initial flake app

flake.nix

@@ -1,5 +1,5 @@
 {
-  description = "Quartz org-roam dev shell";
+  description = "Quartz org-roam dev shell and build app";
 
   inputs = {
     nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
@@ -10,13 +10,76 @@
     flake-utils.lib.eachDefaultSystem (system:
       let
         pkgs = import nixpkgs { inherit system; };
+
+        # Emacs with ox-hugo — shared between devShell and buildApp
+        emacsWithOxHugo = (pkgs.emacsPackagesFor pkgs.emacs-nox).emacsWithPackages
+          (epkgs: [ epkgs.ox-hugo ]);
+
+        # Pre-fetched npm dependency tree (node_modules)
+        quartzDeps = pkgs.buildNpmPackage {
+          pname = "quartz-deps";
+          version = "4.5.2";
+          src = ./.;
+          npmDepsHash = "sha256-7u+VlIx44B3/ivM9vLMIOn+e4TL4eS6B682vhS+Ikb4=";
+          dontBuild = true;
+          installPhase = ''
+            mkdir -p $out
+            cp -r node_modules $out/node_modules
+          '';
+        };
+
+        # Pre-fetched Hex/Mix dependencies for scripts/pipeline
+        pipelineMixDeps = pkgs.beamPackages.fetchMixDeps {
+          pname = "pipeline-mix-deps";
+          version = "0.1.0";
+          src = ./scripts/pipeline;
+          sha256 = "sha256-E79X+nUy86G1Jrwv3T7dXekoGv8Hd14ZgJSKWjvlmAw=";
+        };
+
+        # The build application wrapper script
+        buildApp = pkgs.writeShellApplication {
+          name = "build";
+          runtimeInputs = [ pkgs.nodejs_22 pkgs.elixir emacsWithOxHugo ];
+          text = ''
+            NOTES_DIR="''${1:?Usage: build <path-to-notes-dir>}"
+            NOTES_DIR=$(realpath "$NOTES_DIR")
+            ORIG_CWD=$(pwd)
+
+            # Set up a writable working copy of the repo in a temp dir
+            WORK=$(mktemp -d)
+            trap 'rm -rf "$WORK"' EXIT
+            cp -r ${self}/. "$WORK/repo"
+            chmod -R u+w "$WORK/repo"
+
+            # Drop in pre-built node_modules
+            ln -s ${quartzDeps}/node_modules "$WORK/repo/node_modules"
+
+            # Drop in pre-fetched Mix deps so mix compile runs offline
+            cp -r ${pipelineMixDeps} "$WORK/repo/scripts/pipeline/deps"
+            chmod -R u+w "$WORK/repo/scripts/pipeline/deps"
+
+            # ox-hugo requires static/ to exist before it can copy image assets
+            mkdir -p "$WORK/repo/static"
+
+            # Run the export pipeline (org → md, citations transform)
+            NOTES_DIR="$NOTES_DIR" elixir "$WORK/repo/scripts/export.exs"
+
+            # Build the static site from within the repo copy so relative paths
+            # (e.g. ./package.json in constants.js) resolve correctly.
+            # --output is absolute so the result lands in the caller's cwd.
+            cd "$WORK/repo"
+            node quartz/bootstrap-cli.mjs build \
+              --directory "$WORK/repo/content" \
+              --output "$ORIG_CWD/public"
+          '';
+        };
       in
       {
         devShells.default = pkgs.mkShell {
           buildInputs = [
             pkgs.nodejs_22
             pkgs.elixir
-            ((pkgs.emacsPackagesFor pkgs.emacs-nox).emacsWithPackages (epkgs: [ epkgs.ox-hugo ]))
+            emacsWithOxHugo
             pkgs.mcp-nixos
           ];
 
@@ -26,5 +89,11 @@
             echo "Emacs $(emacs --version | head -1)"
           '';
         };
+
+        packages.default = buildApp;
+        packages.build = buildApp;
+
+        apps.default = { type = "app"; program = "${buildApp}/bin/build"; };
+        apps.build = { type = "app"; program = "${buildApp}/bin/build"; };
       });
 }