# Nimbus
# Copyright (c) 2022 Status Research & Development GmbH
# Licensed under either of
#  * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or
#    http://www.apache.org/licenses/LICENSE-2.0)
#  * MIT license ([LICENSE-MIT](LICENSE-MIT) or
#    http://opensource.org/licenses/MIT)
# at your option. This file may not be copied, modified, or distributed except
# according to those terms.

import
  std/[json, strutils, tables],
  stew/[byteutils, results],
  stint,
  eth/[common, rlp, keys],
  ../../nimbus/transaction,
  ../../nimbus/common/chain_config,
  ../common/helpers,
  ./types,
  ./txpriv

export
  helpers

proc parseHexOrInt[T](x: string): T =
  when T is UInt256:
    if x.startsWith("0x"):
      UInt256.fromHex(x)
    else:
      parse(x, UInt256, 10)
  else:
    if x.startsWith("0x"):
      fromHex[T](x)
    else:
      parseInt(x).T

proc fromJson(T: type EthAddress, n: JsonNode, field: string): EthAddress =
  let x = n[field].getStr()
  var xlen = x.len
  if x.startsWith("0x"):
    xlen = xlen - 2
  if xlen != sizeof(T) * 2:
    raise newError(ErrorJson, "malformed Eth address " & x)
  hexToByteArray(x, sizeof(T))

template fromJson(T: type Blob, n: JsonNode, field: string): Blob =
  hexToSeqByte(n[field].getStr())

proc fromJson(T: type uint64, n: JsonNode, field: string): uint64 =
  if n[field].kind == JInt:
    n[field].getInt().uint64
  else:
    parseHexOrInt[AccountNonce](n[field].getStr())

template fromJson(T: type UInt256, n: JsonNode, field: string): UInt256 =
  parseHexOrInt[UInt256](n[field].getStr())

template fromJson(T: type GasInt, n: JsonNode, field: string): GasInt =
  parseHexOrInt[GasInt](n[field].getStr())

template fromJson(T: type ChainId, n: JsonNode, field: string): ChainId =
  parseHexOrInt[uint64](n[field].getStr()).ChainId

proc fromJson(T: type Hash256, n: JsonNode): Hash256 =
  var num = n.getStr()
  num.removePrefix("0x")
  if num.len < 64:
    num = repeat('0', 64 - num.len) & num
  Hash256(data: hexToByteArray(num, 32))

proc fromJson(T: type Hash256, n: JsonNode, field: string): Hash256 =
  fromJson(T, n[field])

template fromJson(T: type EthTime, n: JsonNode, field: string): EthTime =
  EthTime(parseHexOrInt[uint64](n[field].getStr()))

proc fromJson(T: type AccessList, n: JsonNode, field: string): AccessList =
  let z = n[field]
  if z.kind == JNull:
    return

  for x in z:
    var ap = AccessPair(
      address: EthAddress.fromJson(x, "address")
    )
    let sks = x["storageKeys"]
    for sk in sks:
      ap.storageKeys.add hexToByteArray(sk.getStr(), 32)
    result.add ap

proc fromJson(T: type Ommer, n: JsonNode): Ommer =
  Ommer(
    delta: fromJson(uint64, n, "delta"),
    address: fromJson(EthAddress, n, "address")
  )

proc fromJson(T: type Withdrawal, n: JsonNode): Withdrawal =
  Withdrawal(
    index: fromJson(uint64, n, "index"),
    validatorIndex: fromJson(uint64, n, "validatorIndex"),
    address: fromJson(EthAddress, n, "address"),
    amount: fromJson(uint64, n, "amount")
  )

proc fromJson(T: type VersionedHashes, n: JsonNode, field: string): VersionedHashes =
  let list = n[field]
  for x in list:
    result.add Hash256.fromJson(x)

template `gas=`(tx: var Transaction, x: GasInt) =
  tx.gasLimit = x

template `input=`(tx: var Transaction, x: Blob) =
  tx.payload = x

template `v=`(tx: var Transaction, x: int64) =
  tx.V = x

template `r=`(tx: var Transaction, x: UInt256) =
  tx.R = x

template `s=`(tx: var Transaction, x: UInt256) =
  tx.S = x

template `maxPriorityFeePerGas=`(tx: var Transaction, x: GasInt) =
  tx.maxPriorityFee = x

template `maxFeePerGas=`(tx: var Transaction, x: GasInt) =
  tx.maxFee = x

template `blobVersionedHashes=`(tx: var Transaction, x: VersionedHashes) =
  tx.versionedHashes = x

template required(o: untyped, T: type, oField: untyped) =
  const fName = astToStr(oField)
  if not n.hasKey(fName):
    raise newError(ErrorJson, "missing required field '" & fName & "' in transaction")
  o.oField = T.fromJson(n, fName)

template omitZero(o: untyped, T: type, oField: untyped) =
  const fName = astToStr(oField)
  if n.hasKey(fName):
    o.oField = T.fromJson(n, fName)

template optional(o: untyped, T: type, oField: untyped) =
  const fName = astToStr(oField)
  if n.hasKey(fName) and n[fName].kind != JNull:
    o.oField = some(T.fromJson(n, fName))

proc parseAlloc*(ctx: var TransContext, n: JsonNode) =
  for accAddr, acc in n:
    let address = hexToByteArray[20](accAddr)
    var ga = GenesisAccount()
    if acc.hasKey("code"):
      ga.code = Blob.fromJson(acc, "code")
    if acc.hasKey("nonce"):
      ga.nonce = AccountNonce.fromJson(acc, "nonce")
    if acc.hasKey("balance"):
      ga.balance = UInt256.fromJson(acc, "balance")
    else:
      raise newError(ErrorJson, "GenesisAlloc: balance required")
    if acc.hasKey("storage"):
      let storage = acc["storage"]
      for k, v in storage:
        ga.storage[UInt256.fromHex(k)] = UInt256.fromHex(v.getStr())
    ctx.alloc[address] = ga

proc parseEnv*(ctx: var TransContext, n: JsonNode) =
  required(ctx.env, EthAddress, currentCoinbase)
  required(ctx.env, GasInt, currentGasLimit)
  required(ctx.env, BlockNumber, currentNumber)
  required(ctx.env, EthTime, currentTimestamp)
  optional(ctx.env, DifficultyInt, currentDifficulty)
  optional(ctx.env, Hash256, currentRandom)
  optional(ctx.env, DifficultyInt, parentDifficulty)
  omitZero(ctx.env, EthTime, parentTimestamp)
  optional(ctx.env, UInt256, currentBaseFee)
  omitZero(ctx.env, Hash256, parentUncleHash)
  optional(ctx.env, UInt256, parentBaseFee)
  optional(ctx.env, GasInt, parentGasUsed)
  optional(ctx.env, GasInt, parentGasLimit)
  optional(ctx.env, uint64, currentBlobGasUsed)
  optional(ctx.env, uint64, currentExcessBlobGas)
  optional(ctx.env, uint64, parentBlobGasUsed)
  optional(ctx.env, uint64, parentExcessBlobGas)
  optional(ctx.env, Hash256, parentBeaconBlockRoot)

  if n.hasKey("blockHashes"):
    let w = n["blockHashes"]
    for k, v in w:
      ctx.env.blockHashes[parseHexOrInt[uint64](k)] = Hash256.fromHex(v.getStr())

  if n.hasKey("ommers"):
    let w = n["ommers"]
    for v in w:
      ctx.env.ommers.add Ommer.fromJson(v)

  if n.hasKey("withdrawals"):
    let w = n["withdrawals"]
    var withdrawals: seq[Withdrawal]
    for v in w:
      withdrawals.add Withdrawal.fromJson(v)
    ctx.env.withdrawals = some(withdrawals)

proc parseTx(n: JsonNode, chainId: ChainID): Transaction =
  var tx: Transaction
  if not n.hasKey("type"):
    tx.txType = TxLegacy
  else:
    tx.txType = int64.fromJson(n, "type").TxType

  required(tx, AccountNonce, nonce)
  required(tx, GasInt, gas)
  required(tx, UInt256, value)
  required(tx, Blob, input)

  if n.hasKey("to"):
    tx.to = some(EthAddress.fromJson(n, "to"))

  case tx.txType
  of TxLegacy:
    required(tx, GasInt, gasPrice)
  of TxEip2930:
    required(tx, GasInt, gasPrice)
    required(tx, ChainId, chainId)
    omitZero(tx, AccessList, accessList)
  of TxEip1559:
    required(tx, ChainId, chainId)
    required(tx, GasInt, maxPriorityFeePerGas)
    required(tx, GasInt, maxFeePerGas)
    omitZero(tx, AccessList, accessList)
  of TxEip4844:
    required(tx, ChainId, chainId)
    required(tx, GasInt, maxPriorityFeePerGas)
    required(tx, GasInt, maxFeePerGas)
    omitZero(tx, AccessList, accessList)
    required(tx, UInt256, maxFeePerBlobGas)
    required(tx, VersionedHashes, blobVersionedHashes)

  var eip155 = true
  if n.hasKey("protected"):
    eip155 = n["protected"].bval

  if n.hasKey("secretKey"):
    let data = Blob.fromJson(n, "secretKey")
    let secretKey = PrivateKey.fromRaw(data).tryGet
    signTransaction(tx, secretKey, chainId, eip155)
  else:
    required(tx, int64, v)
    required(tx, UInt256, r)
    required(tx, UInt256, s)
    tx

proc parseTxLegacy(item: var Rlp): Result[Transaction, string] =
  try:
    var tx: Transaction
    item.decodeTxLegacy(tx)
    return ok(tx)
  except RlpError as x:
    return err(x.msg)

proc parseTxTyped(item: var Rlp): Result[Transaction, string] =
  try:
    var tx: Transaction
    var rr = rlpFromBytes(item.read(Blob))
    rr.decodeTxTyped(tx)
    return ok(tx)
  except RlpError as x:
    return err(x.msg)

proc parseTxJson(ctx: TransContext, i: int, chainId: ChainId): Result[Transaction, string] =
  try:
    let n = ctx.txs.n[i]
    return ok(parseTx(n, chainId))
  except Exception as x:
    return err(x.msg)

proc parseTxs*(ctx: TransContext, chainId: ChainId): seq[Result[Transaction, string]] =
  if ctx.txs.txsType == TxsJson:
    let len = ctx.txs.n.len
    result = newSeqOfCap[Result[Transaction, string]](len)
    for i in 0 ..< len:
      result.add ctx.parseTxJson(i, chainId)
    return

  if ctx.txs.txsType == TxsRlp:
    result = newSeqOfCap[Result[Transaction, string]](ctx.txs.r.listLen)
    var rlp = ctx.txs.r
    for item in rlp:
      if item.isList:
        result.add parseTxLegacy(item)
      else:
        result.add parseTxTyped(item)
    return

proc txList*(ctx: TransContext, chainId: ChainId): seq[Transaction] =
  let list = ctx.parseTxs(chainId)
  for txRes in list:
    if txRes.isOk:
      result.add txRes.get

proc parseTxs*(ctx: var TransContext, txs: JsonNode) =
  if txs.kind == JNull:
    return
  if txs.kind != JArray:
    raise newError(ErrorJson,
      "Transaction list should be a JSON array, got=" & $txs.kind)
  ctx.txs = TxsList(
    txsType: TxsJson,
    n: txs)

proc parseTxsRlp*(ctx: var TransContext, hexData: string) =
  let bytes = hexToSeqByte(hexData)
  ctx.txs = TxsList(
    txsType: TxsRlp,
    r: rlpFromBytes(bytes)
  )
  if ctx.txs.r.isList.not:
    raise newError(ErrorRlp, "RLP Transaction list should be a list")

proc parseInputFromStdin*(ctx: var TransContext) =
  let data = stdin.readAll()
  let n = json.parseJson(data)
  if n.hasKey("alloc"): ctx.parseAlloc(n["alloc"])
  if n.hasKey("env"): ctx.parseEnv(n["env"])
  if n.hasKey("txs"): ctx.parseTxs(n["txs"])
  if n.hasKey("txsRlp"): ctx.parseTxsRlp(n["txsRlp"].getStr())

template stripLeadingZeros(value: string): string =
  var cidx = 0
  # ignore the last character so we retain '0' on zero value
  while cidx < value.len - 1 and value[cidx] == '0':
    cidx.inc
  value[cidx .. ^1]

proc `@@`*[K, V](x: Table[K, V]): JsonNode
proc `@@`*[T](x: seq[T]): JsonNode

proc to0xHex(x: UInt256): string =
  "0x" & x.toHex

proc `@@`(x: uint64 | int64 | int): JsonNode =
  let hex = x.toHex.stripLeadingZeros
  %("0x" & hex.toLowerAscii)

proc `@@`(x: UInt256): JsonNode =
  %("0x" & x.toHex)

proc `@@`(x: Hash256): JsonNode =
  %("0x" & x.data.toHex)

proc `@@`*(x: Blob): JsonNode =
  %("0x" & x.toHex)

proc `@@`(x: bool): JsonNode =
  %(if x: "0x1" else: "0x0")

proc `@@`(x: EthAddress): JsonNode =
  %("0x" & x.toHex)

proc `@@`(x: Topic): JsonNode =
  %("0x" & x.toHex)

proc toJson(x: Table[UInt256, UInt256]): JsonNode =
  # special case, we need to convert UInt256 into full 32 bytes
  # and not shorter
  result = newJObject()
  for k, v in x:
    result["0x" & k.dumpHex] = %("0x" & v.dumpHex)

proc `@@`(acc: GenesisAccount): JsonNode =
  result = newJObject()
  if acc.code.len > 0:
    result["code"] = @@(acc.code)
  result["balance"] = @@(acc.balance)
  if acc.nonce > 0:
    result["nonce"] = @@(acc.nonce)
  if acc.storage.len > 0:
    result["storage"] = toJson(acc.storage)

proc `@@`[K, V](x: Table[K, V]): JsonNode =
  result = newJObject()
  for k, v in x:
    result[k.to0xHex] = @@(v)

proc `@@`(x: BloomFilter): JsonNode =
  %("0x" & toHex[256](x))

proc `@@`(x: Log): JsonNode =
  result = %{
    "address": @@(x.address),
    "topics" : @@(x.topics),
    "data"   : @@(x.data)
  }

proc `@@`(x: TxReceipt): JsonNode =
  result = %{
    "root"             : if x.root == Hash256(): %("0x") else: @@(x.root),
    "status"           : @@(x.status),
    "cumulativeGasUsed": @@(x.cumulativeGasUsed),
    "logsBloom"        : @@(x.logsBloom),
    "logs"             : if x.logs.len == 0: newJNull() else: @@(x.logs),
    "transactionHash"  : @@(x.transactionHash),
    "contractAddress"  : @@(x.contractAddress),
    "gasUsed"          : @@(x.gasUsed),
    "blockHash"        : @@(x.blockHash),
    "transactionIndex" : @@(x.transactionIndex)
  }
  if x.txType > TxLegacy:
    result["type"] = %("0x" & toHex(x.txType.int, 1))

proc `@@`(x: RejectedTx): JsonNode =
  result = %{
    "index": %(x.index),
    "error": %(x.error)
  }

proc `@@`[T](x: seq[T]): JsonNode =
  result = newJArray()
  for c in x:
    result.add @@(c)

proc `@@`[T](x: Option[T]): JsonNode =
  if x.isNone:
    newJNull()
  else:
    @@(x.get())

proc `@@`*(x: ExecutionResult): JsonNode =
  result = %{
    "stateRoot"   : @@(x.stateRoot),
    "txRoot"      : @@(x.txRoot),
    "receiptsRoot": @@(x.receiptsRoot),
    "logsHash"    : @@(x.logsHash),
    "logsBloom"   : @@(x.bloom),
    "receipts"    : @@(x.receipts),
    "currentDifficulty": @@(x.currentDifficulty),
    "gasUsed"     : @@(x.gasUsed)
  }
  if x.rejected.len > 0:
    result["rejected"] = @@(x.rejected)
  if x.currentBaseFee.isSome:
    result["currentBaseFee"] = @@(x.currentBaseFee)
  if x.withdrawalsRoot.isSome:
    result["withdrawalsRoot"] = @@(x.withdrawalsRoot)
  if x.currentExcessBlobGas.isSome:
    result["currentExcessBlobGas"] = @@(x.currentExcessBlobGas)
  if x.blobGasUsed.isSome:
    result["blobGasUsed"] = @@(x.blobGasUsed)