#! /usr/bin/env mpenv
#
# This script monitors a user supplied list of MX network fields for
# value changed callbacks.
#

import time

import Mp

#---------------------------------------------------------------------------

def vc_callback( callback, nf ):
        server_name = nf.server.get_field( "hostname" )

        server_port = nf.server.get_field( "port" );

#        print( "vc_callback invoked for server '%s@%s', field '%s'" \
#                % ( server_name, server_port, nf.name ) )
#
#        print( "callback_id = %d" % callback.callback_id )

        value = nf.get_local_value()

        print( "callback: %s@%s:%s = %s" \
                % ( server_name, server_port, nf.name, str(value) ) )

#---------------------------------------------------------------------------

mx_database = Mp.RecordList( None )

callback_list = []

for arg in sys.argv[2:]:

        # Create a network field for this item.
        
        nf = Mp.get_network_field( mx_database, arg )

        print( "Adding nf = '%s'" % nf.name )

        server_name = nf.server.get_field( "hostname" )
        server_port = nf.server.get_field( "port" )

        print( "initial value: %s@%s:%s = %s" \
                % ( server_name, server_port, nf.name, nf.get() ))

        # Add a value changed callback for the network field.

        callback = nf.add_callback( Mp.MXCBT_VALUE_CHANGED, vc_callback, nf )

        callback_list.append( callback )

        del callback

if ( callback_list == [] ):
        print ( "No callbacks requested." )
        sys.exit(0)

# Monitor the callbacks

mx_database.set_program_name( "mp_monitor" )

while (True):

        try:
                mx_database.wait_for_messages(1.0)
        except Mp.Timed_Out_Error:
                pass

        if ( Mp.kbhit() ):
                c = Mp.getch()

                if ( c == 113 ):

                        length = len(callback_list)

                        for i in range(length):
                                c = callback_list[0]

                                del callback_list[0]
                                del c

                        del callback_list
                break

print( "Exiting..." )