from datetime import datetime, timedelta, timezone

from sqlalchemy import and_, asc, case, desc, func, select, text
from sqlalchemy.orm import aliased

from auth.authenticate import login_required
from auth.credentials import AuthCredentials
from base.exceptions import OperationNotAllowed
from base.orm import local_session
from base.resolvers import mutation, query
from orm.reaction import Reaction, ReactionKind
from orm.shout import Shout, ShoutReactionsFollower
from orm.user import User
from services.notifications.notification_service import notification_service


def add_reaction_stat_columns(q):
    aliased_reaction = aliased(Reaction)

    q = q.outerjoin(aliased_reaction, Reaction.id == aliased_reaction.replyTo).add_columns(
        func.sum(aliased_reaction.id).label("reacted_stat"),
        func.sum(case((aliased_reaction.body.is_not(None), 1), else_=0)).label("commented_stat"),
        func.sum(
            case(
                (aliased_reaction.kind == ReactionKind.AGREE, 1),
                (aliased_reaction.kind == ReactionKind.DISAGREE, -1),
                (aliased_reaction.kind == ReactionKind.PROOF, 1),
                (aliased_reaction.kind == ReactionKind.DISPROOF, -1),
                (aliased_reaction.kind == ReactionKind.ACCEPT, 1),
                (aliased_reaction.kind == ReactionKind.REJECT, -1),
                (aliased_reaction.kind == ReactionKind.LIKE, 1),
                (aliased_reaction.kind == ReactionKind.DISLIKE, -1),
                else_=0,
            )
        ).label("rating_stat"),
    )

    return q


def reactions_follow(user_id, shout_id: int, auto=False):
    try:
        with local_session() as session:
            shout = session.query(Shout).where(Shout.id == shout_id).one()

            following = (
                session.query(ShoutReactionsFollower)
                .where(
                    and_(
                        ShoutReactionsFollower.follower == user_id,
                        ShoutReactionsFollower.shout == shout.id,
                    )
                )
                .first()
            )

            if not following:
                following = ShoutReactionsFollower.create(
                    follower=user_id, shout=shout.id, auto=auto
                )
                session.add(following)
                session.commit()
                return True
    except Exception as e:
        print(e)
        return False


def reactions_unfollow(user_id: int, shout_id: int):
    try:
        with local_session() as session:
            shout = session.query(Shout).where(Shout.id == shout_id).one()

            following = (
                session.query(ShoutReactionsFollower)
                .where(
                    and_(
                        ShoutReactionsFollower.follower == user_id,
                        ShoutReactionsFollower.shout == shout.id,
                    )
                )
                .first()
            )

            if following:
                session.delete(following)
                session.commit()
                return True
    except Exception as e:
        print(e)
        pass
    return False


def is_published_author(session, user_id):
    """checks if user has at least one publication"""
    return (
        session.query(Shout)
        .where(Shout.authors.contains(user_id))
        .filter(and_(Shout.publishedAt.is_not(None), Shout.deletedAt.is_(None)))
        .count()
        > 0
    )


def check_to_publish(session, user_id, reaction):
    """set shout to public if publicated approvers amount > 4"""
    if not reaction.replyTo and reaction.kind in [
        ReactionKind.ACCEPT,
        ReactionKind.LIKE,
        ReactionKind.PROOF,
    ]:
        if is_published_author(user_id):
            # now count how many approvers are voted already
            approvers_reactions = (
                session.query(Reaction).where(Reaction.shout == reaction.shout).all()
            )
            approvers = [
                user_id,
            ]
            for ar in approvers_reactions:
                a = ar.createdBy
                if is_published_author(session, a):
                    approvers.append(a)
            if len(approvers) > 4:
                return True
    return False


def check_to_hide(session, user_id, reaction):
    """hides any shout if 20% of reactions are negative"""
    if not reaction.replyTo and reaction.kind in [
        ReactionKind.REJECT,
        ReactionKind.DISLIKE,
        ReactionKind.DISPROOF,
    ]:
        # if is_published_author(user):
        approvers_reactions = session.query(Reaction).where(Reaction.shout == reaction.shout).all()
        rejects = 0
        for r in approvers_reactions:
            if r.kind in [ReactionKind.REJECT, ReactionKind.DISLIKE, ReactionKind.DISPROOF]:
                rejects += 1
        if len(approvers_reactions) / rejects < 5:
            return True
    return False


def set_published(session, shout_id):
    s = session.query(Shout).where(Shout.id == shout_id).first()
    s.publishedAt = datetime.now(tz=timezone.utc)
    s.visibility = text("public")
    session.add(s)
    session.commit()


def set_hidden(session, shout_id):
    s = session.query(Shout).where(Shout.id == shout_id).first()
    s.visibility = text("community")
    session.add(s)
    session.commit()


@mutation.field("createReaction")
@login_required
async def create_reaction(_, info, reaction):
    auth: AuthCredentials = info.context["request"].auth
    reaction["createdBy"] = auth.user_id
    rdict = {}
    with local_session() as session:
        shout = session.query(Shout).where(Shout.id == reaction["shout"]).one()
        author = session.query(User).where(User.id == auth.user_id).one()

        if reaction["kind"] in [ReactionKind.DISLIKE.name, ReactionKind.LIKE.name]:
            existing_reaction = (
                session.query(Reaction)
                .where(
                    and_(
                        Reaction.shout == reaction["shout"],
                        Reaction.createdBy == auth.user_id,
                        Reaction.kind == reaction["kind"],
                        Reaction.replyTo == reaction.get("replyTo"),
                    )
                )
                .first()
            )

            if existing_reaction is not None:
                raise OperationNotAllowed("You can't vote twice")

            opposite_reaction_kind = (
                ReactionKind.DISLIKE
                if reaction["kind"] == ReactionKind.LIKE.name
                else ReactionKind.LIKE
            )
            opposite_reaction = (
                session.query(Reaction)
                .where(
                    and_(
                        Reaction.shout == reaction["shout"],
                        Reaction.createdBy == auth.user_id,
                        Reaction.kind == opposite_reaction_kind,
                        Reaction.replyTo == reaction.get("replyTo"),
                    )
                )
                .first()
            )

            if opposite_reaction is not None:
                session.delete(opposite_reaction)

        r = Reaction.create(**reaction)

        # # Proposal accepting logix
        # FIXME: will break if there will be 2 proposals, will break if shout will be changed
        # if r.replyTo is not None and \
        #         r.kind == ReactionKind.ACCEPT and \
        #         auth.user_id in shout.dict()['authors']:
        #     replied_reaction = session.query(Reaction).where(Reaction.id == r.replyTo).first()
        #     if replied_reaction and replied_reaction.kind == ReactionKind.PROPOSE:
        #         if replied_reaction.range:
        #             old_body = shout.body
        #             start, end = replied_reaction.range.split(':')
        #             start = int(start)
        #             end = int(end)
        #             new_body = old_body[:start] + replied_reaction.body + old_body[end:]
        #             shout.body = new_body
        #             # TODO: update git version control

        session.add(r)
        session.commit()

        await notification_service.handle_new_reaction(r.id)

        rdict = r.dict()
        rdict["shout"] = shout.dict()
        rdict["createdBy"] = author.dict()

        # self-regulation mechanics
        if check_to_hide(session, auth.user_id, r):
            set_hidden(session, r.shout)
        elif check_to_publish(session, auth.user_id, r):
            set_published(session, r.shout)

    try:
        reactions_follow(auth.user_id, reaction["shout"], True)
    except Exception as e:
        print(f"[resolvers.reactions] error on reactions autofollowing: {e}")

    rdict["stat"] = {"commented": 0, "reacted": 0, "rating": 0}
    return {"reaction": rdict}


@mutation.field("updateReaction")
@login_required
async def update_reaction(_, info, id, reaction={}):
    auth: AuthCredentials = info.context["request"].auth

    with local_session() as session:
        user = session.query(User).where(User.id == auth.user_id).first()
        q = select(Reaction).filter(Reaction.id == id)
        q = add_reaction_stat_columns(q)
        q = q.group_by(Reaction.id)

        [r, reacted_stat, commented_stat, rating_stat] = session.execute(q).unique().one()

        if not r:
            return {"error": "invalid reaction id"}
        if r.createdBy != user.id:
            return {"error": "access denied"}

        r.body = reaction["body"]
        r.updatedAt = datetime.now(tz=timezone.utc)
        if r.kind != reaction["kind"]:
            # NOTE: change mind detection can be here
            pass
        if reaction.get("range"):
            r.range = reaction.get("range")
        session.commit()
        r.stat = {"commented": commented_stat, "reacted": reacted_stat, "rating": rating_stat}

    return {"reaction": r}


@mutation.field("deleteReaction")
@login_required
async def delete_reaction(_, info, id):
    auth: AuthCredentials = info.context["request"].auth

    with local_session() as session:
        r = session.query(Reaction).filter(Reaction.id == id).first()
        if not r:
            return {"error": "invalid reaction id"}
        if r.createdBy != auth.user_id:
            return {"error": "access denied"}

        if r.kind in [ReactionKind.LIKE, ReactionKind.DISLIKE]:
            session.delete(r)
        else:
            r.deletedAt = datetime.now(tz=timezone.utc)
        session.commit()
        return {"reaction": r}


@query.field("loadReactionsBy")
async def load_reactions_by(_, _info, by, limit=50, offset=0):
    """
    :param by: {
        :shout - filter by slug
        :shouts - filer by shout slug list
        :createdBy - to filter by author
        :topic - to filter by topic
        :search - to search by reactions' body
        :comment - true if body.length > 0
        :days - a number of days ago
        :sort - a fieldname to sort desc by default
    }
    :param limit: int amount of shouts
    :param offset: int offset in this order
    :return: Reaction[]
    """

    q = (
        select(Reaction, User, Shout)
        .join(User, Reaction.createdBy == User.id)
        .join(Shout, Reaction.shout == Shout.id)
    )

    if by.get("shout"):
        q = q.filter(Shout.slug == by["shout"])
    elif by.get("shouts"):
        q = q.filter(Shout.slug.in_(by["shouts"]))

    if by.get("createdBy"):
        q = q.filter(User.slug == by.get("createdBy"))

    if by.get("topic"):
        # TODO: check
        q = q.filter(Shout.topics.contains(by["topic"]))

    if by.get("comment"):
        q = q.filter(func.length(Reaction.body) > 0)

    if len(by.get("search", "")) > 2:
        q = q.filter(Reaction.body.ilike(f'%{by["body"]}%'))

    if by.get("days"):
        after = datetime.now(tz=timezone.utc) - timedelta(days=int(by["days"]) or 30)
        q = q.filter(Reaction.createdAt > after)

    order_way = asc if by.get("sort", "").startswith("-") else desc
    order_field = by.get("sort", "").replace("-", "") or Reaction.createdAt

    q = q.group_by(Reaction.id, User.id, Shout.id).order_by(order_way(order_field))

    q = add_reaction_stat_columns(q)

    q = q.where(Reaction.deletedAt.is_(None))
    q = q.limit(limit).offset(offset)
    reactions = []

    with local_session() as session:
        for [reaction, user, shout, reacted_stat, commented_stat, rating_stat] in session.execute(
            q
        ):
            reaction.createdBy = user
            reaction.shout = shout
            reaction.stat = {
                "rating": rating_stat,
                "commented": commented_stat,
                "reacted": reacted_stat,
            }

            reaction.kind = reaction.kind.name

            reactions.append(reaction)

    # ?
    if by.get("stat"):
        reactions.sort(lambda r: r.stat.get(by["stat"]) or r.createdAt)

    return reactions