flake.nix

{
  description = "smalltalk - file-folder coordination CLI and TypeScript API";

  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
    flake-utils.url = "github:numtide/flake-utils";
    pty.url = "github:compoundingtech/pty";
    pty.inputs.nixpkgs.follows = "nixpkgs";
  };

  outputs =
    {
      self,
      nixpkgs,
      flake-utils,
      pty,
    }:
    flake-utils.lib.eachDefaultSystem (
      system:
      let
        pkgs = import nixpkgs { inherit system; };

        # package.json is the single source of truth for the version, so a
        # release bump does not need a matching edit here. Reconciling this
        # with a richer build identity (git rev, dirty marker) is issue #103.
        version = (builtins.fromJSON (builtins.readFile ./package.json)).version;

        # npm names of local `file:` deps that resolve to sibling repos, mapped
        # to the store path holding their package root. buildNpmPackage cannot
        # fetch these, so they are linked into node_modules after the copy.
        # The key must match package.json / package-lock.json exactly, since
        # that is the specifier Node resolves.
        siblingLinks = {
          "@compoundingtech/pty" = "${pty.packages.${system}.default}/lib/pty";
        };

        # The shells `st completions <shell>` can generate. The generator emits
        # `complete -c st` etc. unconditionally, so every script is for `st`
        # regardless of which bin name invoked it.
        completionShells = [
          "bash"
          "zsh"
          "fish"
        ];

        smalltalk = pkgs.buildNpmPackage {
          pname = "smalltalk";
          inherit version;
          src = self;

          # TODO(rust): a Rust rewrite drops npm entirely, and this hash with it.
          # Regenerate with: nix run nixpkgs#prefetch-npm-deps -- package-lock.json
          npmDepsHash = "sha256-FsAjO/CYxyMf30F8ESsxFDI30ckYv1uS4+nkvn9Fl+k=";

          nodejs = pkgs.nodejs_24;
          npmInstallFlags = [ "--omit=dev" ];
          # Sources ship as TypeScript and run through node's type stripping;
          # there is no compile step to produce a dist/.
          dontNpmBuild = true;

          nativeBuildInputs = [ pkgs.installShellFiles ];

          installPhase = ''
            runHook preInstall

            mkdir -p $out/lib/smalltalk
            cp -r . $out/lib/smalltalk

            # TODO(rust): sibling linking exists only because npm cannot resolve
            # `file:` deps in a sandbox; a Cargo build has no equivalent.
            ${pkgs.lib.concatLines (
              pkgs.lib.mapAttrsToList (npmName: storePath: ''
                mkdir -p "$out/lib/smalltalk/node_modules/$(dirname ${npmName})"
                ln -s ${storePath} "$out/lib/smalltalk/node_modules/${npmName}"
              '') siblingLinks
            )}

            # package.json declares `st` and `smalltalk`; both reach the same
            # cli.ts. `_ST_INVOKED_AS` is what bin/st exports so help banners and
            # the MCP server report the name the user actually typed.
            # TODO(rust): a compiled binary replaces these strip-types shims.
            mkdir -p $out/bin
            for _binName in st smalltalk; do
              cat > $out/bin/$_binName <<EOF
            #!${pkgs.runtimeShell}
            export _ST_INVOKED_AS=$_binName
            exec ${pkgs.nodejs_24}/bin/node --experimental-strip-types \\
              $out/lib/smalltalk/src/cli.ts "\$@"
            EOF
              chmod +x $out/bin/$_binName
            done

            runHook postInstall
          '';

          # Completions are generated by the binary we just built rather than
          # committed, so they cannot drift from the command tree in
          # src/commands/completions.ts. The CLI touches $HOME on startup, which
          # is not writable in the sandbox.
          postInstall = ''
            export HOME=$(mktemp -d)
            ${pkgs.lib.concatMapStringsSep "\n" (shell: ''
              $out/bin/st completions ${shell} > completions-${shell}
            '') completionShells}

            installShellCompletion --cmd st \
              --bash completions-bash \
              --zsh completions-zsh \
              --fish completions-fish
          '';

          meta = {
            description = "File-folder coordination CLI and embeddable TypeScript API";
            homepage = "https://github.com/compoundingtech/smalltalk";
            license = pkgs.lib.licenses.mit;
            mainProgram = "st";
          };
        };
        # Base for checks that need devDependencies (tsc, vitest), which the
        # shipped package deliberately omits.
        #
        # Two things make this awkward enough to be worth explaining. First,
        # npm cannot resolve the `file:../pty` devDependency from a store
        # symlink: it chmods the linked `bin/pty`, which is read-only in the
        # store, and fails EPERM. So the sibling is *copied* to the exact
        # relative path the lockfile names and made writable. Second,
        # `--ignore-scripts` keeps node-pty's native build (`hasInstallScript`)
        # out of the sandbox; nothing gated here needs the native addon.
        #
        # These run the check in the build dir and `touch $out` rather than
        # installing anything, so the store-external `../pty` symlink npm
        # leaves in node_modules never has to survive into the output.
        mkDevCheck =
          name: script:
          smalltalk.overrideAttrs (old: {
            pname = "smalltalk-${name}";
            npmInstallFlags = [ ];
            npmFlags = [ "--ignore-scripts" ];
            postPatch = ''
              cp -r ${pty.packages.${system}.default}/lib/pty ../pty
              chmod -R u+w ../pty
            '';
            installPhase = ''
              runHook preInstall
              export HOME=$(mktemp -d)
              ${script}
              touch $out
              runHook postInstall
            '';
            postInstall = "";
            # Nothing is installed, so the fixup hooks (patchelf,
            # noBrokenSymlinks) have nothing useful to do.
            dontFixup = true;
          });
      in
      {
        packages.smalltalk = smalltalk;
        packages.default = smalltalk;

        checks.help = pkgs.runCommand "smalltalk-help-${version}" { } ''
          export HOME=$(mktemp -d)
          ${smalltalk}/bin/st --help > /dev/null
          touch $out
        '';

        # Guards the completions contract: every installed shell still gets a
        # non-empty script, and fish in particular still binds to `st` (the name
        # the installed st.fish file claims).
        checks.completions = pkgs.runCommand "smalltalk-completions-${version}" { } ''
          export HOME=$(mktemp -d)
          ${pkgs.lib.concatMapStringsSep "\n" (shell: ''
            ${smalltalk}/bin/st completions ${shell} | grep -q . \
              || { echo "empty ${shell} completions" >&2; exit 1; }
          '') completionShells}

          ${smalltalk}/bin/st completions fish | grep -q '^complete -c st ' \
            || { echo "fish completions do not bind to \`st\`" >&2; exit 1; }

          touch $out
        '';

        # `npm run build` is typecheck-only (both tsconfigs set `noEmit`), so
        # this gates src/ and examples/ against the compiler.
        checks.typecheck = mkDevCheck "typecheck" "npm run build";

        # The vitest `unit` project is NOT gated here yet. It very nearly works
        # (1322/1323 pass in the sandbox), but tests/unit/cli.test.ts asserts
        # `st <semver>+<short-sha>`, and the SHA comes from shelling out to
        # `git rev-parse` in the source dir — which a hermetic build has no
        # `.git` for. That is the build-identity question tracked in #103, not
        # something to paper over here. The `integration` project is a separate
        # matter: it shells out to rsync and spawns real pty sessions, which the
        # build sandbox has no business hosting.

        devShells.default = pkgs.mkShell {
          packages = [
            pkgs.nodejs_24
            smalltalk
          ];
        };
      }
    );
}