#!/bin/sh
set -eu

ROOT=$(CDPATH='' cd -- "$(dirname -- "$0")/.." && pwd)
cd "$ROOT"

if [ "$#" -ne 1 ]; then
  echo "Usage: $0 PATH_TO_CUSTOM_FORMAT_DUMP" >&2
  exit 1
fi

dump=$1
checksum="$dump.sha256"

if [ ! -f "$dump" ] || [ ! -s "$dump" ]; then
  echo "Dump does not exist or is empty: $dump" >&2
  exit 1
fi

if [ ! -f "$checksum" ]; then
  echo "Checksum manifest is required: $checksum" >&2
  exit 1
fi

if [ ! -f "$ROOT/.env" ]; then
  echo "Missing $ROOT/.env." >&2
  exit 1
fi

set -a
# shellcheck source=/dev/null
. "$ROOT/.env"
set +a

: "${POSTGRES_DB:?Set POSTGRES_DB in .env}"
: "${POSTGRES_USER:?Set POSTGRES_USER in .env}"
: "${DATABASE_URL:?Set DATABASE_URL in .env}"

dump_dir=$(CDPATH='' cd -- "$(dirname -- "$dump")" && pwd)
dump_name=$(basename -- "$dump")

(
  cd "$dump_dir"
  sha256sum --check --status "$(basename -- "$checksum")"
)

docker compose exec -T db pg_restore --list <"$dump" >/dev/null

drill_db="who_need_help_restore_drill_$(date -u +%Y%m%d%H%M%S)_$$"
created=false

cleanup() {
  if [ "$created" = true ]; then
    docker compose exec -T db \
      dropdb --username "$POSTGRES_USER" --if-exists "$drill_db" >/dev/null
  fi
}
trap cleanup EXIT HUP INT TERM

docker compose exec -T db \
  createdb \
  --username "$POSTGRES_USER" \
  --template template0 \
  "$drill_db"
created=true

docker compose exec -T db \
  pg_restore \
  --username "$POSTGRES_USER" \
  --dbname "$drill_db" \
  --exit-on-error \
  --no-owner \
  --no-privileges <"$dump"

tables=$(
  docker compose exec -T db \
    psql --username "$POSTGRES_USER" --dbname "$drill_db" --tuples-only --no-align \
    --command "
      SELECT tablename
      FROM pg_tables
      WHERE schemaname = 'public'
        AND tablename <> 'spatial_ref_sys'
      ORDER BY tablename;
    "
)

table_count=0
total_rows=0

for table in $tables; do
  restored_count=$(
    docker compose exec -T db \
      psql --username "$POSTGRES_USER" --dbname "$drill_db" --tuples-only --no-align \
      --command "SELECT count(*) FROM \"$table\";"
  )

  table_count=$((table_count + 1))
  total_rows=$((total_rows + restored_count))
done

if [ "$table_count" -eq 0 ]; then
  echo "The restored database contains no public application tables." >&2
  exit 1
fi

postgis_version=$(
  docker compose exec -T db \
    psql --username "$POSTGRES_USER" --dbname "$drill_db" --tuples-only --no-align \
    --command "SELECT PostGIS_Lib_Version();"
)

case "$DATABASE_URL" in
  *\?*)
    database_base=${DATABASE_URL%%\?*}
    database_query="?${DATABASE_URL#*\?}"
    ;;

  *)
    database_base=$DATABASE_URL
    database_query=
    ;;
esac

database_prefix=${database_base%/*}

if [ "$database_prefix" = "$database_base" ]; then
  echo "Could not derive the temporary drill DATABASE_URL." >&2
  exit 1
fi

drill_database_url="$database_prefix/$drill_db$database_query"

docker compose run --rm --no-deps \
  --env APP_ROLE=migrate \
  --env "DATABASE_URL=$drill_database_url" \
  migrate /app/bin/migrate

docker compose run --rm --no-deps \
  --env APP_ROLE=migrate \
  --env "DATABASE_URL=$drill_database_url" \
  migrate /app/bin/who_need_help eval 'WhoNeedHelp.Release.await_migrations()'

migration_count=$(
  docker compose exec -T db \
    psql --username "$POSTGRES_USER" --dbname "$drill_db" --tuples-only --no-align \
    --command "SELECT count(*) FROM schema_migrations;"
)

docker compose exec -T db \
  dropdb --username "$POSTGRES_USER" "$drill_db"
created=false
trap - EXIT HUP INT TERM

remaining=$(
  docker compose exec -T db \
    psql --username "$POSTGRES_USER" --dbname postgres --tuples-only --no-align \
    --command "SELECT count(*) FROM pg_database WHERE datname = '$drill_db';"
)

if [ "$remaining" != "0" ]; then
  echo "Restore drill database was not removed: $drill_db" >&2
  exit 1
fi

echo "Restore drill passed for: $dump_name"
echo "Readable public tables: $table_count"
echo "Restored rows read: $total_rows"
echo "Applied migrations: $migration_count"
echo "PostGIS library: $postgis_version"
echo "Temporary database removed: $drill_db"