from rest_framework import serializers
from routes.models import Route, City
from django.conf import settings
from routes.constants.routeChoices import cargo_type_choices, type_transport_choices
import pytz

class RouteSerializer(serializers.ModelSerializer):
    from_city_name = serializers.SerializerMethodField()
    to_city_name = serializers.SerializerMethodField()
    from_country_name = serializers.SerializerMethodField()
    to_country_name = serializers.SerializerMethodField()
    formatted_departure = serializers.SerializerMethodField()
    formatted_arrival = serializers.SerializerMethodField()
    formatted_cargo_type = serializers.SerializerMethodField()
    formatted_transport = serializers.SerializerMethodField()

    class Meta:
        model = Route
        fields = '__all__'

    def get_from_city_name(self, obj):
        try:
            city = City.objects.get(id=obj.from_city_id)
            return city.name
        except City.DoesNotExist:
            return None

    def get_to_city_name(self, obj):
        try:
            city = City.objects.get(id=obj.to_city_id)
            return city.name
        except City.DoesNotExist:
            return None

    def get_from_country_name(self, obj):
        try:
            city = City.objects.get(id=obj.from_city_id)
            return city.country.international_name or city.country.official_name
        except (City.DoesNotExist, AttributeError):
            return None

    def get_to_country_name(self, obj):
        try:
            city = City.objects.get(id=obj.to_city_id)
            return city.country.international_name or city.country.official_name
        except (City.DoesNotExist, AttributeError):
            return None

    def _convert_to_local_time(self, dt):
        if dt is None:
            return None
        # проверяем что у datetime есть временная зона (если нет, считаем UTC)
        if dt.tzinfo is None:
            dt = pytz.UTC.localize(dt)
        # конвертируем в локальную временную зону
        local_tz = pytz.timezone(settings.TIME_ZONE)
        local_dt = dt.astimezone(local_tz)
        return local_dt

    def get_formatted_departure(self, obj):
        local_dt = self._convert_to_local_time(obj.departure_DT)
        return local_dt.strftime("%d.%m.%Y, %H:%M") if local_dt else None

    def get_formatted_arrival(self, obj):
        local_dt = self._convert_to_local_time(obj.arrival_DT)
        return local_dt.strftime("%d.%m.%Y, %H:%M") if local_dt else None

    def get_formatted_cargo_type(self, obj):
        cargo_types = dict(cargo_type_choices)
        return cargo_types.get(obj.cargo_type, obj.cargo_type)

    def get_formatted_transport(self, obj):
        transport_types = dict(type_transport_choices)
        return transport_types.get(obj.type_transport, obj.type_transport)