolves ffmpeg via require("ffmpeg-static"); point it at nixpkgs ffmpeg.
+    cp apps/desktop/node_modules/ffmpeg-static/index.js $appdir/node_modules/ffmpeg-static/index.js
+    cp apps/desktop/node_modules/ffmpeg-static/package.json $appdir/node_modules/ffmpeg-static/package.json
+    ln -s ${lib.getExe ffmpeg} $appdir/node_modules/ffmpeg-static/ffmpeg
+
+    makeWrapper ${lib.getExe electron} $out/bin/opencut \
+      --add-flags "$appdir"
+
+    mkdir -p $out/share/applications
+    cat > $out/share/applications/opencut.desktop <<EOF
+    [Desktop Entry]
+    Type=Application
+    Name=OpenCut
+    Comment=Offline-first video editor
+    Exec=opencut
+    Categories=AudioVideo;Video;
+    EOF
+
+    runHook postInstall
+  '';
+
+  meta = {
+    description = "OpenCut desktop (Electron)";
+    license = lib.licenses.mit;
+    mainProgram = "opencut";
+    platforms = lib.platforms.linux;
+  };
+}
diff --git a/nix/web.nix b/nix/web.nix
new file mode 100644
index 00000000..eb464a2a
--- /dev/null
+++ b/nix/web.nix
@@ -0,0 +1,64 @@
+# Static export of the Next.js web app (apps/web/out).
+# Deps come from the bun-deps FOD; the Google-font fetch in next/font is
+# replaced by the npins-pinned Inter so the build runs offline.
+{
+  lib,
+  stdenvNoCC,
+  bun,
+  nodejs,
+  callPackage,
+  sources ? import ../npins,
+}:
+
+let
+  bunDeps = callPackage ./bun-deps.nix { };
+  webPkg = builtins.fromJSON (builtins.readFile ../apps/web/package.json);
+in
+stdenvNoCC.mkDerivation {
+  pname = "opencut-web";
+  version = webPkg.version;
+  src = lib.cleanSource ../.;
+
+  nativeBuildInputs = [
+    bun
+    nodejs
+  ];
+
+  postPatch = ''
+    mkdir -p apps/web/public/fonts
+    cp ${sources.inter}/web/InterVariable.woff2 apps/web/public/fonts/InterVariable.woff2
+    substituteInPlace apps/web/src/app/layout.tsx \
+      --replace-fail 'import { Inter } from "next/font/google";' 'import localFont from "next/font/local";' \
+      --replace-fail 'const siteFont = Inter({ subsets: ["latin"] });' 'const siteFont = localFont({ src: "../../public/fonts/InterVariable.woff2" });'
+  '';
+
+  configurePhase = ''
+    runHook preConfigure
+    cp -r ${bunDeps}/node_modules node_modules
+    cp -r ${bunDeps}/apps/web/node_modules apps/web/node_modules
+    chmod -R u+w node_modules apps/web/node_modules
+    patchShebangs node_modules apps/web/node_modules
+    runHook postConfigure
+  '';
+
+  buildPhase = ''
+    runHook preBuild
+    export HOME=$TMPDIR
+    export NEXT_TELEMETRY_DISABLED=1
+    export NODE_ENV=production
+    cd apps/web
+    bun run build
+    runHook postBuild
+  '';
+
+  installPhase = ''
+    runHook preInstall
+    cp -r out $out
+    runHook postInstall
+  '';
+
+  meta = {
+    description = "OpenCut web app (static export)";
+    license = lib.licenses.mit;
+  };
+}
diff --git a/npins/default.nix b/npins/default.nix
new file mode 100644
index 00000000..8ec5eca6
--- /dev/null
+++ b/npins/default.nix
@@ -0,0 +1,260 @@
+/*
+  This file is provided under the MIT licence:
+
+  Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
+
+  The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
+
+  THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+*/
+# Generated by npins. Do not modify; will be overwritten regularly
+let
+  # Backwards-compatibly make something that previously didn't take any arguments take some
+  # The function must return an attrset, and will unfortunately be eagerly evaluated
+  # Same thing, but it catches eval errors on the default argument so that one may still call it with other arguments
+  mkFunctor =
+    fn:
+    let
+      e = builtins.tryEval (fn { });
+    in
+    (if e.success then e.value else { error = fn { }; }) // { __functor = _self: fn; };
+
+  # https://github.com/NixOS/nixpkgs/blob/0258808f5744ca980b9a1f24fe0b1e6f0fecee9c/lib/lists.nix#L295
+  range =
+    first: last: if first > last then [ ] else builtins.genList (n: first + n) (last - first + 1);
+
+  # https://github.com/NixOS/nixpkgs/blob/0258808f5744ca980b9a1f24fe0b1e6f0fecee9c/lib/strings.nix#L257
+  stringToCharacters = s: map (p: builtins.substring p 1 s) (range 0 (builtins.stringLength s - 1));
+
+  # https://github.com/NixOS/nixpkgs/blob/0258808f5744ca980b9a1f24fe0b1e6f0fecee9c/lib/strings.nix#L269
+  stringAsChars = f: s: concatStrings (map f (stringToCharacters s));
+  concatStrings = builtins.concatStringsSep "";
+
+  # If the environment variable NPINS_OVERRIDE_${name} is set, then use
+  # the path directly as opposed to the fetched source.
+  # (Taken from Niv for compatibility)
+  mayOverride =
+    name: path:
+    let
+      envVarName = "NPINS_OVERRIDE_${saneName}";
+      saneName = stringAsChars (c: if (builtins.match "[a-zA-Z0-9]" c) == null then "_" else c) name;
+      ersatz = builtins.getEnv envVarName;
+    in
+    if ersatz == "" then
+      path
+    else
+      # this turns the string into an actual Nix path (for both absolute and
+      # relative paths)
+      builtins.trace "Overriding path of \"${name}\" with \"${ersatz}\" due to set \"${envVarName}\"" (
+        if builtins.substring 0 1 ersatz == "/" then
+          /. + ersatz
+        else
+          /. + builtins.getEnv "PWD" + "/${ersatz}"
+      );
+
+  mkSource =
+    name: spec:
+    {
+      pkgs ? null,
+    }:
+    assert spec ? type;
+    let
+      # Unify across builtin and pkgs fetchers.
+      # `fetchGit` requires a wrapper because of slight API differences.
+      fetchers =
+        if pkgs == null then
+          {
+            inherit (builtins) fetchTarball fetchurl;
+            # Frustratingly, due to flakes and `fetchTree`, `fetchGit`
+            # has a different signature than the other builtin
+            # fetchers
+            fetchGit = args: (builtins.fetchGit args).outPath;
+          }
+        else
+          {
+            fetchTarball =
+              {
+                url,
+                sha256,
+              }:
+              pkgs.fetchzip {
+                inherit url sha256;
+                extension = "tar";
+              };
+            inherit (pkgs) fetchurl;
+            fetchGit =
+              {
+                url,
+                submodules,
+                rev,
+                name,
+                narHash,
+              }:
+              pkgs.fetchgit {
+                inherit url rev name;
+                fetchSubmodules = submodules;
+                hash = narHash;
+              };
+          };
+
+      path =
+        if spec.type == "Git" then
+          mkGitSource fetchers spec
+        else if spec.type == "GitRelease" then
+          mkGitSource fetchers spec
+        else if spec.type == "PyPi" then
+          mkPyPiSource fetchers spec
+        else if spec.type == "Channel" then
+          mkChannelSource fetchers spec
+        else if spec.type == "Url" || spec.type == "MutableUrl" then
+          mkUrlSource fetchers spec
+        else if spec.type == "Container" then
+          mkContainerSource pkgs spec
+        else
+          builtins.throw "Unknown source type ${spec.type}";
+    in
+    spec // { outPath = mayOverride name path; };
+
+  mkGitSource =
+    {
+      fetchTarball,
+      fetchGit,
+      ...
+    }:
+    {
+      repository,
+      revision,
+      url ? null,
+      submodules,
+      hash,
+      ...
+    }:
+    assert repository ? type;
+    # At the moment, either it is a plain git repository (which has an url), or it is a GitHub/GitLab repository
+    # In the latter case, there we will always be an url to the tarball
+    if url != null && !submodules then
+      fetchTarball {
+        inherit url;
+        sha256 = hash;
+      }
+    else
+      let
+        url =
+          if repository.type == "Git" then
+            repository.url
+          else if repository.type == "GitHub" then
+            "https://github.com/${repository.owner}/${repository.repo}.git"
+          else if repository.type == "GitLab" then
+            "${repository.server}/${repository.repo_path}.git"
+          else if repository.type == "Forgejo" then
+            "${repository.server}/${repository.owner}/${repository.repo}.git"
+          else
+            throw "Unrecognized repository type ${repository.type}";
+        urlToName =
+          url: rev:
+          let
+            matched = builtins.match "^.*/([^/]*)(\\.git)?$" url;
+
+            short = builtins.substring 0 7 rev;
+
+            appendShort = if (builtins.match "[a-f0-9]*" rev) != null then "-${short}" else "";
+          in
+          "${if matched == null then "source" else builtins.head matched}${appendShort}";
+        name = urlToName url revision;
+      in
+      fetchGit {
+        rev = revision;
+        narHash = hash;
+
+        inherit name submodules url;
+      };
+
+  mkPyPiSource =
+    { fetchurl, ... }:
+    {
+      url,
+      hash,
+      ...
+    }:
+    fetchurl {
+      inherit url;
+      sha256 = hash;
+    };
+
+  mkChannelSource =
+    { fetchTarball, ... }:
+    {
+      url,
+      hash,
+      ...
+    }:
+    fetchTarball {
+      inherit url;
+      sha256 = hash;
+    };
+
+  mkUrlSource =
+    {
+      fetchTarball,
+      fetchurl,
+      ...
+    }:
+    {
+      url,
+      hash,
+      unpack,
+      ...
+    }:
+    (if unpack then fetchTarball else fetchurl) {
+      inherit url;
+      sha256 = hash;
+    };
+
+  mkContainerSource =
+    pkgs:
+    {
+      image_name,
+      image_tag,
+      image_digest,
+      hash,
+      ...
+    }@args:
+    if pkgs == null then
+      builtins.throw "container sources require passing in a Nixpkgs value: https://github.com/andir/npins/blob/master/README.md#using-the-nixpkgs-fetchers"
+    else
+      pkgs.dockerTools.pullImage (
+        {
+          imageName = image_name;
+          imageDigest = image_digest;
+          finalImageTag = image_tag;
+          hash = hash;
+        }
+        // (if args.arch or null != null then { arch = args.arch; } else { })
+      );
+
+in
+mkFunctor (
+  {
+    input ? ./sources.json,
+  }:
+  let
+    data =
+      if builtins.isPath input then
+        # while `readFile` will throw an error anyways if the path doesn't exist,
+        # we still need to check beforehand because *our* error can be caught but not the one from the builtin
+        # See: <https://git.lix.systems/lix-project/lix/issues/1098>
+        if builtins.pathExists input then
+          builtins.fromJSON (builtins.readFile input)
+        else
+          throw "Input path ${toString input} does not exist"
+      else if builtins.isAttrs input then
+        input
+      else
+        throw "Unsupported input type ${builtins.typeOf input}, must be a path or an attrset";
+    version = data.version;
+  in
+  if version == 8 then
+    builtins.mapAttrs (name: spec: mkFunctor (mkSource name spec)) data.pins
+  else
+    throw "Unsupported format version ${toString version} in sources.json. Try running `npins upgrade`"
+)
diff --git a/npins/sources.json b/npins/sources.json
new file mode 100644
index 00000000..f4ed4417
--- /dev/null
+++ b/npins/sources.json
@@ -0,0 +1,18 @@
+{
+  "pins": {
+    "inter": {
+      "type": "Url",
+      "url": "https://github.com/rsms/inter/releases/download/v4.1/Inter-4.1.zip",
+      "unpack": true,
+      "hash": "sha256-5vdKKvHAeZi6igrfpbOdhZlDX2/5+UvzlnCQV6DdqoQ="
+    },
+    "nixpkgs": {
+      "type": "Channel",
+      "name": "nixpkgs-unstable",
+      "artifact": "nixexprs.tar.xz",
+      "url": "https://releases.nixos.org/nixpkgs/nixpkgs-26.11pre1043539.9bc02893134c/nixexprs.tar.xz",
+      "hash": "sha256-PlAXr9kpfXhMFU0OQ7qtE8FhLQo21WXFVGqIC85UFyc="
+    }
+  },
+  "version": 8
+}
diff --git a/shell.nix b/shell.nix
new file mode 100644
index 00000000..93c79af8
--- /dev/null
+++ b/shell.nix
@@ -0,0 +1,11 @@
+let
+  sources = import ./npins;
+  pkgs = import sources.nixpkgs { };
+in
+pkgs.mkShell {
+  packages = with pkgs; [
+    bun
+    just
+    nodejs
+  ];
+}