import { TNetInput } from 'tfjs-image-recognition-base';
import { TinyYolov2Options } from 'tfjs-tiny-yolov2';

import { FaceDetection } from '../classes/FaceDetection';
import { extendWithFaceDetection, WithFaceDetection } from '../factories/WithFaceDetection';
import { MtcnnOptions } from '../mtcnn/MtcnnOptions';
import { SsdMobilenetv1Options } from '../ssdMobilenetv1/SsdMobilenetv1Options';
import { TinyFaceDetectorOptions } from '../tinyFaceDetector/TinyFaceDetectorOptions';
import { ComposableTask } from './ComposableTask';
import { DetectAllFaceLandmarksTask, DetectSingleFaceLandmarksTask } from './DetectFaceLandmarksTasks';
import { nets } from './nets';
import { FaceDetectionOptions } from './types';
import { PredictAllFaceExpressionsTask, PredictSingleFaceExpressionTask } from './PredictFaceExpressionsTask';

export class DetectFacesTaskBase<TReturn> extends ComposableTask<TReturn> {
  constructor(
    protected input: TNetInput,
    protected options: FaceDetectionOptions = new SsdMobilenetv1Options()
  ) {
    super()
  }
}

export class DetectAllFacesTask extends DetectFacesTaskBase<FaceDetection[]> {

  public async run(): Promise<FaceDetection[]> {

    const { input, options } = this

    if (options instanceof MtcnnOptions) {
      return (await nets.mtcnn.forward(input, options))
        .map(result => result.detection)
    }

    const faceDetectionFunction = options instanceof TinyFaceDetectorOptions
      ? (input: TNetInput) => nets.tinyFaceDetector.locateFaces(input, options)
      : (
        options instanceof SsdMobilenetv1Options
          ? (input: TNetInput) => nets.ssdMobilenetv1.locateFaces(input, options)
          : (
            options instanceof TinyYolov2Options
              ? (input: TNetInput) => nets.tinyYolov2.locateFaces(input, options)
              : null
          )
      )

    if (!faceDetectionFunction) {
      throw new Error('detectFaces - expected options to be instance of TinyFaceDetectorOptions | SsdMobilenetv1Options | MtcnnOptions | TinyYolov2Options')
    }

    return faceDetectionFunction(input)
  }

  private runAndExtendWithFaceDetections(): Promise<WithFaceDetection<{}>[]> {
    return new Promise<WithFaceDetection<{}>[]>(async res => {
      const detections = await this.run()
      return res(detections.map(detection => extendWithFaceDetection({}, detection)))
    })
  }

  withFaceLandmarks(useTinyLandmarkNet: boolean = false): DetectAllFaceLandmarksTask<WithFaceDetection<{}>> {
    return new DetectAllFaceLandmarksTask<WithFaceDetection<{}>>(
      this.runAndExtendWithFaceDetections(),
      this.input,
      useTinyLandmarkNet
    )
  }

  withFaceExpressions(): PredictAllFaceExpressionsTask<WithFaceDetection<{}>> {
    return new PredictAllFaceExpressionsTask<WithFaceDetection<{}>>(
      this.runAndExtendWithFaceDetections(),
      this.input
    )
  }
}

export class DetectSingleFaceTask extends DetectFacesTaskBase<FaceDetection | undefined> {

  public async run(): Promise<FaceDetection | undefined> {
    const faceDetections = await new DetectAllFacesTask(this.input, this.options);
    let faceDetectionWithHighestScore = faceDetections[0];
    faceDetections.forEach(faceDetection => {
      if (faceDetection.score > faceDetectionWithHighestScore.score) {
        faceDetectionWithHighestScore = faceDetection;
      }
    });
    return faceDetectionWithHighestScore;
  }

  private runAndExtendWithFaceDetection(): Promise<WithFaceDetection<{}>> {
    return new Promise<WithFaceDetection<{}>>(async res => {
      const detection = await this.run()
      return detection ? res(extendWithFaceDetection<{}>({}, detection)) : null
    })
  }

  withFaceLandmarks(useTinyLandmarkNet: boolean = false): DetectSingleFaceLandmarksTask<WithFaceDetection<{}>> {
    return new DetectSingleFaceLandmarksTask<WithFaceDetection<{}>>(
      this.runAndExtendWithFaceDetection(),
      this.input,
      useTinyLandmarkNet
    )
  }

  withFaceExpression(): PredictSingleFaceExpressionTask<WithFaceDetection<{}>> {
    return new PredictSingleFaceExpressionTask<WithFaceDetection<{}>>(
      this.runAndExtendWithFaceDetection(),
      this.input
    )
  }

}