# -*- coding: utf-8 -*-
import asynchat
import asyncore
import socket
import sys

import os
from lxml import objectify
from lxml import etree

"""ebus specific data field formats"""
class fields:
    class DataField(object):
        def __init__(self, name, offset):
            self.name = name
            self.offset = offset
        def value(self,data):
            raise NotImplemented()

    class Data1c(DataField):
        def value(self,data):
            return ord(data[self.offset])/2.0

    class Data2c(DataField):
        """
        Beispiel für die Berechnung:
            if ((x & 8000h) == 8000h) // y negativ
                y = - [dez(High_Byte(!x)) 16 + dez(High_Nibble (Low_Byte (!x)))
                    + (dez(Low_Nibble (Low_Byte (!x))) +1 ) / 16]
            else                       // y positiv
                y = dez(High_Byte(x)) 16 + dez(High_ Nibble (Low Byte (x)))
                    + dez(Low_ Nibble (Low Byte (x))) / 16
        """
        def value(self,data):
            highByte = ord(data[self.offset+1])
            lowByte= ord(data[self.offset])
            if (0x8000 & (highByte<<8 | lowByte)) == 0x8000:
                return (-1) * ( (0xff^highByte)*16 + (0xff^(lowByte>>4)) + (0x0ff^(0xf&lowByte) + 1)/16.0 )
            else:
                return highByte*16 + (lowByte>>4) + (lowByte&0xf)/16.0

    class Data2b(DataField):
        """
        if ((x&8000h) == 8000h) // y negativ
              y = - [dez(High_Byte(!x)) + (dez(Low_Byte(!x)) + 1) / 256]
        else                        // y positiv
              y = dez(High_Byte (x)) + dez(Low_Byte (x)) / 256
        """
        def value(self,data):
            highByte = ord(data[self.offset+1])
            lowByte= ord(data[self.offset])
            if (0x8000 & (highByte<<8 | lowByte)) == 0x8000:
                return (-1) * ((0xff^highByte) + (0xff^lowByte+1)/256.0)
            else:
                return highByte + lowByte/256.0

    class Bit(DataField):
        def value(self, data):
            return ord(data[self.offset]) == 0x1
    
    class Bcd(DataField):
        """
        y = dez(High_Nibble(x))*10 + dez(Low_Nibble(x))
        """
        def value(self, data):
            byte = ord(data[self.offset])
            return (byte >> 4) * 10 + (byte & 0xf)

    class Byte(DataField):
        def value(self, data):
            return ord(data[self.offset])


    class ByteEnum(DataField):
        def __init__(self, name, offset, values):
            fields.DataField.__init__(self, name, offset)
            self.values = values

        def value(self, data):
            value = ord(data[self.offset])
            if self.values.has_key(value):
                return self.values[value]
            else:
                return None

class EbusXMLMixin(object):
    EBUS_SPECIFICATION = os.path.join(os.path.dirname(__file__), "ebus_specification.xml")
    ebus_xml = objectify.parse(open(EBUS_SPECIFICATION))

    @staticmethod
    def address_to_type(address):
        d=[dev.get("type") for dev in EbusXMLMixin.ebus_xml.xpath("/ebus/devices/device[@address=$address]",
                                                                  address="0x%.2x"%address)]
        return len(d)>0 and d[0] or None

    def _get_packet(self):
        p=EbusXMLMixin.ebus_xml.xpath("/ebus/packets/packet[@primary=$primary and @secondary=$secondary]",
                                      primary="0x%.2x"%self.primary_command,
                                      secondary="0x%.2x"%self.secondary_command)
        return len(p)>0 and p[0] or None

    def _get_source(self):
        s=EbusXMLMixin.ebus_xml.xpath("/ebus/devices/device[@address=$address]",
                                      address="0x%.2x"%self.source)
        return len(s)>0 and s[0] or None

    def _get_destination(self):
        d=EbusXMLMixin.ebus_xml.xpath("/ebus/devices/device[@address=$address]",
                                      address="0x%.2x"%self.destination)
        return len(d)>0 and d[0] or None
                                        
    def name(self):
        return self._get_packet().get("name")

    def description(self):
        return self._get_packet().get("description")

    def format(self):
        packet = self._get_packet()
        if packet is not None:
            for field in packet.fields.iterchildren():
                name = field.get("name")
                offset = field.get("offset")
                if not name:
                    continue
                elif field.tag == "bit":
                    yield fields.Bit( name, int(offset))
                elif field.tag == "data1c":
                    yield fields.Data1c( name, int(offset) )
                elif field.tag == "data2b":
                    yield fields.Data2b( name, int(offset) )
                elif field.tag == "data2c":
                    yield fields.Data2c( name, int(offset) )
                elif field.tag == "bcd":
                    yield fields.Bcd( name, int(offset) )
                elif field.tag == "byteEnum":
                    options = dict(map(lambda opt: ( int(opt.get("value"),16), opt.get("name")),
                                      field.xpath("./option")))
                    yield fields.ByteEnum( name, int(offset), options)
                else:
                    print "error: %s in %s" % (name, self.name())


def formatHex(data):
    return " ".join(map(lambda byte: "%.2x"%ord(byte), data))

class EbusPacket(EbusXMLMixin):
    def __init__(self, source, destination, primary_command, secondary_command):
        self.source = source
        self.destination = destination
        self.primary_command = primary_command
        self.secondary_command = secondary_command

    def __str__(self):
        #XXX self.length only in subclasses
        return "<%-18s name=\"%s\" source=\"0x%.2x\" destination=\"0x%.2x\" primary=0x%x secondary=0x%x length=0x%x %s>" % \
            (self.__class__.__name__, self.name(), self.source, self.destination, \
             self.primary_command, self.secondary_command, self.length, \
             " ".join(map(lambda name: "%s=%s" % (name, self.values()[name]),self.values())))

    def values(self):
        return dict( map(lambda format: (format.name, format.value(self.data) ),
                         self.format() ))

class EbusMasterMaster(EbusPacket):
    def __init__(self, source, destination, primary_command, secondary_command, data):
        EbusPacket.__init__(self, source, destination, primary_command, secondary_command)
        self.length = len(data)
        self.data = data

class EbusMasterSlave(EbusPacket):
    def __init__(self, source, destination, primary_command, secondary_command, request, response):
        EbusPacket.__init__(self, source, destination, primary_command, secondary_command)
        self.length = len(request)
        self.request = request
        self.response = response

class EbusBroadcast(EbusPacket):
     def __init__(self, source, destination, primary_command, secondary_command, data):
        EbusPacket.__init__(self, source, destination, primary_command, secondary_command)
        self.length = len(data)
        self.data = data


class EbusReader(asynchat.async_chat):
    def __init__(self):
        asynchat.async_chat.__init__(self)
        self.set_terminator("")
        self.create_socket(socket.AF_INET, socket.SOCK_STREAM)
        self.connect(("10.2.2.200", 7970))

        self.packetIndex = 0
        self.buf = ""
        self.debug = False

    def collect_incoming_data(self,data):
        for it in range(len(data)):
            if data[it] == "\xaa":
                if it+1 < len(data) and data[it+1] != "\xaa":
                    self._parse(self.buf)
                    self.buf = ""
                    self.packetIndex = 0
            else:
                self.buf += data[it]
                self.packetIndex = self.packetIndex + 1
                #print "%.2x [%d]" % (ord(data[it]),self.packetIndex)
        
    def _parse(self,dataRaw):
        #0xaa bug
        i = 0
        data = ""
        while (i+1) < len(dataRaw):
            if ord(dataRaw[i]) == 0xaa and ord(dataRaw[i+1]) == 0x01:
                data += "\xaa"
                i = i + 1
            elif ord(dataRaw[i]) == 0xa9 and ord(dataRaw[i+1]) == 0x00:
                data += "\xa9"
                i = i + 1
            else:
                data += dataRaw[i]
            i = i + 1
        
        if len(data) < 2:
            print "GAGA"
            return
        source = ord(data[0])
        sourceType = EbusXMLMixin.address_to_type(source)
        destination = ord(data[1])
        destinationType = EbusXMLMixin.address_to_type(destination)

        if len(data) < 9:
            print >>sys.stderr, "Unvollständige Daten"
            return

        primaryCommand = ord(data[2])
        secondaryCommand = ord(data[3])
        payloadLength = ord(data[4])
        payload = data[5:5+payloadLength]

        if self.debug:
            print "\033[1;31m%.2x %.2x\033[1;m \033[1;33m%.2x %.2x\033[1;m \033[1;30m%.2x\033[1;m \033[1;45m%s\033[1;m" % (source,destination,primaryCommand,secondaryCommand,payloadLength,formatHex(payload))

        p = None
        if sourceType == 'master' and destinationType == 'master':
            p = EbusMasterMaster(source, destination, primaryCommand, secondaryCommand, payload)
        elif sourceType == 'master' and destinationType == 'slave':
            p = EbusMasterSlave(source, destination, primaryCommand, secondaryCommand, payload, None) #FIXME
        elif sourceType == 'master' and destinationType == 'broadcast':
            p = EbusBroadcast(source, destination, primaryCommand, secondaryCommand, payload)
        else:
            print >>sys.stderr, "KOMISCHES ZEUG"
            print >>sys.stderr, "source=%s sourceType=%s destination=%s destType=%s" % \
                (source, sourceType, destination, destinationType)
            return
        self.handle_ebus(p)

    def handle_ebus(self,ebus_packet):
        print >>sys.stderr, "unhandled ebus_packet"