/*
 * SPDX-License-Identifier: Apache-2.0
 *
 * The OpenSearch Contributors require contributions made to
 * this file be licensed under the Apache-2.0 license or a
 * compatible open source license.
 *
 * Modifications Copyright OpenSearch Contributors. See
 * GitHub history for details.
 */

import { useState, useEffect } from 'react';
import { useDispatch } from 'react-redux';
import { DetectorListItem } from '../../../models/interfaces';
import {
  AD_DOC_FIELDS,
  MIN_IN_MILLI_SECS,
} from '../../../../server/utils/constants';
import {
  EuiBadge,
  EuiButton,
  EuiCallOut,
  EuiFlexGroup,
  EuiFlexItem,
  EuiLoadingChart,
  //@ts-ignore
  EuiStat,
} from '@elastic/eui';
import { get, isEmpty } from 'lodash';
import moment, { Moment } from 'moment';
import ContentPanel from '../../../components/ContentPanel/ContentPanel';
import {
  Chart,
  Axis,
  Settings,
  Position,
  BarSeries,
  niceTimeFormatter,
  ScaleType,
  LineAnnotation,
  AnnotationDomainType,
  LineAnnotationDatum,
} from '@elastic/charts';
import { EuiText, EuiTitle } from '@elastic/eui';
import React from 'react';
import { TIME_NOW_LINE_STYLE } from '../utils/constants';
import { SHOW_DECIMAL_NUMBER_THRESHOLD } from '../../../../server/utils/helpers';
import {
  visualizeAnomalyResultForXYChart,
  getFloorPlotTime,
  getLatestAnomalyResultsForDetectorsByTimeRange,
  getLatestAnomalyResultsByTimeRange,
} from '../utils/utils';
import { MAX_ANOMALIES, SPACE_STR } from '../../../utils/constants';
import { ALL_CUSTOM_AD_RESULT_INDICES } from '../../utils/constants';
import { searchResults } from '../../../redux/reducers/anomalyResults';

export interface AnomaliesLiveChartProps {
  selectedDetectors: DetectorListItem[];
}

interface LiveTimeRangeState {
  startDateTime: Moment;
  endDateTime: Moment;
}

const MAX_LIVE_DETECTORS = 10;

export const AnomaliesLiveChart = (props: AnomaliesLiveChartProps) => {
  const dispatch = useDispatch();

  const [liveTimeRange, setLiveTimeRange] = useState<LiveTimeRangeState>({
    startDateTime: moment().subtract(31, 'minutes'),
    endDateTime: moment(),
  });

  const [lastAnomalyResult, setLastAnomalyResult] = useState<object>();

  const [liveAnomalyData, setLiveAnomalyData] = useState([] as object[]);

  const [isFullScreen, setIsFullScreen] = useState(false);

  const [isLoadingAnomalies, setIsLoadingAnomalies] = useState(true);

  const [hasLatestAnomalyResult, setHasLatestAnomalyResult] = useState(true);

  const [latestAnomalousDetectorsCount, setLatestLiveAnomalousDetectorsCount] =
    useState(0);

  const getLiveAnomalyResults = async () => {
    setIsLoadingAnomalies(true);
    // check if there is any anomaly result in last 30mins
    // need to initially check if there is an error when accessing anomaly results index
    // in the case that it doesn't exist upon cluster initialization
    let latestSingleLiveAnomalyResult = [] as any[];
    try {
      latestSingleLiveAnomalyResult = await getLatestAnomalyResultsByTimeRange(
        searchResults,
        '30m',
        dispatch,
        -1,
        1,
        true,
        ALL_CUSTOM_AD_RESULT_INDICES,
        false
      );
    } catch (err) {
      console.log(
        'Error getting latest anomaly results - index may not exist yet',
        err
      );
      setIsLoadingAnomalies(false);
    }

    setHasLatestAnomalyResult(!isEmpty(latestSingleLiveAnomalyResult));

    // get anomalies(anomaly_grade>0) in last 30mins
    const latestLiveAnomalyResult =
      await getLatestAnomalyResultsForDetectorsByTimeRange(
        searchResults,
        props.selectedDetectors,
        '30m',
        dispatch,
        0,
        MAX_ANOMALIES,
        MAX_LIVE_DETECTORS,
        false,
        ALL_CUSTOM_AD_RESULT_INDICES,
        false
      );
    setLiveAnomalyData(latestLiveAnomalyResult);

    setLatestLiveAnomalousDetectorsCount(
      new Set(
        latestLiveAnomalyResult.map((anomalyData) =>
          get(anomalyData, AD_DOC_FIELDS.DETECTOR_ID, '')
        )
      ).size
    );

    if (!isEmpty(latestLiveAnomalyResult)) {
      setLastAnomalyResult(latestLiveAnomalyResult[0]);
    } else {
      setLastAnomalyResult(undefined);
    }

    setLiveTimeRange({
      startDateTime: moment().subtract(31, 'minutes'),
      endDateTime: moment(),
    });
    setIsLoadingAnomalies(false);
  };

  useEffect(() => {
    getLiveAnomalyResults();
    const id = setInterval(getLiveAnomalyResults, MIN_IN_MILLI_SECS);
    return () => {
      clearInterval(id);
    };
  }, [props.selectedDetectors]);

  const timeFormatter = niceTimeFormatter([
    liveTimeRange.startDateTime.valueOf(),
    liveTimeRange.endDateTime.valueOf(),
  ]);

  const visualizedAnomalies = liveAnomalyData.flatMap((anomalyResult) =>
    visualizeAnomalyResultForXYChart(anomalyResult)
  );
  const prepareVisualizedAnomalies = (
    liveVisualizedAnomalies: object[]
  ): object[] => {
    // add data point placeholder at every minute,
    // to ensure chart evenly distrubted
    const existingPlotTimes = liveVisualizedAnomalies.map((anomaly) =>
      getFloorPlotTime(get(anomaly, AD_DOC_FIELDS.PLOT_TIME, 0))
    );
    const result = [...liveVisualizedAnomalies];

    for (
      let currentTime = getFloorPlotTime(liveTimeRange.startDateTime.valueOf());
      currentTime <= liveTimeRange.endDateTime.valueOf();
      currentTime += MIN_IN_MILLI_SECS
    ) {
      if (existingPlotTimes.includes(currentTime)) {
        continue;
      }
      result.push({
        [AD_DOC_FIELDS.DETECTOR_NAME]: !isEmpty(liveAnomalyData)
          ? ''
          : SPACE_STR,
        [AD_DOC_FIELDS.PLOT_TIME]: currentTime,
        [AD_DOC_FIELDS.ANOMALY_GRADE]: null,
      });
    }
    return result;
  };

  const timeNowAnnotation = {
    dataValue: getFloorPlotTime(liveTimeRange.endDateTime.valueOf()),
    header: 'Now',
    details: liveTimeRange.endDateTime.format('MM/DD/YY h:mm A'),
  } as LineAnnotationDatum;

  const annotations = [timeNowAnnotation];

  const fullScreenButton = () => (
    <EuiButton
      onClick={() => setIsFullScreen((isFullScreen) => !isFullScreen)}
      iconType={isFullScreen ? 'exit' : 'fullScreen'}
      aria-label="View full screen"
      data-test-subj="dashboardFullScreenButton"
    >
      {isFullScreen ? 'Exit full screen' : 'View full screen'}
    </EuiButton>
  );

  return (
    <ContentPanel
      title={
        <EuiTitle size="s" data-test-subj="dashboardLiveAnomaliesHeader">
          <h3>
            Live anomalies{' '}
            <EuiBadge color={hasLatestAnomalyResult ? '#DB1374' : '#DDD'}>
              Live
            </EuiBadge>
          </h3>
        </EuiTitle>
      }
      subTitle={`Live anomaly results across detectors for the last 30 minutes.  
                'The results refresh every 1 minute. 
                'For each detector, if an anomaly occurrence is detected at the end of the detector interval, 
                'you will see a bar representing its anomaly grade.`}
      actions={[fullScreenButton()]}
      contentPanelClassName={isFullScreen ? 'full-screen' : undefined}
    >
      {isLoadingAnomalies ? (
        <EuiFlexGroup
          justifyContent="center"
          style={{ height: '353px', paddingTop: '175px' }}
        >
          <EuiFlexItem grow={false}>
            <EuiLoadingChart size="xl" />
          </EuiFlexItem>
        </EuiFlexGroup>
      ) : !hasLatestAnomalyResult ? (
        <EuiText
          style={{
            color: '#666666',
            paddingTop: '12px',
            paddingBottom: '4px',
          }}
        >
          <p>
            All matching detectors are under initialization or stopped for the
            last 30 minutes. Please adjust filters or come back later.
          </p>
        </EuiText>
      ) : (
        // show below content as long as there exists anomaly data,
        // regardless of whether anomaly grade is 0 or larger.
        [
          <EuiFlexGroup>
            <EuiFlexItem style={{ minWidth: '200px' }}>
              <EuiStat
                description={'Last updated time'}
                title={liveTimeRange.endDateTime.format('MM/DD/YYYY hh:mm A')}
                titleSize="s"
              />
            </EuiFlexItem>
            <EuiFlexItem style={{ minWidth: '310px' }}>
              <EuiStat
                description={'Detector with the most recent anomaly'}
                title={
                  lastAnomalyResult === undefined
                    ? '-'
                    : get(lastAnomalyResult, AD_DOC_FIELDS.DETECTOR_NAME, '')
                }
                titleSize="s"
              />
            </EuiFlexItem>
            <EuiFlexItem style={{ minWidth: '185px' }}>
              <EuiStat
                description={'Most recent anomaly grade'}
                title={
                  lastAnomalyResult === undefined
                    ? '-'
                    : get(lastAnomalyResult, AD_DOC_FIELDS.ANOMALY_GRADE, 0) <
                      SHOW_DECIMAL_NUMBER_THRESHOLD
                    ? Number(
                        get(lastAnomalyResult, AD_DOC_FIELDS.ANOMALY_GRADE, 0)
                      ).toExponential(2)
                    : Number(
                        get(lastAnomalyResult, AD_DOC_FIELDS.ANOMALY_GRADE, 0)
                      ).toFixed(2)
                }
                titleSize="s"
              />
            </EuiFlexItem>
          </EuiFlexGroup>,
          <div>
            {[
              // only show below message when anomalousDetectorCount >= MAX_LIVE_DETECTORS
              latestAnomalousDetectorsCount >= MAX_LIVE_DETECTORS ? (
                <EuiCallOut
                  size="s"
                  title={`You are viewing ${MAX_LIVE_DETECTORS} detectors with the most recent anomaly occurrences.`}
                  style={{
                    width: '88%', // ensure width reaches NOW annotation line
                    marginTop: '20px',
                    marginBottom: '20px',
                  }}
                >
                  <p>
                    {`${MAX_LIVE_DETECTORS} detectors with the most recent anomalies are shown on the
                    chart. Adjust filters if there are specific detectors you
                    would like to monitor.`}
                  </p>
                </EuiCallOut>
              ) : latestAnomalousDetectorsCount === 0 ? (
                // all the data points have anomaly grade as 0
                <EuiCallOut
                  color="success"
                  size="s"
                  title="No anomalies found during the last 30 minutes across all matching detectors."
                  style={{
                    width: '96%', // ensure width reaches NOW line
                    marginTop: '20px',
                    marginBottom: '20px',
                  }}
                />
              ) : null,
              <div
                style={{
                  height: isFullScreen ? '400px' : '200px',
                  width: '100%',
                  opacity: 1,
                }}
              >
                <Chart>
                  <Settings
                    // hide legend if there only exists anomalies with 0 anomaly grade
                    showLegend={!isEmpty(liveAnomalyData)}
                    legendPosition={Position.Right}
                    //TODO: research more why only set this old property will work.
                    showLegendExtra={false}
                    showLegendDisplayValue={false}
                    xDomain={{
                      min: liveTimeRange.startDateTime.valueOf(),
                      max: liveTimeRange.endDateTime.valueOf(),
                    }}
                  />
                  <LineAnnotation
                    id={'lineAnnotation'}
                    domainType={AnnotationDomainType.XDomain}
                    dataValues={annotations}
                    style={TIME_NOW_LINE_STYLE}
                    marker={'Now'}
                  />
                  <Axis
                    id={'bottom'}
                    position={Position.Bottom}
                    tickFormat={timeFormatter}
                    showOverlappingTicks={false}
                  />
                  <Axis
                    id={'left'}
                    title={'Anomaly grade'}
                    position={Position.Left}
                    domain={{ min: 0, max: 1 }}
                  />
                  <BarSeries
                    id={'Detector Anomaly grade'}
                    xScaleType={ScaleType.Time}
                    timeZone="local"
                    yScaleType="linear"
                    xAccessor={AD_DOC_FIELDS.PLOT_TIME}
                    yAccessors={[AD_DOC_FIELDS.ANOMALY_GRADE]}
                    splitSeriesAccessors={[AD_DOC_FIELDS.DETECTOR_NAME]}
                    data={prepareVisualizedAnomalies(visualizedAnomalies)}
                  />
                </Chart>
              </div>,
            ]}
          </div>,
        ]
      )}
    </ContentPanel>
  );
};