#!/usr/bin/env bash
set -euo pipefail

# This script updates Gitlab by following a migration path that Gitlab docs/tools claim is safe
# https://gitlab-com.gitlab.io/support/toolbox/upgrade-path/

APP_DATA_DIR="$(readlink -f $(dirname "${BASH_SOURCE[0]}")/..)"

GITLAB_RAILS_VERSION_FILE="${APP_DATA_DIR}/data/data/gitlab-rails/VERSION"

APP_COMPOSE_FILE="${APP_DATA_DIR}/docker-compose.yml"
APP_COMPOSE_BACKUP_FILE="${APP_DATA_DIR}/docker-compose.yml.bak"

# List of versions on migration path
# gitlab on the umbrel app store was initially released with version 17.2.1
# migration path tool: https://gitlab-com.gitlab.io/support/toolbox/upgrade-path/
VERSIONS=()
VERSIONS+=("17.2.1")
VERSIONS+=("17.3.3")
VERSIONS+=("17.5.1")

# List of images on migration path
# Using zengxs/gitlab which may not have all versions listed in upgrade path tool: https://hub.docker.com/r/zengxs/gitlab/tags
IMAGES=()
IMAGES+=("zengxs/gitlab:17.2.1-ce.0@sha256:ac08a4dd997b6cd5d00d56c0027629de56ac80d9d30f9c4f75a73da73f5ff1b4")
IMAGES+=("zengxs/gitlab:17.3.3-ce.0@sha256:b4369fc8f2a505fdf30bae7fa2befde2a8d6f75c067e5bcf85aeb1c5f345cda0")
IMAGES+=("zengxs/gitlab:17.5.1-ce.0@sha256:61cb4c79fe55de9dc94822d5a64a07ee40ff681d6282ab5733bc8e80479451ff")

find_index() {
	local -r value="${1}"
	shift
	local -r array=("$@")

	for i in "${!array[@]}"; do
		if [[ "${array[$i]}" == "${value}" ]]; then
			echo $i
			exit
		fi
	done

	echo -1
}

wait_for_migrations_complete() {
	local start_time=$(date +%s)
	local max_wait_time=$((1 * 60 * 60))  # 1 hour in seconds

	while true; do
		# We set some max wait time to prevent an infinite loop if something has gone wrong.
		# We may want to handle this better in the future.
		local current_time=$(date +%s)
		local elapsed_time=$((current_time - start_time))
		if [[ ${elapsed_time} -ge ${max_wait_time} ]]; then
			echo "Maximum migration wait time of 1 hour exceeded. Exiting as something is likely wrong..."
			exit 1
		fi
		
		# Set +e because this command will fail until gitlab-psql is ready to accept connections and we don't want to exit the script on failure
		set +e
		echo "Running gitlab-psql command to check if batched migrations are complete"
		# https://docs.gitlab.com/ee/update/background_migrations.html#from-the-database
		command_output=$(docker exec gitlab_gitlab_1 gitlab-psql -tAc "SELECT COUNT(*) FROM batched_background_migrations WHERE status NOT IN(3, 6);" 2>&1)
		# Passing the psql command to scripts/app compose results in the command args being split such that psql errors.
		# Using the `docker exec` command above gets around this issue, but we should revisit this in the future to move away from locking this script to docker.
		# command_output=$("${UMBREL_ROOT}/scripts/app" compose "${APP_ID}" exec gitlab gitlab-psql -tAc "SELECT COUNT(*) FROM batched_background_migrations WHERE status NOT IN(3, 6);" 2>&1)
		exit_code=$?
		# Set -e to restore default behavior
		set -e

		if [[ ${exit_code} -eq 0 ]]; then
			remaining_migrations=$(echo "${command_output}" | tr -d '[:space:]')
			echo "Parsed remaining batched migrations: '${remaining_migrations}'"

      # We only want to continue if there are "0" remaining batched migrations
			if [[ "${remaining_migrations}" == "0" ]]; then
				echo "GitLab migration completed successfully."
				return
			fi
		else
			echo "Command failed with exit code ${exit_code}. Error output: ${command_output}"
		fi

		echo "Waiting 30 seconds before checking migration status again..."
		sleep 30
	done
}

check_compose_file() {
	local -r image="${1}"

	gitlab_image=$(cat "${APP_COMPOSE_FILE}" 2>/dev/null | yq '.services.gitlab.image' || true)

	if [[ "${gitlab_image}" != "${image}" ]]; then
		echo "The docker-compose.yml now looks bad. Restoring..."

		mv "${APP_COMPOSE_BACKUP_FILE}" "${APP_COMPOSE_FILE}"

		exit
	fi
}

get_version() {
	cat "${GITLAB_RAILS_VERSION_FILE}"
}

# Main script execution starts here
# ================================

# If a gitlab-rails version file does not yet exist
# Then it's likely a new install
# Therefore there is nothing to do
if [[ ! -f "${GITLAB_RAILS_VERSION_FILE}" ]]; then
	exit
fi

current_version=$(get_version)
echo "Current GitLab version: ${current_version}"

# check if current version has "-patch" appended to it and exit if it does so we allow the migration to complete
# we add "-patch" to the version below during migration
if [[ "${current_version}" == *"-patch"* ]]; then
	echo "Active GitLab version is undergoing migration. Exiting..."
	exit
fi

# Check if active version is in migration list
active_version_idx=$(find_index "${current_version}" "${VERSIONS[@]}")
if [[ "${active_version_idx}" == "-1" ]]; then
	echo "Active version is not supported in the list of migrations"
	exit
fi

# Check if already up to date
if [[ "${VERSIONS[-1]}" == "${current_version}" ]]; then
	echo "GitLab is already on the latest major version. No migration needed."
	exit
fi

# Loop through versions, ignoring past versions
for i in "${!VERSIONS[@]}"; do
	[[ "${i}" -le "${active_version_idx}" ]] && continue

	version="${VERSIONS[$i]}"
	image="${IMAGES[$i]}"

	echo "Migrating to version: ${version} (${image})"
	echo

	cp --archive "${APP_COMPOSE_FILE}" "${APP_COMPOSE_BACKUP_FILE}"

	yq -i ".services.gitlab.image = \"${image}\"" "${APP_COMPOSE_FILE}"

	check_compose_file "${image}"

	# Mark the current version as being in the middle of an update
	current_version=$(get_version)
	sed -i "s/${current_version}/${current_version}-patch/" "${GITLAB_RAILS_VERSION_FILE}"

	# Start the app
	# pre-start hook will be executed in subshell, but will exit on -patch check to allow migration to complete
	"${UMBREL_ROOT}/scripts/app" start gitlab

	echo "Waiting for update to complete..."

	# Wait for app to undergo any migrations
	# Indicated by gitlab-rails runner output
	wait_for_migrations_complete

	# Stop the app
	"${UMBREL_ROOT}/scripts/app" stop gitlab

	# Delete image of intermediate version
	# Unless it's the latest image
	# Otherwise it will have to be re-downloaded
	if [[ "${version}" != "${VERSIONS[-1]}" ]]; then
		echo "Deleting intermediary image: ${image}"

		docker rmi "${image}" || true
	fi
done

# Remove the backup file
rm -rf "${APP_COMPOSE_BACKUP_FILE}"

echo "Migration completed successfully"