# Copyright (c) 2018-2022 Status Research & Development GmbH
# Licensed and distributed under either of
#   * MIT license (license terms in the root directory or at https://opensource.org/licenses/MIT).
#   * Apache v2 license (license terms in the root directory or at https://www.apache.org/licenses/LICENSE-2.0).
# at your option. This file may not be copied, modified, or distributed except according to those terms.

{.push raises: [Defect].}

import
  std/[os, sequtils, times],
  chronicles,
  ./spec/eth2_apis/rest_beacon_client,
  ./spec/signatures,
  ./validators/keystore_management,
  "."/[conf, beacon_clock, filepath]

proc getSignedExitMessage(config: BeaconNodeConf,
                          validatorKeyAsStr: string,
                          exitAtEpoch: Epoch,
                          validatorIdx: uint64 ,
                          fork: Fork,
                          genesis_validators_root: Eth2Digest): SignedVoluntaryExit =
  let
    validatorsDir = config.validatorsDir
    keystoreDir = validatorsDir / validatorKeyAsStr

  if not dirExists(keystoreDir):
    echo "The validator keystores directory '" & validatorsDir &
         "' does not contain a keystore for the selected validator with public " &
         "key '" & validatorKeyAsStr & "'."
    quit 1

  let signingItem = loadKeystore(
    validatorsDir,
    config.secretsDir,
    validatorKeyAsStr,
    config.nonInteractive)

  if signingItem.isNone:
    fatal "Unable to continue without decrypted signing key"
    quit 1

  var signedExit = SignedVoluntaryExit(
    message: VoluntaryExit(
      epoch: exitAtEpoch,
      validator_index: validatorIdx))

  signedExit.signature =
    block:
      let key = signingItem.get.privateKey
      get_voluntary_exit_signature(fork, genesis_validators_root,
                                   signedExit.message, key).toValidatorSig()

  signedExit

type
  ClientExitAction = enum
    quiting = "q"
    confirmation = "I understand the implications of submitting a voluntary exit"

proc askForExitConfirmation(): ClientExitAction =
  template ask(prompt: string): string =
    try:
      stdout.write prompt, ": "
      stdin.readLine()
    except IOError:
      fatal "Failed to read user input from stdin"
      quit 1

  echoP "PLEASE BEWARE!"

  echoP "Publishing a voluntary exit is an irreversible operation! " &
        "You won't be able to restart again with the same validator."

  echoP "By requesting an exit now, you'll be exempt from penalties " &
        "stemming from not performing your validator duties, but you " &
        "won't be able to withdraw your deposited funds for the time " &
        "being. This means that your funds will be effectively frozen " &
        "until withdrawals are enabled in a future phase of Eth2."

  echoP "To understand more about the Eth2 roadmap, we recommend you " &
        "have a look at\n" &
        "https://ethereum.org/en/eth2/#roadmap"

  echoP "You must keep your validator running for at least 5 epochs " &
        "(32 minutes) after requesting a validator exit, as you will " &
        "still be required to perform validator duties until your exit " &
        "has been processed. The number of epochs could be significantly " &
        "higher depending on how many other validators are queued to exit."

  echoP "As such, we recommend you keep track of your validator's status " &
        "using an Eth2 block explorer before shutting down your beacon node."

  var choice = ""

  while not(choice == $ClientExitAction.confirmation or
            choice == $ClientExitAction.quiting) :
    echoP "To proceed to submitting your voluntary exit, please type '" &
          $ClientExitAction.confirmation &
          "' (without the quotes) in the prompt below and " &
          "press ENTER or type 'q' to quit."
    echo ""

    choice = ask "Your choice"

  if choice == $ClientExitAction.confirmation:
    ClientExitAction.confirmation
  else:
    ClientExitAction.quiting

proc restValidatorExit(config: BeaconNodeConf) {.async.} =
  let
    client = RestClientRef.new(config.restUrlForExit).valueOr:
      raise (ref RestError)(msg: $error)

    stateIdHead = StateIdent(kind: StateQueryKind.Named,
                             value: StateIdentType.Head)
    blockIdentHead = BlockIdent(kind: BlockQueryKind.Named,
                                value: BlockIdentType.Head)
    validatorIdent = ValidatorIdent.decodeString(config.exitedValidator)

  if validatorIdent.isErr():
    fatal "Incorrect validator index or key specified",
           err = $validatorIdent.error()
    quit 1

  let restValidator = try:
    let response = await client.getStateValidatorPlain(stateIdHead,
                                                       validatorIdent.get())
    if response.status == 200:
      let validator = decodeBytes(GetStateValidatorResponse,
                                  response.data,
                                  response.contentType)
      if validator.isErr():
        raise newException(RestError, $validator.error)
      validator.get().data
    else:
      raiseGenericError(response)
  except CatchableError as err:
    fatal "Failed to obtain information for validator", err = err.msg
    quit 1

  let
    validator = restValidator.validator
    validatorIdx = restValidator.index.uint64

  let genesis = try:
    let response = await client.getGenesisPlain()
    if response.status == 200:
      let genesis = decodeBytes(GetGenesisResponse,
                                response.data,
                                response.contentType)
      if genesis.isErr():
        raise newException(RestError, $genesis.error)
      genesis.get().data
    else:
      raiseGenericError(response)
  except CatchableError as err:
    fatal "Failed to obtain the genesis validators root of the network",
           err = err.msg
    quit 1

  let exitAtEpoch = if config.exitAtEpoch.isSome:
    Epoch config.exitAtEpoch.get
  else:
    let
      genesisTime =  genesis.genesis_time
      beaconClock = BeaconClock.init(genesisTime)
      time = getTime()
      slot = beaconClock.toSlot(time).slot
      epoch = slot.uint64 div 32
    Epoch epoch

  let fork = try:
    let response = await client.getStateForkPlain(stateIdHead)
    if response.status == 200:
      let fork = decodeBytes(GetStateForkResponse,
                             response.data,
                             response.contentType)
      if fork.isErr():
        raise newException(RestError, $fork.error)
      fork.get().data
    else:
      raiseGenericError(response)
  except CatchableError as err:
    fatal "Failed to obtain the fork id of the head state",
           err = err.msg
    quit 1

  let
    genesis_validators_root = genesis.genesis_validators_root
    validatorKeyAsStr = "0x" & $validator.pubkey
    signedExit = getSignedExitMessage(config,
                                      validatorKeyAsStr,
                                      exitAtEpoch,
                                      validatorIdx,
                                      fork,
                                      genesis_validators_root)

  try:
    let choice = askForExitConfirmation()
    if choice == ClientExitAction.quiting:
      quit 0
    elif choice == ClientExitAction.confirmation:
      let
        response = await client.submitPoolVoluntaryExit(signedExit)
        success = response.status == 200
      if success:
        echo "Successfully published voluntary exit for validator " &
              $validatorIdx & "(" & validatorKeyAsStr[0..9] & ")."
        quit 0
      else:
        let responseError = try:
              Json.decode(response.data, RestGenericError)
        except CatchableError as err:
          fatal "Failed to decode invalid error server response on `submitPoolVoluntaryExit` request",
            err = err.msg
          quit 1

        let
          responseMessage = responseError.message
          responseStacktraces = responseError.stacktraces

        echo "The voluntary exit was not submitted successfully."
        echo responseMessage & ":"
        for el in responseStacktraces.get():
          echo el
        echoP "Please try again."
        quit 1

  except CatchableError as err:
    fatal "Failed to send the signed exit message",
           err = err.msg
    quit 1

proc handleValidatorExitCommand(config: BeaconNodeConf) {.async.} =
  await restValidatorExit(config)

proc doDeposits*(config: BeaconNodeConf, rng: var HmacDrbgContext) {.
    raises: [Defect, CatchableError].} =
  case config.depositsCmd
  of DepositsCmd.createTestnetDeposits:
    if config.eth2Network.isNone:
      fatal "Please specify the intended testnet for the deposits"
      quit 1
    let metadata = config.loadEth2Network()
    var seed: KeySeed
    defer: burnMem(seed)
    var walletPath: WalletPathPair

    if config.existingWalletId.isSome:
      let
        id = config.existingWalletId.get
        found = findWallet(config, id).valueOr:
          fatal "Failed to locate wallet", error = error
          quit 1

      if found.isSome:
        walletPath = found.get
      else:
        fatal "Unable to find wallet with the specified name/uuid", id
        quit 1

      var unlocked = unlockWalletInteractively(walletPath.wallet)
      if unlocked.isOk:
        swap(seed, unlocked.get)
      else:
        # The failure will be reported in `unlockWalletInteractively`.
        quit 1
    else:
      var walletRes = createWalletInteractively(rng, config)
      if walletRes.isErr:
        fatal "Unable to create wallet", err = walletRes.error
        quit 1
      else:
        swap(seed, walletRes.get.seed)
        walletPath = walletRes.get.walletPath

    if (let res = secureCreatePath(config.outValidatorsDir); res.isErr):
      fatal "Could not create directory",
        path = config.outValidatorsDir, err = ioErrorMsg(res.error)
      quit QuitFailure

    if (let res = secureCreatePath(config.outSecretsDir); res.isErr):
      fatal "Could not create directory",
        path = config.outSecretsDir, err = ioErrorMsg(res.error)
      quit QuitFailure

    let deposits = generateDeposits(
      metadata.cfg,
      rng,
      seed,
      walletPath.wallet.nextAccount,
      config.totalDeposits,
      config.outValidatorsDir,
      config.outSecretsDir,
      @[], 0, 0,
      KeystoreMode.Fast)

    if deposits.isErr:
      fatal "Failed to generate deposits", err = deposits.error
      quit 1

    try:
      let depositDataPath = if config.outDepositsFile.isSome:
        config.outDepositsFile.get.string
      else:
        config.outValidatorsDir / "deposit_data-" & $epochTime() & ".json"

      let launchPadDeposits =
        mapIt(deposits.value, LaunchPadDeposit.init(metadata.cfg, it))

      Json.saveFile(depositDataPath, launchPadDeposits)
      echo "Deposit data written to \"", depositDataPath, "\""

      walletPath.wallet.nextAccount += deposits.value.len
      let status = saveWallet(walletPath)
      if status.isErr:
        fatal "Failed to update wallet file after generating deposits",
                wallet = walletPath.path,
                error = status.error
        quit 1
    except CatchableError as err:
      fatal "Failed to create launchpad deposit data file", err = err.msg
      quit 1
  #[
  of DepositsCmd.status:
    echo "The status command is not implemented yet"
    quit 1
  ]#

  of DepositsCmd.`import`:
    let validatorKeysDir = if config.importedDepositsDir.isSome:
      config.importedDepositsDir.get
    else:
      let cwd = os.getCurrentDir()
      if dirExists(cwd / "validator_keys"):
        InputDir(cwd / "validator_keys")
      else:
        echo "The default search path for validator keys is a sub-directory " &
              "named 'validator_keys' in the current working directory. Since " &
              "no such directory exists, please either provide the correct path" &
              "as an argument or copy the imported keys in the expected location."
        quit 1

    importKeystoresFromDir(
      rng,
      validatorKeysDir.string,
      config.validatorsDir, config.secretsDir)

  of DepositsCmd.exit:
    waitFor handleValidatorExitCommand(config)