upgrade-scripts.sh

#!/bin/bash

set -euo pipefail

source_dir="$(dirname "$0")"
export INTERNALS="${source_dir}/scripts/internal"

source "${INTERNALS}/util.sh"

if [ -n "${PYTHON+x}" ]; then
	if ! command -v "${PYTHON}" &> "/dev/null"; then
		>&2 echo "Error: Python command '${PYTHON}' set by environment variable 'PYTHON' does not exist."
		exit 3
	fi
else
	if command -v "python3" &> "/dev/null"; then
		PYTHON="python3"
	elif command -v "python" &> "/dev/null"; then
		PYTHON="python"
	else
		>&2 echo "Error: Environment variable 'PYTHON' is not set and neither of python commands 'python3' nor 'python' exists."
		exit 3
	fi
fi


function usage {
	errcho "Usage: upgrade-scripts.sh [options] <problem-dir>"
	errcho "Options:"
	errcho -e "  -h, --help"
	errcho -e "  -d, --dry"
}


dry_run="false"

function handle_option {
	local -r curr_arg="$1"; shift
	case "${curr_arg}" in
		-h|--help)
			usage
			exit 0
			;;
		-d|--dry)
			dry_run="true"
			;;
		*)
			invalid_arg_with_usage "${curr_arg}" "undefined option"
			;;
	esac
}

function handle_positional_arg {
	local -r curr_arg="$1"; shift
	if variable_not_exists "problem_dir"; then
		problem_dir="${curr_arg}"
		return
	fi
	invalid_arg_with_usage "${curr_arg}" "meaningless argument"
}

argument_parser "handle_positional_arg" "handle_option" "invalid_arg_with_usage" "$@"

if variable_not_exists "problem_dir"; then
	cecho red >&2 "Problem directory is not specified."
	usage
	exit 2
fi

if [ ! -d "${problem_dir}" ]; then
	cecho red >&2 "Problem directory '${problem_dir}' not found"
	exit 4
fi


problem_scripts="${problem_dir}/scripts"
source_scripts="scripts"
old_scripts="old"
problem_scripts_version_file="${problem_dir}/scripts/internal/version"
problem_scripts_version_legacy_file_name=".scripts_version"
problem_scripts_version_legacy_file="${problem_dir}/${problem_scripts_version_legacy_file_name}"


function ask_yes_no {
	local prompt="$1"; shift
	local res
	read -p "${prompt} [y/n] " res
	while : ; do
		res="$(echo "${res}" | tr '[:upper:]' '[:lower:]')"
		[ "${res}" == "y" ] && return 0
		[ "${res}" == "n" ] && return 1
		read -p "Please, respond with 'y' or 'n': " res
	done
}

function check_proceed {
	local exit_code="$1"; shift
	local prompt="$1"; shift
	if ! ask_yes_no "${prompt}"; then
		exit "${exit_code}"
	fi
}


if [ -f "${problem_scripts_version_file}" ]; then
	old_scripts_version="$(cat "${problem_scripts_version_file}")"
	old_scripts_commit="v${old_scripts_version}"
elif [ -f "${problem_scripts_version_legacy_file}" ]; then
	old_scripts_commit="$(cat "${problem_scripts_version_legacy_file}")"
else
	old_scripts_commit="$(git log --pretty=format:"%H" | tail -n 1)"
fi

if ! git show -s --oneline "${old_scripts_commit}" > /dev/null; then
	cecho red >&2 "Problem scripts commit '${old_scripts_commit}' not found in this source repository."
	exit 4
fi


function check_repo_is_clean {
	dir="$1"
	pushd "${dir}" > /dev/null 2>&1 || exit 1
	ret=0
	if [ -n "$(git status --porcelain)" ]; then
		ret=1
	fi
	popd > /dev/null 2>&1
	return ${ret}
}

if ! check_repo_is_clean "$(dirname ${problem_scripts})"; then
	cecho red >&2 "There are uncommitted changes in the problem repository."
	check_proceed 1 "Are you sure you want to proceed?"
	echo
fi

if ! check_repo_is_clean "$(dirname ${source_scripts})"; then
	cecho red >&2 "There are uncommitted changes in source scripts repository."
	check_proceed 1 "Are you sure you want to proceed?"
	echo
fi

ret=0
tag="$(git describe --tags | head -1)" || ret=$?
if [ "${ret}" -eq 0 ] && [[ ${tag} == v* ]]; then
	source_current_scripts_version="${tag#*v}"
else
	cecho red >&2 "There is no version tag on the current source scripts repository commit."
	check_proceed 1 "Are you sure you want to proceed with commit hash as a version?"
	echo
	source_current_scripts_version="$(git log --pretty=format:"%H" -n 1)"
fi

function list_dir_files {
	dir="$1"
	pushd "${dir}" > /dev/null 2>&1 || exit 1
	git ls-files | while read file; do
		[ -f "${file}" ] && echo "${file}"
	done
	popd  > /dev/null 2>&1
}

function get_all_scripts_files {
	{
		list_dir_files "${source_scripts}"
		list_dir_files "${problem_scripts}"
	} | sort | uniq
}

has_conflicts="false"
declare -a conflict_list
conflict_index=0

function push_conflict {
	status="FAIL"
	has_conflicts="true"
	conflict_list["${conflict_index}"]="$1"
	conflict_index=$((conflict_index + 1))
}

function do_action {
	if ! "${dry_run}"; then
		status="FAIL"
		ret=0
		"$@" || ret=$?
		if [ ${ret} -eq 0 ]; then
			changed="true"
			status="OK"
		fi
		return ${ret}
	fi
}

recreate_dir "${old_scripts}"

while read file; do
	c="${problem_scripts}/${file}"
	b="${source_scripts}/${file}"
	a="${old_scripts}/${file}"

	a_exists="true"
	mkdir -p "$(dirname "${a}")"
	git show "${old_scripts_commit}:${source_scripts}/${file}" > "${a}" 2> /dev/null || a_exists="false"

	b_exists="true"
	[ -f "${b}" ] || b_exists="false"

	c_exists="true"
	[ -f "${c}" ] || c_exists="false"

	changed="false"
	status="OK"
	"${dry_run}" && status="SKIP"
	message=""
	if "${b_exists}"; then
		if "${c_exists}"; then
			if are_same "${b}" "${c}"; then
				if "${a_exists}" && are_same "${a}" "${b}"; then
					message="not changed"
				else
					message="both problem and script source changed this file in the same way"
				fi
			elif "${a_exists}" && are_same "${a}" "${b}"; then
				message="keeping changes in problem"
			elif "${a_exists}" && are_same "${a}" "${c}"; then
				message="applying changes in problem"
				do_action cp "${b}" "${c}"
			else
				push_conflict "${file}"
				message="CONFLICT! both problem and script source changed this file"
			fi
		else
			if ! "${a_exists}"; then
				message="added as new file"
				do_action mkdir -p "$(dirname "${c}")"
				do_action cp "${b}" "${c}"
			elif are_same "${a}" "${b}"; then
				message="keeping deleted"
			else
				push_conflict "${file}"
				message="CONFLICT! deleted file in problem has been updated"
			fi
		fi
	else
		if "${c_exists}"; then
			if ! "${a_exists}"; then
				message="keeping extra file in problem"
			elif are_same "${a}" "${c}"; then
				message="file deleted because it is deleted in source"
				do_action rm -f "${c}"
			else
				push_conflict "${file}"
				message="CONFLICT! changed file in problem has been deleted"
			fi
		else
			cecho red >&2 "Unreachable code reached!"
			exit 1
		fi
	fi

	printf >&2 "%-40s" "${file}"
	BOX_PADDING=10
	echo_status "${status}"
	if "${changed}"; then
		cecho yellow >&2 "${message}"
	else
		errcho "${message}"
	fi
done <<< "$(get_all_scripts_files)"

if ! "${dry_run}" && [ -e "${problem_scripts_version_legacy_file}" ]; then
	errcho

	remove_legacy_version="true"
	if "${has_conflicts}"; then
		remove_legacy_version="false"
		if ask_yes_no "There are some conflicts. Should the legacy file '${problem_scripts_version_legacy_file_name}' be deleted?"; then
			remove_legacy_version="true"
		fi
	fi
	if "${remove_legacy_version}"; then
		rm -f "${problem_scripts_version_legacy_file}"
		cecho yellow "Removed legacy file '${problem_scripts_version_legacy_file_name}' in problem."
	fi
fi

errcho


if "${has_conflicts}"; then
	cecho red >&2 "Please resolve the following conflicts now!"
	sleep 0.1
	for file in "${conflict_list[@]}"; do
		echo "${file}"
	done

	exit 10
else
	cecho green >&2 "OK"
fi