export const PLAY_RUNTIME_BACKENDS = {
  localProcess: 'local_process',
  daytona: 'daytona',
  modal: 'modal',
} as const;

export type PlayRuntimeBackendId =
  (typeof PLAY_RUNTIME_BACKENDS)[keyof typeof PLAY_RUNTIME_BACKENDS];

/**
 * The one executable Play artifact contract. Daytona and local-process both
 * load CommonJS under Node 20.
 */
export const PLAY_ARTIFACT_KINDS = {
  cjsNode20: 'cjs_node20',
} as const;

export type PlayArtifactKind =
  (typeof PLAY_ARTIFACT_KINDS)[keyof typeof PLAY_ARTIFACT_KINDS];

export type PlayBackendDescriptor = {
  id: PlayRuntimeBackendId;
  /** What artifact kind this backend's runner consumes. */
  artifactKind: PlayArtifactKind;
  /** Human label for logs. */
  label: string;
};

export const PLAY_BACKEND_DESCRIPTORS: Record<
  PlayRuntimeBackendId,
  PlayBackendDescriptor
> = {
  [PLAY_RUNTIME_BACKENDS.localProcess]: {
    id: PLAY_RUNTIME_BACKENDS.localProcess,
    artifactKind: PLAY_ARTIFACT_KINDS.cjsNode20,
    label: 'Local node subprocess',
  },
  [PLAY_RUNTIME_BACKENDS.daytona]: {
    id: PLAY_RUNTIME_BACKENDS.daytona,
    artifactKind: PLAY_ARTIFACT_KINDS.cjsNode20,
    label: 'Daytona sandbox',
  },
  [PLAY_RUNTIME_BACKENDS.modal]: {
    id: PLAY_RUNTIME_BACKENDS.modal,
    artifactKind: PLAY_ARTIFACT_KINDS.cjsNode20,
    label: 'Modal sandbox',
  },
};

export function describePlayBackend(
  id: PlayRuntimeBackendId,
): PlayBackendDescriptor {
  return PLAY_BACKEND_DESCRIPTORS[id];
}

export function artifactKindForBackend(
  id: PlayRuntimeBackendId,
): PlayArtifactKind {
  return PLAY_BACKEND_DESCRIPTORS[id].artifactKind;
}

export function normalizePlayRuntimeBackend(
  value?: string | null,
): PlayRuntimeBackendId {
  const normalized = value?.trim().toLowerCase();
  if (!normalized) {
    return defaultPlayRuntimeBackend();
  }

  if (normalized === PLAY_RUNTIME_BACKENDS.daytona) {
    return PLAY_RUNTIME_BACKENDS.daytona;
  }

  if (normalized === PLAY_RUNTIME_BACKENDS.modal) {
    return PLAY_RUNTIME_BACKENDS.modal;
  }

  if (normalized === PLAY_RUNTIME_BACKENDS.localProcess) {
    return PLAY_RUNTIME_BACKENDS.localProcess;
  }

  throw new Error(
    `Unsupported play runtime backend "${normalized}". Expected one of: ${Object.values(
      PLAY_RUNTIME_BACKENDS,
    ).join(', ')}.`,
  );
}

export function defaultPlayRuntimeBackend(input?: {
  deeplineEnv?: string | null;
  vercelEnv?: string | null;
  nodeEnv?: string | null;
  previewPlaysDeployment?: boolean;
}): PlayRuntimeBackendId {
  if (input?.previewPlaysDeployment) {
    return PLAY_RUNTIME_BACKENDS.daytona;
  }

  const candidates = [
    input?.deeplineEnv ?? process.env.DEEPLINE_ENV,
    input?.vercelEnv ?? process.env.VERCEL_ENV,
    input?.nodeEnv ?? process.env.NODE_ENV,
  ]
    .filter(Boolean)
    .map((value) => String(value).trim().toLowerCase());

  for (const value of candidates) {
    if (
      value === 'production' ||
      value === 'prod' ||
      value === 'live' ||
      value === 'preview' ||
      value === 'staging' ||
      value === 'stage'
    ) {
      return PLAY_RUNTIME_BACKENDS.daytona;
    }
  }

  return PLAY_RUNTIME_BACKENDS.localProcess;
}

export function isPlayRuntimeBackendId(
  value: unknown,
): value is PlayRuntimeBackendId {
  return (
    typeof value === 'string' &&
    Object.values(PLAY_RUNTIME_BACKENDS).includes(value as PlayRuntimeBackendId)
  );
}

export function isManagedSandboxRuntimeBackend(
  value: string | null | undefined,
): boolean {
  return (
    value === PLAY_RUNTIME_BACKENDS.daytona ||
    value === PLAY_RUNTIME_BACKENDS.modal
  );
}