from django.db import models
from django.contrib.auth.models import User


class Ticket(models.Model):
    STATUS_CHOICES = [
        ("new", "Neu"),
        ("in_progress", "In Bearbeitung"),
        ("resolved", "Gelöst"),
        ("pending_close", "Wartend - Schließen"),
        ("closed", "Geschlossen"),
    ]

    PRIORITY_CHOICES = [
        ("low", "Niedrig"),
        ("medium", "Mittel"),
        ("high", "Hoch"),
    ]

    title = models.CharField(max_length=200)
    description = models.TextField()
    status = models.CharField(max_length=20, choices=STATUS_CHOICES, default="new")
    priority = models.CharField(
        max_length=10, choices=PRIORITY_CHOICES, default="medium"
    )
    created_by = models.ForeignKey(
        User, related_name="tickets_created", on_delete=models.CASCADE
    )
    assigned_to = models.ForeignKey(
        User, related_name="tickets_assigned", null=True, blank=True, on_delete=models.CASCADE,
    )
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

    def __str__(self):
        return f"[{self.get_priority_display()}] {self.title} ({self.get_status_display()})"


class Comment(models.Model):
    ticket = models.ForeignKey(
        "Ticket", on_delete=models.CASCADE, related_name="comments"
    )
    author = models.ForeignKey(User, on_delete=models.CASCADE)
    text = models.TextField()
    created_at = models.DateTimeField(auto_now_add=True)

    def __str__(self):
        return f"Kommentar von {self.author} zu Ticket #{self.ticket.id}"


class TicketHistory(models.Model):
    ticket = models.ForeignKey(
        "Ticket", on_delete=models.CASCADE, related_name="history"
    )
    changed_by = models.ForeignKey(User, on_delete=models.SET_NULL, null=True)
    changed_at = models.DateTimeField(auto_now_add=True)

    field = models.CharField(max_length=100)  # z. B. "status" oder "description"
    old_value = models.TextField(null=True, blank=True)
    new_value = models.TextField(null=True, blank=True)

    class Meta:
        ordering = ["-changed_at"]