feat(zellij): add zellij configuration

users/modules/shell/default.nix

@@ -78,6 +78,7 @@ in {
     ./fish.nix
     ./starship.nix
     ./tmux.nix
+    ./zellij.nix
     ./zsh.nix
     ./zoxide.nix
   ];

users/modules/shell/zellij.nix

@@ -0,0 +1,173 @@
+{
+  pkgs,
+  lib,
+  config,
+  ...
+}:
+with lib; let
+  cfg = config.home.shell.zellij;
+  isEmpty = list: list == [];
+  keybind = {
+    options = {
+      bind = mkOption {
+        type = types.either types.str (types.listOf types.str);
+        example = "Alt j";
+        description = "Value used as a string after `bind` in zellij config";
+      };
+      actions = mkOption {
+        type = with types; let
+          allowed = oneOf [int str];
+        in
+          attrsOf (either (listOf allowed) allowed);
+        default = {};
+        example = {
+          SwitchToMode = ["normal"];
+          SwitchFocus = [];
+          PaneNameInput = [0];
+        };
+      };
+      useUnlockFirst = mkOption {
+        type = types.bool;
+        default = false;
+        description = ''
+          Go back to locked mode after the actions are done.
+
+          Only works when `config.home.shell.zellij.useUnlockFirst` is true.
+        '';
+      };
+    };
+  };
+  convertBind = item: {
+    bind = let
+      useUnlockFirst = cfg.useUnlockFirst && item.useUnlockFirst;
+      children =
+        mapAttrsToList (action: args: let
+          actualArgs =
+            if isEmpty args
+            then {}
+            else {_args = lists.toList args;};
+        in {"${action}" = actualArgs;})
+        (item.actions
+          // (
+            if useUnlockFirst
+            then {SwitchToMode = ["locked"];}
+            else {}
+          ));
+    in {
+      _args = lists.toList item.bind;
+      _children = children;
+    };
+  };
+  keybindsModule = {
+    options = mergeAttrsList (forEach [
+        "normal"
+        "locked"
+        "resize"
+        "pane"
+        "move"
+        "tab"
+        "scroll"
+        "search"
+        "entersearch"
+        "renametab"
+        "renamepane"
+        "session"
+        "tmux"
+      ]
+      (x: {
+        "${x}" = mkOption {
+          type = types.listOf (types.submodule keybind);
+          default = [];
+        };
+      }));
+  };
+  makeKeybinds = keybinds: let
+    values =
+      attrsets.concatMapAttrs (
+        mode: binds:
+          if (isEmpty binds)
+          then {}
+          else {
+            "${mode}"._children = lists.forEach binds convertBind;
+          }
+      )
+      keybinds;
+  in
+    if values == {}
+    then {}
+    else {
+      keybinds = values;
+    };
+in {
+  options.home.shell.zellij = let
+    jsonFormat = pkgs.formats.yaml {};
+  in {
+    enable = mkEnableOption "Enable Zellij";
+    clearDefaultKeybinds = mkEnableOption "Clear default keybinds";
+    settings = mkOption {
+      inherit (jsonFormat) type;
+      default = {};
+    };
+    layouts = mkOption {
+      inherit (jsonFormat) type;
+      default = {};
+    };
+    extraSettings = mkOption {
+      type = types.lines;
+      default = "";
+      description = ''
+        Extra configuration lines to add to `$XDG_CONFIG_HOME/zellij/config.kdl`
+      '';
+    };
+    useUnlockFirst = mkEnableOption "Use Unlock-First (non-colliding) behaviour by default";
+    plugins = mkOption {
+      type = types.listOf (types.submodule plugin);
+      default = {};
+      example = [
+        {name = "about";}
+        {
+          name = "filepicker";
+          location = "zellij:strider";
+          options = {
+            cwd = "/";
+          };
+        }
+      ];
+    };
+    keybinds = mkOption {
+      type = types.submodule keybindsModule;
+      default = {};
+      example = {
+        pane = [
+          {
+            bind = "c";
+            actions = [
+              {
+                action = "SwitchToMode";
+                args = ["renamepane"];
+              }
+              {
+                action = "PaneNameInput";
+                args = [0];
+              }
+            ];
+          }
+        ];
+      };
+    };
+  };
+  config.programs.zellij = mkIf cfg.enable {
+    inherit (cfg) enable layouts;
+    extraConfig = cfg.extraSettings;
+    settings = let
+      resetKeybinds =
+        if cfg.clearDefaultKeybinds
+        then {
+          keybinds._props.clear-defaults = true;
+        }
+        else {};
+      keybinds = makeKeybinds cfg.keybinds;
+    in
+      cfg.settings // resetKeybinds // keybinds;
+  };
+}