from django import forms
from django.contrib.auth import password_validation
from django.contrib.auth.forms import ReadOnlyPasswordHashField
from django.contrib.auth.models import Group, User
from django.core.exceptions import ValidationError
from django.urls import reverse_lazy
from django.utils.text import format_lazy
from django.utils.translation import gettext_lazy as _

from accounts.models import UserAttributes

from .models import Permission


class GroupForm(forms.ModelForm):
    permissions = forms.ModelMultipleChoiceField(
        widget=forms.CheckboxSelectMultiple,
        queryset=Permission.objects.filter(content_type__model="permissionset"),
        required=False,
    )

    users = forms.ModelMultipleChoiceField(
        widget=forms.CheckboxSelectMultiple,
        queryset=User.objects.all(),
        required=False,
    )

    def __init__(self, *args, **kwargs):
        super(GroupForm, self).__init__(*args, **kwargs)
        instance = getattr(self, "instance", None)
        if instance and instance.id:
            self.fields["users"].initial = self.instance.user_set.all()

    def save_m2m(self):
        self.instance.user_set.set(self.cleaned_data["users"])

    def save(self, *args, **kwargs):
        instance = super(GroupForm, self).save()
        self.save_m2m()
        return instance

    class Meta:
        model = Group
        fields = "__all__"


class UserForm(forms.ModelForm):
    user_permissions = forms.ModelMultipleChoiceField(
        widget=forms.CheckboxSelectMultiple,
        queryset=Permission.objects.filter(content_type__model="permissionset"),
        label=_("Permissions"),
        required=False,
    )

    groups = forms.ModelMultipleChoiceField(
        widget=forms.CheckboxSelectMultiple,
        queryset=Group.objects.all(),
        label=_("Groups"),
        required=False,
    )

    class Meta:
        model = User
        fields = [
            "username",
            "groups",
            "first_name",
            "last_name",
            "email",
            "user_permissions",
            "is_staff",
            "is_active",
            "is_superuser",
        ]

    def __init__(self, *args, **kwargs):
        super(UserForm, self).__init__(*args, **kwargs)
        if self.instance.id:
            password = ReadOnlyPasswordHashField(
                label=_("Password"),
                help_text=format_lazy(
                    _(
                        """Raw passwords are not stored, so there is no way to see this user's password, 
                    but you can change the password using <a href='{}'>this form</a>."""
                    ),
                    reverse_lazy(
                        "admin:user_update_password",
                        args=[
                            self.instance.id,
                        ],
                    ),
                ),
            )
            self.fields["Password"] = password


class UserCreateForm(UserForm):
    password = forms.CharField(widget=forms.PasswordInput)

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        # New users may change their own password unless unticked here
        self.fields["user_permissions"].initial = Permission.objects.filter(
            content_type__app_label="accounts", codename="change_password"
        )

    def _post_clean(self):
        # The validators in AUTH_PASSWORD_VALIDATORS, as on the password change
        # forms; after the instance has the form's values (username, email).
        super()._post_clean()
        password = self.cleaned_data.get("password")
        if password:
            try:
                password_validation.validate_password(password, self.instance)
            except ValidationError as error:
                self.add_error("password", error)

    def save(self, commit=True):
        # hashed before the user is first written: the raw password never
        # reaches the database
        user = super().save(commit=False)
        user.set_password(self.cleaned_data["password"])
        if commit:
            user.save()
            self.save_m2m()
        return user

    class Meta:
        model = User
        fields = [
            "username",
            "password",
            "groups",
            "first_name",
            "last_name",
            "email",
            "user_permissions",
            "is_staff",
            "is_active",
            "is_superuser",
        ]


class UserAttributesForm(forms.ModelForm):
    class Meta:
        model = UserAttributes
        exclude = ["user", "can_clone_instances", "must_change_password"]