Integrate init-app.nu for system path initialization to standard

- observe '/etc/environment' and compute standard path
- update comments and tested
- depends on ~/.local/sdkman/bin/sdkman-init.sh and ~/.local/sdkman/src/sdkman-path-helpers.sh path

Author: atiq-cs

init-app.nu

@@ -1,19 +1,28 @@
 #!/usr/bin/env nu
 #------------------------------------------------------------------------------
 # .SYNOPSIS
-#   Initialize Specified Application
+#   Initialize application-specific env path
+#
 # .DESCRIPTION
-#   TODO: Add Linux support (remove ~/bin when it doesn't exist)
-#   Initializes shell/env for application
-#   rewrite of pwsh/Init-App.ps1 *
+#  Resets PATH to platform-specific defaults or adds application paths.
+#  Notes:
+#  - currently 2 apps: system default and git
+#  - system defaults with SDKMAN tools on Unix/Linux
+#  - On Windows, PFiles is currently used by git
+#
+# .PARAMETER app_name
+#   Application to initialize: 'git', 'reset-env-path' (default)
 #
 # .EXAMPLE
-#   init-app reset-env-path
+#   source ./init-app.nu
+#   $env.Path = (main APP_NAME)
 #
 # .NOTES
-#   Targeting apps i.e., choco, python (ML).
-#   Required Env Vars:
-#     - $pfiles_x64_dir
+#   Platform-specific behavior:
+#   - Windows: Uses SystemRoot, PFiles_x64 paths (overlaps with choco)
+#   - Unix/Linux: Includes SDKMAN (Java, Kotlin, Gradle) + system paths
+#   - Unix/Linux: Warns if current PATH differs from expected baseline
+#   - Target apps: git, choco, python (ML) etc. more in future
 #------------------------------------------------------------------------------
 
 def main [
@@ -26,22 +35,55 @@ def main [
 
   match $app_name {
     'git' => {
-      let git_path = ($pfiles_x64_dir | path join 'git' 'cmd')
-      let path_with_git = ($prior_env_path | append $git_path)
-      $path_with_git
+      # not required in Unix, return default
+      if ($nu.os-info.name != "windows") {
+        $prior_env_path
+      } else {
+        let git_path = ($pfiles_x64_dir | path join 'git' 'cmd')
+        let path_with_git = ($prior_env_path | append $git_path)
+        $path_with_git
+      }
     }
     'reset-env-path' => {
-      # Reset PATH to default
-      [
-        ($env.SystemRoot | path join 'system32'),
-        $env.SystemRoot,
-        ($env.SystemRoot | path join 'System32' 'Wbem'),
-        ($env.LOCALAPPDATA | path join 'Microsoft' 'WindowsApps'),
-        ($env.SystemRoot | path join 'System32' 'OpenSSH'),
-        # ($env.SystemRoot | path join 'System32' 'WindowsPowerShell' 'v1.0'),
-        "C:\\PFiles_x64\\bin",  # /usr/bin emulation
-        $ShellHome
-      ]
+      # Reset PATH to platform-specific default
+      if ($nu.os-info.name != "windows") {
+        # backup of /etc/environment, pop_os 10-03-2025
+        # $ cat /etc/environment
+        # PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin"
+
+        # Expected default system PATH for comparison
+        let expected_system_path = [
+          "/usr/bin",
+          "/usr/sbin",
+          "/usr/local/bin",
+          "/home/atiq/.local/sdkman/candidates/kotlin/current/bin",
+          "/home/atiq/.local/sdkman/candidates/java/current/bin",
+          "/home/atiq/.local/sdkman/candidates/gradle/current/bin"
+        ]
+        
+        # Check if current PATH differs from expected
+        if ($env.Path != $expected_system_path) {
+          print "WARN: System environment PATH has changed from expected defaults:"
+          print $"Actual: ($env.Path)"
+          print ""
+          print $"Expected: ($expected_system_path)"
+          print ""
+        }
+
+        # return standard system path with our shell's dir appended
+        ($expected_system_path | append $ShellHome)
+      } else {
+        [
+          ($env.SystemRoot | path join 'system32'),
+          $env.SystemRoot,
+          ($env.SystemRoot | path join 'System32' 'Wbem'),
+          ($env.LOCALAPPDATA | path join 'Microsoft' 'WindowsApps'),
+          ($env.SystemRoot | path join 'System32' 'OpenSSH'),
+          # ($env.SystemRoot | path join 'System32' 'WindowsPowerShell' 'v1.0'),
+          "C:\\PFiles_x64\\bin",  # /usr/bin emulation
+          $ShellHome
+        ]
+      }
     }
     _ => {
       print $"Invalid command line argument: ($app_name)"

init.nu

@@ -63,6 +63,12 @@ print $"NuShell ($env.NU_VERSION) on ($nu.os-info.name) ($nu.os-info.kernel_vers
 
 print ""
 
+source ./init-app.nu
+# print $"Path: (main reset-env-path)"
+$env.Path = (main reset-env-path)
+$env.Path = (main git)
+
+
 # Porting tasks TODO
 # - InitConsoleUI, and probably
 # - app specific adjustments that are coming from sdkman
@@ -71,9 +77,6 @@ print ""
 # Hence, utilize the method/custom command, yet, assign it here
 #  resetEnvPath and `git add` support on Win below
 if ($nu.os-info.name == "windows") {
-  source ./init-app.nu
-  $env.Path = (main reset-env-path)
-  $env.Path = (main git)
   source ./win/init.nu
 } else {
   # ssh initialization
@@ -87,6 +90,8 @@ if ($nu.os-info.name == "windows") {
 # OS dependent inits for same instructions, differnet invocation syntax
 #  since windows nushell keeps throwing error
 if ($nu.os-info.name == "windows") {
+  # TODO: try following on windows, if it works might as well generalize
+  # nu ./fs-helper.nu
   # this is separately invoked on windows since it throws an error
   .\fs-helper.nu
 } else {