# SPDX-FileCopyrightText: 2020 Luke Granger-Brown <depot@lukegb.com>
#
# SPDX-License-Identifier: Apache-2.0

{ depot, system, pkgs, ... }:
pkgs.writeShellScriptBin "switch-prebuilt" ''
  set -ue

  export AWS_ACCESS_KEY_ID="$(${pkgs.vault}/bin/vault kv get --address=unix:///run/tokend/sock -field=cacheAccessKeyID kv/apps/nix-daemon)"
  export AWS_SECRET_ACCESS_KEY="$(${pkgs.vault}/bin/vault kv get --address=unix:///run/tokend/sock -field=cacheSecretAccessKey kv/apps/nix-daemon)"
  system="''${1}"

  if [[ "$system" == "latest" ]]; then
    tmpdir="$(mktemp -d)"
    trap '{ rm -rf -- "$tmpdir"; }' EXIT

    ${pkgs.curl}/bin/curl -so "$tmpdir/archive.zip" 'https://hg.lukegb.com/api/v4/projects/lukegb%2Fdepot/jobs/artifacts/branch%2Fdefault/download?job=nixCache-${system}'
    ${pkgs.unzip}/bin/unzip -d "$tmpdir" -q -o "$tmpdir/archive.zip"
    system="$(${pkgs.jq}/bin/jq -r ".\"$(hostname)\"" "$tmpdir/systems.json")"

    echo "Switching to system ''$system"
  fi

  if [[ ! -e "$system" ]]; then
    # We should be a trusted-user.
    nix build -v "$system"
  fi

  diff "$system/etc/hostname" "/etc/hostname"

  # The next phase requires sudo, but it's harmless to run the preceding commands twice.
  if [[ $EUID -ne 0 ]]; then
    exec sudo "$0" "$system"
  fi

  nix-env -p /nix/var/nix/profiles/system --set "$system"
  "$system/bin/switch-to-configuration" switch
''