new script 'git-compose', allows you to easily group staged changes into several commits at once

overlay/scripts/commands/git-compose.nix

@@ -0,0 +1,77 @@
+{ pkgs }:
+pkgs.writeShellApplication {
+  name = "git-compose";
+  runtimeInputs = with pkgs; [
+    git
+    gawk
+  ];
+  text = ''
+    toplevel=$(git rev-parse --show-toplevel 2>/dev/null)
+
+    if [ -z "$toplevel" ]; then
+      echo "You aren't in a git repository."
+      exit 1
+    fi
+
+    (
+      cd "$toplevel" || { echo "Failed to change to repo root"; exit 1; }
+
+      git reset
+      unstaged=$(git status --porcelain | awk '{print $2}') || { echo "Failed to get git status"; exit 1; }
+
+      if [ -z "$unstaged" ]; then
+        echo "No unstaged files found."
+        exit 0
+      fi
+
+      tmpfile=$(mktemp) || { echo "Failed to create a temporary file"; exit 1; }
+      trap 'rm -f "$tmpfile"' EXIT
+
+      {
+        echo "# Compose your commits here"
+        echo "#"
+        echo "# Format should be as follows:"
+        echo "# <some_commit_message>"
+        echo "# <file1>"
+        echo "# <file2>"
+        echo "# <file3>"
+        echo "#"
+        echo "# Groups are separated by empty lines"
+        echo "# Commits will be created for each group of files"
+        echo "# using the given commit message at the top of the group"
+        echo
+        echo "$unstaged"
+      } >> "$tmpfile"
+
+      nvim -c 'setfiletype gitcommit' "$tmpfile"
+
+      collecting=false
+      msg=""
+      lines=()
+
+      while IFS= read -r line; do
+        [[ "$line" =~ ^#[[:space:]]* ]] && continue
+        if [ -z "$line" ]; then
+          if [ -n "$msg" ] && [ ''${#lines[@]} -gt 0 ]; then
+            git add "''${lines[@]}"
+            git commit -m "$msg"
+          fi
+          collecting=false
+          msg=""
+          lines=()
+        elif [ "$collecting" = "false" ]; then
+          collecting=true
+          msg="$line"
+        else
+          lines+=("$line")
+        fi
+      done < "$tmpfile"
+
+      # Final cleanup
+      if [ -n "$msg" ] && [ ''${#lines[@]} -gt 0 ]; then
+      git add "''${lines[@]}"
+      git commit -m "$msg"
+      fi
+    )
+  '';
+}