from typing import List
from datetime import datetime, timedelta
from sqlalchemy import Table, Column, Integer, String, ForeignKey, DateTime, Boolean, func
from sqlalchemy.orm import relationship
from sqlalchemy.orm.attributes import flag_modified
from orm import Permission, User, Topic, TopicSubscription
from orm.comment import Comment
from orm.base import Base, local_session

from functools import reduce

import asyncio

class ShoutCommentsSubscription(Base):
	__tablename__ = "shout_comments_subscription"
	
	id = None
	subscriber = Column(ForeignKey('user.slug'), primary_key = True)
	shout = Column(ForeignKey('shout.slug'), primary_key = True)
	createdAt: str = Column(DateTime, nullable=False, default = datetime.now, comment="Created at")
	auto = Column(Boolean, nullable=False, default = False)
	deletedAt: str = Column(DateTime, nullable=True)

class ShoutAuthor(Base):
	__tablename__ = "shout_author"
	
	id = None
	shout = Column(ForeignKey('shout.slug'), primary_key = True)
	user = Column(ForeignKey('user.slug'), primary_key = True)
	
class ShoutViewer(Base):
	__tablename__ = "shout_viewer"
	
	id = None
	shout = Column(ForeignKey('shout.slug'), primary_key = True)
	user = Column(ForeignKey('user.id'), primary_key = True)

class ShoutTopic(Base):
	__tablename__ = 'shout_topic'
	
	id = None
	shout = Column(ForeignKey('shout.slug'), primary_key = True)
	topic = Column(ForeignKey('topic.slug'), primary_key = True)

class ShoutRating(Base):
	__tablename__ = "shout_rating"

	id = None
	rater = Column(ForeignKey('user.slug'), primary_key = True)
	shout = Column(ForeignKey('shout.slug'), primary_key = True)
	ts = Column(DateTime, nullable=False, default = datetime.now, comment="Timestamp")
	value = Column(Integer)

class ShoutRatingStorage:

	ratings = []

	lock = asyncio.Lock()

	@staticmethod
	def init(session):
		ShoutRatingStorage.ratings = session.query(ShoutRating).all()

	@staticmethod
	async def get_total_rating(shout_slug):
		async with ShoutRatingStorage.lock:
			shout_ratings = list(filter(lambda x: x.shout == shout_slug, ShoutRatingStorage.ratings))
		return reduce((lambda x, y: x + y.value), shout_ratings, 0)

	@staticmethod
	async def get_ratings(shout_slug):
		async with ShoutRatingStorage.lock:
			shout_ratings = list(filter(lambda x: x.shout == shout_slug, ShoutRatingStorage.ratings))
		return shout_ratings

	@staticmethod
	async def update_rating(new_rating):
		async with ShoutRatingStorage.lock:
			rating = next((x for x in ShoutRatingStorage.ratings \
				if x.rater == new_rating.rater and x.shout == new_rating.shout), None)
			if rating:
				rating.value = new_rating.value
				rating.ts = new_rating.ts
			else:
				ShoutRatingStorage.ratings.append(new_rating)


class ShoutViewByDay(Base):
	__tablename__ = "shout_view_by_day"

	id = None
	shout = Column(ForeignKey('shout.slug'), primary_key = True)
	day = Column(DateTime, primary_key = True, default = datetime.now)
	value = Column(Integer)

class ShoutViewStorage:

	view_by_shout = {}
	this_day_views = {}
	to_flush = []

	period = 30*60 #sec

	lock = asyncio.Lock()

	@staticmethod
	def init(session):
		self = ShoutViewStorage
		views = session.query(ShoutViewByDay).all()
		for view in views:
			shout = view.shout
			value = view.value
			old_value = self.view_by_shout.get(shout, 0)
			self.view_by_shout[shout] = old_value + value;
			if not shout in self.this_day_views:
				self.this_day_views[shout] = view
			this_day_view = self.this_day_views[shout]
			if this_day_view.day < view.day:
				self.this_day_views[shout] = view

	@staticmethod
	async def get_view(shout_slug):
		self = ShoutViewStorage
		async with self.lock:
			return self.view_by_shout.get(shout_slug, 0)

	@staticmethod
	async def inc_view(shout_slug):
		self = ShoutViewStorage
		async with self.lock:
			this_day_view = self.this_day_views.get(shout_slug)
			day_start = datetime.now().replace(hour = 0, minute = 0, second = 0)
			if not this_day_view or this_day_view.day < day_start:
				if this_day_view and getattr(this_day_view, "modified", False):
					self.to_flush.append(this_day_view)
				this_day_view = ShoutViewByDay.create(shout = shout_slug, value = 1)
				self.this_day_views[shout_slug] = this_day_view
			else:
				this_day_view.value = this_day_view.value + 1

			this_day_view.modified = True

			old_value = self.view_by_shout.get(shout_slug, 0)
			self.view_by_shout[shout_slug] = old_value + 1;

	@staticmethod
	async def flush_changes(session):
		self = ShoutViewStorage
		async with self.lock:
			for view in self.this_day_views.values():
				if getattr(view, "modified", False):
					session.add(view)
					flag_modified(view, "value")
					view.modified = False
			for view in self.to_flush:
				session.add(view)
			self.to_flush.clear()
		session.commit()

	@staticmethod
	async def worker():
		print("[shout.views] worker start")
		while True:
			try:
				print("[shout.views] worker flush changes")
				with local_session() as session:
					await ShoutViewStorage.flush_changes(session)
			except Exception as err:
				print("[shout.views] worker error: %s" % (err))
			await asyncio.sleep(ShoutViewStorage.period)

class TopicStat:
	shouts_by_topic = {}
	authors_by_topic = {}
	subs_by_topic = {}
	views_by_topic = {}
	lock = asyncio.Lock()

	period = 30*60 #sec

	@staticmethod
	async def load_stat(session):
		self = TopicStat

		self.shouts_by_topic = {}
		self.authors_by_topic = {}
		self.subs_by_topic = {}
		self.views_by_topic = {}

		shout_topics = session.query(ShoutTopic)
		for shout_topic in shout_topics:
			topic = shout_topic.topic
			shout = shout_topic.shout
			if topic in self.shouts_by_topic:
				self.shouts_by_topic[topic].append(shout)
			else:
				self.shouts_by_topic[topic] = [shout]

			authors = await ShoutAuthorStorage.get_authors(shout)
			if topic in self.authors_by_topic:
				self.authors_by_topic[topic].update(authors)
			else:
				self.authors_by_topic[topic] = set(authors)

			old_views = self.views_by_topic.get(topic, 0)
			self.views_by_topic[topic] = old_views + await ShoutViewStorage.get_view(shout)

		subs = session.query(TopicSubscription)
		for sub in subs:
			topic = sub.topic
			user = sub.subscriber
			if topic in self.subs_by_topic:
				self.subs_by_topic[topic].append(user)
			else:
				self.subs_by_topic[topic] = [user]

	@staticmethod
	async def get_shouts(topic):
		self = TopicStat
		async with self.lock:
			return self.shouts_by_topic.get(topic, [])

	@staticmethod
	async def get_stat(topic):
		self = TopicStat
		async with self.lock:
			shouts = self.shouts_by_topic.get(topic, [])
			subs = self.subs_by_topic.get(topic, [])
			authors = self.authors_by_topic.get(topic, [])
			views = self.views_by_topic.get(topic, 0)

		return  { 
			"shouts" : len(shouts),
			"authors" : len(authors),
			"subscriptions" : len(subs),
			"views" : views
		}

	@staticmethod
	async def worker():
		self = TopicStat
		print("[topic.stats] worker start")
		while True:
			try:
				print("[topic.stats] worker load stat")
				with local_session() as session:
					async with self.lock:
						await self.load_stat(session)
			except Exception as err:
				print("[topic.stats] worker error: %s" % (err))
			await asyncio.sleep(self.period)

class ShoutAuthorStorage:
	authors_by_shout = {}
	lock = asyncio.Lock()

	period = 30*60 #sec

	@staticmethod
	async def load(session):
		self = ShoutAuthorStorage
		authors = session.query(ShoutAuthor)
		for author in authors:
			user = author.user
			shout = author.shout
			if shout in self.authors_by_shout:
				self.authors_by_shout[shout].append(user)
			else:
				self.authors_by_shout[shout] = [user]

	@staticmethod
	async def get_authors(shout):
		self = ShoutAuthorStorage
		async with self.lock:
			return self.authors_by_shout.get(shout, [])

	@staticmethod
	async def worker():
		self = ShoutAuthorStorage
		print("[shout.authors] worker start")
		while True:
			try:
				print("[shout.authors] worker load stat")
				with local_session() as session:
					async with self.lock:
						await self.load(session)
			except Exception as err:
				print("[shout.authors] worker error: %s" % (err))
			await asyncio.sleep(self.period)

class CommentStat:
	stat_by_topic = {}
	lock = asyncio.Lock()

	period = 30*60 #sec

	@staticmethod
	async def load(session):
		self = CommentStat

		stats = session.query(Comment.shout, func.count(Comment.id).label("count")).\
			group_by(Comment.shout)
		self.stat_by_topic = dict([(stat.shout, stat.count) for stat in stats])

	@staticmethod
	async def get_stat(shout):
		self = CommentStat
		async with self.lock:
			return self.stat_by_topic.get(shout, 0)

	@staticmethod
	async def worker():
		self = CommentStat
		print("[comment.stats] worker start")
		while True:
			try:
				print("[comment.stats] worker load stat")
				with local_session() as session:
					async with self.lock:
						await self.load(session)
			except Exception as err:
				print("[comment.stats] worker error: %s" % (err))
			await asyncio.sleep(self.period)

class Shout(Base):
	__tablename__ = 'shout'

	id = None

	slug: str = Column(String, primary_key=True)
	community: str = Column(Integer, ForeignKey("community.id"), nullable=False, comment="Community")
	body: str = Column(String, nullable=False, comment="Body")
	createdAt: str = Column(DateTime, nullable=False, default = datetime.now, comment="Created at")
	updatedAt: str = Column(DateTime, nullable=True, comment="Updated at")
	replyTo: int = Column(ForeignKey("shout.slug"), nullable=True)
	versionOf: int = Column(ForeignKey("shout.slug"), nullable=True)
	tags: str = Column(String, nullable=True)
	publishedBy: int = Column(ForeignKey("user.id"), nullable=True)
	publishedAt: str = Column(DateTime, nullable=True)
	cover: str = Column(String, nullable = True)
	title: str = Column(String, nullable = True)
	subtitle: str = Column(String, nullable = True)
	comments = relationship(Comment)
	layout: str = Column(String, nullable = True)
	authors = relationship(lambda: User, secondary=ShoutAuthor.__tablename__) # NOTE: multiple authors
	topics = relationship(lambda: Topic, secondary=ShoutTopic.__tablename__)
	mainTopic = Column(ForeignKey("topic.slug"), nullable=True)
	visibleFor = relationship(lambda: User, secondary=ShoutViewer.__tablename__)
	draft: bool = Column(Boolean, default=True)
	oid: str = Column(String, nullable=True)

	@property
	async def stat(self):
		return {
			"views": await ShoutViewStorage.get_view(self.slug),
			"comments": await CommentStat.get_stat(self.slug),
			"ratings": await ShoutRatingStorage.get_total_rating(self.slug)
		}