from operator import mul
import os

from django.conf import settings
from django.contrib.auth.models import User
from django.core.validators import RegexValidator
from django.db import models
from django.db.models import Max, CASCADE
from django.urls import reverse
from django.utils.functional import cached_property
from django.utils.timezone import now
from django.utils.translation import gettext_lazy as _
from django.dispatch import receiver
from django.db.models.signals import post_save, pre_save


from fernet_fields import EncryptedCharField
from sortedm2m.fields import SortedManyToManyField

from judge.models.choices import ACE_THEMES, MATH_ENGINES_CHOICES, TIMEZONE
from judge.models.runtime import Language
from judge.ratings import rating_class
from judge.caching import cache_wrapper


__all__ = ["Organization", "Profile", "OrganizationRequest", "Friend"]


class EncryptedNullCharField(EncryptedCharField):
    def get_prep_value(self, value):
        if not value:
            return None
        return super(EncryptedNullCharField, self).get_prep_value(value)


def profile_image_path(profile, filename):
    tail = filename.split(".")[-1]
    new_filename = f"user_{profile.id}.{tail}"
    return os.path.join(settings.DMOJ_PROFILE_IMAGE_ROOT, new_filename)


class Organization(models.Model):
    name = models.CharField(max_length=128, verbose_name=_("organization title"))
    slug = models.SlugField(
        max_length=128,
        verbose_name=_("organization slug"),
        help_text=_("Organization name shown in URL"),
        unique=True,
        validators=[
            RegexValidator("^[-a-zA-Z0-9]+$", _("Only alphanumeric and hyphens"))
        ],
    )
    short_name = models.CharField(
        max_length=20,
        verbose_name=_("short name"),
        help_text=_("Displayed beside user name during contests"),
    )
    about = models.TextField(verbose_name=_("organization description"))
    registrant = models.ForeignKey(
        "Profile",
        verbose_name=_("registrant"),
        on_delete=models.CASCADE,
        related_name="registrant+",
        help_text=_("User who registered this organization"),
    )
    admins = models.ManyToManyField(
        "Profile",
        verbose_name=_("administrators"),
        related_name="admin_of",
        help_text=_("Those who can edit this organization"),
    )
    creation_date = models.DateTimeField(
        verbose_name=_("creation date"), auto_now_add=True
    )
    is_open = models.BooleanField(
        verbose_name=_("is open organization?"),
        help_text=_("Allow joining organization"),
        default=True,
    )
    slots = models.IntegerField(
        verbose_name=_("maximum size"),
        null=True,
        blank=True,
        help_text=_(
            "Maximum amount of users in this organization, "
            "only applicable to private organizations"
        ),
    )
    access_code = models.CharField(
        max_length=7,
        help_text=_("Student access code"),
        verbose_name=_("access code"),
        null=True,
        blank=True,
    )
    logo_override_image = models.CharField(
        verbose_name=_("Logo override image"),
        default="",
        max_length=150,
        blank=True,
        help_text=_(
            "This image will replace the default site logo for users "
            "viewing the organization."
        ),
    )

    def __contains__(self, item):
        if isinstance(item, int):
            return self.members.filter(id=item).exists()
        elif isinstance(item, Profile):
            return self.members.filter(id=item.id).exists()
        else:
            raise TypeError(
                "Organization membership test must be Profile or primany key"
            )

    def delete(self, *args, **kwargs):
        contests = self.contest_set
        for contest in contests.all():
            if contest.organizations.count() == 1:
                contest.delete()
        super().delete(*args, **kwargs)

    def __str__(self):
        return self.name

    def get_absolute_url(self):
        return reverse("organization_home", args=(self.id, self.slug))

    def get_users_url(self):
        return reverse("organization_users", args=(self.id, self.slug))

    def get_problems_url(self):
        return reverse("organization_problems", args=(self.id, self.slug))

    def get_contests_url(self):
        return reverse("organization_contests", args=(self.id, self.slug))

    def get_submissions_url(self):
        return reverse("organization_submissions", args=(self.id, self.slug))

    class Meta:
        ordering = ["name"]
        permissions = (
            ("organization_admin", "Administer organizations"),
            ("edit_all_organization", "Edit all organizations"),
        )
        verbose_name = _("organization")
        verbose_name_plural = _("organizations")
        app_label = "judge"


class Profile(models.Model):
    user = models.OneToOneField(
        User, verbose_name=_("user associated"), on_delete=models.CASCADE
    )
    about = models.TextField(verbose_name=_("self-description"), null=True, blank=True)
    timezone = models.CharField(
        max_length=50,
        verbose_name=_("location"),
        choices=TIMEZONE,
        default=settings.DEFAULT_USER_TIME_ZONE,
    )
    language = models.ForeignKey(
        "Language",
        verbose_name=_("preferred language"),
        on_delete=models.SET_DEFAULT,
        default=Language.get_default_language_pk,
    )
    points = models.FloatField(default=0, db_index=True)
    performance_points = models.FloatField(default=0, db_index=True)
    problem_count = models.IntegerField(default=0, db_index=True)
    ace_theme = models.CharField(max_length=30, choices=ACE_THEMES, default="github")
    last_access = models.DateTimeField(verbose_name=_("last access time"), default=now)
    ip = models.GenericIPAddressField(verbose_name=_("last IP"), blank=True, null=True)
    organizations = SortedManyToManyField(
        Organization,
        verbose_name=_("organization"),
        blank=True,
        related_name="members",
        related_query_name="member",
    )
    display_rank = models.CharField(
        max_length=10,
        default="user",
        verbose_name=_("display rank"),
        choices=(
            ("user", "Normal User"),
            ("setter", "Problem Setter"),
            ("admin", "Admin"),
        ),
        db_index=True,
    )
    mute = models.BooleanField(
        verbose_name=_("comment mute"),
        help_text=_("Some users are at their best when silent."),
        default=False,
    )
    is_unlisted = models.BooleanField(
        verbose_name=_("unlisted user"),
        help_text=_("User will not be ranked."),
        default=False,
    )
    is_banned_problem_voting = models.BooleanField(
        verbose_name=_("banned from voting"),
        help_text=_("User will not be able to vote on problems' point values."),
        default=False,
    )
    rating = models.IntegerField(null=True, default=None, db_index=True)
    current_contest = models.OneToOneField(
        "ContestParticipation",
        verbose_name=_("current contest"),
        null=True,
        blank=True,
        related_name="+",
        on_delete=models.SET_NULL,
    )
    math_engine = models.CharField(
        verbose_name=_("math engine"),
        choices=MATH_ENGINES_CHOICES,
        max_length=4,
        default=settings.MATHOID_DEFAULT_TYPE,
        help_text=_("the rendering engine used to render math"),
    )
    is_totp_enabled = models.BooleanField(
        verbose_name=_("2FA enabled"),
        default=False,
        help_text=_("check to enable TOTP-based two factor authentication"),
    )
    totp_key = EncryptedNullCharField(
        max_length=32,
        null=True,
        blank=True,
        verbose_name=_("TOTP key"),
        help_text=_("32 character base32-encoded key for TOTP"),
        validators=[
            RegexValidator("^$|^[A-Z2-7]{32}$", _("TOTP key must be empty or base32"))
        ],
    )
    notes = models.TextField(
        verbose_name=_("internal notes"),
        null=True,
        blank=True,
        help_text=_("Notes for administrators regarding this user."),
    )
    profile_image = models.ImageField(upload_to=profile_image_path, null=True)
    email_change_pending = models.EmailField(blank=True, null=True)
    css_background = models.TextField(
        verbose_name=_("Custom background"),
        null=True,
        blank=True,
        help_text=_('CSS custom background properties: url("image_url"), color, etc'),
        max_length=300,
    )

    @cache_wrapper(prefix="Pgbi2")
    def _get_basic_info(self):
        profile_image_url = None
        if self.profile_image:
            profile_image_url = self.profile_image.url
        return {
            "first_name": self.user.first_name,
            "last_name": self.user.last_name,
            "email": self.user.email,
            "username": self.user.username,
            "mute": self.mute,
            "profile_image_url": profile_image_url,
        }

    @cached_property
    def _cached_info(self):
        return self._get_basic_info()

    @cached_property
    def organization(self):
        # We do this to take advantage of prefetch_related
        orgs = self.organizations.all()
        return orgs[0] if orgs else None

    @cached_property
    def username(self):
        return self._cached_info["username"]

    @cached_property
    def first_name(self):
        return self._cached_info["first_name"]

    @cached_property
    def last_name(self):
        return self._cached_info["last_name"]

    @cached_property
    def email(self):
        return self._cached_info["email"]

    @cached_property
    def is_muted(self):
        return self._cached_info["mute"]

    @cached_property
    def profile_image_url(self):
        return self._cached_info["profile_image_url"]

    @cached_property
    def count_unseen_notifications(self):
        from judge.models.notification import unseen_notifications_count

        return unseen_notifications_count(self)

    @cached_property
    def count_unread_chat_boxes(self):
        from chat_box.utils import get_unread_boxes

        return get_unread_boxes(self)

    _pp_table = [pow(settings.DMOJ_PP_STEP, i) for i in range(settings.DMOJ_PP_ENTRIES)]

    def calculate_points(self, table=_pp_table):
        from judge.models import Problem

        public_problems = Problem.get_public_problems()
        data = (
            public_problems.filter(
                submission__user=self, submission__points__isnull=False
            )
            .annotate(max_points=Max("submission__points"))
            .order_by("-max_points")
            .values_list("max_points", flat=True)
            .filter(max_points__gt=0)
        )
        extradata = (
            public_problems.filter(submission__user=self, submission__result="AC")
            .values("id")
            .distinct()
            .count()
        )
        bonus_function = settings.DMOJ_PP_BONUS_FUNCTION
        points = sum(data)
        problems = len(data)
        entries = min(len(data), len(table))
        pp = sum(map(mul, table[:entries], data[:entries])) + bonus_function(extradata)
        if (
            self.points != points
            or problems != self.problem_count
            or self.performance_points != pp
        ):
            self.points = points
            self.problem_count = problems
            self.performance_points = pp
            self.save(update_fields=["points", "problem_count", "performance_points"])
        return points

    calculate_points.alters_data = True

    def remove_contest(self):
        self.current_contest = None
        self.save()

    remove_contest.alters_data = True

    def update_contest(self):
        from judge.models import ContestParticipation

        try:
            contest = self.current_contest
            if contest is not None and (
                contest.ended or not contest.contest.is_accessible_by(self.user)
            ):
                self.remove_contest()
        except ContestParticipation.DoesNotExist:
            self.remove_contest()

    update_contest.alters_data = True

    def get_absolute_url(self):
        return reverse("user_page", args=(self.user.username,))

    def __str__(self):
        return self.user.username

    @classmethod
    def get_user_css_class(
        cls, display_rank, rating, rating_colors=settings.DMOJ_RATING_COLORS
    ):
        if rating_colors:
            return "rating %s %s" % (
                rating_class(rating) if rating is not None else "rate-none",
                display_rank,
            )
        return display_rank

    @cached_property
    def css_class(self):
        return self.get_user_css_class(self.display_rank, self.rating)

    def get_friends(self):  # list of ids, including you
        friend_obj = self.following_users.prefetch_related("users")
        ret = []
        if friend_obj:
            ret = [friend.id for friend in friend_obj[0].users.all()]
        ret.append(self.id)
        return ret

    def can_edit_organization(self, org):
        if not self.user.is_authenticated:
            return False
        profile_id = self.id
        return (
            org.admins.filter(id=profile_id).exists()
            or org.registrant_id == profile_id
            or self.user.is_superuser
        )

    class Meta:
        indexes = [
            models.Index(fields=["is_unlisted", "performance_points"]),
        ]
        permissions = (
            ("test_site", "Shows in-progress development stuff"),
            ("totp", "Edit TOTP settings"),
        )
        verbose_name = _("user profile")
        verbose_name_plural = _("user profiles")


class OrganizationRequest(models.Model):
    user = models.ForeignKey(
        Profile,
        verbose_name=_("user"),
        related_name="requests",
        on_delete=models.CASCADE,
    )
    organization = models.ForeignKey(
        Organization,
        verbose_name=_("organization"),
        related_name="requests",
        on_delete=models.CASCADE,
    )
    time = models.DateTimeField(verbose_name=_("request time"), auto_now_add=True)
    state = models.CharField(
        max_length=1,
        verbose_name=_("state"),
        choices=(
            ("P", "Pending"),
            ("A", "Approved"),
            ("R", "Rejected"),
        ),
    )
    reason = models.TextField(verbose_name=_("reason"))

    class Meta:
        verbose_name = _("organization join request")
        verbose_name_plural = _("organization join requests")


class Friend(models.Model):
    users = models.ManyToManyField(Profile)
    current_user = models.ForeignKey(
        Profile,
        related_name="following_users",
        on_delete=CASCADE,
    )

    @classmethod
    def is_friend(self, current_user, new_friend):
        try:
            return current_user.following_users.filter(users=new_friend).exists()
        except:
            return False

    @classmethod
    def make_friend(self, current_user, new_friend):
        friend, created = self.objects.get_or_create(current_user=current_user)
        friend.users.add(new_friend)

    @classmethod
    def remove_friend(self, current_user, new_friend):
        friend, created = self.objects.get_or_create(current_user=current_user)
        friend.users.remove(new_friend)

    @classmethod
    def toggle_friend(self, current_user, new_friend):
        if self.is_friend(current_user, new_friend):
            self.remove_friend(current_user, new_friend)
        else:
            self.make_friend(current_user, new_friend)

    @classmethod
    def get_friend_profiles(self, current_user):
        try:
            ret = self.objects.get(current_user=current_user).users.all()
        except Friend.DoesNotExist:
            ret = Profile.objects.none()
        return ret

    def __str__(self):
        return str(self.current_user)


class OrganizationProfile(models.Model):
    users = models.ForeignKey(
        Profile,
        verbose_name=_("user"),
        related_name="last_visit",
        on_delete=models.CASCADE,
        db_index=True,
    )
    organization = models.ForeignKey(
        Organization,
        verbose_name=_("organization"),
        related_name="last_vist",
        on_delete=models.CASCADE,
    )
    last_visit = models.AutoField(
        verbose_name=_("last visit"),
        primary_key=True,
    )

    @classmethod
    def remove_organization(self, users, organization):
        organizationprofile = self.objects.filter(
            users=users, organization=organization
        )
        if organizationprofile.exists():
            organizationprofile.delete()

    @classmethod
    def add_organization(self, users, organization):
        self.remove_organization(users, organization)
        new_organization = OrganizationProfile(users=users, organization=organization)
        new_organization.save()

    @classmethod
    def get_most_recent_organizations(self, users):
        return self.objects.filter(users=users).order_by("-last_visit")[:5]


@receiver([post_save], sender=User)
def on_user_save(sender, instance, **kwargs):
    try:
        profile = instance.profile
        profile._get_basic_info.dirty(profile)
    except:
        pass


@receiver([pre_save], sender=Profile)
def on_profile_save(sender, instance, **kwargs):
    if instance.id is None:
        return
    prev = sender.objects.get(id=instance.id)
    if prev.mute != instance.mute or prev.profile_image != instance.profile_image:
        instance._get_basic_info.dirty(instance)