export interface AppConfig {
  host: string; port: number; harnessDir: string; thtBin: string; piBin: string;
  authMode: "none" | "mock" | "upstream";
  defaults: { provider?: string; model?: string; thinking?: string };
  maxPiProcesses: number;
  settingsFile: string;
  dataRoot?: string;
  ollamaEnsureTimeoutMs: number;
}
export function loadConfig(env: Record<string, string | undefined>): AppConfig {
  const authMode = env.AUTH_MODE ?? "none";
  if (!(["none", "mock", "upstream"] as const).includes(authMode as AppConfig["authMode"])) {
    throw new Error(`unsupported AUTH_MODE=${authMode}; use none, mock, or upstream`);
  }
  if (env.THOTH_PUBLIC_EXPOSURE === "true" && authMode !== "upstream") {
    throw new Error("public exposure requires AUTH_MODE=upstream behind a trusted proxy");
  }
  return {
    host: env.HOST ?? "127.0.0.1",
    port: Number(env.PORT ?? 8787),
    harnessDir: env.THT_HARNESS_DIR ?? "../harness",
    thtBin: env.THT_BIN ?? "tht",
    piBin: env.PI_BIN ?? "pi",
    authMode: authMode as AppConfig["authMode"],
    defaults: { provider: env.PI_PROVIDER, model: env.PI_MODEL, thinking: env.PI_THINKING },
    maxPiProcesses: Number(env.MAX_PI_PROCESSES ?? 4),
    settingsFile: env.SETTINGS_FILE ?? "data/settings.json",
    dataRoot: env.THT_DATA_ROOT,
    ollamaEnsureTimeoutMs: Number(env.OLLAMA_ENSURE_TIMEOUT_MS ?? 60000),
  };
}