"""Models for integration with Packeta (Zásilkovna) API.

These models wrap calls to the SOAP API via the immutable client defined in
`client.py` (PacketaAPI). DO NOT modify the client; we only consume it here.

Workflow:
 - Create a `PacketaPacket` instance locally with required recipient data.
 - On first save (when `packet_id` is empty) call the remote API to create
   the packet and persist the returned identifier + metadata.
 - Use helper methods to refresh remote info, fetch label PDF, cancel packet.
 - Group packets into a `PacketaShipment` and create shipment remotely.

Edge cases handled:
 - API faults raise exceptions (to be surfaced by serializer validation).
 - Missing remote fields are stored in `metadata` JSON.
 - Label PDF stored as binary field; can be re-fetched if empty.
"""

import json
from django.db import models
from django.utils import timezone
from django.core.validators import RegexValidator
from django.core.files.base import ContentFile
from django.apps import apps
from rest_framework.exceptions import ValidationError

from .client import PacketaAPI

from configuration.models import ShopConfiguration

packeta_client = PacketaAPI()  # single reusable instance


class ZasilkovnaPacket(models.Model):
    created_at = models.DateTimeField(auto_now_add=True)
    
    class STATE(models.TextChoices):
        WAITING_FOR_ORDER = "WAITING_FOR_ORDERING_SHIPMENT", "cz#Čeká na objednání zásilkovny"
        PENDING = "PENDING", "cz#Podáno"
        SENDED = "SENDED", "cz#Odesláno"
        ARRIVED = "ARRIVED", "cz#Doručeno"
        CANCELED = "CANCELED", "cz#Zrušeno"

        RETURNING = "RETURNING", "cz#Posláno zpátky"
        RETURNED = "RETURNED", "cz#Vráceno"
    state = models.CharField(max_length=20, choices=STATE.choices, default=STATE.PENDING)

    # ------- API -------
    # https://client.packeta.com/cs/senders  (admin rozhraní)
    
    addressId = models.IntegerField(null=True, blank=True, help_text="ID adresy/pointu, ve Widgetu zásilkovny který si vybere uživatel.")
    
    packet_id = models.IntegerField(null=True, blank=True, help_text="Číslo zásilky v Packetě (vraceno od API od Packety)")
    barcode = models.CharField(null=True, blank=True, max_length=64, help_text="Čárový kód zásilky od Packety")

    weight = models.IntegerField(
        default=0,
        help_text="Hmotnost zásilky v gramech"
    )

    # 🚚 návratové směrovací kódy (pro vrácení zásilky)
    return_routing = models.JSONField(
        default=list,
        blank=True,
        null=True,
        help_text="Seznam 2 routing stringů pro vrácení zásilky"
    )

    class PDF_SIZE(models.TextChoices):
        A6_ON_A6 = ("A6 on A6", "105x148 mm (A6) label on a page of the same size")
        A7_ON_A7 = ("A7 on A7", "105x74 mm (A7) label on a page of the same size")
        A6_ON_A4 = ("A6 on A4", "105x148 mm (A6) label on a page of size 210x297 mm (A4)")
        A7_ON_A4 = ("A7 on A4", "105x74 mm (A7) label on a page of size 210x297 mm (A4)")
        A8_ON_A8 = ("A8 on A8", "50x74 mm (A8) label on a page of the same size")
    size_of_pdf = models.CharField(max_length=20, choices=PDF_SIZE.choices, default=PDF_SIZE.A6_ON_A6)

    def save(self, *args, **kwargs):
        return super().save(args, **kwargs)
    

    def order_shippment(self):
        if self.addressId is None:
            raise ValidationError("AddressId must be set to order shipping.")
        
        Carrier = apps.get_model('commerce', 'Carrier')
        Order = apps.get_model('commerce', 'Order')

        carrier = Carrier.objects.get(zasilkovna=self)
        order = Order.objects.get(carrier=carrier)

        cash_on_delivery = order.payment.payment_method == order.payment.PAYMENT.CASH_ON_DELIVERY

        if not self.packet_id:
            response = packeta_client.create_packet(
                addressId=self.addressId, # ID z widgetu
                weight=self.weight,
                number=order.id,
                name=order.first_name,
                surname=order.last_name,
                company=order.company,
                email=order.email,
                
                cod=order.total_price if cash_on_delivery else 0, # dobírka
                value=order.total_price,

                currency=ShopConfiguration.get_solo().currency, #CZK
                eshop= ShopConfiguration.get_solo().name,
            )
            self.packet_id = response['packet_id']
            self.barcode = response['barcode']
        else:
            raise ValidationError("Přeprava už byla objednana!!!.")

        return self.save()
        
    def cancel_packet(self):
        """Cancel this packet via the Packeta API."""
        packeta_client.cancel_packet(self.packet_id)
        self.state = self.STATE.CANCELED
        self.save()  # persist state change

    def get_tracking_url(self):
        """Vrátí veřejnou URL pro sledování zásilky (Zásilkovna.cz)."""
        base_url = "https://www.zasilkovna.cz/vyhledavani?query="
        return f"{base_url}{self.barcode}"
    
    def returning_packet(self):
        """Mark this packet as returning via the Packeta API."""
        response = packeta_client.get_return_routing(self.packet_id)
        
        self.return_routing = json.loads(response)
        self.state = self.STATE.RETURNING

        self.save()  # persist state change
    

class ZasilkovnaShipment(models.Model):
    created_at = models.DateTimeField(auto_now_add=True, editable=False)
    shipment_id = models.CharField(max_length=255, unique=True, help_text="ID zásilky v Packetě", editable=False)

    barcode = models.CharField(
        max_length=64, 
        help_text="Čárový kód zásilky v Packetě (format: )", 
        validators=[
            RegexValidator(r'D-***-XM-<id>', message="Neplatný formát čárového kódu.")
        ]
    )

    packets = models.ManyToManyField(ZasilkovnaPacket, related_name="shipments", help_text="Seznam zásilek v této zásilce (packet_id)")

    def save(self, *args, **kwargs):
        if not self.shipment_id:
            response = packeta_client.create_shipment(
                packet_ids=[packet.packet_id for packet in self.packets.all()]
            )
            self.shipment_id = response['shipment_id']
            self.barcode = response['barcode']

        return super().save(args, **kwargs)