containers: Add obsidian

Mainly a proof of concept. Eventually I'll devise an easy way to view
notes in a pretty way and edit them with neovim (likely through your
typical web framework tools).

containers/obsidian.nix

@@ -0,0 +1,73 @@
+{ lib, ... }:
+let VARIABLES = import ../src/variables.nix; in {
+  containers.obsidian = {
+    privateNetwork = true;
+    ephemeral = true;
+
+    bindMounts = {
+      "/mnt" = {
+        hostPath = "/home/${VARIABLES.username}/containers/obsidian";
+        isReadOnly = false;
+      };
+
+      waylandDisplay = rec {
+        hostPath = "/run/user/1000";
+        mountPoint = hostPath;
+      };
+
+      x11Display = rec {
+        hostPath = "/tmp/.X11-unix";
+        mountPoint = hostPath;
+        isReadOnly = true;
+      };
+    };
+
+    config = { pkgs, ... }: {
+      i18n.defaultLocale = VARIABLES.defaultLocale;
+      i18n.supportedLocales = VARIABLES.supportedLocales;
+
+      users = {
+        mutableUsers = false;
+        allowNoPasswordLogin = true;
+
+        users.user = {
+          isNormalUser = true;
+          home = "/home/user";
+        };
+      };
+
+      environment = {
+        variables = {
+          TERM = "xterm-kitty";
+        };
+
+        defaultPackages = [ ];
+      };
+
+      environment.systemPackages = with pkgs; [
+        kitty
+        obsidian
+      ];
+
+      environment.sessionVariables = {
+        WAYLAND_DISPLAY = "wayland-1";
+        QT_QPA_PLATFORM = "wayland";
+        QT_WAYLAND_DISABLE_WINDOWDECORATION = "1";
+        SDL_VIDEODRIVER = "wayland";
+        CLUTTER_BACKEND = "wayland";
+        MOZ_ENABLE_WAYLAND = "1";
+        XDG_RUNTIME_DIR = "/run/user/1000";
+        DISPLAY = ":0";
+      };
+
+      services.xserver.enable = true;
+
+      nixpkgs.config.allowUnfreePredicate = pkg:
+        builtins.elem (lib.getName pkg) [
+          "obsidian"
+        ];
+
+      system.stateVersion = VARIABLES.stateVersion;
+    };
+  };
+}