enhance-scope

#!/bin/sh
# commit-msg:
# enhance commit messages touching a single file to include the filename in the summary

# shellcheck source=lib/commit-msg.sh disable=SC1091
. "$(dirname "$0")/lib/commit-msg.sh"

COMMIT_MSG_FILE="$1"

# Read and parse commit message
read_commit_msg "$COMMIT_MSG_FILE"
COMMIT_SUMMARY="$COMMIT_FIRST_LINE"
COMMIT_BODY="$COMMIT_REST"

# Get the list of files touched in the commit
FILES_TOUCHED=$(git diff --cached --name-only)

# Exit if no files staged
if [ -z "$FILES_TOUCHED" ]; then
	exit 0
fi

# Count files (handles filenames with spaces correctly)
FILE_COUNT=$(printf '%s\n' "$FILES_TOUCHED" | grep -c .)

# Exit if not exactly one file
if [ "$FILE_COUNT" -ne 1 ]; then
	exit 0
fi

FILENAME="${FILES_TOUCHED%%"${NL}"*}"

# Check if commit matches conventional format without scope
ORIGINAL_TYPE=""
case "$COMMIT_SUMMARY" in
feat:\ ?* | fix:\ ?* | chore:\ ?* | docs:\ ?* | refactor:\ ?* | \
	test:\ ?* | build:\ ?* | ci:\ ?* | style:\ ?* | perf:\ ?* | revert:\ ?* | \
	feat!:\ ?* | fix!:\ ?* | chore!:\ ?* | docs!:\ ?* | refactor!:\ ?* | \
	test!:\ ?* | build!:\ ?* | ci!:\ ?* | style!:\ ?* | perf!:\ ?* | revert!:\ ?*)
	ORIGINAL_TYPE="${COMMIT_SUMMARY%%:*}"
	;;
esac

# Exit if not a conventional commit
if [ -z "$ORIGINAL_TYPE" ]; then
	exit 0
fi

# Exit if filename already in summary
case "$COMMIT_SUMMARY" in
*"$FILENAME"*) exit 0 ;;
esac

PREFIX="$ORIGINAL_TYPE: "
SUFFIX="${COMMIT_SUMMARY#"$PREFIX"}"
MODIFIED_SUMMARY="$ORIGINAL_TYPE($FILENAME): $SUFFIX"

# Only modify if new summary is under 51 chars
if [ "${#MODIFIED_SUMMARY}" -lt 51 ]; then
	write_commit_msg "$COMMIT_MSG_FILE" "$MODIFIED_SUMMARY" "$COMMIT_BODY"
	echo "Modified commit message summary: $MODIFIED_SUMMARY" >&2
fi