#! /usr/bin/env bash
set -xeuo pipefail
declare username host key_file ssh_opts nixos_conf
IFS=" " read -r -a ssh_opts <<< "$( (echo "$ssh_opts" | jq -r '@sh') | tr -d \'\")"

# DEPLOY
sshOpts=(
  -o BatchMode=yes
  -o StrictHostKeyChecking=no
)
for ssh_opt in "${ssh_opts[@]}"; do
  sshOpts+=(
    -o "$ssh_opt"
  )
done
if [[ -n "$key_file" ]]; then
  sshOpts+=(
    -i "$key_file"
  )
fi
destination="$username@$host"

command=(nix-instantiate --show-trace "${nixos_conf}")

# INSTANTIATE
# instantiate the config in /nix/store
"${command[@]}" -A out_path

# get the realized derivation to deploy
"${command[@]}" --show-trace --eval --strict --json

# FIXME explore import/readFile as ways to instantiate the derivation, potentially allowing to realize the store path up-front from Nix?
outPath=$(nix-store --realize "$("${command[@]}" --show-trace --eval --strict --json | jq -r '.drv_path')")
# deploy the config by nix-copy-closure
NIX_SSHOPTS="${sshOpts[*]}" nix-copy-closure --to "$destination" "$outPath" --gzip --use-substitutes
# switch the remote host to the config
# shellcheck disable=SC2029
ssh "${sshOpts[@]}" "$destination" "nix-env --profile /nix/var/nix/profiles/system --set $outPath"
# shellcheck disable=SC2029
output=$(ssh -o "ConnectTimeout=1" -o "ServerAliveInterval=1" "${sshOpts[@]}" "$destination" "nohup $outPath/bin/switch-to-configuration switch &" 2>&1) || echo "status code: $?"
echo "output: $output"
if [[ $output != *"Timeout, server $host not responding"* ]]; then
  echo "non-timeout error: $output"
  exit 1
else
  exit 0
fi