# Leon Seng and Ahmet Sekercioglu last modified: 23 May 2020
from random import expovariate, random
import functools
import simpy

from SimComponents import PacketGenerator, PacketSink, PortMonitor
from IQSwitchComponents import IQSwitchInputPort, IQSwitchOutputPort

def run_sim():
    # Create the SimPy environment
    # Operating in bytes unless specified otherwise

    link_rate_bps = 10e6
    link_rate = link_rate_bps/8
    link_load = 0.1
    mean_packet_size = 300
    mean_interarrival_time = mean_packet_size/(link_rate*link_load)

    input_queue_size = 10*mean_packet_size  # bytes - should give an
                                            # indication of average queue
                                            # size when loaded

    env = simpy.Environment()

    # define elements
    interarrival_dist = functools.partial(expovariate, 1/mean_interarrival_time)
    size_dist = functools.partial(expovariate, 1/mean_packet_size)
    pg1 = PacketGenerator(env, "LAN1", adist=interarrival_dist, sdist=size_dist)
    pg2 = PacketGenerator(env, "LAN2", adist=interarrival_dist, sdist=size_dist)

    input_sp1 = IQSwitchInputPort(env, id="in1", qlimit=input_queue_size,
                                  limit_bytes=True, rate=link_rate_bps,
                                  probs=[0.5, 0.5])
    input_sp2 = IQSwitchInputPort(env, id="in2", qlimit=input_queue_size,
                                  limit_bytes=True, rate=link_rate_bps,
                                  probs=[0.5, 0.5])

    output_sp1 = IQSwitchOutputPort(env, rate=link_rate_bps, debug=True)
    output_sp2 = IQSwitchOutputPort(env, rate=link_rate_bps, debug=True)

    ps_debug = True
    ps1 = PacketSink(env, debug=True)
    ps2 = PacketSink(env, debug=ps_debug)

    # Wire packet generators and sinks together
    pg1.out = input_sp1
    pg2.out = input_sp2

    input_sp1.outs = [output_sp1, output_sp2]
    input_sp2.outs = [output_sp1, output_sp2]

    output_sp1.out = ps1
    output_sp2.out = ps2

    # Using a PortMonitor to track queue sizes over time
    sample_dist = lambda : 100*mean_interarrival_time
    pm = PortMonitor(env, input_sp1, dist=sample_dist)

    env.run(until=2)
    # print(pm.sizes)
    print(input_sp1.packets_drop)
    print(output_sp1.packets_drop)
    print(input_sp2.packets_drop)
    print(output_sp2.packets_drop)

if __name__ == '__main__':
    run_sim()