/*
 * © 2021 Thoughtworks, Inc.
 */

import { reduceBy } from 'ramda'
import { GroupBy } from './Config'
import { getPeriodEndDate } from './helpers'

export interface EstimationResult {
  readonly timestamp: Date
  readonly serviceEstimates: ServiceData[]
  periodStartDate?: Date
  periodEndDate?: Date
  groupBy: GroupBy
}

export interface ServiceData {
  readonly cloudProvider: string
  readonly kilowattHours: number
  readonly co2e: number
  readonly cost: number
  readonly usesAverageCPUConstant?: boolean
  readonly accountId: string
  // these attributes are mutable because it is required by the client package
  accountName: string
  serviceName: string
  region: string
  tags?: TagCollection
}

export interface TagCollection {
  [index: string]: string
}

export const reduceByTimestamp = (
  estimationResults: EstimationResult[],
): EstimationResult[] => {
  // We need this mutable type in order to set the first timestamp based on the estimationResults values.
  interface MutableEstimationResult {
    timestamp: Date | undefined
    serviceEstimates: ServiceData[]
    periodStartDate: Date
    periodEndDate: Date
    groupBy: GroupBy
  }

  const accumulatingFn = (
    acc: MutableEstimationResult,
    value: MutableEstimationResult,
  ) => {
    acc.timestamp = acc.timestamp || new Date(value.timestamp)
    acc.serviceEstimates = acc.serviceEstimates.concat(value.serviceEstimates)
    acc.groupBy = acc.groupBy || value.groupBy
    acc.periodStartDate = acc.timestamp || new Date(value.timestamp)
    acc.periodEndDate = getPeriodEndDate(acc.periodStartDate, acc.groupBy)
    return acc
  }
  const getTimeOfEstimate = (estimationResult: { timestamp: Date }) =>
    estimationResult.timestamp.toISOString()

  const result = reduceBy(
    accumulatingFn,
    {
      timestamp: undefined,
      serviceEstimates: [],
      periodStartDate: undefined,
      periodEndDate: undefined,
      groupBy: undefined,
    },
    getTimeOfEstimate,
    estimationResults,
  )

  return Object.values(result)
}