Option Explicit

' Relay controlling the humidifiers. It will be closed to enable humidifiers and opened to disable them
' First relay is 1. Zero means it is not configured and this script will do nothing
Dim humidifiersRelay
humidifiersRelay = 1

'
' Optional parameters (have a default value)
'
' If the difference between Dew Point and Ambient Temperature is less than this value
' the relay specified in "humidifiersRelay" will be closed
Dim humOnMargin
humOnMargin = 4

' If the difference between Dew Point and Ambient Temperature is bigger than this value
' the relay specified in "humidifiersRelay" will be open
Dim humOffMargin
humOffMargin = 6

' How often (seconds) weather data is retrieved. Once a minute should be good enough
Dim requestInterval
requestInterval = 60

' Maximum allowed difference between current date and weather data date
Dim maxSecondsGap
maxSecondsGap = 300

'
' DO NOT EDIT FROM THIS POINT UNLESS YOU KNOW WHAT YOU ARE DOING
'
Dim df
Set df = CreateObject("Dragonfly.Help")
df.LogShow

Sub Log(str)
    df.LogAddLine("Humidity Control: " & str)
End Sub

Function ToDouble(str)
    On Error Resume Next

    ToDouble = CDbl(str)
    If (Err.Number <> 0) Then
        ToDouble = "NaN"
    End If
End Function

Function ReadFromRegistry(strRegistryKey, strDefault)
    Dim WSHShell, value

    On Error Resume Next
    Set WSHShell = CreateObject("WScript.Shell")
    value = WSHShell.RegRead( strRegistryKey )

    If err.number <> 0 Then
        readFromRegistry = strDefault
    Else
        readFromRegistry = value
    End If

    Set WSHShell = Nothing
End Function

Function GetJsonAttribute(json, attributeName)
    On Error Resume Next

    Dim re, match, attributeValue
    Set re = New RegExp
    re.Global = True
    re.IgnoreCase = True
    re.Pattern = """" & attributeName & """\s*:\s*(?:""([^""]*)""|(\d+\.?\d*))"

    Set match = re.Execute(json)
    If match.Count > 0 Then
        attributeValue = match.Item(0).SubMatches.Item(0)
        If (Len(attributeValue) = 0) Then
            attributeValue = match.Item(0).SubMatches.Item(1)
        End If
    Else
        attributeValue = ""
    End If

    GetJsonAttribute = attributeValue
End Function

Function ParseDate(dateString)
    On Error Resume Next

    Dim parts
    parts = Split(dateString, " ")
    Dim dateParts
    dateParts = Split(parts(0), "/")
    Dim timeParts
    timeParts = Split(parts(1), ":")
    ParseDate = DateSerial(CInt(dateParts(0)), CInt(dateParts(1)), CInt(dateParts(2))) + TimeSerial(timeParts(0), timeParts(1), timeParts(2))

    If Err.Number <> 0 Then
        Log("Invalid Date '" & dateDiff & "'")
        ParseDate = DateSerial(1970, 1, 1)
    End If
End Function

Function ReadWeatherData
    On Error Resume Next

    Dim filePath, fso, file, contents, dateDiff
    filePath = ReadfromRegistry("HKEY_CURRENT_USER\SOFTWARE\VB and VBA Program Settings\AAG_CloudWatcher\Window\PathName", "")
    If (Len(filePath) <= 0) Then
        Log("Cannot find file path in the registry. Quitting")
        WScript.Quit(1)
    End If
    filePath = filePath & "\aag_json.dat"
    Log("Reading weather data from '" & filePath & "'")

    Set fso = WScript.CreateObject("Scripting.FileSystemObject")
    Set file = fso.OpenTextFile(filePath, 1)
    contents = file.ReadAll
    file.Close
    Set file = Nothing
    Set fso = Nothing

    If (Len(contents) = 0) Then
        Log("Error reading file '" & filePath & "'")
        ReadWeatherData = ""
        Exit Function
    End If

    dateDiff = Now() - ParseDate(GetJsonAttribute(contents, "dateLocalTime"))

    If (dateDiff >= 1) Then
        Log("Weather data more than 1 day old")
        ReadWeatherData = ""
        Exit Function
    End If

    dateDiff = dateDiff * 24 * 3600 ' (24 * 3600) = Number of seconds in one day
    If (dateDiff > maxSecondsGap) Then
        Log("Weather data too old: " & dateDiff & " seconds")
        ReadWeatherData = ""
        Exit Function
    End If

    ReadWeatherData = contents
End Function

Sub CheckDewPoint(json)
    Dim temperature
    temperature = ToDouble(GetJsonAttribute(json, "temp"))

    Dim dewPoint
    dewPoint = ToDouble(GetJsonAttribute(json, "dewp"))
    If (Not IsNumeric(temperature) Or Not IsNumeric(dewPoint)) Then
        Log("Error reading temperature or dew point. Switching OFF humidifiers")
        df.RelayOpen(humidifiersRelay)
        Exit Sub
    End If
    Log("Temperature: " & temperature & " vs Dew Point:" & dewPoint)

    Dim temperatureDifference
    temperatureDifference = Abs(temperature - dewPoint)
    If (temperatureDifference > humOffMargin) then
        Log("Switching OFF humidifiers in relay #" & humidifiersRelay)
        df.RelayOpen(humidifiersRelay)
    ElseIf (temperatureDifference < humOnMargin) then
        Log("Switching ON humidifiers in relay #" & humidifiersRelay)
        df.RelayClose(humidifiersRelay)
    End If
End Sub

If (humidifiersRelay < 1) Then
    WScript.Echo("Humidifiers relay is not configured. Exiting")
    WScript.Quit(1)
End if

Dim doLoop
doLoop = True
If (WScript.Arguments.Count > 0) Then
    If (WScript.Arguments(0) = "/once") Then
        Log("Only running once")
        doLoop = False
    End If
End If

Dim json
Do
    json = ReadWeatherData
    If (Len(json) > 0) Then
        CheckDewPoint(json)
    End If

    If (doLoop) Then
        Log("Waiting " & requestInterval & " seconds for next reading")
        WScript.Sleep(requestInterval * 1000)
    End If
Loop While(doLoop)