src/hooks/useGetVariable.js

import { useMemo } from 'react'
import { useSelector } from 'react-redux'
import {
    findIn,
    getDateLists,
    getDataForBins,
    getFetchParams,
    findSecondaryMonth,
    getClosestIndex,
    onlyUniqueArray,
} from '../utils'
import useGetTable from './useGetTable'
import { paramsSelectors } from '../stores/paramsStore'
import { dataSelectors } from '../stores/dataStore'
const { selectGeojsonData } = dataSelectors
const {
    selectCurrentData,
    selectDataParams,
    selectDatasets,
    selectTables,
    selectVariables,
} = paramsSelectors
const dateLists = getDateLists()

/**
 * Hook to get a variable, returning a 1 dimensional array of values. Arguments
 * use predefined variable names, dataset selection, and date index.
 *
 * @category Hooks
 * @param {Object} props
 * @param {string} props.variable - Name of the variable to get data for
 * @param {string} props.dataset - Name of the geojson dataset to use when using
 *   a multi-dataset variable (cases and deaths)
 * @param {number} props.dateIndex - Index of the date to use -- days since
 *   01/21/2020
 * @returns {Array} - A 1 dimensional array of data for the variable, ordered by
 *   the geojson features
 */
function useGetVariable({
    variable,
    // priorityLoad = false,
    dataset = false,
    dateIndex = false,
}) {
    const canLoadInBackground = useSelector(
        ({ data }) => data.canLoadInBackground
    )
    // pieces of redux state
    const stateDataset = useSelector(selectCurrentData)
    const currentData = dataset || stateDataset
    const geojsonData = useSelector(selectGeojsonData(currentData))
    const dataParams = useSelector(selectDataParams)
    const datasets = useSelector(selectDatasets)
    const tables = useSelector(selectTables)
    const variables = useSelector(selectVariables)
    // current state data params

    const params = findIn(variables, 'variableName', variable)
    const currDataset = findIn(datasets, 'file', currentData)

    const [nIsTimeSeries, dIsTimeSeries] = [
        params?.nType && params.nType.includes('time'),
        params?.dType && params.dType.includes('time'),
    ]
    const isTimeSeries = nIsTimeSeries || dIsTimeSeries

    const [defaultNumeratorParams, defaultDenominatorParams] = [
        params,
        params,
    ].map((dataParams, i) =>
        getFetchParams({
            dataParams,
            tables,
            currDataset,
            predicate: i === 1 ? 'denominator' : 'numerator',
            dateList: dateLists['isoDateList'],
        })
    )

    const currIndex = isTimeSeries
        ? getClosestIndex(
              dateIndex || dataParams.nIndex || dataParams.dIndex,
              defaultNumeratorParams.name || ''
          ) || 30
        : null
    const currRangeIndex = currIndex - (dataParams.nRange || dataParams.dRange)
    const currTimespans = [currIndex, currRangeIndex]
        .map((index) => [
            !currIndex || dateLists.isoDateList.length - index < 30
                ? 'latest'
                : dateLists.isoDateList[index]?.slice(0, 7),
            !currIndex || dateLists.isoDateList.length - index < 30
                ? false
                : findSecondaryMonth(index, dateLists.isoDateList),
        ])
        .flat()
        .filter((f) => !!f)
        .filter(onlyUniqueArray)
    const fetchParams = [defaultNumeratorParams, defaultDenominatorParams].map(
        (params) =>
            currTimespans.map((timespan, i) => ({
                ...params,
                timespan,
            }))
    )

    const [[numData, numReady], [denData, denReady]] = [
        useGetTable({
            filesToFetch: fetchParams[0],
            shouldFetch: canLoadInBackground,
            dateLists,
        }),
        useGetTable({
            filesToFetch: fetchParams[1],
            shouldFetch: canLoadInBackground,
            dateLists,
        }),
    ]

    const data = useMemo(
        () =>
            getDataForBins({
                numeratorData:
                    params.numerator === 'properties'
                        ? geojsonData?.properties
                        : numData?.data,
                denominatorData:
                    params.denominator === 'properties'
                        ? geojsonData?.properties
                        : denData?.data,
                dataParams: params,
                binIndex: currIndex,
                fixedOrder:
                    geojsonData?.order?.indexOrder &&
                    Object.values(geojsonData.order.indexOrder),
                dataReady: numReady && denReady,
            }),
        [numReady && denReady && JSON.stringify(params)]
    )
    // if (numReady && denReady && variable === 'Adult Obesity') {
    //     debugger
    // }

    return data
}

export default useGetVariable