#!/bin/bash

if [ "$#" -lt 1 ]; then
	printf 'Usage: %s <commit range>\n' "$0" 1>&2
	exit 1
fi

commits=$(git rev-list --no-merges "$@")
if [ -z "$commits" ]; then
	printf 'No commits\n'
	exit 0
fi

declare -a author_missing committer_missing

print_commits()
{
	if [ "$#" -eq 1 ]; then
		return
	fi

	local t="$1"

	shift

	s=
	is='is'
	its='its'
	if [ "$#" -gt 1 ]; then
		s='s'
		is='are'
		its='their'
	fi
	printf 'Commit%s\n\n' "$s"
	git log --no-walk --pretty='format:  %h ("%s")' "$@"
	printf '\n%s missing a Signed-off-by from %s %s%s.\n\n' \
		"$is" "$its" "$t" "$s"
}

for c in $commits; do
	ae=$(git log -1 --format='<%ae>%n<%aE>%n %an %n %aN ' "$c" | sort -u)
	ce=$(git log -1 --format='<%ce>%n<%cE>%n %cn %n %cN ' "$c" | sort -u)
	sob=$(git log -1 --format='%b' "$c" |
		sed -En 's/^\s*Signed-off-by:?\s*/ /ip')

	if ! grep -i -F -q "$ae" <<<"$sob"; then
		author_missing+=("$c")
	fi
	if ! grep -i -F -q "$ce" <<<"$sob"; then
		committer_missing+=("$c")
	fi
done

print_commits 'author' "${author_missing[@]}"
print_commits 'committer' "${committer_missing[@]}"

exec gitk "$@"