from django.contrib.auth import get_user_model
from django.core.exceptions import ValidationError as DjangoValidationError
from rest_framework import serializers
from rest_framework_simplejwt.tokens import RefreshToken

from ..models import Role
from ..validators import normalize_iran_mobile, validate_iran_mobile

User = get_user_model()


class IranPhoneField(serializers.CharField):
    def to_internal_value(self, data):
        v = super().to_internal_value(data)
        normalized = normalize_iran_mobile(v)
        try:
            validate_iran_mobile(normalized)
        except DjangoValidationError:
            raise serializers.ValidationError("Enter a valid Iranian mobile number.")
        return normalized


class OTPSendSerializer(serializers.Serializer):
    phone_number = IranPhoneField()


class OTPVerifySerializer(serializers.Serializer):
    phone_number = IranPhoneField()
    code = serializers.CharField(min_length=4, max_length=6)
    full_name = serializers.CharField(required=False, allow_blank=True, max_length=150)
    role = serializers.ChoiceField(
        required=False,
        choices=[(Role.STUDENT.value, "student"), (Role.TEACHER.value, "teacher")],
    )

    def validate(self, attrs):
        if not User.objects.filter(phone_number=attrs["phone_number"]).exists():
            missing = {}
            if not attrs.get("full_name"):
                missing["full_name"] = "Required for new account"
            if not attrs.get("role"):
                missing["role"] = "Required for new account"
            if missing:
                raise serializers.ValidationError(missing)
        return attrs


class UserSerializer(serializers.ModelSerializer):
    class Meta:
        model = User
        fields = ["id", "phone_number", "full_name", "role", "email", "language"]
        read_only_fields = fields


def issue_tokens_for(user) -> dict:
    refresh = RefreshToken.for_user(user)
    return {"access": str(refresh.access_token), "refresh": str(refresh)}