/**
 * @license
 * Copyright 2020 Google LLC. All Rights Reserved.
 * 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 {Tensor} from '../tensor';
import {convertToTensor} from '../tensor_util_env';
import {TensorLike} from '../types';
import {squeezeShape} from '../util';

import {op} from './operation';
import {reshape} from './reshape';

/**
 * Removes dimensions of size 1 from the shape of a `tf.Tensor`.
 *
 * ```js
 * const x = tf.tensor([1, 2, 3, 4], [1, 1, 4]);
 * x.squeeze().print();
 * ```
 *
 * @param x The input tensor to be squeezed.
 * @param axis An optional list of numbers. If specified, only
 *     squeezes the dimensions listed. The dimension index starts at 0. It
 * is an error to squeeze a dimension that is not 1.
 *
 * @doc {heading: 'Tensors', subheading: 'Transformations'}
 */
function squeeze_<T extends Tensor>(x: Tensor|TensorLike, axis?: number[]): T {
  const $x = convertToTensor(x, 'x', 'squeeze');
  return reshape($x, squeezeShape($x.shape, axis).newShape) as T;
}

export const squeeze = op({squeeze_});