// Copyright (c) Microsoft Corporation. All rights reserved.
// Licensed under the MIT License.

import { Graph } from '../../../graph';
import { OperatorImplementation, OperatorInitialization } from '../../../operators';
import { Tensor } from '../../../tensor';
import { ProtoUtil } from '../../../util';
import { WebGLInferenceHandler } from '../inference-handler';

export const cast: OperatorImplementation<Tensor.DataType> = (
  handler: WebGLInferenceHandler,
  inputs: Tensor[],
  to: Tensor.DataType,
): Tensor[] => {
  validateInputs(inputs);
  return [handler.cast(inputs[0], to)];
};

export const parseCastAttributes: OperatorInitialization<Tensor.DataType> = (node: Graph.Node): Tensor.DataType =>
  ProtoUtil.tensorDataTypeFromProto(node.attributes.getInt('to'));

const validateInputs = (inputs: Tensor[]): void => {
  if (!inputs || inputs.length !== 1) {
    throw new Error('Cast requires 1 input.');
  }

  if (inputs[0].type === 'string') {
    throw new Error('Invalid input type.');
  }
};