from django.db import models
from django.core.exceptions import ValidationError
from simple_history.models import HistoricalRecords


class Directie(models.Model):
    name = models.CharField(max_length=255, verbose_name="Nume Direcție")
    history = HistoricalRecords()

    def __str__(self):
        return self.name

    class Meta:
        verbose_name = "Direcție"
        verbose_name_plural = "Direcții"


class Serviciu(models.Model):
    name = models.CharField(max_length=255, verbose_name="Nume Serviciu")
    # A Serviciu is directly assigned to a Direcție
    directie = models.ForeignKey(
        Directie,
        on_delete=models.CASCADE,
        related_name="servicii",
        verbose_name="Direcție",
    )
    history = HistoricalRecords()

    def __str__(self):
        return self.name

    class Meta:
        verbose_name = "Serviciu"
        verbose_name_plural = "Servicii"


class Compartiment(models.Model):
    name = models.CharField(max_length=255, verbose_name="Nume Compartiment")
    # A Compartiment can be part of a Serviciu or directly included in a Direcție
    directie = models.ForeignKey(
        Directie,
        on_delete=models.CASCADE,
        null=True,
        blank=True,
        related_name="compartimente_directe",
        verbose_name="Direcție (Direct)",
    )
    serviciu = models.ForeignKey(
        Serviciu,
        on_delete=models.CASCADE,
        null=True,
        blank=True,
        related_name="compartimente_subordonate",
        verbose_name="Serviciu",
    )
    history = HistoricalRecords()

    def clean(self):
        # Validation to ensure the Compartiment belongs to either a Direcție OR a Serviciu, but not both or neither.
        if not self.directie and not self.serviciu:
            raise ValidationError(
                "Un compartiment trebuie să aparțină de o Direcție sau de un Serviciu."
            )
        if self.directie and self.serviciu:
            raise ValidationError(
                "Un compartiment nu poate aparține simultan și de o Direcție și de un Serviciu."
            )

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

    def __str__(self):
        return self.name

    class Meta:
        verbose_name = "Compartiment"
        verbose_name_plural = "Compartimente"


class Employee(models.Model):
    """
    Represents the 'Users' from the project specification who will hold equipment.
    Named 'Employee' to avoid conflicts with Django's built-in auth.User model.
    """

    name = models.CharField(max_length=255, verbose_name="Name")
    username = models.CharField(max_length=150, unique=True, verbose_name="User name")
    role = models.CharField(max_length=255, verbose_name="Function/role")
    office_number = models.CharField(max_length=50, verbose_name="Office number")
    email = models.EmailField(verbose_name="Email address")

    # Keep only this single observations field
    observations = models.TextField(blank=True, null=True, verbose_name="Observații")

    # Organizational Placement - Employees can be placed at any of the three levels
    directie = models.ForeignKey(
        Directie,
        on_delete=models.SET_NULL,
        null=True,
        blank=True,
        related_name="employees",
        verbose_name="Direcție",
    )
    serviciu = models.ForeignKey(
        Serviciu,
        on_delete=models.SET_NULL,
        null=True,
        blank=True,
        related_name="employees",
        verbose_name="Serviciu",
    )
    compartiment = models.ForeignKey(
        Compartiment,
        on_delete=models.SET_NULL,
        null=True,
        blank=True,
        related_name="employees",
        verbose_name="Compartiment",
    )

    @property
    def get_active_inventory(self):
        """Returns a dictionary of all active equipment and certificates assigned to the user."""
        return {
            "computers": self.computers.filter(status="activ"),
            "monitors": self.monitors.filter(status="activ"),
            "peripherals": self.peripherals.filter(status="activ"),
            "certificates": self.digital_certificates.filter(is_canceled=False),
        }

    history = HistoricalRecords()

    def __str__(self):
        return f"{self.name} ({self.username})"

    class Meta:
        verbose_name = "Angajat / Utilizator"
        verbose_name_plural = "Angajați / Utilizatori"
        ordering = ["name"]