#!/bin/bash
set -eo pipefail

BUILDER=""
DISTRO_REPO="${DISTRO_REPO:=openhab/openhab-distro}"
VERSIONS=""

get_released_versions_from_tags() {
	git ls-remote --refs --tags "https://github.com/${DISTRO_REPO}.git" | grep -E '.+/tags/[0-9]+\.[0-9]+\.[0-9]+(\.(M|RC)[0-9]+)?$' | sed -E 's#.+/tags/(.+)#\1#g' || echo ""
}

get_snapshot_versions_from_poms() {
	local branch_names="$(git ls-remote --refs --heads "https://github.com/${DISTRO_REPO}.git" | grep -E '.+/heads/(main)$' | sed -E 's#.+/heads/(.+)#\1#g')"
	for branch_name in $branch_names; do
		curl -sS "https://raw.githubusercontent.com/${DISTRO_REPO}/${branch_name}/pom.xml" | grep -E '^  <version>' | grep 'SNAPSHOT' | sed -E 's#.+<version>(.+)-SNAPSHOT</version>#\1-snapshot#g' || echo ""
	done
}

get_versions() {
	(get_released_versions_from_tags && get_snapshot_versions_from_poms) | sort --unique --version-sort
}

VERSIONS=$(get_versions)

# Supported base images
bases() {
	echo "debian alpine"
}

docker_repo() {
	echo "${DOCKER_REPO:=openhab/openhab}"
}

# Supported Docker platforms
platforms() {
	local version="$1"
	local base="$2"

	if [[ "$version" =~ ^4.*$ ]] && [ "$base" == "debian" ]; then
		echo "linux/amd64,linux/arm64,linux/arm/v7"
	else
		# There are no linux/arm/v7 images for openHAB 5 (or newer) because this platform is no longer supported.
		# There are no linux/arm/v7 Alpine images for openHAB 3 (or newer) because the required openjdk package is unavailable for this platform.
		echo "linux/amd64,linux/arm64"
	fi
}

tags() {
	local version="$1"
	local base="$2"

	local tags=()

	if [ "$base" == "debian" ]; then
		tags+=("$(docker_repo):$version")
	fi

	tags+=("$(docker_repo):$version-$base")

	if [ "$version" == "$(last_stable_version)" ]; then
		if [ "$base" == "debian" ]; then
			tags+=("$(docker_repo):latest")
		fi
		tags+=("$(docker_repo):latest-$base")
	fi

	milestone_maturity_version="$(last_milestone_version)"
	if [ "$milestone_maturity_version" == "" ]; then
		milestone_maturity_version="$(last_stable_version)"
	fi

	if [ "$version" == "$milestone_maturity_version" ]; then
		if [ "$base" == "debian" ]; then
			tags+=("$(docker_repo):milestone")
		fi
		tags+=("$(docker_repo):milestone-$base")
	fi

	if [ "$version" == "$(last_snapshot_version)" ]; then
		if [ "$base" == "debian" ]; then
			tags+=("$(docker_repo):snapshot")
		fi
		tags+=("$(docker_repo):snapshot-$base")
	fi

	echo $(IFS=' '; echo "${tags[*]}")
}

last_stable_version() {
	grep -E '^[0-9]+\.[0-9]+\.[0-9]+$' <<< $VERSIONS | tail -n 1
}

stable_versions() {
	grep -E '^[0-9]+\.[0-9]+\.[0-9]+$' <<< $VERSIONS
}

last_stable_minor_versions() {
	local minor_versions=$(grep -E '^[0-9]+\.[0-9]+\.[0-9]+$' <<< $VERSIONS | sed -E 's/^([0-9]+\.[0-9]+).+/\1/' | sort --unique --version-sort)
	for minor_version in $minor_versions; do
		stable_versions | grep -E "^$minor_version" | tail -n 1
	done
}

snapshot_versions() {
	grep -E '^[0-9]+\.[0-9]+\.[0-9]+-snapshot$' <<< $VERSIONS || echo ""
}

last_snapshot_version() {
	grep -E '^[0-9]+\.[0-9]+\.[0-9]+-snapshot$' <<< $VERSIONS | tail -n 1 || echo ""
}

next_stable_version() {
	sed 's/-snapshot//' <<< $(last_snapshot_version)
}

milestone_versions() {
	grep -E "$(next_stable_version)\.(M|RC)[0-9]+$" <<< $VERSIONS | tail -n 3 || echo ""
}

last_milestone_version() {
	grep -E "$(next_stable_version)\.(M|RC)[0-9]+$" <<< $VERSIONS | tail -n 1 || echo ""
}

generate_readme_versions() {
	local text="$1"
	local versions="$(echo "$2" | sort --reverse --version-sort | head -n 2)"

	if [ "$versions" != "" ]; then
		echo "* $text"
		for version in $versions; do
			case $version in
			*-snapshot)	echo "  * \`$version\`";;
			*)			echo "  * \`$version\` ([Release notes](https://github.com/openhab/openhab-distro/releases/tag/$version))";;
			esac
		done
	fi
}

update_readme() {
	local file=README.md

	if [ "$(last_stable_version)" == "" ]; then
		echo "Cannot update $file because the last stable version is unknown!"
		exit 1
	fi

	local generate="false"
	while IFS= read -r line
	do
		if [[ $line =~ ^\*\ \*\*Stable:\*\*.+$ ]]; then
			generate="true"
		else
			if [ "$generate" == "true" ]; then
				if [ "$line" == "" ]; then
					generate="false"

					generate_readme_versions \
						'**Stable:** Thoroughly tested semi-annual official releases of openHAB. Use the stable version for your production environment if you do not need the latest enhancements and prefer a robust system.' \
						"$(last_stable_minor_versions)"
					generate_readme_versions \
						'**Milestone:** Intermediary releases of the next openHAB version which are released about once a month. They include recently added features and bugfixes and are a good compromise between the current stable version and the bleeding-edge and potentially unstable snapshot version.' \
						"$(milestone_versions)"
					generate_readme_versions \
						'**Snapshot:** Usually 1 or 2 days old and include the latest code. Use these for testing out very recent changes using the latest code. Be aware that some snapshots might be unstable so use these in production at your own risk!' \
						"$(snapshot_versions)"
					echo
				fi
			else
				echo "$line"
			fi
		fi
	done < $file > $file.new && mv $file.new $file

	sed -i "s#version-[0-9]*\.[0-9]*\.[0-9]*-blue#version-$(last_stable_version)-blue#g" $file
	sed -i "s#openhab/tags?name=[0-9]*\.[0-9]*\.[0-9]*#openhab/tags?name=$(last_stable_version)#g" $file
	sed -i "s#openhab/openhab:[0-9]*\.[0-9]*\.[0-9]*#openhab/openhab:$(last_stable_version)#g" $file
	sed -i "s#OPENHAB_VERSION=[0-9]*\.[0-9]*\.[0-9]*#OPENHAB_VERSION=$(last_stable_version)#g" $file
}

validate_readme_constraints() {
	local count=$(wc -m <README.md)
	if [ $count -gt 25000 ]; then
		echo "README.md contains $count characters which exceeds the 25000 character limit of Docker Hub" >&2
		exit 1
	else
		echo "README.md contains $count characters which is below the 25000 character limit of Docker Hub"
	fi
}

update_dockerhub_readme() {
	if [ "$(docker info 2>&1 | grep 'pushrm: Push Readme to container registry' | wc -l)" -eq "0" ]; then
		# The pushrm plugin is available from https://github.com/christian-korneck/docker-pushrm
		echo "Failed to update README for $(docker_repo) on Docker Hub (pushrm Docker CLI plugin not installed)" >&2
		exit 1
	fi

	if docker pushrm $(docker_repo); then
		echo "Successfully updated README for $(docker_repo) on Docker Hub"
	else
		echo "Failed to update README for $(docker_repo) on Docker Hub" >&2
		exit 1
	fi
}

prepare_builder() {
	if [ "$BUILDER" == "" ]; then
		docker run --privileged --rm tonistiigi/binfmt:qemu-v8.1.5 --install all &> /dev/null
		(docker buildx inspect builder &> /dev/null && echo -e "\nReusing existing builder") || \
			(docker buildx create --name builder --use &> /dev/null && echo -e "\nCreated builder")
		BUILDER="builder"
	fi
}

build() {
	prepare_builder

	local openhab_version="${1/SNAPSHOT/snapshot}"
	local dist="$2"
	local push="$3"

	local java_version=""
	case $openhab_version in
	4.*) java_version="17";;
	*)   java_version="21";;
	esac

	local build_arg_options="--build-arg BUILD_DATE=$(date +"%Y-%m-%dT%H:%M:%SZ") --build-arg VCS_REF=$(git rev-parse HEAD) --build-arg JAVA_VERSION=$java_version --build-arg OPENHAB_VERSION=$openhab_version"
	local tags=$(tags $openhab_version $dist)
	local tag_options=${tags//$(docker_repo)/--tag $(docker_repo)}
	local output_options="--output type=image,oci-mediatypes=false,push=$([ "$push" == "--push" ] && echo true || echo false)"
	local build_options="$build_arg_options --platform $(platforms $openhab_version $dist) $tag_options $output_options --progress plain --provenance=false"
	local dockerfile_path="./$dist"
	local build_command="docker buildx build $build_options $dockerfile_path"

	echo
	echo "Building openHAB $openhab_version $dist Docker image"
	echo
	set -x

	$build_command

	{ set +x; } 2> /dev/null
	echo
}