iot.nix

{pkgs, ...}:
pkgs.writeShellScript "iot" ''
  set -e

  jq="${pkgs.jq}/bin/jq"
  cmd="$1"
  shift

  rm -rf iot-build
  nix build --out-link "iot-build/sources" .#iot-devices

  for target in "$@"; do
    # Convert to lower case
    target_name="''${target,,}"

    # Replace spaces with dashes
    target_name="''${target_name// /-}"

    # Remove apostrophes
    target_name="''${target_name//\'/}"

    target_path="./iot-build/sources/''${target_name}.yaml"

    # Replace password commands with password values by:
    # 1) Extract the list of password commands using jq
    # 2) Send the list through bash and jq -R to actually execute the
    #    commands and format the output into json strings
    # 3) Build a subshell that outputs, first, the raw json input file, and
    #    second the list of json-stringified passwords from step 2
    # 4) Pipe the output of the subshell in step 3 into another jq command
    #    that recursively looks for password commands.  When it finds one,
    #    it replaces it with the next input.
    # This works because the order of the list generated in step 2 should
    # always match the order that jq's recursive walk finds key commands.
    # If for some reason that assumption ever fails, we'd need to change 2
    # to output something that actually keys the passwords by command to
    # reconcile them later, or switch back to python or something, but I'd
    # prefer to stay in jq for something this simple.
    (
        cat "''${target_path}";
        $jq -r '.. | .keyCommand? | select(. != null) | map("\"\(.)\"") | join(" ")' <"''${target_path}" | bash | $jq -R
    ) | $jq -c 'walk(if type == "object" and .keyCommand? then input else . end)' > "iot-build/''${target}.yaml"
  done

  ${pkgs.esphome}/bin/esphome $cmd iot-build/*.yaml
''