nnn: add cd on quit option

- add bash, zsh, fish, and nushell integration options
- add quitcd configuration for bash, zsh, fish, and nushell

modules/programs/nnn.nix

@@ -104,6 +104,46 @@ in {
         '';
         default = { };
       };
+
+      enableBashIntegration = mkOption {
+        default = true;
+        type = types.bool;
+        description = ''
+          Whether to enable Bash integration.
+        '';
+      };
+
+      enableZshIntegration = mkOption {
+        default = true;
+        type = types.bool;
+        description = ''
+          Whether to enable Zsh integration.
+        '';
+      };
+
+      enableFishIntegration = mkOption {
+        default = true;
+        type = types.bool;
+        description = ''
+          Whether to enable Fish integration.
+        '';
+      };
+
+      enableNushellIntegration = mkOption {
+        default = true;
+        type = types.bool;
+        description = ''
+          Whether to enable Nushell integration.
+        '';
+      };
+
+      quitcd = mkOption {
+        default = false;
+        type = types.bool;
+        description = ''
+          Whether to enable cd on quit.
+        '';
+      };
     };
   };
 
@@ -120,10 +160,127 @@ in {
           --prefix NNN_PLUG : "${renderSettings cfg.plugins.mappings}"
       '';
     });
+
+    quitcd = {
+      bash_sh_zsh = ''
+        n ()
+        {
+            # Block nesting of nnn in subshells
+            [ "''${NNNLVL:-0}" -eq 0 ] || {
+                echo "nnn is already running"
+                return
+            }
+
+            # The behaviour is set to cd on quit (nnn checks if NNN_TMPFILE is set)
+            # If NNN_TMPFILE is set to a custom path, it must be exported for nnn to
+            # see. To cd on quit only on ^G, remove the "export" and make sure not to
+            # use a custom path, i.e. set NNN_TMPFILE *exactly* as follows:
+            #      NNN_TMPFILE="''${XDG_CONFIG_HOME:-$HOME/.config}/nnn/.lastd"
+            export NNN_TMPFILE="''${XDG_CONFIG_HOME:-$HOME/.config}/nnn/.lastd"
+
+            # Unmask ^Q (, ^V etc.) (if required, see `stty -a`) to Quit nnn
+            # stty start undef
+            # stty stop undef
+            # stty lwrap undef
+            # stty lnext undef
+
+            # The command builtin allows one to alias nnn to n, if desired, without
+            # making an infinitely recursive alias
+            command nnn "$@"
+
+            [ ! -f "$NNN_TMPFILE" ] || {
+                . "$NNN_TMPFILE"
+                rm -f -- "$NNN_TMPFILE" > /dev/null
+            }
+        }
+      '';
+      fish = ''
+        function n --wraps nnn --description 'support nnn quit and change directory'
+            # Block nesting of nnn in subshells
+            if test -n "$NNNLVL" -a "$NNNLVL" -ge 1
+                echo "nnn is already running"
+                return
+            end
+
+            # The behaviour is set to cd on quit (nnn checks if NNN_TMPFILE is set)
+            # If NNN_TMPFILE is set to a custom path, it must be exported for nnn to
+            # see. To cd on quit only on ^G, remove the "-x" from both lines below,
+            # without changing the paths.
+            if test -n "$XDG_CONFIG_HOME"
+                set -x NNN_TMPFILE "$XDG_CONFIG_HOME/nnn/.lastd"
+            else
+                set -x NNN_TMPFILE "$HOME/.config/nnn/.lastd"
+            end
+
+            # Unmask ^Q (, ^V etc.) (if required, see `stty -a`) to Quit nnn
+            # stty start undef
+            # stty stop undef
+            # stty lwrap undef
+            # stty lnext undef
+
+            # The command function allows one to alias this function to `nnn` without
+            # making an infinitely recursive alias
+            command nnn $argv
+
+            if test -e $NNN_TMPFILE
+                source $NNN_TMPFILE
+                rm -- $NNN_TMPFILE
+            end
+        end'';
+      nu = ''
+        # Run nnn with dynamic changing directory to the environment.
+        #
+        # $env.XDG_CONFIG_HOME sets the home folder for `nnn` folder and its $env.NNN_TMPFILE variable.
+        # See manual NNN(1) for more information.
+        #
+        # Import module using `use quitcd.nu n` to have `n` command in your context.
+        export def --env n [
+        	...args : string # Extra flags to launch nnn with.
+        	--selective = false # Change directory only when exiting via ^G.
+        ] -> nothing {
+
+        	# The behaviour is set to cd on quit (nnn checks if $env.NNN_TMPFILE is set).
+        	# Hard-coded to its respective behaviour in `nnn` source-code.
+        	let nnn_tmpfile = $env
+        		| default '~/.config/' 'XDG_CONFIG_HOME'
+        		| get 'XDG_CONFIG_HOME'
+        		| path join 'nnn/.lastd'
+        		| path expand
+
+        	# Launch nnn. Add desired flags after `^nnn`, ex: `^nnn -eda ...$args`,
+        	# or make an alias `alias n = n -eda`.
+        	if $selective {
+        		^nnn ...$args
+        	} else {
+        		NNN_TMPFILE=$nnn_tmpfile ^nnn ...$args
+        	}
+
+        	if ($nnn_tmpfile | path exists) {
+        		# Remove <cd '> from the first part of the string and the last single quote <'>.
+        		# Fix post-processing of nnn's given path that escapes its single quotes with POSIX syntax.
+        		let path = open $nnn_tmpfile
+        			| str replace --all --regex `^cd '|'$` ``
+        			| str replace --all `'\''''` `'`
+
+        		^rm -- $nnn_tmpfile
+
+        		cd $path
+        	}
+        }'';
+    };
   in mkIf cfg.enable {
     programs.nnn.finalPackage = nnnPackage;
     home.packages = [ nnnPackage ];
     xdg.configFile."nnn/plugins" =
       mkIf (cfg.plugins.src != null) { source = cfg.plugins.src; };
+
+    programs.bash.initExtra =
+      mkIf cfg.enableBashIntegration (mkAfter quitcd.bash_sh_zsh);
+    programs.zsh.initExtra =
+      mkIf cfg.enableZshIntegration (mkAfter quitcd.bash_sh_zsh);
+    programs.fish.interactiveShellInit =
+      mkIf cfg.enableFishIntegration (mkAfter quitcd.fish);
+    programs.nushell.extraConfig =
+      mkIf cfg.enableNushellIntegration (mkAfter quitcd.nu);
   };
 }