blockno: block that the trade is executed

input: param of the network.trade()
  - value (msg.value, ether amount that was sent along with the tx)
  - owner (the address that made the trade)
  - gas_price
  - source
  - srcAmount
  - dest
  - destAddress
  - maxDestAmount
  - minConversionRate
  - walletID
  - reserves (list of existing reserves at blockno)

network_issues: array of issues []string

reserve_issues: map of reserve to array of issues map[reserve][]string


function debug(input, blockno) returns (network_issues and reserve_issues) {
  init network_issues
  init reserve_issues

  // simple network scope checks

  if input.gas_price > wrapperGetGasCap(input, blockno) {
    "gas price exceeded max limit" -> network_issues
  }

  if input.source is token {
    if input.value > 0 {
      "failed because of sending ether along the tx when it is trying to trade token to ether" -> network_issues
    }
    if allowance(input.source, input.owner) < input.srcAmount {
      "failed because allowance is lower than srcAmount" -> network_issues
    }
    if balance(input.source, input.owner) < input.srcAmount {
      "failed because token balance is lower than srcAmount" -> network_issues
    }
  } else it is ether {
    if input.value != input.srcAmount {
      "failed because the user didn't send the exact amount of ether along" -> network_issues
    }
  }

  if input.source is ether {
    if input.srcAmount > wrapperGetUserCap(input, blockno) {
      "failed because the source amount exceeded user cap" -> network_issues
    }
  }
  if input.dest is ether {
    if input.destAmount > wrapperGetUserCap(input, blockno) {
      "failed because the dest amount exceeded user cap" -> network_issues
    }
  }

  // taking into reserve scope
  rates = wrapperGetConversionRate(reserve, input, blockno) for all reserve in input.reserves
  if all rates are 0 {
    "no reserve was chosen because all returned rates are 0" -> network_issues
    for reserve in input.reserves {
      reasons = wrapperGetReasons(reserve, input, blockno)
      if len(reasons) == 0 {
        // we can't really tell what is the reason
        "is block volume cap and volume between prices changes" -> reserve_issues[reserve]
      } else {
        reasons -> reserve_issues[reserve]
      }
    }
  } else {
    // there is at least one reserve is chosen
    chosenReserve = wrapperGetChosenReserve(input, blockno)
    wrapperGetReasons(reserve, input) -> reserve_issues[reserve]
  }

  return network_issues and reserve_issues
}


Wrapper functions:
  wrapperGetGasCap(input, blockno)
  wrapperGetUserCap(input, blockno)
  wrapperGetConversionRate(reserve, input, blockno)
  wrapperGetChosenReserve(input, blockno)
  wrapperGetReasons(reserve, input, blockno) returns one or more of following reasons:
    - trade is disabled in reserve level
    - volume limit exceeded
    - some internal configuration errors by the operator (just a validation)
    - price exceeds sanity price
    - price was not updated in last X blocks