import
  json, strutils, times, options, os,
  eth/[rlp, common], httputils, nimcrypto, chronicles,
  stint, stew/byteutils

import
  ../nimbus/[transaction, rpc/hexstrings]

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 =
  encodeQuantity(x.uint64).toLowerAscii

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) =
  hexToByteArray(n[name].getStr(), x)
  doAssert(x.prefixHex == toLowerAscii(n[name].getStr()))

proc fromJson(n: JsonNode, name: string, x: var Hash256) =
  hexToByteArray(n[name].getStr(), x.data)
  doAssert(x.prefixHex == toLowerAscii(n[name].getStr()))

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

proc fromJson(n: JsonNode, name: string, x: var UInt256) =
  x = UInt256.fromHex(n[name].getStr())
  doAssert(x.prefixHex == toLowerAscii(n[name].getStr()))

proc fromJson(n: JsonNode, name: string, x: var SomeInteger) =
  x = hexToInt(n[name].getStr(), type(x))
  doAssert(x.prefixHex == toLowerAscii(n[name].getStr()))

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()))

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

proc parseTransaction*(n: JsonNode): Transaction =
  n.fromJson "nonce", result.accountNonce
  n.fromJson "gasPrice", result.gasPrice
  n.fromJson "gas", result.gasLimit

  result.isContractCreation = n["to"].kind == JNull
  if not result.isContractCreation:
    n.fromJson "to", result.to

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

  var sender = result.getSender()
  doAssert sender.prefixHex == n["from"].getStr()
  doAssert n["hash"].getStr() == result.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 =
  if n.hasKey("root"):
    var hash: Hash256
    n.fromJson "root", hash
    result.stateRootOrStatus = hashOrStatus(hash)
  else:
    var status: int
    n.fromJson "status", status
    result.stateRootOrStatus = hashOrStatus(status == 1)

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

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