/**
 * 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 type TViewData from '../../common/TViewData';
import {
  type Indicator,
  type IndicatorTemplate,
} from '../../component/Indicator';

interface Emv {
  emv?: number;
  maEmv?: number;
}

/**
 *
 * EMV 简易波动指标
 * 公式：
 * A=（今日最高+今日最低）/2
 * B=（前日最高+前日最低）/2
 * C=今日最高-今日最低
 * EM=（A-B）*C/今日成交额
 * EMV=N日内EM的累和
 * MAEMV=EMV的M日的简单移动平均
 *
 */
const easeOfMovementValue: IndicatorTemplate<Emv> = {
  name: 'EMV',
  shortName: 'EMV',
  calcParams: [14, 9],
  figures: [
    { key: 'emv', title: 'EMV: ', type: 'line' },
    { key: 'maEmv', title: 'MAEMV: ', type: 'line' },
  ],
  calc: (dataList: TViewData[], indicator: Indicator<Emv>) => {
    const params = indicator.calcParams as number[];
    let emvValueSum = 0;
    const emvValueList: number[] = [];
    return dataList.map((TViewData: TViewData, i: number) => {
      const emv: Emv = {};
      if (i > 0) {
        const prevTViewData = dataList[i - 1];
        const high = TViewData.high;
        const low = TViewData.low;
        const volume = TViewData.volume ?? 0;
        const distanceMoved =
          (high + low) / 2 - (prevTViewData.high + prevTViewData.low) / 2;

        if (volume === 0 || high - low === 0) {
          emv.emv = 0;
        } else {
          const ratio = volume / 100000000 / (high - low);
          emv.emv = distanceMoved / ratio;
        }
        emvValueSum += emv.emv;
        emvValueList.push(emv.emv);
        if (i >= params[0]) {
          emv.maEmv = emvValueSum / params[0];
          emvValueSum -= emvValueList[i - params[0]];
        }
      }
      return emv;
    });
  },
};

export default easeOfMovementValue;