from django.contrib.auth.models import AbstractUser
from django.core.exceptions import ValidationError
from django.db import models
from .managers import CustomUserManager

DEFAULT_EMAIL_SIGNATURE_TEMPLATE = (
    "Poslano iz aplikacije\n"
    "S poštovanjem / Freundliche Grüße / Kind regards\n\n"
    "{name_line}\n\n"
    "KNEZ LJUBO d.o.o.\n"
    "Ivlje 44, 10040 Zagreb\n\n"
    "Office: Donje Svetice 40, 10000 Zagreb\n\n"
    "Mobile: {mobile}\n\n"
    "www.knezljubo.hr"
)

class CustomUser(AbstractUser):
    # Email koristimo za login, pa mora biti jedinstven
    username=None
    email = models.EmailField(unique=True)

    # ERP Specifična polja
    is_serviser = models.BooleanField(default=False) # Razlikovanje uloga
    is_kupac = models.BooleanField(default=False, verbose_name="Kupac")
    is_team_member = models.BooleanField(default=False, verbose_name="Član tima")

    # Dodatne informacije o servisera
    telefon = models.CharField(max_length=20, blank=True)
    oib = models.CharField(max_length=11, blank=True, null=True)
    occupation = models.CharField(max_length=120, blank=True, default='', verbose_name="Zanimanje")
    residence = models.CharField(max_length=255, blank=True, default='', verbose_name="Prebivalište")
    work_position = models.CharField(max_length=120, blank=True, default='', verbose_name="Na radnom mjestu")
    signature = models.TextField(blank=True, default='', verbose_name="Email potpis")
    licence_number = models.CharField(max_length=50, blank=True, null=True, verbose_name="Broj licence")
    is_verified = models.BooleanField(default=False, verbose_name="Verificiran profil")

    # Poveznica na klijenta (ako je korisnik kupac)
    client_profile = models.ForeignKey(
        'crm.Client',
        on_delete=models.SET_NULL,
        null=True,
        blank=True,
        related_name='users',      # Omogućuje pristup: klijent.users.all()
        verbose_name="Povezani klijent"
    )

    objects = CustomUserManager()
    # Govorimo Djangu da koristi email umjesto username-a
    USERNAME_FIELD = 'email'
    REQUIRED_FIELDS = ['first_name', 'last_name']

    def __str__(self):
        return f"{self.first_name} {self.last_name} ({self.email})"

    def clean(self):
        # if self.email == "bot@erp.hr":
        #     return # Preskoči validaciju za bota
        super().clean()
        if self.is_kupac and not self.client_profile:
            raise ValidationError({'client_profile': "Korisnik koji je označen kao kupac mora imati povezan klijentski profil."})

    def build_default_signature(self):
        full_name = self.get_full_name().strip()
        fallback_name = self.email.strip() if isinstance(self.email, str) and self.email.strip() else 'Ime i prezime'
        display_name = full_name or fallback_name
        occupation = self.occupation.strip() if isinstance(self.occupation, str) else ''
        name_line = f"{occupation} {display_name}".strip() if occupation else display_name
        mobile = self.telefon.strip() if isinstance(self.telefon, str) and self.telefon.strip() else "+385 91 636 3466"
        return DEFAULT_EMAIL_SIGNATURE_TEMPLATE.format(
            name_line=name_line,
            mobile=mobile,
        )

    def get_email_signature(self):
        stored_signature = self.signature.strip() if isinstance(self.signature, str) else ''
        if stored_signature:
            return stored_signature
        return self.build_default_signature()

    def save(self, *args, **kwargs):
        signature = self.signature.strip() if isinstance(self.signature, str) else ''
        if not signature:
            self.signature = self.build_default_signature()
        self.full_clean() # Prisiljava pokretanje clean() prije svakog save()
        super().save(*args, **kwargs)