#!/bin/sh

# prepare-commit-msg: Prepare a commit message upon `git commit` for the
# user to edit.  A script (rather than a static template) is used, so
# that we can insert our template text other than at the top of the
# message.
#
# Install by either setting the configuration of the repository to:
#   git config --add core.hooksPath .hooks
# or copy it to the hooks directory, but it will not get automatically updated:
#   cp .hooks/prepare-commit-msg .git/hooks/

case "$2" in
commit|message)
	# It appears git invokes this script for interactive rebase but does
	# not remove commented lines, so just exit if we're not called with the
	# default (comment-containing) template.
	grep -E -q '^#' "$1" || exit 0
	;;
template)
	exit 0
	;;
merge)
	exit 0
	;;
esac

outfile=$(mktemp /tmp/freebsd-git-commit.XXXXXXXX)
exec 3> "$outfile"

if [ -z "$3" ]
then
  what=$(git diff-index --name-only --cached --diff-filter=ACMR HEAD|sed -Ee 's/^([^\/]+\/[^\/]+).*/\1/'|sort -u|xargs)

  case $what in
    *\ *)
      # More than one port, do nothing
      ;;
    *)
      # One port, prepare the commit message.
      {
	echo "# Uncomment and add a short description of why things changed."
	echo "# $what: "
	echo
      } >&3
      ;;
esac
fi

# Create a commit message template from three parts:
#
# 1. The beginning of the git-provided template (up to the first comment-only
#    line) which explains commented lines and such.
#
# 2. Our template.
#
# 3. The remainder of the git-provided template (from the first comment-only
#    line to the end of the file) which lists files staged for commit, files
#    not staged, and untracked files.

awk '1;/^#$/{exit}' "$1" >&3

cat >&3 <<EOF
# category/port: Subject goes here, max 50 cols -|
# <then a blank line>
#                                                         72 columns --|
#
# Do not add a Submitted by line.  If someone besides the committer sent in the
# change, the commit author should be set using \`git commit --author\`.
#
# Uncomment and complete these metadata fields, as appropriate:
#
# PR:		<If and which Problem Report is related.>
# Reported by:	<If someone else reported the issue.>
# Reviewed by:	<If someone else reviewed your modification.>
# Tested by:	<If someone else tested the change.>
# Approved by:	<If you needed approval for this commit.>
# Obtained from:	<If the change is from a third party.>
# Fixes:	<Short hash and title line of commit fixed by this change>
# MFH:		<Ports tree branch name you plan to merge to.>
# Relnotes:	<Set to 'yes' for mention in release notes.>
# Security:	<Vulnerability reference (one per line) or description.>
# Sponsored by:	<If the change was sponsored by an organization.>
# Pull Request:	<https://github.com/freebsd/freebsd-ports/pull/###>
# Differential Revision:	<https://reviews.freebsd.org/D###>
#
# "Pull Request" and "Differential Revision" require the *full* GitHub or
# Phabricator URL.
EOF

awk '/^#$/,EOF' "$1" >&3

exec 3>&-

mv "$outfile" "$1"