/**
 * @license
 * Copyright 2021 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 {TaskModel} from '../../task_model';
import {Class} from '../common';

/**
 * The base class for all ObjectDetection task models.
 *
 * @template IO The type of options used during the inference process. Different
 *     models have different inference options. See individual model for more
 *     details.
 *
 * @doc {heading: 'Object Detection', subheading: 'Base model'}
 */
export abstract class ObjectDetector<IO> implements TaskModel {
  /**
   * Detects objects on the given image-like input, and returns result.
   *
   * @param img The image-like element to detect objects on.
   * @param options Inference options. Different models have different
   *     inference options. See individual model for more details.
   * @returns
   *
   * @docunpackreturn ['ObjectDetectionResult', 'DetectedObject', 'BoundingBox',
   * 'Class']
   * @doc {heading: 'Object Detection', subheading: 'Base model'}
   */
  abstract predict(
      img: ImageData|HTMLImageElement|HTMLCanvasElement|HTMLVideoElement,
      options?: IO): Promise<ObjectDetectionResult>;

  /**
   * Cleans up resources if needed.
   *
   * @doc {heading: 'Object Detection', subheading: 'Base model'}
   */
  cleanUp() {}
}

/** Object detection result. */
export interface ObjectDetectionResult {
  /** All detected objects. */
  objects: DetectedObject[];
}

/** A single detected object. */
export interface DetectedObject extends Class {
  /** The bounding box of the object. */
  boundingBox: BoundingBox;
}

/** A bounding box for the detected object. */
export interface BoundingBox {
  /** The X coordinate of the top-left corner of the bounding box. */
  originX: number;
  /** The Y coordinate of the top-left corner of the bounding box. */
  originY: number;
  /** The width of bounding box. */
  width: number;
  /** The height of bounding box. */
  height: number;
}