#!/usr/bin/env python
# coding: utf-8

# **SimPy** is a process-based discrete-event simulation framework based on standard Python. Its event dispatcher is based on the time of events and the processes it contains. It provides the modeller with components of a simulation model, including processes, for active components like vehicles or customers, and resources, for passive components like servers or counters. SimPy also provides monitors to aid in understanding the model.  
# 
**Features of SimPy:**
# - Processes: SimPy has a built-in concept of processes, which are the active components of a simulation. They can be used to model active entities like customers, vehicles, or messages.
# - Events: SimPy uses events to schedule processes. Events are triggered at a specific time and can be used to model interactions between processes.
# - Resources: SimPy provides resources, which are used to model passive components like servers, counters, or channels. Resources can be used by processes and can be limited in their capacity.
# - Monitors: SimPy provides monitors, which are used to observe and analyze the simulation. Monitors can be used to collect data on processes, resources, and events.
# - Randomness: SimPy has built-in support for randomness, which is essential for simulation models. It uses the Mersenne Twister random number generator.
# - Easy to Learn: SimPy is built on top of Python and uses a syntax that is easy to learn, even for those without prior experience with simulation or Python.
# - Fast: SimPy is fast and can handle large simulations with millions of events.
# - Extensive Libraries: SimPy has extensive libraries for various domains like manufacturing, healthcare, and logistics.
# - Visualization: SimPy provides tools for visualization, which can be used to visualize the simulation and insights.
# 
# **To install:**  
# > pip intall simpy

# In[3]:


import simpy


# In[4]:


print('simpy version: ' + simpy.__version__)


# In[7]:


class Car(object):
    ''' stop and drive the car '''
    def __init__(self, env):
        # reference to current simulation environment
        self.env = env
        
        # Start the park_and_drive process everytime an instance is created
        self.action = env.process(self.park_and_drive())
        
    def park_and_drive(self):
        while True:
            print('Start parking at %d' % self.env.now)
            parking_duration = 5
            yield self.env.timeout(parking_duration)

            print('Start driving at %d' % self.env.now)
            trip_duration = 2
            yield self.env.timeout(trip_duration)            
        
# create an environment        
env = simpy.Environment()

# create an instance of the Car class
# add car process to the environment
car = Car(env)

# start simulation
# run for 15 seconds (note the number could mean anything, i.e. seconds/hours/days/years/etc.)
env.run(until=15)        


# # Resources  
# 
# * [SimPY Tutorial](https://simpy.readthedocs.io/en/latest/simpy_intro/basic_concepts.html)

# <p class="text-muted">This tutorial was created by <a href="https://www.hedaro.com" target="_blank"><strong>HEDARO</strong></a></p>