#!/usr/bin/env bash
set -eux

new_version=14

# Require the `yq` tool
if ! command -v yq >/dev/null; then
	echo "You must install the 'yq' tool to use this script."
	exit 1
fi

# Require docker-compose 2.1.1 or higher, for `docker-compose up --wait`
docker_compose_version=$(docker-compose --version --short)
if [ "${docker_compose_version}" = "$(echo -e "2.1.0\n${docker_compose_version}" | sort -V | head -n1)" ]; then
	echo "Your docker-compose is too old (${docker_compose_version}); upgrade to at least 2.1.1."
	exit 1
fi

image=$(yq ".services.database.image" docker-compose.yml)
if [[ $image =~ ^zulip/zulip-postgresql:([0-9]+)$ ]]; then
	old_version="${BASH_REMATCH[1]}"
else
	echo "Unexpected PostgreSQL image: $image"
	exit 1
fi

volume_mount=$(yq ".services.database.volumes.0" docker-compose.yml)
if [[ "$volume_mount" =~ ^([^:]+):/var/lib/postgresql/data:rw$ ]]; then
	old_mountpoint="${BASH_REMATCH[1]}"
else
	echo "Unexpected volume mount: $volume_mount"
	exit 1
fi

if [ "$new_version" -eq "$old_version" ]; then
	echo "PostgreSQL image is already version $new_version!"
	exit 1
fi

# Create a new volume for the data; scope it with the current
# directory, like docker-compose
docker_compose_project="$(basename "$(pwd)")"
new_volume="postgresql-$new_version"
full_new_volume="${docker_compose_project}_${new_volume}"
docker volume create "$full_new_volume"
trap 'docker volume --force "$full_new_volume"' EXIT

# Start a new PostgreSQL container of the right version to read in the
# dumped database and write a new data dir on the new volume
temp_container=$(
	docker run -d \
		-e POSTGRES_DB=zulip \
		-e POSTGRES_USER=zulip \
		-e POSTGRES_PASSWORD=zulip \
		-v "$full_new_volume:/var/lib/postgresql/data:rw" \
		--health-cmd 'psql -U zulip -c "select 1"' \
		--health-interval 10s \
		"zulip/zulip-postgresql:$new_version"
)
trap 'docker rm --force "$temp_container"; docker volume rm --force "$full_new_volume"' EXIT

# Wait for the new PostgreSQL container to become available
tries=0
while [ "$(docker inspect --format='{{json .State.Health.Status}}' "$temp_container")" != '"healthy"' ]; do
	tries=$((tries + 1))
	if [ "$tries" -gt 5 ]; then
		echo "PostgreSQL $new_version container failed to start!"
		exit 1
	fi
	sleep 10
done

# Ensure database is running
docker-compose up --wait database

# Stop the zulip processes which talk to the database
zulip_is_running=$(docker-compose ps --filter status=running --services | grep zulip || true)
if [ -n "$zulip_is_running" ]; then
	docker-compose stop zulip
fi

# Transfer the data to the new container
docker-compose exec database pg_dumpall -U zulip |
	docker exec -i "$temp_container" psql -U zulip

if [ "$old_version" -eq "10" ]; then
	# Upgrade MD5 password to SCRAM-SHA-256.  We escape all 's by doubling them.
	database_password=$(yq .services.database.environment.POSTGRES_PASSWORD docker-compose.yml |
		perl -pe "s/'/''/g")
	echo "ALTER USER zulip WITH PASSWORD '$database_password';" |
		docker exec -i "$temp_container" psql -U zulip
fi

# Stop the running database
docker-compose rm --force --stop database

# Stop the temporary PostgreSQL container
docker stop "$temp_container"
docker rm "$temp_container"
trap '' EXIT

# Update the docker-compose.yml file for the new version and data path
IMAGE="zulip/zulip-postgresql:$new_version" yq -i '.services.database.image = strenv(IMAGE)' docker-compose.yml
VOLUME="$new_volume:/var/lib/postgresql/data:rw" yq -i '.services.database.volumes.0 = strenv(VOLUME)' docker-compose.yml
VOLUME="$new_volume" yq -i 'with(.volumes.[strenv(VOLUME)]; . = "" | . tag="!!null")' docker-compose.yml

# Restart zulip, and the new database container
docker-compose up --wait

echo "Old data from PostgreSQL $old_version is available in $old_mountpoint"