# backend/modules/task_management/models.py

from django.db import models
from django.conf import settings
from django.core.exceptions import ValidationError
from django.utils.translation import gettext_lazy as _
from core.base_models import BaseModel # Uvozimo naš Base

class Task(BaseModel):
    """
    Modularni Task model nasljeđuje sva polja iz BaseModel.
    """
    STATUS_CHOICES = [
        ('aktivan', 'Aktivan'),
        ('servis', 'U tijeku'),
        ('neaktivan', 'Otkazano'),
    ]
    title = models.CharField(max_length=255)
    description = models.TextField(blank=True)
    status = models.CharField(
        max_length=20,
        choices=STATUS_CHOICES,
        default='aktivan'
    )
    assigned_to = models.ForeignKey(
        settings.AUTH_USER_MODEL, 
        on_delete=models.SET_NULL, 
        null=True, 
        related_name='tasks'
    )
    vehicle = models.ForeignKey(
        'fleet.Vehicle',
        on_delete=models.SET_NULL,
        null=True,
        blank=True,
        related_name='tasks',
        verbose_name=_("Dizalica"),
    )
    work_order = models.ForeignKey(
        'fleet.WorkOrder',
        on_delete=models.SET_NULL,
        null=True,
        blank=True,
        related_name='work_order_tasks',
        verbose_name=_("Putni nalog"),
    )

    class Meta:
        ordering = ['-created_at']

    def __str__(self):
        return f"{self.title} ({self.status})"

    def clean(self):
        super().clean()
        if self.status == 'neaktivan' and not self.work_order_id:
            raise ValidationError({
                'work_order': "Putni nalog je obavezan prije zatvaranja zadatka."
            })