# Trusted host construction only. Authored Workers cannot choose the caller,
# reserved identities, engine directory or sandbox executable.
{
  pkgs,
  sandbox,
  authorityUser ? "quixos-graph",
  engineDirectory ? "/run/quixos-restricted-engines",
  firstUid ? 610000,
  identityCount ? 64,
}:
assert builtins.match "[a-z][a-z0-9_-]{0,63}" authorityUser != null;
assert builtins.match "/run/[a-zA-Z0-9_/-]+" engineDirectory != null;
assert !(pkgs.lib.hasInfix ".." engineDirectory);
assert !(pkgs.lib.hasSuffix "/" engineDirectory);
assert builtins.isInt firstUid && builtins.isInt identityCount;
assert firstUid >= 610000 && firstUid + identityCount <= 2147483647;
assert identityCount >= 1 && identityCount <= 64;
pkgs.runCommand "quixos-restricted-identity-launcher"
  {
    nativeBuildInputs = [
      pkgs.stdenv.cc
      pkgs.nodejs_24
    ];
    QUIXOS_RESTRICTED_ENGINE_DIRECTORY = engineDirectory;
  }
  ''
    # Validate the complete generated filename with the shared UTF-8 policy,
    # before compiling or installing a launcher for this configured /run root.
    node --input-type=module <<'JS'
    import { checkedSocketPath } from '${../socket-address.mjs}';
    for (const filename of ["broker.sock", "engine.sock"])
      checkedSocketPath(process.env.QUIXOS_RESTRICTED_ENGINE_DIRECTORY + "/qx-engine-XXXXXX/" + filename);
    JS
    mkdir -p "$out/bin"
    $CC -O2 -Wall -Wextra -Werror ${./identity-launcher.c} \
      -DSANDBOX_EXECUTABLE='"${sandbox}/bin/quixos-restricted-sandbox"' \
      -DAUTHORITY_USER='"${authorityUser}"' \
      -DENGINE_DIRECTORY='"${engineDirectory}"' \
      -DENGINE_FIRST_UID=${toString firstUid} \
      -DENGINE_IDENTITY_COUNT=${toString identityCount} \
      -o "$out/bin/quixos-restricted-engine"
  ''