dev: Added Nix Flake support

- Enables Nix users to get the git version of waybar
- Enables Nix users to develop waybar easily
- Adds a fully reproducible development environment
  - The user only has to install Nix, no other depencencies
  - Automatic dev env on directory entry through .envrc

.envrc

@@ -0,0 +1 @@
+use flake

.gitignore

@@ -41,3 +41,4 @@ packagecache
 *.exe
 *.out
 *.app
+/.direnv/

flake.lock

@@ -0,0 +1,94 @@
+{
+  "nodes": {
+    "devshell": {
+      "inputs": {
+        "flake-utils": "flake-utils",
+        "nixpkgs": "nixpkgs"
+      },
+      "locked": {
+        "lastModified": 1667210711,
+        "narHash": "sha256-IoErjXZAkzYWHEpQqwu/DeRNJGFdR7X2OGbkhMqMrpw=",
+        "owner": "numtide",
+        "repo": "devshell",
+        "rev": "96a9dd12b8a447840cc246e17a47b81a4268bba7",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "devshell",
+        "type": "github"
+      }
+    },
+    "flake-utils": {
+      "locked": {
+        "lastModified": 1642700792,
+        "narHash": "sha256-XqHrk7hFb+zBvRg6Ghl+AZDq03ov6OshJLiSWOoX5es=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "846b2ae0fc4cc943637d3d1def4454213e203cba",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    },
+    "flake-utils_2": {
+      "locked": {
+        "lastModified": 1667395993,
+        "narHash": "sha256-nuEHfE/LcWyuSWnS8t12N1wc105Qtau+/OdUAjtQ0rA=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "5aed5285a952e0b949eb3ba02c12fa4fcfef535f",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    },
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1643381941,
+        "narHash": "sha256-pHTwvnN4tTsEKkWlXQ8JMY423epos8wUOhthpwJjtpc=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "5efc8ca954272c4376ac929f4c5ffefcc20551d5",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixpkgs-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "nixpkgs_2": {
+      "locked": {
+        "lastModified": 1670152712,
+        "narHash": "sha256-LJttwIvJqsZIj8u1LxVRv82vwUtkzVqQVi7Wb8gxPS4=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "14ddeaebcbe9a25748221d1d7ecdf98e20e2325e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixos-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "devshell": "devshell",
+        "flake-utils": "flake-utils_2",
+        "nixpkgs": "nixpkgs_2"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

flake.nix

@@ -0,0 +1,65 @@
+{
+  description = "Highly customizable Wayland bar for Sway and Wlroots based compositors.";
+
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+    devshell.url = "github:numtide/devshell";
+    flake-utils.url = "github:numtide/flake-utils";
+  };
+
+  outputs = { self, flake-utils, devshell, nixpkgs }:
+    let
+      inherit (nixpkgs) lib;
+      genSystems = lib.genAttrs [
+        "x86_64-linux"
+      ];
+
+      pkgsFor = genSystems (system:
+        import nixpkgs {
+          inherit system;
+        });
+
+      mkDate = longDate: (lib.concatStringsSep "-" [
+        (builtins.substring 0 4 longDate)
+        (builtins.substring 4 2 longDate)
+        (builtins.substring 6 2 longDate)
+      ]);
+    in
+    {
+      overlays.default = _: prev: rec {
+        waybar = prev.callPackage ./nix/default.nix {
+          version = "0.9.16" + "+date=" + (mkDate (self.lastModifiedDate or "19700101")) + "_" + (self.shortRev or "dirty");
+        };
+      };
+      packages = genSystems
+        (system:
+          (self.overlays.default null pkgsFor.${system})
+          // {
+            default = self.packages.${system}.waybar;
+          });
+    } //
+    flake-utils.lib.eachDefaultSystem (system: {
+      devShell =
+        let pkgs = import nixpkgs {
+          inherit system;
+
+          overlays = [ devshell.overlay ];
+        };
+        in
+        pkgs.devshell.mkShell {
+          imports = [ "${pkgs.devshell.extraModulesDir}/language/c.nix" ];
+          commands = [
+            {
+              package = pkgs.devshell.cli;
+              help = "Per project developer environments";
+            }
+          ];
+          devshell.packages = with pkgs; [
+            clang-tools
+            gdb
+          ];
+          language.c.libraries = with pkgs; [
+          ];
+        };
+    });
+}

nix/default.nix

@@ -0,0 +1,139 @@
+{ lib
+, stdenv
+, fetchFromGitHub
+, meson
+, pkg-config
+, ninja
+, wrapGAppsHook
+, wayland
+, wlroots
+, gtkmm3
+, libsigcxx
+, jsoncpp
+, scdoc
+, spdlog
+, gtk-layer-shell
+, howard-hinnant-date
+, libinotify-kqueue
+, libxkbcommon
+, evdevSupport ? true
+, libevdev
+, inputSupport ? true
+, libinput
+, jackSupport ? true
+, libjack2
+, mpdSupport ? true
+, libmpdclient
+, nlSupport ? true
+, libnl
+, pulseSupport ? true
+, libpulseaudio
+, rfkillSupport ? true
+, runTests ? true
+, catch2_3
+, sndioSupport ? true
+, sndio
+, swaySupport ? true
+, sway
+, traySupport ? true
+, libdbusmenu-gtk3
+, udevSupport ? true
+, udev
+, upowerSupport ? true
+, upower
+, wireplumberSupport ? true
+, wireplumber
+, withMediaPlayer ? false
+, glib
+, gobject-introspection
+, python3
+, playerctl
+, version
+}:
+
+stdenv.mkDerivation rec {
+  pname = "waybar";
+  inherit version;
+  # version = "0.9.16";
+
+  src = lib.cleanSourceWith {
+    filter = name: type:
+      let
+        baseName = baseNameOf (toString name);
+      in
+        ! (
+          lib.hasSuffix ".nix" baseName
+        );
+    src = lib.cleanSource ../.;
+  };
+
+  nativeBuildInputs = [
+    meson
+    ninja
+    pkg-config
+    scdoc
+    wrapGAppsHook
+  ] ++ lib.optional withMediaPlayer gobject-introspection;
+
+  propagatedBuildInputs = lib.optionals withMediaPlayer [
+    glib
+    playerctl
+    python3.pkgs.pygobject3
+  ];
+  strictDeps = false;
+
+  buildInputs = with lib;
+    [ wayland wlroots gtkmm3 libsigcxx jsoncpp spdlog gtk-layer-shell howard-hinnant-date libxkbcommon ]
+    ++ optional (!stdenv.isLinux) libinotify-kqueue
+    ++ optional evdevSupport libevdev
+    ++ optional inputSupport libinput
+    ++ optional jackSupport libjack2
+    ++ optional mpdSupport libmpdclient
+    ++ optional nlSupport libnl
+    ++ optional pulseSupport libpulseaudio
+    ++ optional sndioSupport sndio
+    ++ optional swaySupport sway
+    ++ optional traySupport libdbusmenu-gtk3
+    ++ optional udevSupport udev
+    ++ optional upowerSupport upower
+    ++ optional wireplumberSupport wireplumber;
+
+  checkInputs = [ catch2_3 ];
+  doCheck = runTests;
+
+  mesonFlags = (lib.mapAttrsToList
+    (option: enable: "-D${option}=${if enable then "enabled" else "disabled"}")
+    {
+      dbusmenu-gtk = traySupport;
+      jack = jackSupport;
+      libinput = inputSupport;
+      libnl = nlSupport;
+      libudev = udevSupport;
+      mpd = mpdSupport;
+      pulseaudio = pulseSupport;
+      rfkill = rfkillSupport;
+      sndio = sndioSupport;
+      tests = runTests;
+      upower_glib = upowerSupport;
+      wireplumber = wireplumberSupport;
+    }
+  ) ++ [
+    "-Dsystemd=disabled"
+    "-Dgtk-layer-shell=enabled"
+    "-Dman-pages=enabled"
+  ];
+
+  preFixup = lib.optionalString withMediaPlayer ''
+    cp $src/resources/custom_modules/mediaplayer.py $out/bin/waybar-mediaplayer.py
+    wrapProgram $out/bin/waybar-mediaplayer.py \
+      --prefix PYTHONPATH : "$PYTHONPATH:$out/${python3.sitePackages}"
+  '';
+
+  meta = with lib; {
+    description = "Highly customizable Wayland bar for Sway and Wlroots based compositors";
+    license = licenses.mit;
+    maintainers = with maintainers; [ FlorianFranzen minijackson synthetica lovesegfault ];
+    platforms = platforms.unix;
+    homepage = "https://github.com/alexays/waybar";
+  };
+}