#!/usr/bin/python

from __future__ import generators
from SimPy.Simulation import *
from random import expovariate, normalvariate

# Constants

NUM_GATE = 5   # number of gate
NUM_RUNWAY = 2  # number of runway

T_RUNWAY = 10  # runway occupation
T_GATES = 30   # gate occupation

PG_INT = 15.0  # average new plane comes

pcnt = 10

#

class PlaneGenerator(Process):
	def __init__(self,name):
		Process.__init__(self,name)
		self.cnt = 0

	def generate(self):
		while True:
			p = Plane('Plane #' + str(self.cnt))
			activate(p, p.execute())
			yield hold,self,r.expovariate(1/PG_INT)
			self.cnt += 1

class Plane(Process):
	def __init__(self,name):
		Process.__init__(self,name)

	def execute(self):
		# landing
		start = now()
		yield request, self, runways
		finish = now()
		yield hold, self, T_RUNWAY
		yield release, self, runways
		mrwl.observe(finish - start)

		am.add()

		# gate
		start = now()
		yield request, self, gates
		finish = now()
		am.sub()
		yield hold, self, T_GATES
		yield release, self, gates
		mg.observe(finish - start)

		am.add()

		# take off
		start = now()
		yield request, self, runways
		finish = now()
		am.sub()
		yield hold, self, T_RUNWAY
		yield release, self, runways
		mrwt.observe(finish - start)

class AirportMonitor:
	def __init__(self):
		self.cnt = 0
		self.max = 0

	def add(self):
		self.cnt += 1
		if (self.cnt > self.max):
			self.max = self.cnt

	def sub(self):
		self.cnt -= 1


initialize()

r = random.Random()

am = AirportMonitor()

mrwl = Monitor("runway landing")
mrwt = Monitor("runway takeoff")
mg = Monitor("gate")

runways = Resource(NUM_RUNWAY)
gates = Resource(NUM_GATE)

pg = PlaneGenerator('Source')
activate(pg, pg.generate(), 0.0)

simulate(until=24*60)

print "total planes generated: " + str(pg.cnt)
print "average waiting time for runway (landing): " + str(mrwl.mean())
print "average waiting time for runway (takeoff): " + str(mrwt.mean())
print "average waiting time for gate: " + str(mg.mean())
print "max planes waiting for gate/runway: " + str(am.max)