import { Dictionary, groupBy, last, partition, sum, sumBy, uniq } from 'lodash'
import { calculatePayout, getContractBetMetrics } from './calculate'
import { Bet, LimitBet } from './bet'
import {
  Contract,
  CPMMBinaryContract,
  CPMMContract,
  DPMContract,
} from './contract'
import { PortfolioMetrics, User } from './user'
import { DAY_MS } from './util/time'
import { getBinaryCpmmBetInfo, getNewMultiBetInfo } from './new-bet'
import { getCpmmProbability } from './calculate-cpmm'
import { removeUndefinedProps } from './util/object'

const computeInvestmentValue = (
  bets: Bet[],
  contractsDict: { [k: string]: Contract }
) => {
  return sumBy(bets, (bet) => {
    const contract = contractsDict[bet.contractId]
    if (!contract || contract.isResolved) return 0
    if (bet.sale || bet.isSold) return 0

    const payout = calculatePayout(contract, bet, 'MKT')
    const value = payout - (bet.loanAmount ?? 0)
    if (isNaN(value)) return 0
    return value
  })
}

export const computeInvestmentValueCustomProb = (
  bets: Bet[],
  contract: Contract,
  p: number
) => {
  return sumBy(bets, (bet) => {
    if (!contract || contract.isResolved) return 0
    if (bet.sale || bet.isSold) return 0
    const { outcome, shares } = bet

    const betP = outcome === 'YES' ? p : 1 - p

    const value = betP * shares
    if (isNaN(value)) return 0
    return value
  })
}

export const computeElasticity = (
  bets: Bet[],
  contract: Contract,
  betAmount = 50
) => {
  const { mechanism, outcomeType } = contract
  return mechanism === 'cpmm-1' &&
    (outcomeType === 'BINARY' || outcomeType === 'PSEUDO_NUMERIC')
    ? computeBinaryCpmmElasticity(bets, contract, betAmount)
    : computeDpmElasticity(contract, betAmount)
}

export const computeBinaryCpmmElasticity = (
  bets: Bet[],
  contract: CPMMContract,
  betAmount: number
) => {
  const limitBets = bets
    .filter(
      (b) =>
        !b.isFilled &&
        !b.isSold &&
        !b.isRedemption &&
        !b.sale &&
        !b.isCancelled &&
        b.limitProb !== undefined
    )
    .sort((a, b) => a.createdTime - b.createdTime) as LimitBet[]

  const userIds = uniq(limitBets.map((b) => b.userId))
  // Assume all limit orders are good.
  const userBalances = Object.fromEntries(
    userIds.map((id) => [id, Number.MAX_SAFE_INTEGER])
  )

  const { newPool: poolY, newP: pY } = getBinaryCpmmBetInfo(
    'YES',
    betAmount,
    contract,
    undefined,
    limitBets,
    userBalances
  )
  const resultYes = getCpmmProbability(poolY, pY)

  const { newPool: poolN, newP: pN } = getBinaryCpmmBetInfo(
    'NO',
    betAmount,
    contract,
    undefined,
    limitBets,
    userBalances
  )
  const resultNo = getCpmmProbability(poolN, pN)

  // handle AMM overflow
  const safeYes = Number.isFinite(resultYes) ? resultYes : 1
  const safeNo = Number.isFinite(resultNo) ? resultNo : 0

  return safeYes - safeNo
}

export const computeDpmElasticity = (
  contract: DPMContract,
  betAmount: number
) => {
  return getNewMultiBetInfo('', 2 * betAmount, contract).newBet.probAfter
}

const computeTotalPool = (userContracts: Contract[], startTime = 0) => {
  const periodFilteredContracts = userContracts.filter(
    (contract) => contract.createdTime >= startTime
  )
  return sum(
    periodFilteredContracts.map((contract) => sum(Object.values(contract.pool)))
  )
}

export const computeVolume = (contractBets: Bet[], since: number) => {
  return sumBy(contractBets, (b) =>
    b.createdTime > since && !b.isRedemption ? Math.abs(b.amount) : 0
  )
}

const calculateProbChangeSince = (descendingBets: Bet[], since: number) => {
  const newestBet = descendingBets[0]
  if (!newestBet) return 0

  const betBeforeSince = descendingBets.find((b) => b.createdTime < since)

  if (!betBeforeSince) {
    const oldestBet = last(descendingBets) ?? newestBet
    return newestBet.probAfter - oldestBet.probBefore
  }

  return newestBet.probAfter - betBeforeSince.probAfter
}

export const calculateProbChanges = (descendingBets: Bet[]) => {
  const now = Date.now()
  const yesterday = now - DAY_MS
  const weekAgo = now - 7 * DAY_MS
  const monthAgo = now - 30 * DAY_MS

  return {
    day: calculateProbChangeSince(descendingBets, yesterday),
    week: calculateProbChangeSince(descendingBets, weekAgo),
    month: calculateProbChangeSince(descendingBets, monthAgo),
  }
}

export const calculateCreatorVolume = (userContracts: Contract[]) => {
  const allTimeCreatorVolume = computeTotalPool(userContracts, 0)
  const monthlyCreatorVolume = computeTotalPool(
    userContracts,
    Date.now() - 30 * DAY_MS
  )
  const weeklyCreatorVolume = computeTotalPool(
    userContracts,
    Date.now() - 7 * DAY_MS
  )

  const dailyCreatorVolume = computeTotalPool(
    userContracts,
    Date.now() - 1 * DAY_MS
  )

  return {
    daily: dailyCreatorVolume,
    weekly: weeklyCreatorVolume,
    monthly: monthlyCreatorVolume,
    allTime: allTimeCreatorVolume,
  }
}

export const calculateNewPortfolioMetrics = (
  user: User,
  contractsById: { [k: string]: Contract },
  currentBets: Bet[]
) => {
  const investmentValue = computeInvestmentValue(currentBets, contractsById)
  const newPortfolio = {
    investmentValue: investmentValue,
    balance: user.balance,
    totalDeposits: user.totalDeposits,
    timestamp: Date.now(),
    userId: user.id,
  }
  return newPortfolio
}

const calculateProfitForPeriod = (
  startingPortfolio: PortfolioMetrics | undefined,
  currentProfit: number
) => {
  if (startingPortfolio === undefined) {
    return currentProfit
  }

  const startingProfit = calculatePortfolioProfit(startingPortfolio)

  return currentProfit - startingProfit
}

export const calculatePortfolioProfit = (portfolio: PortfolioMetrics) => {
  return portfolio.investmentValue + portfolio.balance - portfolio.totalDeposits
}

export const calculateNewProfit = (
  portfolioHistory: Record<
    'current' | 'day' | 'week' | 'month',
    PortfolioMetrics | undefined
  >,
  newPortfolio: PortfolioMetrics
) => {
  const allTimeProfit = calculatePortfolioProfit(newPortfolio)

  const newProfit = {
    daily: calculateProfitForPeriod(portfolioHistory.day, allTimeProfit),
    weekly: calculateProfitForPeriod(portfolioHistory.week, allTimeProfit),
    monthly: calculateProfitForPeriod(portfolioHistory.month, allTimeProfit),
    allTime: allTimeProfit,
  }

  return newProfit
}

export const calculateMetricsByContract = (
  bets: Bet[],
  contractsById: Dictionary<Contract>
) => {
  const betsByContract = groupBy(bets, (bet) => bet.contractId)
  const unresolvedContracts = Object.keys(betsByContract)
    .map((cid) => contractsById[cid])
    .filter((c) => c && !c.isResolved)

  return unresolvedContracts.map((c) => {
    const bets = betsByContract[c.id] ?? []
    const current = getContractBetMetrics(c, bets)

    let periodMetrics
    if (c.mechanism === 'cpmm-1' && c.outcomeType === 'BINARY') {
      const periods = ['day', 'week', 'month'] as const
      periodMetrics = Object.fromEntries(
        periods.map((period) => [
          period,
          calculatePeriodProfit(c, bets, period),
        ])
      )
    }

    return removeUndefinedProps({
      contractId: c.id,
      ...current,
      from: periodMetrics,
    })
  })
}

export type ContractMetrics = ReturnType<
  typeof calculateMetricsByContract
>[number]

const calculatePeriodProfit = (
  contract: CPMMBinaryContract,
  bets: Bet[],
  period: 'day' | 'week' | 'month'
) => {
  const days = period === 'day' ? 1 : period === 'week' ? 7 : 30
  const fromTime = Date.now() - days * DAY_MS
  const [previousBets, recentBets] = partition(
    bets,
    (b) => b.createdTime < fromTime
  )

  const prevProb = contract.prob - contract.probChanges[period]
  const prob = contract.resolutionProbability
    ? contract.resolutionProbability
    : contract.prob

  const previousBetsValue = computeInvestmentValueCustomProb(
    previousBets,
    contract,
    prevProb
  )
  const currentBetsValue = computeInvestmentValueCustomProb(
    previousBets,
    contract,
    prob
  )

  const { profit: recentProfit, invested: recentInvested } =
    getContractBetMetrics(contract, recentBets)

  const profit = currentBetsValue - previousBetsValue + recentProfit
  const invested = previousBetsValue + recentInvested
  const profitPercent = invested === 0 ? 0 : 100 * (profit / invested)

  return {
    profit,
    profitPercent,
    invested,
    prevValue: previousBetsValue,
    value: currentBetsValue,
  }
}