#!/bin/bash

set -euo pipefail

declare -r TAGBRANCH=main
declare CURRENTBRANCH=""
declare ORIGBRANCH=""
declare -r ARG1="${1:-}"
declare -r ARG2="${2:-}"
declare is_dry_run=false
declare release_input=""

showHelp() {
	cat <<'EOF'
Usage:
  makerelease.sh VERSION
  makerelease.sh +0.0.1
  makerelease.sh +0.1
  makerelease.sh +1
  makerelease.sh --dry-run VERSION
  makerelease.sh --dry-run +0.0.1
  makerelease.sh --dry-run +0.1
  makerelease.sh --dry-run +1

Creates an annotated Git tag from the current dev branch.

If VERSION starts with +, it is treated as an increment:
- +0.0.1 increments patch
- +0.1 increments minor
- +1 increments major

Use --dry-run to show the computed release version without running Git actions.

Requirements:
- run from a clean Git working tree
- current branch must be dev for real releases
- main branch must exist locally
EOF
}

cleanup() {
	if [ -n "${ORIGBRANCH}" ] && [ "${CURRENTBRANCH}" != "${ORIGBRANCH}" ]; then
		git checkout "${ORIGBRANCH}" >/dev/null 2>&1 || true
	fi
}

trap cleanup EXIT

if [ "${ARG1}" = "--dry-run" ] || [ "${ARG1}" = "-n" ]; then
	is_dry_run=true
	release_input="${ARG2:-}"
else
	release_input="${ARG1}"
fi

if [ -z "${release_input}" ]; then
	showHelp
	echo ""
	echo "no version provided!"
	exit 1
fi

if ! git rev-parse --is-inside-work-tree >/dev/null 2>&1; then
	echo "You are not inside a Git repository!"
	exit 1
fi

if [ -n "$(git status --porcelain)" ]; then
	echo "Working tree is not clean!"
	echo "Commit or stash your changes before creating a release."
	exit 1
fi

CURRENTBRANCH=$(git rev-parse --abbrev-ref HEAD)
ORIGBRANCH="${CURRENTBRANCH}"

if [ "${is_dry_run}" = false ] && [ "${CURRENTBRANCH}" != "dev" ]; then
	echo "You are not in dev branch!"
	echo "Use dev branch to make a release!"
	exit 1
fi

release_tag="${release_input}"
if [ "${release_input}" != "${release_input#+}" ]; then
	current_tag="$(git describe --tags --abbrev=0 2>/dev/null || true)"
	if [ -z "${current_tag}" ]; then
		echo "No existing tag found to increment from!"
		exit 1
	fi
	case "${release_input}" in
		+1)
			release_tag="$(printf '%s' "${current_tag}" | awk -F. 'BEGIN{OFS="."} { $1+=1; $2=0; $3=0; print }')"
			;;
			+0.1)
			release_tag="$(printf '%s' "${current_tag}" | awk -F. 'BEGIN{OFS="."} { $2+=1; $3=0; print }')"
			;;
			+0.0.1)
			release_tag="$(printf '%s' "${current_tag}" | awk -F. 'BEGIN{OFS="."} { $3+=1; print }')"
			;;
		*)
			echo "Unsupported increment syntax: ${release_input}"
			exit 1
			;;
	esac
fi

if git rev-parse -q --verify "refs/tags/${release_tag}" >/dev/null; then
	echo "Tag ${release_tag} already exists!"
	exit 1
fi

if [ "${is_dry_run}" = true ]; then
	echo "Dry run: computed release tag ${release_tag}"
	exit 0
fi

echo "Release tag selected: ${release_tag}"
read -r -p "Proceed with release? [y/N] " confirm
case "${confirm}" in
	y|Y)
		;;
	*)
		echo "Release cancelled."
		exit 1
		;;
esac

git checkout "${TAGBRANCH}"
CURRENTBRANCH="${TAGBRANCH}"
git merge "${ORIGBRANCH}"
git push
git tag -a "${release_tag}" -m "Release ${release_tag}"
git push --tags

echo "Created release tag ${release_tag}"