/**
 * Copyright 2025 Google LLC
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import { GenkitError } from 'genkit';

/**
 * Gets the model name without certain prefixes..
 * e.g. for "models/googleai/gemini-2.5-pro" it returns just 'gemini-2.5-pro'
 * @param name A string containing the model string with possible prefixes
 * @returns the model string stripped of certain prefixes
 */
export function modelName(name?: string): string | undefined {
  if (!name) return name;

  // Remove any of these prefixes:
  const prefixesToRemove =
    /background-model\/|model\/|models\/|embedders\/|vertex-model-garden\/|vertexai\//g;
  return name.replace(prefixesToRemove, '');
}

/**
 * Gets the suffix of a model string.
 * Throws if the string is empty.
 * @param name A string containing the model string
 * @returns the model string stripped of prefixes and guaranteed not empty.
 */
export function checkModelName(name?: string): string {
  const version = modelName(name);
  if (!version) {
    throw new GenkitError({
      status: 'INVALID_ARGUMENT',
      message: 'Model name is required.',
    });
  }
  return version;
}