tax-scripts/fifo/index.js

const csvToJson = require('convert-csv-to-json')
const converter = require('json-2-csv')
const fs = require('fs')
const BN = require('bignumber.js')
const { PDFDocument } = require('pdf-lib')
const year = 2024

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)
)

// **** 8949 ****

const getDate = (date) => {
  const dateObj = new Date(date)
  const month = dateObj.getMonth() + 1
  const day = dateObj.getDate()
  const year = dateObj.getFullYear()

  return month + "/" + day + "/" + year;
}

const fillFormRows = (form, page, disposition, i) => {
  const dateAcquired = getDate(disposition.DateAcquired)
  const dateSold = getDate(disposition.Date)

  const name = `topmostSubform[0].Page${page}[0].Table_Line1[0].Row${i + 1}[0].f${page}_`
  form.getTextField(`${name}${i * 8 + 3}[0]`).setText(`${disposition.Amount} ${disposition.Asset}`)
  form.getTextField(`${name}${i * 8 + 4}[0]`).setText(dateAcquired)
  form.getTextField(`${name}${i * 8 + 5}[0]`).setText(dateSold)
  form.getTextField(`${name}${i * 8 + 6}[0]`).setText(disposition.Proceeds.toString())
  form.getTextField(`${name}${i * 8 + 7}[0]`).setText(disposition.CostBasis.toString())
  form.getTextField(`${name}${i * 8 + 10}[0]`).setText(disposition.GainLoss.toString())
}

const fillFormTotals = (form, page, proceeds, basis) => {
  form.getTextField(`topmostSubform[0].Page${page}[0].f${page}_115[0]`).setText(proceeds.toFixed(2))
  form.getTextField(`topmostSubform[0].Page${page}[0].f${page}_116[0]`).setText(basis.toFixed(2))
  form.getTextField(`topmostSubform[0].Page${page}[0].f${page}_119[0]`).setText(proceeds.minus(basis).toFixed(2))
}

const createPDF = async () => {
  const pdfDoc = await PDFDocument.create()
  
  const stDispositions = dispositions.filter(d => d.ShortTerm && new Date(d.Date).getFullYear() === year)
  const ltDispositions = dispositions.filter(d => !d.ShortTerm  && new Date(d.Date).getFullYear() === year)
  
  const maxTxs = Math.max(stDispositions.length, ltDispositions.length)
  const numPages = Math.ceil(maxTxs / 14)
  
  for (let i = 0; i < numPages; i++) {
    const blank8949Bytes = fs.readFileSync('../' + year + '-f8949.pdf')
    const blank8949 = await PDFDocument.load(blank8949Bytes)
    const form = blank8949.getForm()
    const start = i * 14
    // short term
    const st = stDispositions.slice(start, start + 14)
    const stTotals = st.reduce((totals, d, i) => {
      fillFormRows(form, 1, d, i)
      totals.proceeds = totals.proceeds.plus(d.Proceeds)
      totals.basis = totals.basis.plus(d.CostBasis)
      return totals
    }, { proceeds: new BN(0), basis: new BN(0) })
    fillFormTotals(form, 1, stTotals.proceeds, stTotals.basis)
    // long term
    const lt = ltDispositions.slice(start, start + 14)
    const ltTotals = lt.reduce((totals, d, i) => {
      fillFormRows(form, 2, d, i)
      totals.proceeds = totals.proceeds.plus(d.Proceeds)
      totals.basis = totals.basis.plus(d.CostBasis)
      return totals
    }, { proceeds: new BN(0), basis: new BN(0) })
    fillFormTotals(form, 2, ltTotals.proceeds, ltTotals.basis)

    await blank8949.save()

    const [page1, page2] = await pdfDoc.copyPages(blank8949, [0,1])
    pdfDoc.addPage(page1)
    pdfDoc.addPage(page2)
  }
  
  const pdfBytes = await pdfDoc.save()

  fs.writeFileSync(`./8949.pdf`, pdfBytes)
}

createPDF()