From fa2ad42ecfd2caa14cc46eb1732912bf8c9a44f6 Mon Sep 17 00:00:00 2001
From: Dmitry Voronin <hi@voronind.com>
Date: Mon, 30 Sep 2024 13:55:32 +0300
Subject: [PATCH] PS1 : Add shell lvl.

---
 home/program/bash/default.nix    | 5 +++++
 home/program/bash/module/Dvd.nix | 2 +-
 home/program/bash/module/Nix.nix | 6 +++---
 home/program/bash/module/Ps1.nix | 8 +++++---
 4 files changed, 14 insertions(+), 7 deletions(-)

diff --git a/home/program/bash/default.nix b/home/program/bash/default.nix
index 40467e1..5a6d736 100644
--- a/home/program/bash/default.nix
+++ b/home/program/bash/default.nix
@@ -14,6 +14,11 @@ in {
 		export -f $(find_function | tr '\n' ' ')
 		export -f find_function
 
+		# Nested shell indicator support.
+		if [ -z ''${SHLVLMIN} ]; then
+			export SHLVLMIN=''${SHLVL}
+		fi
+
 		# Autostart Sway.
 		if [[ -z $DISPLAY ]] && [[ "$(tty)" = "/dev/tty1" ]]; then
 			exec sway
diff --git a/home/program/bash/module/Dvd.nix b/home/program/bash/module/Dvd.nix
index 24a9d9b..3d44cda 100644
--- a/home/program/bash/module/Dvd.nix
+++ b/home/program/bash/module/Dvd.nix
@@ -37,7 +37,7 @@
 
 		# Spawn Nix shell with required tools.
 		function dvd_shell() {
-			NIX_SHELL="dvd" tmpshell dvdplusrwtools cdrkit
+			SHELL_NAME="dvd" tmpshell dvdplusrwtools cdrkit
 		}
 	'';
 }
diff --git a/home/program/bash/module/Nix.nix b/home/program/bash/module/Nix.nix
index e136e03..bba27ce 100644
--- a/home/program/bash/module/Nix.nix
+++ b/home/program/bash/module/Nix.nix
@@ -32,7 +32,7 @@
 			# Create Nix GC root in .NixRoot{NAME}.
 			nix build ".#devShells.''${NIX_CURRENT_SYSTEM}.''${target}" -o ".NixRoot''${target^}"
 
-			NIX_SHELL="''${target}" nix develop ".#devShells.''${NIX_CURRENT_SYSTEM}.''${target}"
+			SHELL_NAME="''${target}" nix develop ".#devShells.''${NIX_CURRENT_SYSTEM}.''${target}"
 		}
 		alias shell="nix_shell"
 
@@ -42,7 +42,7 @@
 			local IFS=$'\n'
 			local input=("''${@}")
 			local pkgs=()
-			local tag="''${NIX_SHELL}"
+			local tag="''${SHELL_NAME}"
 
 			if [[ "''${input}" = "" ]]; then
 				help nix_tmpshell
@@ -55,7 +55,7 @@
 				pkgs+=("nixpkgs#''${pkg}")
 			done
 
-			NIX_SHELL="''${tag}" NIXPKGS_ALLOW_UNFREE=1 nix shell --impure ''${pkgs[@]}
+			SHELL_NAME="''${tag}" NIXPKGS_ALLOW_UNFREE=1 nix shell --impure ''${pkgs[@]}
 		}
 		alias tmpshell="nix_tmpshell"
 
diff --git a/home/program/bash/module/Ps1.nix b/home/program/bash/module/Ps1.nix
index c3529a2..5dc49d9 100644
--- a/home/program/bash/module/Ps1.nix
+++ b/home/program/bash/module/Ps1.nix
@@ -85,9 +85,11 @@ in {
 			# Command on new line.
 			PS1+="\n"
 
-			# Show nix shell name.
-			if [ -n "''${NIX_SHELL}" ]; then
-				PS1+="''${NIX_SHELL} "
+			# Show nix shell name or shell depth.
+			if [ -n "''${SHELL_NAME}" ]; then
+				PS1+="''${SHELL_NAME} "
+			elif [[ "''${SHLVL}" -gt "''${SHLVLMIN}" ]]; then
+				PS1+="($((''${SHLVL} - ''${SHLVLMIN}))) "
 			fi
 
 			# Show remote connections.