import
  json, strutils, times, options, os,
  eth/common, httputils, nimcrypto/utils,
  stint, stew/byteutils

import ../nimbus/transaction, ../nimbus/utils/ec_recover
from ../nimbus/rpc/hexstrings import encodeQuantity

func hexToInt*(s: string, T: typedesc[SomeInteger]): T =
  var i = 0
  if s[i] == '0' and (s[i+1] in {'x', 'X'}): inc(i, 2)
  if s.len - i > sizeof(T) * 2:
    raise newException(ValueError, "input hex too big for destination int")
  while i < s.len:
    result = result shl 4 or readHexChar(s[i]).T
    inc(i)

proc prefixHex*(x: Hash256): string =
  "0x" & toLowerAscii($x)

proc prefixHex*(x: int64 | uint64 | byte | int): string =
  toLowerAscii(encodeQuantity(x.uint64).string)

proc prefixHex*(x: openArray[byte]): string =
  "0x" & toHex(x, true)

proc prefixHex*(x: UInt256): string =
  "0x" & stint.toHex(x)

proc prefixHex*(x: string): string =
  "0x" & toLowerAscii(x)

type
  SomeData* = EthAddress | BloomFilter | BlockNonce

proc fromJson*(n: JsonNode, name: string, x: var SomeData) =
  let node = n[name]
  if node.kind == JString:
    hexToByteArray(node.getStr(), x)
    doAssert(x.prefixHex == toLowerAscii(node.getStr()), name)
  else:
    hexToByteArray(node["value"].getStr(), x)
    doAssert(x.prefixHex == toLowerAscii(node["value"].getStr()), name)

proc fromJson*(n: JsonNode, name: string, x: var Hash256) =
  let node = n[name]
  if node.kind == JString:
    hexToByteArray(node.getStr(), x.data)
    doAssert(x.prefixHex == toLowerAscii(node.getStr()), name)
  else:
    hexToByteArray(node["value"].getStr(), x.data)
    doAssert(x.prefixHex == toLowerAscii(node["value"].getStr()), name)

proc fromJson*(n: JsonNode, name: string, x: var Blob) =
  x = hexToSeqByte(n[name].getStr())
  doAssert(x.prefixHex == toLowerAscii(n[name].getStr()), name)

proc fromJson*(n: JsonNode, name: string, x: var UInt256) =
  let node = n[name]
  if node.kind == JString:
    x = UInt256.fromHex(node.getStr())
    doAssert(x.prefixHex == toLowerAscii(node.getStr()), name)
  else:
    x = node.getInt().u256
    doAssert($x == $node.getInt, name)

proc fromJson*(n: JsonNode, name: string, x: var SomeInteger) =
  let node = n[name]
  if node.kind == JString:
    x = hexToInt(node.getStr(), type(x))
    doAssert(x.prefixHex == toLowerAscii(node.getStr()), name)
  else:
    type T = type x
    x = T(node.getInt)
    doAssert($x == $node.getInt, name)

proc fromJson*(n: JsonNode, name: string, x: var EthTime) =
  x = initTime(hexToInt(n[name].getStr(), int64), 0)
  doAssert(x.toUnix.prefixHex == toLowerAscii(n[name].getStr()), name)

proc fromJson*[T](n: JsonNode, name: string, x: var Option[T]) =
  if name in n:
    var val: T
    n.fromJson(name, val)
    x = some(val)

proc fromJson*(n: JsonNode, name: string, x: var TxType) =
  let node = n[name]
  if node.kind == JInt:
    x = TxType(node.getInt)
  else:
    x = hexToInt(node.getStr(), int).TxType

proc parseBlockHeader*(n: JsonNode): BlockHeader =
  n.fromJson "parentHash", result.parentHash
  n.fromJson "sha3Uncles", result.ommersHash
  n.fromJson "miner", result.coinbase
  n.fromJson "stateRoot", result.stateRoot
  n.fromJson "transactionsRoot", result.txRoot
  n.fromJson "receiptsRoot", result.receiptRoot
  n.fromJson "logsBloom", result.bloom
  n.fromJson "difficulty", result.difficulty
  n.fromJson "number", result.blockNumber
  n.fromJson "gasLimit", result.gasLimit
  n.fromJson "gasUsed", result.gasUsed
  n.fromJson "timestamp", result.timestamp
  n.fromJson "extraData", result.extraData
  n.fromJson "mixHash", result.mixDigest
  n.fromJson "nonce", result.nonce
  n.fromJson "baseFeePerGas", result.fee
  n.fromJson "withdrawalsRoot", result.withdrawalsRoot

  if result.baseFee == 0.u256:
    # probably geth bug
    result.fee = none(UInt256)

proc parseAccessPair(n: JsonNode): AccessPair =
  n.fromJson "address", result.address
  let keys = n["storageKeys"]
  for kn in keys:
    result.storageKeys.add hexToByteArray[32](kn.getStr())

proc parseTransaction*(n: JsonNode): Transaction =
  var tx = Transaction(txType: TxLegacy)
  n.fromJson "nonce", tx.nonce
  n.fromJson "gasPrice", tx.gasPrice
  n.fromJson "gas", tx.gasLimit

  if n["to"].kind != JNull:
    var to: EthAddress
    n.fromJson "to", to
    tx.to = some(to)

  n.fromJson "value", tx.value
  n.fromJson "input", tx.payload
  n.fromJson "v", tx.V
  n.fromJson "r", tx.R
  n.fromJson "s", tx.S

  if n.hasKey("type") and n["type"].kind != JNull:
    n.fromJson "type", tx.txType

  if tx.txType >= TxEip1559:
    n.fromJson "maxPriorityFeePerGas", tx.maxPriorityFee
    n.fromJson "maxFeePerGas", tx.maxFee

  if tx.txType >= TxEip2930:
    if n.hasKey("chainId"):
      let id = hexToInt(n["chainId"].getStr(), int)
      tx.chainId = ChainId(id)

    let accessList = n["accessList"]
    if accessList.len > 0:
      for acn in accessList:
        tx.accessList.add parseAccessPair(acn)
  tx

proc parseWithdrawal*(n: JsonNode): Withdrawal =
  n.fromJson "index", result.index
  n.fromJson "validatorIndex", result.validatorIndex
  n.fromJson "address", result.address
  n.fromJson "amount", result.amount

proc validateTxSenderAndHash*(n: JsonNode, tx: Transaction) =
  var sender = tx.getSender()
  var fromAddr: EthAddress
  n.fromJson "from", fromAddr
  doAssert sender.prefixHex == fromAddr.prefixHex
  doAssert n["hash"].getStr() == tx.rlpHash().prefixHex

proc parseLog(n: JsonNode): Log =
  n.fromJson "address", result.address
  n.fromJson "data", result.data
  let topics = n["topics"]
  result.topics = newSeqOfCap[Topic](n.len)
  var topicHash: Topic
  for tp in topics:
    hexToByteArray(tp.getStr(), topicHash)
    result.topics.add topicHash

proc parseLogs(n: JsonNode): seq[Log] =
  if n.len > 0:
    result = newSeqOfCap[Log](n.len)
    for log in n:
      result.add parseLog(log)
  else:
    result = @[]

proc parseReceipt*(n: JsonNode): Receipt =
  var rec = Receipt(receiptType: LegacyReceipt)
  if n.hasKey("root"):
    var hash: Hash256
    n.fromJson "root", hash
    rec.isHash = true
    rec.hash = hash
  else:
    var status: int
    n.fromJson "status", status
    rec.isHash = false
    rec.status = status == 1

  n.fromJson "cumulativeGasUsed", rec.cumulativeGasUsed
  n.fromJson "logsBloom", rec.bloom
  rec.logs = parseLogs(n["logs"])
  rec

proc headerHash*(n: JsonNode): Hash256 =
  n.fromJson "hash", result

proc parseAccount*(n: JsonNode): Account =
  n.fromJson "nonce", result.nonce
  n.fromJson "balance", result.balance
  n.fromJson "storageRoot", result.storageRoot
  n.fromJson "codeHash", result.codeHash