#!/bin/bash

find_tags() {
	local rev taglistfd commitish
	rev="$(git rev-parse "${1}")"
	exec {taglistfd}< <(git show-ref --tags)
	while read commitish tag <&${taglistfd}; do
		tag="${tag#refs/tags/}"
		if [[ "${tag}" =~ -ptx-old$ ]]; then
			continue
		fi
		if [ "${commitish}" = "${rev}" ]; then
			tags="${tags} ${tag}"
		fi
	done
}

push_tags() {
	local tag
	for tag in ${tags}; do
		echo "exec git tag -f ${tag}-ptx-old $(git rev-parse "${tag}")" >> "${tmpfile}"
		echo "exec git tag -f ${tag}" >> "${tmpfile}"
	done
	tags=
}

filter_rebase() {
	file="${1}"
	tmpfile="$(mktemp "${file}.XXXXX")"
	tags=
	cat "${file}" | while read cmd commitish subject; do
		case "${cmd}" in
		"#"|"")
			;;
		pick|p|reword|r|edit|e)
			push_tags
			find_tags "${commitish}"
			;;
		squash|s|fixup|f)
			find_tags "${commitish}"
			;;
		*)
			push_tags
			;;
		esac
		echo "${cmd}${commitish:+ }${commitish}${subject:+ }${subject}" >> "${tmpfile}"
	done
	push_tags

	mv "${tmpfile}" "${file}"
}

filter_rebase "${1}"

# find the editor outside the local repository
editor="$(cd / && git var GIT_EDITOR)"
exec ${editor} "${@}"