from django import forms
from django.core.exceptions import ValidationError

from character.models import Character
from party.models import Party


class PartyForm(forms.ModelForm):
    def __init__(self, *args, **kwargs):
        self.original_instance = kwargs.get("instance")
        super().__init__(*args, **kwargs)
        qs = Character.objects.filter(private=False)
        if self.original_instance:
            qs = qs.union(self.original_instance.invited_characters.all())
        self.fields["invited_characters"].queryset = qs

    class Meta:
        model = Party
        fields = ["name", "invited_characters"]

    def clean_invited_characters(self):
        invited = self.cleaned_data["invited_characters"]
        if not self.original_instance:
            return invited
        members = self.original_instance.characters.all()
        for character in invited:
            if character in members:
                self.add_error(
                    "invited_characters",
                    ValidationError(f"{character} is already a group member."),
                )
        return invited