from operator import attrgetter

import pyotp
from django import forms
from django.conf import settings
from django.contrib.auth.forms import AuthenticationForm
from django.core.exceptions import ValidationError, ObjectDoesNotExist
from django.core.validators import RegexValidator
from django.db.models import Q
from django.forms import CharField, ChoiceField, Form, ModelForm
from django.urls import reverse_lazy
from django.utils.translation import gettext_lazy as _
from django.utils import timezone

from django_ace import AceWidget
from judge.models import (
    Contest,
    Language,
    Organization,
    PrivateMessage,
    Problem,
    ProblemPointsVote,
    Profile,
    Submission,
    BlogPost,
)
from judge.utils.subscription import newsletter_id
from judge.widgets import (
    HeavyPreviewPageDownWidget,
    MathJaxPagedownWidget,
    PagedownWidget,
    Select2MultipleWidget,
    Select2Widget,
)


def fix_unicode(string, unsafe=tuple("\u202a\u202b\u202d\u202e")):
    return (
        string + (sum(k in unsafe for k in string) - string.count("\u202c")) * "\u202c"
    )


class ProfileForm(ModelForm):
    if newsletter_id is not None:
        newsletter = forms.BooleanField(
            label=_("Subscribe to contest updates"), initial=False, required=False
        )
    test_site = forms.BooleanField(
        label=_("Enable experimental features"), initial=False, required=False
    )

    class Meta:
        model = Profile
        fields = [
            "about",
            "organizations",
            "timezone",
            "language",
            "ace_theme",
            "user_script",
        ]
        widgets = {
            "user_script": AceWidget(theme="github"),
            "timezone": Select2Widget(attrs={"style": "width:200px"}),
            "language": Select2Widget(attrs={"style": "width:200px"}),
            "ace_theme": Select2Widget(attrs={"style": "width:200px"}),
        }

        has_math_config = bool(settings.MATHOID_URL)
        if has_math_config:
            fields.append("math_engine")
            widgets["math_engine"] = Select2Widget(attrs={"style": "width:200px"})

        if HeavyPreviewPageDownWidget is not None:
            widgets["about"] = HeavyPreviewPageDownWidget(
                preview=reverse_lazy("profile_preview"),
                attrs={"style": "max-width:700px;min-width:700px;width:700px"},
            )

    def clean(self):
        organizations = self.cleaned_data.get("organizations") or []
        max_orgs = settings.DMOJ_USER_MAX_ORGANIZATION_COUNT

        if sum(org.is_open for org in organizations) > max_orgs:
            raise ValidationError(
                _("You may not be part of more than {count} public groups.").format(
                    count=max_orgs
                )
            )

        return self.cleaned_data

    def __init__(self, *args, **kwargs):
        user = kwargs.pop("user", None)
        super(ProfileForm, self).__init__(*args, **kwargs)
        if not user.has_perm("judge.edit_all_organization"):
            self.fields["organizations"].queryset = Organization.objects.filter(
                Q(is_open=True) | Q(id__in=user.profile.organizations.all()),
            )


class ProblemSubmitForm(ModelForm):
    source = CharField(
        max_length=65536, widget=AceWidget(theme="twilight", no_ace_media=True)
    )
    judge = ChoiceField(choices=(), widget=forms.HiddenInput(), required=False)

    def __init__(self, *args, judge_choices=(), **kwargs):
        super(ProblemSubmitForm, self).__init__(*args, **kwargs)
        self.fields["language"].empty_label = None
        self.fields["language"].label_from_instance = attrgetter("display_name")
        self.fields["language"].queryset = Language.objects.filter(
            judges__online=True
        ).distinct()

        if judge_choices:
            self.fields["judge"].widget = Select2Widget(
                attrs={"style": "width: 150px", "data-placeholder": _("Any judge")},
            )
            self.fields["judge"].choices = judge_choices

    class Meta:
        model = Submission
        fields = ["language"]


class EditOrganizationForm(ModelForm):
    class Meta:
        model = Organization
        fields = ["about", "logo_override_image", "admins", "is_open"]
        widgets = {"admins": Select2MultipleWidget()}
        if HeavyPreviewPageDownWidget is not None:
            widgets["about"] = HeavyPreviewPageDownWidget(
                preview=reverse_lazy("organization_preview")
            )


class AddOrganizationMemberForm(ModelForm):
    new_users = CharField(
        max_length=65536,
        widget=forms.Textarea,
        help_text=_("Enter usernames separating by space"),
    )

    def clean(self):
        new_users = self.cleaned_data.get("new_users") or ""
        usernames = new_users.split()
        invalid_usernames = []
        valid_usernames = []

        for username in usernames:
            try:
                valid_usernames.append(Profile.objects.get(user__username=username))
            except ObjectDoesNotExist:
                invalid_usernames.append(username)

        if invalid_usernames:
            raise ValidationError(
                _("These usernames don't exist: {usernames}").format(
                    usernames=str(invalid_usernames)
                )
            )
        self.cleaned_data["new_users"] = valid_usernames
        return self.cleaned_data

    class Meta:
        model = Organization
        fields = ()


class OrganizationBlogForm(ModelForm):
    class Meta:
        model = BlogPost
        fields = ("title", "content", "publish_on")
        widgets = {
            "publish_on": forms.HiddenInput,
        }
        if HeavyPreviewPageDownWidget is not None:
            widgets["content"] = HeavyPreviewPageDownWidget(
                preview=reverse_lazy("organization_preview")
            )

    def __init__(self, *args, **kwargs):
        super(OrganizationBlogForm, self).__init__(*args, **kwargs)
        self.fields["publish_on"].required = False
        self.fields["publish_on"].is_hidden = True

    def clean(self):
        self.cleaned_data["publish_on"] = timezone.now()
        return self.cleaned_data


class OrganizationAdminBlogForm(OrganizationBlogForm):
    class Meta:
        model = BlogPost
        fields = ("visible", "sticky", "title", "content", "publish_on")
        widgets = {
            "publish_on": forms.HiddenInput,
        }
        if HeavyPreviewPageDownWidget is not None:
            widgets["content"] = HeavyPreviewPageDownWidget(
                preview=reverse_lazy("organization_preview")
            )


class NewMessageForm(ModelForm):
    class Meta:
        model = PrivateMessage
        fields = ["title", "content"]
        widgets = {}
        if PagedownWidget is not None:
            widgets["content"] = MathJaxPagedownWidget()


class CustomAuthenticationForm(AuthenticationForm):
    def __init__(self, *args, **kwargs):
        super(CustomAuthenticationForm, self).__init__(*args, **kwargs)
        self.fields["username"].widget.attrs.update({"placeholder": _("Username")})
        self.fields["password"].widget.attrs.update({"placeholder": _("Password")})

        self.has_google_auth = self._has_social_auth("GOOGLE_OAUTH2")
        self.has_facebook_auth = self._has_social_auth("FACEBOOK")
        self.has_github_auth = self._has_social_auth("GITHUB_SECURE")

    def _has_social_auth(self, key):
        return getattr(settings, "SOCIAL_AUTH_%s_KEY" % key, None) and getattr(
            settings, "SOCIAL_AUTH_%s_SECRET" % key, None
        )


class NoAutoCompleteCharField(forms.CharField):
    def widget_attrs(self, widget):
        attrs = super(NoAutoCompleteCharField, self).widget_attrs(widget)
        attrs["autocomplete"] = "off"
        return attrs


class TOTPForm(Form):
    TOLERANCE = settings.DMOJ_TOTP_TOLERANCE_HALF_MINUTES

    totp_token = NoAutoCompleteCharField(
        validators=[
            RegexValidator(
                "^[0-9]{6}$",
                _("Two Factor Authentication tokens must be 6 decimal digits."),
            ),
        ]
    )

    def __init__(self, *args, **kwargs):
        self.totp_key = kwargs.pop("totp_key")
        super(TOTPForm, self).__init__(*args, **kwargs)

    def clean_totp_token(self):
        if not pyotp.TOTP(self.totp_key).verify(
            self.cleaned_data["totp_token"], valid_window=self.TOLERANCE
        ):
            raise ValidationError(_("Invalid Two Factor Authentication token."))


class ProblemCloneForm(Form):
    code = CharField(
        max_length=20,
        validators=[
            RegexValidator("^[a-z0-9]+$", _("Problem code must be ^[a-z0-9]+$"))
        ],
    )

    def clean_code(self):
        code = self.cleaned_data["code"]
        if Problem.objects.filter(code=code).exists():
            raise ValidationError(_("Problem with code already exists."))
        return code


class ContestCloneForm(Form):
    key = CharField(
        max_length=20,
        validators=[RegexValidator("^[a-z0-9]+$", _("Contest id must be ^[a-z0-9]+$"))],
    )

    def clean_key(self):
        key = self.cleaned_data["key"]
        if Contest.objects.filter(key=key).exists():
            raise ValidationError(_("Contest with key already exists."))
        return key


class ProblemPointsVoteForm(ModelForm):
    class Meta:
        model = ProblemPointsVote
        fields = ["points"]