import time
from datetime import UTC, datetime
from typing import Any

import orjson
from graphql import GraphQLResolveInfo
from sqlalchemy import and_, select
from sqlalchemy.exc import SQLAlchemyError
from sqlalchemy.orm import aliased
from sqlalchemy.sql import not_

from orm.author import Author
from orm.notification import (
    Notification,
    NotificationAction,
    NotificationEntity,
    NotificationSeen,
)
from orm.shout import Shout
from services.auth import login_required
from storage.db import local_session
from storage.schema import mutation, query
from utils.logger import root_logger as logger


def query_notifications(author_id: int, after: int = 0) -> tuple[int, int, list[tuple[Notification, bool]]]:
    notification_seen_alias = aliased(NotificationSeen)
    q = select(Notification, notification_seen_alias.viewer.label("seen")).outerjoin(
        NotificationSeen,
        and_(
            NotificationSeen.viewer == author_id,
            NotificationSeen.notification == Notification.id,
        ),
    )
    if after:
        # Convert Unix timestamp to datetime for PostgreSQL compatibility
        after_datetime = datetime.fromtimestamp(after, tz=UTC)
        q = q.where(Notification.created_at > after_datetime)

    with local_session() as session:
        # Build query conditions
        conditions = [Notification.action == NotificationAction.CREATE.value]
        if after:
            after_datetime = datetime.fromtimestamp(after, tz=UTC)
            conditions.append(Notification.created_at > after_datetime)

        total = session.query(Notification).where(and_(*conditions)).count()

        unread_conditions = [*conditions, not_(Notification.seen)]
        unread = session.query(Notification).where(and_(*unread_conditions)).count()

        notifications_result = session.execute(q)
        notifications = []
        for n, seen in notifications_result:
            notifications.append((n, seen))

    return total, unread, notifications


def group_notification(
    thread: str,
    authors: list[Any] | None = None,
    shout: Any | None = None,
    reactions: list[Any] | None = None,
    entity: str = "follower",
    action: str = "follow",
) -> dict:
    reactions = reactions or []
    authors = authors or []
    return {
        "thread": thread,
        "authors": authors,
        "updated_at": int(time.time()),
        "shout": shout,
        "reactions": reactions,
        "entity": entity,
        "action": action,
    }


def get_notifications_grouped(author_id: int, after: int = 0, limit: int = 10, offset: int = 0) -> list[dict]:
    """
    Retrieves notifications for a given author.

    Args:
        author_id (int): The ID of the author for whom notifications are retrieved.
        after (int, optional): If provided, selects only notifications created after this timestamp will be considered.
        limit (int, optional): The maximum number of groupa to retrieve.
        offset (int, optional): offset

    Returns:
        Dict[str, NotificationGroup], int, int: A dictionary where keys are thread IDs
        and values are NotificationGroup objects, unread and total amounts.

    This function queries the database to retrieve notifications for the specified author, considering optional filters.
    The result is a dictionary where each key is a thread ID, and the corresponding value is a NotificationGroup
    containing information about the notifications within that thread.

    NotificationGroup structure:
    {
        entity: str,        # Type of entity (e.g., 'reaction', 'shout', 'follower').
        updated_at: int,    # Timestamp of the latest update in the thread.
        shout: Optional[NotificationShout]
        reactions: List[int],  # List of reaction ids within the thread.
        authors: List[NotificationAuthor],  # List of authors involved in the thread.
    }
    """
    _total, _unread, notifications = query_notifications(author_id, after)
    groups_by_thread = {}
    groups_amount = 0

    for notification, _seen in notifications:
        if (groups_amount + offset) >= limit:
            break

        payload = orjson.loads(str(notification.payload))

        if str(notification.entity) == NotificationEntity.SHOUT.value:
            shout = payload
            shout_id = shout.get("id")
            author_id = shout.get("created_by")
            thread_id = f"shout-{shout_id}"

            with local_session() as session:
                author = session.query(Author).where(Author.id == author_id).first()
                shout = session.query(Shout).where(Shout.id == shout_id).first()
                if author and shout:
                    author_dict = author.dict()
                    shout_dict = shout.dict()
                    group = group_notification(
                        thread_id,
                        shout=shout_dict,
                        authors=[author_dict],
                        action=str(notification.action),
                        entity=str(notification.entity),
                    )
                    groups_by_thread[thread_id] = group
                    groups_amount += 1

        elif str(notification.entity) == NotificationEntity.REACTION.value:
            reaction = payload
            if not isinstance(reaction, dict):
                msg = "reaction data is not consistent"
                raise ValueError(msg)
            shout_id = reaction.get("shout")
            author_id = reaction.get("created_by", 0)
            if shout_id and author_id:
                with local_session() as session:
                    author = session.query(Author).where(Author.id == author_id).first()
                    shout = session.query(Shout).where(Shout.id == shout_id).first()
                    if shout and author:
                        author_dict = author.dict()
                        shout_dict = shout.dict()
                        reply_id = reaction.get("reply_to")
                        thread_id = f"shout-{shout_id}"
                        if reply_id and reaction.get("kind", "").lower() == "comment":
                            thread_id = f"shout-{shout_id}::{reply_id}"

                        existing_group = groups_by_thread.get(thread_id)
                        if existing_group:
                            existing_group["seen"] = False
                            existing_group["authors"].append(author_id)
                            existing_group["reactions"] = existing_group["reactions"] or []
                            existing_group["reactions"].append(reaction)
                            groups_by_thread[thread_id] = existing_group
                        else:
                            group = group_notification(
                                thread_id,
                                authors=[author_dict],
                                shout=shout_dict,
                                reactions=[reaction],
                                entity=str(notification.entity),
                                action=str(notification.action),
                            )
                            if group:
                                groups_by_thread[thread_id] = group
                                groups_amount += 1

            elif str(notification.entity) == "follower":
                thread_id = "followers"
                follower = orjson.loads(payload)
                existing_group = groups_by_thread.get(thread_id)
                if existing_group:
                    if str(notification.action) == "follow":
                        existing_group["authors"].append(follower)
                    elif str(notification.action) == "unfollow":
                        follower_id = follower.get("id")
                        for author in existing_group["authors"]:
                            if isinstance(author, dict) and author.get("id") == follower_id:
                                existing_group["authors"].remove(author)
                                break
                else:
                    group = group_notification(
                        thread_id,
                        authors=[follower],
                        entity=str(notification.entity),
                        action=str(notification.action),
                    )
                    groups_amount += 1
                    existing_group = group
                groups_by_thread[thread_id] = existing_group
    return list(groups_by_thread.values())


@query.field("load_notifications")
@login_required
async def load_notifications(_: None, info: GraphQLResolveInfo, after: int, limit: int = 50, offset: int = 0) -> dict:
    author_dict = info.context.get("author") or {}
    author_id = author_dict.get("id")
    error = None
    total = 0
    unread = 0
    notifications = []
    try:
        if author_id:
            groups_list = get_notifications_grouped(author_id, after, limit)
            notifications = sorted(groups_list, key=lambda group: group.get("updated_at", 0), reverse=True)

            # Считаем реальное количество сгруппированных уведомлений
            total = len(notifications)
            unread = sum(1 for n in notifications if not n.get("seen", False))
    except Exception as e:
        error = str(e)
        logger.error(e)
    return {
        "notifications": notifications,
        "total": total,
        "unread": unread,
        "error": error,
    }


@mutation.field("notification_mark_seen")
@login_required
async def notification_mark_seen(_: None, info: GraphQLResolveInfo, notification_id: int) -> dict:
    author_id = info.context.get("author", {}).get("id")
    if author_id:
        with local_session() as session:
            try:
                ns = NotificationSeen(notification=notification_id, viewer=author_id)
                session.add(ns)
                session.commit()
            except SQLAlchemyError as e:
                session.rollback()
                logger.error(f"seen mutation failed: {e}")
                return {"error": "cant mark as read"}
    return {"error": None}


@mutation.field("notifications_seen_after")
@login_required
async def notifications_seen_after(_: None, info: GraphQLResolveInfo, after: int) -> dict:
    """Mark all notifications after given timestamp as seen."""
    error = None
    try:
        author_id = info.context.get("author", {}).get("id")
        if author_id:
            with local_session() as session:
                # Convert Unix timestamp to datetime for PostgreSQL compatibility
                after_datetime = datetime.fromtimestamp(after, tz=UTC) if after else None
                if after_datetime:
                    nnn = session.query(Notification).where(and_(Notification.created_at > after_datetime)).all()
                else:
                    nnn = session.query(Notification).all()
                for notification in nnn:
                    ns = NotificationSeen(notification=notification.id, author=author_id)
                    session.add(ns)
                session.commit()
    except Exception as e:
        print(e)
        error = "cant mark as read"
    return {"error": error}


@mutation.field("notifications_seen_thread")
@login_required
async def notifications_seen_thread(_: None, info: GraphQLResolveInfo, thread: str, after: int) -> dict:
    error = None
    author_id = info.context.get("author", {}).get("id")
    if author_id:
        with local_session() as session:
            # Convert Unix timestamp to datetime for PostgreSQL compatibility
            after_datetime = datetime.fromtimestamp(after, tz=UTC) if after else None

            # Handle different thread types: shout reactions, followers, or new shouts
            if thread == "followers":
                # Mark follower notifications as seen
                query_conditions = [
                    Notification.entity == NotificationEntity.FOLLOWER.value,
                ]
                if after_datetime:
                    query_conditions.append(Notification.created_at > after_datetime)

                follower_notifications = session.query(Notification).where(and_(*query_conditions)).all()
                for n in follower_notifications:
                    try:
                        ns = NotificationSeen(notification=n.id, viewer=author_id)
                        session.add(ns)
                    except Exception as e:
                        logger.warning(f"Failed to mark follower notification as seen: {e}")
                session.commit()
                return {"error": None}

            # Handle shout and reaction notifications
            thread_parts = thread.split(":")
            if len(thread_parts) < 2:
                return {"error": "Invalid thread format"}

            shout_id = thread_parts[0]
            reply_to_id = thread_parts[1] if len(thread_parts) > 1 else None

            # Query for new shout notifications in this thread
            shout_query_conditions = [
                Notification.entity == NotificationEntity.SHOUT.value,
                Notification.action == NotificationAction.CREATE.value,
            ]
            if after_datetime:
                shout_query_conditions.append(Notification.created_at > after_datetime)

            shout_notifications = session.query(Notification).where(and_(*shout_query_conditions)).all()

            # Mark relevant shout notifications as seen
            for n in shout_notifications:
                payload = orjson.loads(str(n.payload))
                if str(payload.get("id")) == shout_id:
                    try:
                        ns = NotificationSeen(notification=n.id, viewer=author_id)
                        session.add(ns)
                    except Exception as e:
                        logger.warning(f"Failed to mark shout notification as seen: {e}")

            # Query for reaction notifications
            if after_datetime:
                new_reaction_notifications = (
                    session.query(Notification)
                    .where(
                        Notification.action == NotificationAction.CREATE.value,
                        Notification.entity == NotificationEntity.REACTION.value,
                        Notification.created_at > after_datetime,
                    )
                    .all()
                )
                removed_reaction_notifications = (
                    session.query(Notification)
                    .where(
                        Notification.action == NotificationAction.DELETE.value,
                        Notification.entity == NotificationEntity.REACTION.value,
                        Notification.created_at > after_datetime,
                    )
                    .all()
                )
            else:
                new_reaction_notifications = (
                    session.query(Notification)
                    .where(
                        Notification.action == NotificationAction.CREATE.value,
                        Notification.entity == NotificationEntity.REACTION.value,
                    )
                    .all()
                )
                removed_reaction_notifications = (
                    session.query(Notification)
                    .where(
                        Notification.action == NotificationAction.DELETE.value,
                        Notification.entity == NotificationEntity.REACTION.value,
                    )
                    .all()
                )
            exclude = set()
            for nr in removed_reaction_notifications:
                reaction = orjson.loads(str(nr.payload))
                reaction_id = reaction.get("id")
                exclude.add(reaction_id)
            for n in new_reaction_notifications:
                reaction = orjson.loads(str(n.payload))
                reaction_id = reaction.get("id")
                if (
                    reaction_id not in exclude
                    and reaction.get("shout") == shout_id
                    and reaction.get("reply_to") == reply_to_id
                ):
                    try:
                        ns = NotificationSeen(notification=n.id, viewer=author_id)
                        session.add(ns)
                        session.commit()
                    except Exception as e:
                        logger.warn(e)
                        session.rollback()
    else:
        error = "You are not logged in"
    return {"error": error}