/**
 * 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 IndicatorTemplate } from '../../component/Indicator';

interface Pvt {
  pvt?: number;
}

/**
 * 价量趋势指标
 * 公式:
 * X = (CLOSE - REF(CLOSE, 1)) / REF(CLOSE, 1) * VOLUME
 * PVT = SUM(X)
 *
 */
const priceAndVolumeTrend: IndicatorTemplate<Pvt> = {
  name: 'PVT',
  shortName: 'PVT',
  figures: [{ key: 'pvt', title: 'PVT: ', type: 'line' }],
  calc: (dataList: TViewData[]) => {
    let sum = 0;
    return dataList.map((TViewData, i) => {
      const pvt: Pvt = {};
      const close = TViewData.close;
      const volume = TViewData.volume ?? 1;
      const prevClose = (dataList[i - 1] ?? TViewData).close;
      let x = 0;
      const total = prevClose * volume;
      if (total !== 0) {
        x = (close - prevClose) / total;
      }
      sum += x;
      pvt.pvt = sum;
      return pvt;
    });
  },
};

export default priceAndVolumeTrend;