const csvToJson = require('convert-csv-to-json')
const converter = require('json-2-csv')
const fs = require('fs')
const BN = require('bignumber.js')

const txs = csvToJson.fieldDelimiter(',').getJsonFromCsv(`../Ledger.csv`)
let lots = []
let dispositions = []

const handleBuy = (tx, i) => {
  const { Date: date, Asset, Received, Price } = tx
  lots.push({
    Date: date,
    Id: i,
    Asset,
    Amount: Received,
    Price,
    Remaining: new BN(Received),
  })
}

const createDisposition = (tx, lot, amount) => {
  const st = new Date(tx.Date).valueOf() - new Date(lot.Date).valueOf() < 31556926000
  const costBasis = amount.times(lot.Price)
  const proceeds =  amount.times(tx.Price)
  const gainLoss = proceeds.minus(costBasis)
  const disposition = {
    Date: tx.Date,
    Asset: tx.Asset,
    Lot: lot.Id,
    Amount: amount.toFixed(8),
    PurchasePrice: lot.Price,
    DateAcquired: lot.Date,
    SalePrice: tx.Price,
    CostBasis: costBasis.toFixed(2),
    Proceeds: proceeds.toFixed(2),
    GainLoss: gainLoss.toFixed(2),
    ShortTerm: st ? 'true' : '',
    Tax: gainLoss.gt(0) ? gainLoss.times(st ? .24 : .15).toFixed(2) : 0
  }
  dispositions.push(disposition)
}

const consumeLots = (tx) => {
	for (let i = 0; i < lots.length; i++) {
    let lot = lots[i]

    if (!lot) {
      console.error(`WARNING: No lot available! Assuming $0 cost basis:\n-Date:${tx.Date}\n-Asset: ${tx.Asset}\n-Sent: ${tx.Sent}\n-Remaining: ${tx.Remaining.toFixed(8)}\n`)
      lot = {
        Date: '2017-01-01',
        Id: -1,
        Asset: tx.Asset,
        Amount: tx.Remaining.toFixed(8),
        Price: '0',
        Remaining: tx.Remaining,
      }
    }

		if (lot.Asset !== tx.Asset || lot.Remaining.isZero()) continue

    if (lot.Remaining.gte(tx.Remaining)) {
      createDisposition(tx, lot, tx.Remaining)
      lot.Remaining = lot.Remaining.minus(tx.Remaining)
      return
		} else {
      createDisposition(tx, lot, lot.Remaining)
      tx.Remaining = tx.Remaining.minus(lot.Remaining)
			lot.Remaining = new BN(0)
			return consumeLots(tx)
		}
	}
}

txs.forEach((tx, i) => {
  if (tx.Received) return handleBuy(tx, i)
  tx.Remaining = new BN(tx.Sent)
  return consumeLots(tx)
})

let balances = lots.reduce((prev,  curr) => {
  const asset = curr.Asset
  if (prev[asset]) {
    prev[asset] = prev[asset].plus(curr.Remaining)
  } else {
    prev[asset] = curr.Remaining
  }
  return prev
}, {})

lots = lots.map(u => ({
  ...u,
  Remaining: u.Remaining.toFixed(8),
}))

balances = Object.keys(balances)
  .filter(asset => !balances[asset].isZero())
  .map(asset => ({
    Asset: asset,
    balance: balances[asset].toFixed(8)
  }))

converter.json2csv(lots).then(csv =>
	fs.appendFileSync(`./lots.csv`, csv)
)

converter.json2csv(dispositions).then(csv =>
	fs.appendFileSync(`./dispositions.csv`, csv)
)

converter.json2csv(balances).then(csv =>
	fs.appendFileSync(`./balances.csv`, csv)
)