punchd/message.nim

import strutils
from net import IpAddress, parseIpAddress, Port, `$`

proc parseField(input: string, output: var string) =
  output = input

proc parseField[T: SomeUnsignedInt](input: string, output: var T) =
  let parsed = parseUInt(input)
  if parsed > T.high:
    raise newException(ValueError, "Unsigned integer out of range")
  output = parsed.T

proc parseField(input: string, output: var IpAddress) =
  output = parseIpAddress(input)

proc parseField(input: string, output: var Port) =
  var portNumber: uint16
  parseField(input, portNumber)
  output = Port(portNumber)

proc parseField[S, T](input: string, output: var array[S, T]) =
  let parts = input.split(",", S.high)
  if parts.len != S.high + 1:
    raise newException(ValueError, "Array has wrong length")
  for i in 0 .. S.high:
    parseField(parts[i], output[i])

proc parseField[T](input: string, output: var seq[T]) =
  let parts = input.split(",")
  output = newSeq[T](parts.len)
  if parts.len > 0:
    for i in 0 .. parts.len - 1:
      parseField(parts[i], output[i])

proc parseField[T: tuple | object](input: string, output: var T) =
  var fieldCount = 0
  for _ in output.fields:
    fieldCount = fieldCount + 1
  let args = input.parseArgs(fieldCount)
  var i = 0
  for value in output.fields:
    parseField(args[i], value)
    i.inc

proc parseArgs*(input: string, count: int, optionalCount = 0): seq[string] =
  assert(optionalCount <= count)
  result = input.split("|", count - 1)
  if result.len < count:
    if result.len < count - optionalCount:
      raise newException(ValueError, "invalid message")
    result.add(repeat("", count - result.len))

proc parseMessage*[T: tuple | object](input: string): T =
  parseField(input, result)