from django.contrib.auth import get_user_model
from rest_framework import serializers

from core.models import Persoon

from .models import Gebruikersprofiel, Gebruikersrol

User = get_user_model()


class GebruikerSerializer(serializers.ModelSerializer):
    password = serializers.CharField(write_only=True, required=False, allow_blank=True, style={"input_type": "password"})
    rol = serializers.ChoiceField(choices=Gebruikersrol.choices, required=False)
    persoon = serializers.PrimaryKeyRelatedField(
        queryset=Persoon.objects.all(), required=False, allow_null=True
    )
    persoon_naam = serializers.SerializerMethodField()
    rol_label = serializers.SerializerMethodField()

    class Meta:
        model = User
        fields = [
            "id", "username", "password", "first_name", "last_name", "email",
            "is_staff", "is_active", "rol", "rol_label", "persoon", "persoon_naam",
            "last_login",
        ]
        read_only_fields = ["last_login"]

    # --- profiel-helpers ---
    def _profiel(self, user):
        return getattr(user, "gebruikersprofiel", None)

    def get_persoon_naam(self, user):
        p = self._profiel(user)
        return p.persoon.volledige_naam if (p and p.persoon_id) else None

    def get_rol_label(self, user):
        p = self._profiel(user)
        return p.get_rol_display() if p else None

    def to_representation(self, user):
        data = super().to_representation(user)
        p = self._profiel(user)
        data["rol"] = p.rol if p else None
        data["persoon"] = p.persoon_id if p else None
        return data

    def validate(self, data):
        if not self.instance and not data.get("password"):
            raise serializers.ValidationError({"password": "Een wachtwoord is verplicht voor een nieuwe gebruiker."})
        return data

    def create(self, validated_data):
        rol = validated_data.pop("rol", Gebruikersrol.MEDEWERKER)
        persoon = validated_data.pop("persoon", None)
        password = validated_data.pop("password", None)
        user = User(**validated_data)
        user.set_password(password)
        user.save()
        Gebruikersprofiel.objects.create(user=user, rol=rol, persoon=persoon)
        return user

    def update(self, user, validated_data):
        rol = validated_data.pop("rol", None)
        persoon = validated_data.pop("persoon", "__keep__")
        password = validated_data.pop("password", None)
        for k, v in validated_data.items():
            setattr(user, k, v)
        if password:
            user.set_password(password)
        user.save()
        profiel, _ = Gebruikersprofiel.objects.get_or_create(user=user)
        if rol is not None:
            profiel.rol = rol
        if persoon != "__keep__":
            profiel.persoon = persoon
        profiel.save()
        # Ververs de gecachete reverse-relatie, anders toont de respons de oude rol.
        user.gebruikersprofiel = profiel
        return user