feat: add nix flake

.gitignore

@@ -5,3 +5,6 @@ cmake-build-release/
 node_modules/
 *.dSYM
 .vs/
+.direnv/
+.envrc
+build/

flake.lock

@@ -0,0 +1,27 @@
+{
+  "nodes": {
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1747327360,
+        "narHash": "sha256-LSmTbiq/nqZR9B2t4MRnWG7cb0KVNU70dB7RT4+wYK4=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "e06158e58f3adee28b139e9c2bcfcc41f8625b46",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixos-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "nixpkgs": "nixpkgs"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

flake.nix

@@ -0,0 +1,164 @@
+{
+  description = "Clay (short for C Layout) is a high performance 2D UI layout library.";
+
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+  };
+
+  outputs = {
+    self,
+    nixpkgs,
+  }: let
+    inherit (nixpkgs) lib;
+    systems = lib.systems.flakeExposed;
+    forAllSystems = lib.genAttrs systems;
+    nixpkgsFor = forAllSystems (system: nixpkgs.legacyPackages.${system});
+  in {
+    checks = forAllSystems (
+      system: let
+        pkgs = nixpkgsFor.${system};
+      in {
+        formatting =
+          pkgs.runCommand "format-flake" {
+            nativeBuildInputs = with pkgs; [
+              alejandra
+              deadnix
+              statix
+            ];
+          } ''
+            echo "Checking nix formatting"
+            alejandra --check .
+
+            echo "Checking dead code"
+            deadnix --fail .
+
+            echo "Checking statix"
+            statix check .
+          '';
+      }
+    );
+
+    devShells = forAllSystems (
+      system: let
+        pkgs = nixpkgsFor.${system};
+      in {
+        default = pkgs.mkShell {
+          # For testing renderers and examples, aswell as tests
+          packages = with pkgs; [
+            # Renderers
+            SDL2
+            SDL2_image
+            SDL2_ttf
+
+            sdl3
+            sdl3-ttf
+            sdl3-image
+
+            cairo
+            raylib
+            sokol
+
+            cmake # this is needed for building examples and tests
+            gcc
+            clang-tools # for clangd and clang-tidy
+            pkg-config
+            alejandra # for formatting nix
+
+            # for tests
+            docker
+            docker-compose
+
+            # dependencies for examples and tests
+            xorg.libXrandr
+            xorg.libXinerama
+            xorg.libXcursor
+            xorg.libXi
+          ];
+
+          LD_LIBRARY_PATH = "${lib.makeLibraryPath [
+            # Renderers
+            pkgs.SDL2
+            pkgs.SDL2_image
+            pkgs.SDL2_ttf
+
+            pkgs.sdl3
+            pkgs.sdl3-ttf
+            pkgs.sdl3-image
+
+            pkgs.cairo
+            pkgs.raylib
+            pkgs.sokol
+
+            # dependencies for examples and tests
+            pkgs.xorg.libXrandr
+            pkgs.xorg.libXinerama
+            pkgs.xorg.libXcursor
+            pkgs.xorg.libXi
+          ]}";
+        };
+      }
+    );
+
+    formatter = forAllSystems (system: nixpkgsFor.${system}.alejandra);
+
+    packages = forAllSystems (
+      system: let
+        pkgs = nixpkgsFor.${system};
+        git_tag
+        date = let
+          # YYYYMMDD
+          date' = lib.substring 0 8 self.lastModifiedDate;
+          year = lib.substring 0 4 date';
+          month = lib.substring 4 2 date';
+          date = lib.substring 6 2 date';
+        in
+          if (self ? "lastModifiedDate")
+          then
+            lib.concatStringsSep "-" [
+              year
+              month
+              date
+            ]
+          else "unknown";
+      in {
+        default = pkgs.stdenv.mkDerivation (finalAttrs {
+          pname = "clay";
+          version = "v0.14-master-${date}";
+          src = ./.;
+
+          dontBuild = true;
+
+          installPhase = ''
+            mkdir -p $out/include
+            mkdir -p $out/lib/pkgconfig
+
+            cp clay.h $out/include
+
+            cat <<EOF >$out/lib/pkgconfig/clay.pc
+            prefix=$out
+            includedir=$out/include
+            Name: Clay
+            Description: Clay (short for C Layout) is a high performance 2D UI layout library.
+            Version: $version
+            Cflags: -I$out/include
+            EOF
+          '';
+
+          passthru.tests.pkg-config = testers.testMetaPkgConfig finalAttrs.finalPackage;
+
+          meta = with lib; {
+            description = "Clay (short for C Layout) is a high performance 2D UI layout library.";
+            homepage = "https://github.com/nicbarker/clay";
+            license = licenses.zlib;
+            maintainers = with maintainers; [nicbarker];
+            pkgConfigModules = ["clay"];
+            # FIXME: I'm not sure what platforms this supports.
+            platforms = platforms.all;
+          };
+        });
+
+        defaultPackage = self.packages.${system}.default;
+      }
+    );
+  };
+}