import multiprocessing, requests
import copy
import time
import pprint
from enum import Enum
from queue import Queue

from datetime import datetime, timedelta
from multiprocessing import Pool

class QueueState(Enum):
    Inactive = 0
    Sleeping = 1
    Processing = 2

class DelayQueue:

    def __init__(self):
        self.state = QueueState.Inactive
        self.queue = []

    def run(self):
        while True:
            currentwork = [item for item in self.queue if item.time <= datetime.now()]
            currentwork.sort(key=lambda x: x.time, reverse=False)

            print(len(currentwork), 'tasks ready for processing')
            #Process the currentwork
            for i, task in list(enumerate(currentwork)):
                if i == 0:
                    print('Processing currentwork')

                print('Processing item', i)
                if task.process() == True:
                    currentwork.remove(task)
                    self.queue.remove(task)

            print('Processing current tasks complete')
            #No work ready yet
            if len(currentwork) == 0 and len(self.queue) > 0:
                print("No work ready to process")

            if len(self.queue) == 0:
                print('Queue empty closing queue')
                self.state = QueueState.Inactive
                break
            elif len(currentwork) == 0:
                self.queue.sort(key=lambda x: x.time, reverse=False)
                nexttask = self.queue[0]
                print("Getting next task", nexttask)
                delta =  nexttask.time - datetime.now()
                print('Sleeping', delta.total_seconds(), 'seconds')
                self.state = QueueState.Sleeping
                if delta.total_seconds() > 0:
                    time.sleep(delta.total_seconds())

    def add(self, func, delay=0, **kwargs):
        self.queue.append(Task(func, datetime.now() + timedelta(milliseconds=delay), **kwargs))
        #if self.state == QueueState.Inactive:
        #self.run()

    def remove():
        raise NotImplementedError

class Task:
    def __init__(self, func, time, **kwargs):
        print("New task", (func.__name__, time, kwargs))
        self.func = func
        self.time = time
        self.args = kwargs

    def process(self):
        self.func(**self.args)
        return True
    def __str__(self):
        return str((self.func.__name__, self.time, self.args))

def get(**kwargs):
    url = kwargs['url']
    print('Requesting', url)
    r = requests.get(url=url)
    print("Status Code", r.status_code)


queue = DelayQueue()

queue.add(get, 1500, url='http://www.google.com')
queue.add(get, 4300, url='http://www.yahoo.com')
queue.add(get, 3900, url='http://www.att.com')
queue.add(get, 2500, url='http://www.nbc.com')
queue.add(get, 2450, url='http://www.msn.com')
queue.add(get, 2450, url='http://www.gmail.com')

queue.run()

New task ('get', datetime.datetime(2018, 1, 19, 17, 18, 51, 843225), {'url': 'http://www.google.com'})
New task ('get', datetime.datetime(2018, 1, 19, 17, 18, 54, 643616), {'url': 'http://www.yahoo.com'})
New task ('get', datetime.datetime(2018, 1, 19, 17, 18, 54, 243917), {'url': 'http://www.att.com'})
New task ('get', datetime.datetime(2018, 1, 19, 17, 18, 52, 844260), {'url': 'http://www.nbc.com'})
New task ('get', datetime.datetime(2018, 1, 19, 17, 18, 52, 794472), {'url': 'http://www.msn.com'})
New task ('get', datetime.datetime(2018, 1, 19, 17, 18, 52, 794630), {'url': 'http://www.gmail.com'})
0 tasks ready for processing
Processing current tasks complete
No work ready to process
Getting next task ('get', datetime.datetime(2018, 1, 19, 17, 18, 51, 843225), {'url': 'http://www.google.com'})
Sleeping 1.498037 seconds
1 tasks ready for processing
Processing currentwork
Processing item 0
Requesting http://www.google.com
Status Code 200
Processing current tasks complete
No work ready to process
Getting next task ('get', datetime.datetime(2018, 1, 19, 17, 18, 52, 794472), {'url': 'http://www.msn.com'})
Sleeping 0.820134 seconds
2 tasks ready for processing
Processing currentwork
Processing item 0
Requesting http://www.msn.com
Status Code 200
Processing item 1
Requesting http://www.gmail.com
Status Code 200
Processing current tasks complete
No work ready to process
Getting next task ('get', datetime.datetime(2018, 1, 19, 17, 18, 52, 844260), {'url': 'http://www.nbc.com'})
Sleeping -0.540612 seconds
1 tasks ready for processing
Processing currentwork
Processing item 0
Requesting http://www.nbc.com
Status Code 200
Processing current tasks complete
No work ready to process
Getting next task ('get', datetime.datetime(2018, 1, 19, 17, 18, 54, 243917), {'url': 'http://www.att.com'})
Sleeping 0.708722 seconds
1 tasks ready for processing
Processing currentwork
Processing item 0
Requesting http://www.att.com
Status Code 200
Processing current tasks complete
No work ready to process
Getting next task ('get', datetime.datetime(2018, 1, 19, 17, 18, 54, 643616), {'url': 'http://www.yahoo.com'})
Sleeping 0.143595 seconds
1 tasks ready for processing
Processing currentwork
Processing item 0
Requesting http://www.yahoo.com
Status Code 200
Processing current tasks complete
Queue empty closing queue