from datetime import datetime
from typing import Any

from django.core.validators import MaxValueValidator, MinValueValidator
from django.db import models
from django.db.models import Avg, Count, Q
from django.utils.translation import gettext_lazy as _

from catalog.models import Item
from users.models import APIdentity

from .common import Content

MIN_RATING_COUNT = 5
RATING_INCLUDES_CHILD_ITEMS = ["tvshow", "performance"]


class Rating(Content):
    class Meta:
        unique_together = [["owner", "item"]]

    grade = models.PositiveSmallIntegerField(
        default=0, validators=[MaxValueValidator(10), MinValueValidator(1)], null=True
    )

    @property
    def ap_object(self):
        return {
            "id": self.absolute_url,
            "type": "Rating",
            "best": 10,
            "worst": 1,
            "value": self.grade,
            "published": self.created_time.isoformat(),
            "updated": self.edited_time.isoformat(),
            "attributedTo": self.owner.actor_uri,
            "withRegardTo": self.item.absolute_url,
            "href": self.absolute_url,
        }

    @classmethod
    def update_by_ap_object(cls, owner, item, obj, post_id, visibility):
        p = cls.objects.filter(owner=owner, item=item).first()
        if p and p.edited_time >= datetime.fromisoformat(obj["updated"]):
            return p  # incoming ap object is older than what we have, no update needed
        value = obj.get("value", 0) if obj else 0
        if not value:
            cls.objects.filter(owner=owner, item=item).delete()
            return
        best = obj.get("best", 5)
        worst = obj.get("worst", 1)
        if best <= worst:
            return
        if value < worst:
            value = worst
        if value > best:
            value = best
        if best != 10 or worst != 1:
            value = round(9 * (value - worst) / (best - worst)) + 1
        else:
            value = round(value)
        d = {
            "grade": value,
            "local": False,
            "remote_id": obj["id"],
            "visibility": visibility,
            "created_time": datetime.fromisoformat(obj["published"]),
            "edited_time": datetime.fromisoformat(obj["updated"]),
        }
        p, _ = cls.objects.update_or_create(owner=owner, item=item, defaults=d)
        p.link_post_id(post_id)
        return p

    @staticmethod
    def get_rating_for_item(item: Item) -> float | None:
        stat = Rating.objects.filter(grade__isnull=False)
        if item.class_name in RATING_INCLUDES_CHILD_ITEMS:
            stat = stat.filter(item_id__in=item.child_item_ids + [item.id])
        else:
            stat = stat.filter(item=item)
        stat = stat.aggregate(average=Avg("grade"), count=Count("item"))
        return round(stat["average"], 1) if stat["count"] >= MIN_RATING_COUNT else None

    @staticmethod
    def get_rating_count_for_item(item: Item) -> int:
        stat = Rating.objects.filter(grade__isnull=False)
        if item.class_name in RATING_INCLUDES_CHILD_ITEMS:
            stat = stat.filter(item_id__in=item.child_item_ids + [item.id])
        else:
            stat = stat.filter(item=item)
        stat = stat.aggregate(count=Count("item"))
        return stat["count"]

    @staticmethod
    def get_rating_distribution_for_item(item: Item):
        stat = Rating.objects.filter(grade__isnull=False)
        if item.class_name in RATING_INCLUDES_CHILD_ITEMS:
            stat = stat.filter(item_id__in=item.child_item_ids + [item.id])
        else:
            stat = stat.filter(item=item)
        stat = stat.values("grade").annotate(count=Count("grade")).order_by("grade")
        g = [0] * 11
        t = 0
        for s in stat:
            g[s["grade"]] = s["count"]
            t += s["count"]
        if t < MIN_RATING_COUNT:
            return [0] * 5
        r = [
            100 * (g[1] + g[2]) // t,
            100 * (g[3] + g[4]) // t,
            100 * (g[5] + g[6]) // t,
            100 * (g[7] + g[8]) // t,
            100 * (g[9] + g[10]) // t,
        ]
        return r

    @staticmethod
    def update_item_rating(
        item: Item,
        owner: APIdentity,
        rating_grade: int | None,
        visibility: int = 0,
        created_time: datetime | None = None,
    ):
        if rating_grade and (rating_grade < 1 or rating_grade > 10):
            raise ValueError(f"Invalid rating grade: {rating_grade}")
        if not rating_grade:
            Rating.objects.filter(owner=owner, item=item).delete()
        else:
            d: dict[str, Any] = {"grade": rating_grade, "visibility": visibility}
            if created_time:
                d["created_time"] = created_time
            r, _ = Rating.objects.update_or_create(owner=owner, item=item, defaults=d)
            return r

    @staticmethod
    def get_item_rating(item: Item, owner: APIdentity) -> int | None:
        rating = Rating.objects.filter(owner=owner, item=item).first()
        return (rating.grade or None) if rating else None