#!/usr/bin/env python

# Copyright (c) 2009
#      Daniel O'Connor <darius@dons.net.au>.  All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
# 1. Redistributions of source code must retain the above copyright
#    notice, this list of conditions and the following disclaimer.
# 2. Redistributions in binary form must reproduce the above copyright
#    notice, this list of conditions and the following disclaimer in the
#    documentation and/or other materials provided with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND
# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED.  IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
# SUCH DAMAGE.
#

# Reverse engineered from the Linux library & example program at
# http://epsrv.astro.umk.pl/~ep/irbene/rsib/library/RSIB-Linux.zip
#
# There are 2 socket connections for some reason.
# The first seems to do [nearly] all the work
#
# Packets to the instrument
# On connection:
# -> 00 00 00 40
# <- 00 00 00 40 a0 04 00 00
#
# We need to echo back the last 4 bytes of the reply to a second
# socket opened to the same port. I don't know what that socket is for
# though.
#
# Send a command:
# -> 00 00 00 05 90 00 01 2a  49 44 4e 3f             .......* IDN?
#
# Offs	Value	Meaning
# 00	00	?
# 01	00	?
# 02	00	?
# 03	05	Length
# 04	90	MsgID
# 05	00	?
# 06	03	Seq number
# 07	2a (*)	Cmd byte 0
# 08	49 (I)	Cmd byte 1
# 09	44 (D)	Cmd byte 2
# 10	4a (N)	Cmd byte 3
# 10	3f (?)	Cmd byte 4
#
# Interactive program seems to cap length at 0x99 but perhaps the
# first 4 bytes are length.
#
# Reply to command:
# <- 00 00 00 23 80 00 01 52 6f 68 ...
#
# Offs	Value	Meaning
# 00	00	Length 31..24
# 01	00	       23..16
# 02	00	       15..8
# 03	23	        7..0
# 04	80	MsgID
# 05	00	?
# 06	01	Seq number

MSG_HELLO = 0x40   # We send this on connect
MSG_CMDREP = 0x80  # Reply from the instrument to us
MSG_CMD = 0x90     # Command to the instrument

import socket

class RSIBDevice(object):
    hello = '\x00\x00\x00\x40'
    docmd = '\x00\x00\x00\x05\x90\x00\x01'

    def __init__(self, host, port = 2525):
        self.host = host
        self.port = port

        s1 = socket.socket()
        s1.settimeout(5)
        s1.connect((self.host, self.port))
        s1.send('\x00\x00\x00\x40')
        rx = ''
        while len(rx) < 8:
            rx = rx + s1.recv(8)
            if rx == '':
                raise "EOF from device"

        s2 = socket.socket()
        s2.settimeout(5)
        s2.connect((self.host, self.port))
        s2.send(rx[4:])

        self.s1 = s1
        self.s2 = s2
        self.tag = 0
        
    def write(self, cmd, timeout = 0.5):
        """Send data (string) to the instrument"""
        self.s1.settimeout(timeout)

        if len(cmd) > 0x99:
            raise "Command too long"
        
        # Pre-increment for easy comparison in read
        self.tag = (self.tag + 1) & 0xff
        msg = '\x00\x00\x00' + chr(len(cmd)) + '\x90\x00' + chr(self.tag) + cmd
        self.s1.send(msg)
        
    def read(self, timeout = 0.5):
        """Read data from the device, waits for up to timeout seconds for each TCP read"""

        self.s1.settimeout(timeout)
        
        # Fetch the header
        rx = ''
        while len(rx) < 7:
            rx = self.s1.recv(7)
            if rx == '':
                raise "EOF from device"
        
        if self.tag != ord(rx[6]):
            raise "Reply out of order, got 0x%02x expected 0x%02x" % (ord(rx[6]), self.tag)

        rxlen = ord(rx[0]) << 24 | ord(rx[1]) << 16 | ord(rx[2]) << 8 | ord(rx[3])
        if ord(rx[5]) != 0:
            print "Mystery byte %d != 0" % (ord(rx[5]))
            
        # Fetch the actual reply now we know the length
        reply = ''
        while len(reply) < rxlen:
            rx = self.s1.recv(rxlen)
            if rx == '':
                raise "EOF from device"
            reply += rx
            
        return(reply)


def test(r):
    import numpy
    from matplotlib import pylab
    
    r.write('*IDN?')
    print "ID is " + r.read(5)
    r.write("*RST")
    r.write("INIT:CONT OFF")
    r.write("SYST:DISP:UPD ON")
    r.write("FREQ:STAR 85MHz;STOP 125MHz")
    r.write("DISP:WIND:TRAC:T:RLEV -20dBm")
    r.write("INIT;*WAI")
    r.write("*OPC?")
    print "OPC - " + r.read(10)
    r.write("CALC:MARK:PEXC 6DB")
    r.write("CALC:MARK:FUNC:TOI ON")
    r.write("CALC:MARK:FUNC:TOI:RES?")
    print "Result " + r.read(10)

    r.write("FORM:DAYA ASC")
    r.write("CALC:LIM5:NAME 'TEST1'")
    r.write("CALC:LIM5:COMM 'Upper limit line'")
    r.write("CALC1:LIM5:TRAC 2")
    r.write("TRAC1? TRACE1")
    data = r.read(10)
    #print "Data - " + dat
    data = map(float, data.split(','))
    ary = numpy.array(data)
    pylab.plot(ary)
    pylab.show()