#!/bin/sh

set -e

debug() {
	if [ "$GIT_TRAILER_DEBUG" = 1 ]; then
		"$@" >&2
	fi
}

trailer_order="
Closes:
Fixes:
Implements:
References:
Link:
Changelog-added:
Changelog-fixed:
Changelog-changed:
Changelog-deprecated:
Cc:
Suggested-by:
Requested-by:
Reported-by:
Co-authored-by:
Signed-off-by:
Tested-by:
Reviewed-by:
Acked-by:
"
file=${1?file}
tmp=$(mktemp)
trap "rm -f $tmp" EXIT

# Read unfolded trailers and normalize case.
git interpret-trailers --parse --trim-empty "$file" |
while read -r key value; do
	# Force title case on trailer key.
	first_letter=$(echo "$key" | sed 's/^\(.\).*/\1/' | tr '[:lower:]' '[:upper:]')
	other_letters=$(echo "$key" | sed 's/^.\(.*\)/\1/' | tr '[:upper:]' '[:lower:]')
	key="$first_letter$other_letters"

	# Find sort order of this key.
	order=$(echo "$trailer_order" | grep -Fxn "$key" | sed -nE 's/^([0-9]+):.*/\1/p')
	if [ -z "$order" ]; then
		echo "warning: unknown trailer '$key'" >&2
		# Unknown trailers are always first.
		order="0"
	fi

	echo "$order $key $value"
done |
# Sort trailers according to their numeric order, trim the numeric order.
LC_ALL=C sort -n | sed -E 's/^[0-9]+ //' > "$tmp"

debug echo ==== sanitized trailers ====
debug cat "$tmp"

# Unfortunately, reordering trailers is not possible at the moment. Delete all
# trailers first. The only way to do it is to force replace existing trailers
# with empty values and trim empty trailers one by one.
while read -r key value; do
	git interpret-trailers --in-place --if-exists=replace \
		--trailer="$key " "$file"
	git interpret-trailers --in-place --trim-empty "$file"
done < "$tmp"

set --
while read -r trailer; do
	case "$trailer" in
	Changelog-*)
		# Wrap changelog entries indenting with a space.
		trailer=$(echo "$trailer" | fmt -w 72 | sed '2,$s/^/ /')
		;;
	esac
	set -- "$@" --trailer="$trailer"
done < "$tmp"

# Remove duplicate "key: value" trailers (e.g. duplicate signed-off-by).
git interpret-trailers --in-place --if-exists=addIfDifferent "$@" "$file"