/*
  This is an end-to-end test adapted from the send-bch example. It's purpose
  is to test the sendRawTransaction endpoint.

  This version tests the single send call.

  Instructions:
  - Ensure the address in the wallet.json file has some tBCH.
  - Ensure the address in the wallet.json file has a UTXOs between 0.1 and
    0.001 tBCH
  - This test will generate a single transaction from a UTXOs and broadcast it
    using the sendrawtransaction single GET endpoint.
*/

// Replace the address below with the address you want to send the BCH to.
const RECV_ADDR1 = `bchtest:qzfn2mly05t6fjsh5kjj0dqq0jjtct27ng089dgg05`
const SATOSHIS_TO_SEND = 1000

// Instantiate BITBOX.
const bitboxLib = "../../../lib/BITBOX"
const BITBOXSDK = require(bitboxLib)
const BITBOX = new BITBOXSDK({ restURL: "https://trest.bitcoin.com/v2/" })
//const BITBOX = new BITBOXSDK({ restURL: "http://localhost:3000/v2/" })

const util = require("util")

// Open the wallet generated with create-wallet.
try {
  var walletInfo = require(`./wallet.json`)
} catch (err) {
  console.log(
    `Could not open wallet.json. Generate a wallet with create-wallet first.`
  )
  process.exit(0)
}

const SEND_ADDR = walletInfo.cashAddress
const SEND_MNEMONIC = walletInfo.mnemonic

async function testSend() {
  try {
    const hex1 = await buildTx1(RECV_ADDR1)
    //const hex2 = await buildTx2(RECV_ADDR2)

    console.log(`hex1: ${hex1}\n\n`)
    //console.log(`hex2: ${hex2}\n\n`)

    const broadcast = await BITBOX.RawTransactions.sendRawTransaction(hex1)

    console.log(`Transaction IDs: ${JSON.stringify(broadcast, null, 2)}`)
    console.log(`Should return a TXID string.`)
  } catch (err) {
    console.log(`Error in testSend: `, err)
  }
}
testSend()

// Build a TX hex with the largest UTXO.
async function buildTx1(recAddr) {
  try {
    // Get the balance of the sending address.
    const balance = await getBCHBalance(SEND_ADDR, false)
    console.log(`balance: ${JSON.stringify(balance, null, 2)}`)
    console.log(`Balance of sending address ${SEND_ADDR} is ${balance} BCH.`)

    // Exit if the balance is zero.
    if (balance <= 0.0) {
      console.log(`Balance of sending address is zero. Exiting.`)
      process.exit(0)
    }

    const SEND_ADDR_LEGACY = BITBOX.Address.toLegacyAddress(SEND_ADDR)
    const RECV_ADDR_LEGACY = BITBOX.Address.toLegacyAddress(recAddr)
    console.log(`Sender Legacy Address: ${SEND_ADDR_LEGACY}`)
    console.log(`Receiver Legacy Address: ${RECV_ADDR_LEGACY}`)

    const balance2 = await getBCHBalance(recAddr, false)
    //console.log(`Balance of recieving address ${recAddr} is ${balance2} BCH.`)

    const u = await BITBOX.Address.utxo(SEND_ADDR)
    //console.log(`u: ${JSON.stringify(u, null, 2)}`)
    const utxo = findBiggestUtxo(u.utxos)
    console.log(`utxo: ${JSON.stringify(utxo, null, 2)}`)

    // instance of transaction builder
    const transactionBuilder = new BITBOX.TransactionBuilder("testnet")

    const satoshisToSend = SATOSHIS_TO_SEND
    const originalAmount = utxo.satoshis
    const vout = utxo.vout
    const txid = utxo.txid

    // add input with txid and index of vout
    transactionBuilder.addInput(txid, vout)

    // get byte count to calculate fee. paying 1.2 sat/byte
    const byteCount = BITBOX.BitcoinCash.getByteCount(
      { P2PKH: 1 },
      { P2PKH: 2 }
    )
    console.log(`byteCount: ${byteCount}`)
    const satoshisPerByte = 1.0
    const txFee = Math.floor(satoshisPerByte * byteCount)
    console.log(`txFee: ${txFee}`)

    // amount to send back to the sending address.
    // It's the original amount - 1 sat/byte for tx size
    const remainder = originalAmount - satoshisToSend - txFee

    // add output w/ address and amount to send
    transactionBuilder.addOutput(recAddr, satoshisToSend)
    transactionBuilder.addOutput(SEND_ADDR, remainder)

    // Generate a change address from a Mnemonic of a private key.
    const change = changeAddrFromMnemonic(SEND_MNEMONIC)

    // Generate a keypair from the change address.
    const keyPair = BITBOX.HDNode.toKeyPair(change)

    // Sign the transaction with the HD node.
    let redeemScript
    transactionBuilder.sign(
      0,
      keyPair,
      redeemScript,
      transactionBuilder.hashTypes.SIGHASH_ALL,
      originalAmount
    )

    // build tx
    const tx = transactionBuilder.build()
    // output rawhex
    const hex = tx.toHex()

    return hex
  } catch (err) {
    console.log(`Error in buildTx().`)
    throw err
  }
}

// Generate a change address from a Mnemonic of a private key.
function changeAddrFromMnemonic(mnemonic) {
  // root seed buffer
  const rootSeed = BITBOX.Mnemonic.toSeed(mnemonic)

  // master HDNode
  const masterHDNode = BITBOX.HDNode.fromSeed(rootSeed, "testnet")

  // HDNode of BIP44 account
  const account = BITBOX.HDNode.derivePath(masterHDNode, "m/44'/145'/0'")

  // derive the first external change address HDNode which is going to spend utxo
  const change = BITBOX.HDNode.derivePath(account, "0/0")

  return change
}

// Get the balance in BCH of a BCH address.
async function getBCHBalance(addr, verbose) {
  try {
    const result = await BITBOX.Address.details(addr)

    if (verbose) console.log(result)

    const bchBalance = result

    return bchBalance.balance
  } catch (err) {
    console.error(`Error in getBCHBalance: `, err)
    console.log(`addr: ${addr}`)
    throw err
  }
}

// Returns the utxo with the biggest balance from an array of utxos.
function findBiggestUtxo(utxos) {
  // Sort the utxos by the amount of satoshis, largest first.
  utxos.sort(function(a, b) {
    return b.satoshis - a.satoshis
  })

  return utxos[0]
}