import argparse
import threading
import logging
import signal
import requests

from multiprocessing import Process, Event, Queue
from logging.handlers import QueueHandler
from imapclient import IMAPClient, exceptions
from datetime import datetime
from clacksme.model import *

_shutdown = Event()

class MailboxNotifier(object):

    def __init__(self, mailbox):
        self.mailbox = mailbox
        self.last_check = mailbox.last_check

    def start(self, log_queue, event_queue):
        imap_log = logging.getLogger('imapclient')
        imap_log.level = logging.INFO
        log_queue_handler = QueueHandler(log_queue)
        self.log = logging.getLogger(self.mailbox.user)
        self.log.level = logging.DEBUG
        self.log.addHandler(log_queue_handler)
        imap_log.addHandler(log_queue_handler)
        self.event_queue = event_queue

        self.log.info(
            f"Starting up IMAP connection for {self.mailbox.user}")
        while not _shutdown.is_set():
            try:
                with IMAPClient(self.mailbox.imap_host) as self.imap:
                    self.imap.login(self.mailbox.imap_user, 
                        self.mailbox.imap_pass)
                    self.imap.select_folder("INBOX", readonly=True)
                    self.log.info("Connected to INBOX")
                    messages = self.imap.search("UNSEEN")
                    if len(messages) > 0:
                        notify = self.check_events(messages)

                    self.imap_idle()

            except Exception:
                self.log.error("IMAP exception of some kind")
                self.log.exception("IMAP")

    def imap_idle(self):
        while not _shutdown.is_set():
            try:
                self.imap.idle()
                self.log.info("Waiting for new messages")
                responses = self.imap.idle_check(timeout=30)
                self.log.debug(responses)
                for resp in responses:
                    if len(resp) == 2:
                        if resp[1] == b"RECENT":
                            self.imap.idle_done()
                            messages = self.imap.search("UNSEEN")
                            if len(messages) > 0:
                                notify = self.check_events(messages)
                            self.imap.idle()

                self.log.info("IDLE done")
                self.imap.idle_done()

            except IMAPClient.AbortError:
                self.log.error("IMAP abort, break")
                break

    def check_events(self, messages):
        notify = False
        events = Events.select().where(Events.user == self.mailbox.user)
        event_ids = [event.event_id for event in events]
        for uid in messages:
            if str(uid) not in event_ids:
                self.log.info("New message")
                now = datetime.now()
                self.event_queue.put({
                    "mailbox": self.mailbox,
                    "now": now,
                    "event_id": uid})
                if self.last_check is not None:
                    delta = now - self.last_check

                    try:
                        backoff = System.get(System.key == "backoff")
                    except System.DoesNotExist:
                        backoff = System(key="backoff", value="60")
                        backoff.save()

                    if delta.seconds > int(backoff.value):
                        notify = True
                else:
                    notify = True

                if notify:
                    self.log.debug("Notify")
                    self.last_check = now
                    self.on_notify()

    def on_notify(self):
        self.log.info("Triggering notifications")
        text = f"New messages have been received at {self.mailbox.imap_user}"
        targets = Services.select().where(Services.user == self.mailbox.user)
        for target in targets:

            if target.service == "pushover" and target.enabled:
                self.send_pushover(target.target, text)

            if target.service == "mattermost" and target.enabled:
                self.send_mattermost(target.target, text)

    def send_pushover(self, po_user, text):
        notifier = Notifier.get(Notifier.service == "pushover")
        url = "https://api.pushover.net/1/messages.json"
        params = {
            "token": notifier.secret,
            "user": po_user,
            "message": text
        }
        response = requests.post(url, data=params)
        self.log.debug(response.status_code)
        self.log.debug(response.text)

    def send_mattermost(self, url, text):
        params = {
            "text": text
        }
        response = requests.post(url, json=params)
        self.log.debug(response.status_code)
        self.log.debug(response.text)


def shutdown_handler(signal, frame):
    _shtudown.set()

def logger_thread(log_queue):
    logging.debug("starting logger thread")
    while True:
        entry = log_queue.get()
        if entry is None:
            logging.debug(".break.")
            break
        logger = logging.getLogger(entry.name)
        logger.handle(entry)

def event_thread(event_queue):
    logging.debug("starting event thread")
    while not _shutdown.is_set():
        entry = event_queue.get()
        if entry is not None:
            mailbox = entry['mailbox']
            new_event = Events(
                user=mailbox.user,
                mailbox=mailbox.imap_user,
                event_id=entry['event_id'])
            new_event.save()
            mailbox.last_check = entry['now']
            mailbox.save()
        else:
            logging.debug("..break..")
            break

def main():
    signal.signal(signal.SIGTERM, shutdown_handler)

    a_parser = argparse.ArgumentParser(
        description="IMAP notification suite")
    a_parser.add_argument(
        '-s', '--store', default="store.db",
        help="sqlite database filepath")
    args = a_parser.parse_args()

    db.init(args.store, pragmas={'journal_mode': 'wal'})
    create_tables()

    log_queue = Queue()
    event_queue = Queue()
    processes = []
    for mailbox in Mailbox.select():
        imap_process = MailboxNotifier(mailbox)
        p = Process(
            target=imap_process.start, name=mailbox.user,
            args=(log_queue,event_queue,))
        processes.append(p)
        p.daemon = True
        p.start()

    logging.basicConfig(level=logging.DEBUG)
    logging.debug("starting up main")
    log_thread = threading.Thread(target=logger_thread, args=(log_queue,))
    log_thread.start()
    e_thread = threading.Thread(target=event_thread, args=(event_queue,))
    e_thread.start()

    logging.debug(processes)
    try:
        for p in processes:
            p.join()

    except KeyboardInterrupt:
        logging.debug("CTRL+C")
        logging.debug("Keyboard interrupt, shutting down from main")
        for p in processes:
            p.terminate()
            logging.debug("..terminate..")
        _shutdown.set()

    log_queue.put(None)
    event_queue.put(None)
    log_thread.join()
    e_thread.join()
    logging.debug("exiting main")

if __name__ == "__main__":
    main()