interface ModelRuntimeLike {
  modelId?: string | null;
  defaultParams?: unknown;
}

interface ResolveModelRuntimeIdOptions {
  overrideModelId?: string | null;
  providerType?: string | null;
}

function fallbackRuxaRuntimeId(modelId: string) {
  if (!modelId.startsWith("google/")) {
    return modelId;
  }

  const candidate = modelId.slice("google/".length).trim();
  return candidate || modelId;
}

function toRecord(value: unknown): Record<string, unknown> | null {
  if (typeof value !== "object" || value === null || Array.isArray(value)) {
    return null;
  }
  return value as Record<string, unknown>;
}

function normalizeRuntimeModelId(value: unknown): string | null {
  if (typeof value !== "string") return null;
  const normalized = value.trim();
  return normalized || null;
}

export function resolveModelRuntimeId(
  model: ModelRuntimeLike | null | undefined,
  options?: ResolveModelRuntimeIdOptions,
): string {
  const overrideModelId = normalizeRuntimeModelId(options?.overrideModelId);
  if (overrideModelId) {
    return overrideModelId;
  }

  const defaultParams = toRecord(model?.defaultParams);
  const endpointModelId = normalizeRuntimeModelId(defaultParams?.endpoint);
  if (endpointModelId) {
    return endpointModelId;
  }

  const resolvedModelId = normalizeRuntimeModelId(model?.modelId) || "";
  if (options?.providerType === "ruxa-image") {
    return fallbackRuxaRuntimeId(resolvedModelId);
  }

  return resolvedModelId;
}