const { describe, it, before } = require('mocha')
const assert = require('assert')
const bitcoin = require('../../')
const regtestUtils = require('./_regtest')
const regtest = regtestUtils.network
const bip65 = require('bip65')

const alice = bitcoin.ECPair.fromWIF('cScfkGjbzzoeewVWmU2hYPUHeVGJRDdFt7WhmrVVGkxpmPP8BHWe', regtest)
const bob = bitcoin.ECPair.fromWIF('cMkopUXKWsEzAjfa1zApksGRwjVpJRB3831qM9W4gKZsLwjHXA9x', regtest)

describe('bitcoinjs-lib (transactions w/ CLTV)', function () {
  // force update MTP
  before(async function () {
    await regtestUtils.mine(11)
  })

  const hashType = bitcoin.Transaction.SIGHASH_ALL

  function cltvCheckSigOutput (aQ, bQ, lockTime) {
    return bitcoin.script.compile([
      bitcoin.opcodes.OP_IF,
      bitcoin.script.number.encode(lockTime),
      bitcoin.opcodes.OP_CHECKLOCKTIMEVERIFY,
      bitcoin.opcodes.OP_DROP,

      bitcoin.opcodes.OP_ELSE,
      bQ.publicKey,
      bitcoin.opcodes.OP_CHECKSIGVERIFY,
      bitcoin.opcodes.OP_ENDIF,

      aQ.publicKey,
      bitcoin.opcodes.OP_CHECKSIG
    ])
  }

  function utcNow () {
    return Math.floor(Date.now() / 1000)
  }

  // expiry past, {Alice's signature} OP_TRUE
  it('can create (and broadcast via 3PBP) a Transaction where Alice can redeem the output after the expiry (in the past)', async function () {
    // 3 hours ago
    const lockTime = bip65.encode({ utc: utcNow() - (3600 * 3) })
    const redeemScript = cltvCheckSigOutput(alice, bob, lockTime)
    const { address } = bitcoin.payments.p2sh({ redeem: { output: redeemScript, network: regtest }, network: regtest })

    // fund the P2SH(CLTV) address
    const unspent = await regtestUtils.faucet(address, 1e5)
    const txb = new bitcoin.TransactionBuilder(regtest)
    txb.setLockTime(lockTime)
    // Note: nSequence MUST be <= 0xfffffffe otherwise LockTime is ignored, and is immediately spendable.
    txb.addInput(unspent.txId, unspent.vout, 0xfffffffe)
    txb.addOutput(regtestUtils.RANDOM_ADDRESS, 7e4)

    // {Alice's signature} OP_TRUE
    const tx = txb.buildIncomplete()
    const signatureHash = tx.hashForSignature(0, redeemScript, hashType)
    const redeemScriptSig = bitcoin.payments.p2sh({
      redeem: {
        input: bitcoin.script.compile([
          bitcoin.script.signature.encode(alice.sign(signatureHash), hashType),
          bitcoin.opcodes.OP_TRUE
        ]),
        output: redeemScript
      }
    }).input
    tx.setInputScript(0, redeemScriptSig)

    await regtestUtils.broadcast(tx.toHex())

    await regtestUtils.verify({
      txId: tx.getId(),
      address: regtestUtils.RANDOM_ADDRESS,
      vout: 0,
      value: 7e4
    })
  })

  // expiry will pass, {Alice's signature} OP_TRUE
  it('can create (and broadcast via 3PBP) a Transaction where Alice can redeem the output after the expiry (in the future)', async function () {
    const height = await regtestUtils.height()
    // 5 blocks from now
    const lockTime = bip65.encode({ blocks: height + 5 })
    const redeemScript = cltvCheckSigOutput(alice, bob, lockTime)
    const { address } = bitcoin.payments.p2sh({ redeem: { output: redeemScript, network: regtest }, network: regtest })

    // fund the P2SH(CLTV) address
    const unspent = await regtestUtils.faucet(address, 1e5)
    const txb = new bitcoin.TransactionBuilder(regtest)
    txb.setLockTime(lockTime)
    // Note: nSequence MUST be <= 0xfffffffe otherwise LockTime is ignored, and is immediately spendable.
    txb.addInput(unspent.txId, unspent.vout, 0xfffffffe)
    txb.addOutput(regtestUtils.RANDOM_ADDRESS, 7e4)

    // {Alice's signature} OP_TRUE
    const tx = txb.buildIncomplete()
    const signatureHash = tx.hashForSignature(0, redeemScript, hashType)
    const redeemScriptSig = bitcoin.payments.p2sh({
      redeem: {
        input: bitcoin.script.compile([
          bitcoin.script.signature.encode(alice.sign(signatureHash), hashType),
          bitcoin.opcodes.OP_TRUE
        ]),
        output: redeemScript
      }
    }).input
    tx.setInputScript(0, redeemScriptSig)

    // TODO: test that it failures _prior_ to expiry, unfortunately, race conditions when run concurrently
    // ...
    // into the future!
    await regtestUtils.mine(5)
    await regtestUtils.broadcast(tx.toHex())
    await regtestUtils.verify({
      txId: tx.getId(),
      address: regtestUtils.RANDOM_ADDRESS,
      vout: 0,
      value: 7e4
    })
  })

  // expiry ignored, {Bob's signature} {Alice's signature} OP_FALSE
  it('can create (and broadcast via 3PBP) a Transaction where Alice and Bob can redeem the output at any time', async function () {
    // two hours ago
    const lockTime = bip65.encode({ utc: utcNow() - (3600 * 2) })
    const redeemScript = cltvCheckSigOutput(alice, bob, lockTime)
    const { address } = bitcoin.payments.p2sh({ redeem: { output: redeemScript, network: regtest }, network: regtest })

    // fund the P2SH(CLTV) address
    const unspent = await regtestUtils.faucet(address, 2e5)
    const txb = new bitcoin.TransactionBuilder(regtest)
    txb.setLockTime(lockTime)
    // Note: nSequence MUST be <= 0xfffffffe otherwise LockTime is ignored, and is immediately spendable.
    txb.addInput(unspent.txId, unspent.vout, 0xfffffffe)
    txb.addOutput(regtestUtils.RANDOM_ADDRESS, 8e4)

    // {Alice's signature} {Bob's signature} OP_FALSE
    const tx = txb.buildIncomplete()
    const signatureHash = tx.hashForSignature(0, redeemScript, hashType)
    const redeemScriptSig = bitcoin.payments.p2sh({
      redeem: {
        input: bitcoin.script.compile([
          bitcoin.script.signature.encode(alice.sign(signatureHash), hashType),
          bitcoin.script.signature.encode(bob.sign(signatureHash), hashType),
          bitcoin.opcodes.OP_FALSE
        ]),
        output: redeemScript
      }
    }).input
    tx.setInputScript(0, redeemScriptSig)

    await regtestUtils.broadcast(tx.toHex())
    await regtestUtils.verify({
      txId: tx.getId(),
      address: regtestUtils.RANDOM_ADDRESS,
      vout: 0,
      value: 8e4
    })
  })

  // expiry in the future, {Alice's signature} OP_TRUE
  it('can create (but fail to broadcast via 3PBP) a Transaction where Alice attempts to redeem before the expiry', async function () {
    // two hours from now
    const lockTime = bip65.encode({ utc: utcNow() + (3600 * 2) })
    const redeemScript = cltvCheckSigOutput(alice, bob, lockTime)
    const { address } = bitcoin.payments.p2sh({ redeem: { output: redeemScript, network: regtest }, network: regtest })

    // fund the P2SH(CLTV) address
    const unspent = await regtestUtils.faucet(address, 2e4)
    const txb = new bitcoin.TransactionBuilder(regtest)
    txb.setLockTime(lockTime)
    // Note: nSequence MUST be <= 0xfffffffe otherwise LockTime is ignored, and is immediately spendable.
    txb.addInput(unspent.txId, unspent.vout, 0xfffffffe)
    txb.addOutput(regtestUtils.RANDOM_ADDRESS, 1e4)

    // {Alice's signature} OP_TRUE
    const tx = txb.buildIncomplete()
    const signatureHash = tx.hashForSignature(0, redeemScript, hashType)
    const redeemScriptSig = bitcoin.payments.p2sh({
      redeem: {
        input: bitcoin.script.compile([
          bitcoin.script.signature.encode(alice.sign(signatureHash), hashType),
          bitcoin.script.signature.encode(bob.sign(signatureHash), hashType),
          bitcoin.opcodes.OP_TRUE
        ]),
        output: redeemScript
      }
    }).input
    tx.setInputScript(0, redeemScriptSig)

    await regtestUtils.broadcast(tx.toHex()).catch(err => {
      assert.throws(function () {
        if (err) throw err
      }, /Error: non-final \(code 64\)/)
    })
  })
})