#!/usr/bin/env python
#Transmission and reception, one ata a time on the same antena

from gnuradio import gr, gru, modulation_utils
from gnuradio import eng_notation
from gnuradio.eng_option import eng_option
from optparse import OptionParser
from numpy import random
import random, time, struct, sys, math

# from current dir
from transmit_path import transmit_path
from receive_path import receive_path
global sync_status,mode,ch
sync_status = "False"
mode = "sync"#default mode is sync
class my_top_block(gr.top_block):

    def __init__(self, mod_class, demod_class,
                 rx_callback, options_tx,options_rx):

        gr.top_block.__init__(self)
        self.rxpath = receive_path(demod_class, rx_callback, options_rx)
	self.txpath = transmit_path(mod_class, options_tx)
	self.connect(self.txpath);
	self.connect(self.rxpath);
	
#//////main//////  

global n_rcvd, n_right

def main():
    global n_rcvd, n_right,sync_status,mode,ch
    n_rcvd = 0
    n_right = 0
    def send_pkt(self, payload='', eof=False):
        return self.txpath.send_pkt(payload, eof)

    def rx_callback(ok, payload):
        print "inside rx callback"
        global n_rcvd, n_right, sync_status,mode,ch
	##############################################################
	if mode == "sync":
		if ok:
        		(pktno,) = struct.unpack('!H', payload[0:2])
       			(sync_signal,) = struct.unpack('!s', payload[2]) 
        		(data_channel,) = struct.unpack('!H', payload[3:5])
        		print "printing the elements of packet  ",sync_signal,"  !!!!!!!!!!!  ",data_channel," !!!!!\n"    
        		if str(sync_signal) == 'o' and str(data_channel) == str(ch):
        			#print "inside if2"
        			sync_status = "True"
				#tb.stop()
				#print "after tb stop ans sync status is ",sync_status," sync status\n"
                   
	##############################################################
	
	######################### traffic ############################
	if mode == "traffic":
		
		if ok:
			(data_header,) = struct.unpack('!s', payload[0])
			if data_header == 'd':
				comm = struct.unpack('!14s', payload[1:15])
				print("received this ", comm) 
	
	##############################################################

        n_rcvd += 1
        if ok:
            n_right += 1

        #print "ok = %5s  pktno = %4d  n_rcvd = %4d  n_right = %4d" % (
        #    ok, pktno, n_rcvd, n_right)

    mods = modulation_utils.type_1_mods()
    demods = modulation_utils.type_1_demods()

    #setting up the tx options parser
    parser_tx = OptionParser(option_class=eng_option, conflict_handler="resolve")
    expert_grp_tx = parser_tx.add_option_group("Expert_tx")
    print "printing Expert_tx group",expert_grp_tx,"printing Expert_tx group"
    parser_tx.add_option("-m", "--modulation", type="choice", choices=mods.keys(),
                      default='gmsk',
                      help="Select modulation from: %s [default=%%default]"
                            % (', '.join(mods.keys()),))

    parser_tx.add_option("-s", "--size", type="eng_float", default=1500,
                      help="set packet size [default=%default]")
    parser_tx.add_option("-M", "--megabytes", type="eng_float", default=1.0,
                      help="set megabytes to transmit [default=%default]")
    parser_tx.add_option("","--discontinuous", action="store_true", default=False,
                      help="enable discontinous transmission (bursts of 5 packets)")
    parser_tx.add_option("","--from-file", default=None,
                      help="use file for packet contents")
    print "printing parser_tx",parser_tx,"printing parser_tx"
    transmit_path.add_options(parser_tx, expert_grp_tx)

    for mod in mods.values():
        mod.add_options(expert_grp_tx)

    (options_tx, args_tx) = parser_tx.parse_args ()
    ############# Setting some default values for tx side of the block
    options_tx.tx_freq = 480e6#462.5625e6 
    options_tx.samples_per_symbol =  2
    options_tx.modulation = 'dbpsk'
    #options_tx.fusb_block_size = 4096
    #options_tx.fusb_nblocks = 16
    options_tx.bitrate = 0.0125e6
    #############
    if len(args_tx) != 0:
        parser_tx.print_help()
        sys.exit(1)

    if options_tx.tx_freq is None:
        sys.stderr.write("You must specify -f FREQ or --freq FREQ\n")
        parser_tx.print_help(sys.stderr)
        sys.exit(1)

    if options_tx.from_file is not None:
        source_file = open(options_tx.from_file, 'r')
    print "printing modulation type",mods[options_tx.modulation],"**"
    # build the graph
    print "printing tx options",options_tx,"&&&&\n"

    parser_rx = OptionParser (option_class=eng_option, conflict_handler="resolve")
    print "printing parser_rx",parser_rx,"!!!!!\n"
    print "after option parser"
    expert_grp_rx = parser_rx.add_option_group("Expert_rx")
    print "printing expert group rx",expert_grp_rx,"@@@@\n"
    parser_rx.add_option("-m", "--modulation", type="choice", choices=demods.keys(), 
                      default='gmsk',
                      help="Select modulation from: %s [default=%%default]"
                            % (', '.join(demods.keys()),))
    print "inside rx option parser"
    receive_path.add_options(parser_rx, expert_grp_rx)

    for mod in demods.values():
        mod.add_options(expert_grp_rx)

    (options_rx, args_rx) = parser_rx.parse_args ()

    if len(args_rx) != 0:
        parser_rx.print_help(sys.stderr)
        sys.exit(1)
    ############# Setting some default values for rx side of the block
    options_rx.rx_freq = 480e6#462.5625e6 #setting default rx_freq value
    options_rx.samples_per_symbol =  2
    options_rx.modulation = 'dbpsk'
    #options_rx.fusb_block_size = 4096
    #options_rx.fusb_nblocks = 16
    options_rx.bitrate = 0.0125e6
    #############
    if options_rx.rx_freq is None:
        sys.stderr.write("You must specify -f FREQ or --freq FREQ\n")
        parser_rx.print_help(sys.stderr)
        sys.exit(1)
    print "printing rx options",options_rx,"&&&&\n"

# build the graph

    tb = my_top_block(mods[options_tx.modulation],
                      demods[options_rx.modulation],
                      rx_callback,options_tx,
                      options_rx)
    r = gr.enable_realtime_scheduling()
    if r != gr.RT_OK:
        print "Warning: failed to enable realtime scheduling"

    tb.start()
    #tb.rxpath.disconnect(tb.rxpath.u, tb.rxpath.s2v,tb.rxpath.fft, tb.rxpath.c2mag, tb.rxpath.stats)

    
    #options_tx.size = 6 #2 bytes for packet size,2 bytes for the synchronization request(including redundant bit) and 2 bits to specify the channel number(including redundant bit)
    
    #print "printing packet size",pkt_size,"pkt size\n"
    
    myfile = file("logfile.txt", 'w')
    myfile.write("") 
    #sending sync packet-format 
    global ch
    running = True
    
    while running:
	
	################################################sync mode####################################
	if mode == "sync":
		#sync_status = "False"
		if sync_status != "True":
	    		ch = int(random.choice([1,7,8,14]))
	    		if ch < 8:
				hop_freq = float(1e6 * (462.5625+(ch-1)*0.025))#setting the centre freq frequency for sending packets
	    		else:
				hop_freq = float(1e6 * (467.5625+(ch-8)*0.025))#setting the centre freq frequency for sending packets
	    		
	    
	    		tb.txpath.set_freq(hop_freq)
	    		tb.rxpath.set_freq(hop_freq)
        		
			k = 0
			total_energy = 0 
			while k <  1:
				ch_energy = tb.rxpath.probe.level() #check if primary user is present
				total_energy = total_energy + ch_energy
				k+=1
			
			avg_energy = total_energy/1
			print "printing hop frequency ",hop_freq,"and energy is ",avg_energy,"\n"
			if int(avg_energy) > 2e7: #if primary user is there then dont transmit on this channel
				#while 
				continue
				#print "present"
			
			nbytes = 5 #int(1e6 * .0003)
			pkt_size = 5
	    		n = 0
	    		pktno = 0
    	    		while n < nbytes:
                		if options_tx.from_file is None:
                    			#data = (pkt_size - 2) * chr(pktno & 0xff) #0xff is 255
                    			data = 's'#+'s'+str(ch)+str(ch) #adding redundant bits for sync and channel
	        		else:
            	    			data = source_file.read(pkt_size - 2)
            	    			if data == '':
                        			break;

                		payload = struct.pack('!HsH', pktno & 0xffff,data,ch & 0xffff) #+ data
	        		#print "printing payload",payload,"**\n"
	
                		send_pkt(tb,payload)
				#print "sending this data ",data,"\n"
                		n += len(payload)
                		sys.stderr.write('.')
                		if options_tx.discontinuous and pktno % 5 == 4:
                    			time.sleep(1)
                			pktno += 1
	    		time.sleep(0.1)
            	#resend_count += 1 
		else:
			print "sync channel found..channel ",ch,"\n"  
			mode = "traffic"
			sync_status = "False"
	################################################end of sync mode####################################

    	################################################Communications mode####################################
    	if mode == "traffic":
		print "inside traffic mode \n"
		nbytes = 15
    	    	pkt_size = 15
		data_pktno = 0
		n = 0
		while n < nbytes:
                	#print >> myfile, "inside while"
               		if options_tx.from_file is None:
                 		#data = (pkt_size - 2) * chr(data_pktno & 0xff) #0xff is 255
                		data = 'dHi how are you' #Sending this message
	        		#print >> myfile, data
                		#print "printing data",data,"****\n"
                	else:
            		    	data = source_file.read(pkt_size - 2)
            		    	if data == '':
                	        	break;
	
			
                	payload = struct.pack('!15s', data)
	       		#print "printing payload",payload,"**\n"
				
                	send_pkt(tb,payload)
			#print "printing payload",payload,"**\n"
                	n += len(payload)
                	sys.stderr.write('.')
                	if options_tx.discontinuous and data_pktno % 5 == 4:
                		time.sleep(1)
                	data_pktno += 1
	    		#print "before sleeping for 10 seconds and value of resend count is",resend_count
			time.sleep(0.2)
			ch_energy = tb.rxpath.probe.level() #check if primary user is present
			print "energy is ",ch_energy,"\n"
			if int(ch_energy) > 2e7: #if primary user is there then dont transmit on this channel
				print "primary user detected..moving out of this channel\n"
				mode = "sync"
				continue
				
	################################################ end of Communications mode####################################		
	
    

if __name__ == '__main__':
    try:
        main()
    except KeyboardInterrupt:
        pass