commit-msg

#!/usr/bin/env bash

#	Automated Timestamping
#
#	Copyright (c) 2021 - 2022 Johannes Milczewski
#
#	Permission is hereby granted, free of charge, to any person obtaining a copy
#	of this software and associated documentation files (the "Software"), to deal
#	in the Software without restriction, including without limitation the rights
#	to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
#	copies of the Software, and to permit persons to whom the Software is
#	furnished to do so, subject to the following conditions:
#
#	The above copyright notice and this permission notice shall be included in all
#	copies or substantial portions of the Software.
#
#	THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
#	IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
#	FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
#	AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
#	LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
#	OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
#	SOFTWARE.

function hook_echo() {
	local TAG="commit-msg"
	echo -e "[\e[0;32m${TAG}\e[0m]: $1"
}

function hook_error() {
  local TAG="commit-msg"
  echo -e "[\e[0;31m${TAG}\e[0m]: $1"
}

function ts-commit-msg_impl() {
	if [[ -z ${GIT_DIR+x} || $# -lt 1 ]]; then
		die 'Call this script only through "git commit".'
	fi

	# Get current branch
	local BRANCH
	BRANCH=$(get_branch)

	# Return if already on signing branch
	if on_signing_branch; then
		return 0
	fi

	hook_echo "Branch is ${BRANCH}"

	local TSA_LIST=()
	mapfile -t TSA_LIST < <(get_tsa_list "${BRANCH}")

	# Get applicable diff of staged files
	hook_echo "Creating diff"
	local DIFF
	DIFF=$(get_diff)
	if [[ $? -eq 3 ]]; then
		hook_echo 'ERROR: ts.diff.type must be either "staged" or "full"'
	fi

	# Get TSA-specific diffs
	local TSA_DIFF=()
	for i in "${!TSA_LIST[@]}"; do
		if TSA_DIFF[${i}]=$(get_tsa_diff "${BRANCH}" "${TSA_LIST[${i}]}"); then
			hook_echo "Getting diff for ${TSA_LIST[${i}]}"
		fi
	done

	# Get commit message
	local COMMIT_MSG_FILE=$1
	local COMMIT_MSG
	COMMIT_MSG=$(cat "${COMMIT_MSG_FILE}")

	# Stash changes to be committed
	local STASH
	maybe_stash
	STASH=$?

	# Create signing branch if non-existent
	checkout_signing "${BRANCH}" || {
		local RETURN=$?
		hook_echo "ERROR: Could not check out signing branch"
		exit $?
	}

	# Write diff file
	write_diff "${DIFF}"

	# Write TSA-specific diffs
	for i in "${!TSA_LIST[@]}"; do
		if [[ -n "${TSA_DIFF[${i}]}" ]]; then
			write_tsa_diff "${TSA_DIFF[${i}]}" "${TSA_LIST[${i}]}"
		fi
	done

	create_timestamps "${BRANCH}"
	RETURN=$?

	# Checkout original branch
	checkout_actual "${BRANCH}"

	# Restore original commit message
	echo "${COMMIT_MSG}" >"${COMMIT_MSG_FILE}"

	# Unstash changes to be committed
	maybe_unstash "${STASH}"

	# Wait one second for different commit timestamps
	sleep 1s

	return ${RETURN}
}

function ts-commit-msg() {
	# shellcheck source=timestamping.sh
	source "$(dirname "$(realpath "$0")")/timestamping.sh" || return 128

	if_enabled in_environment ts-commit-msg_impl "$@"
	return $?
}

if [[ "${BASH_SOURCE[0]}" == "${0}" ]]; then
	ts-commit-msg "$1"
	exit $?
fi