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


class Course(models.Model):
    """Kurs-Model für Backend-Verwaltung"""
    name = models.CharField(max_length=200, verbose_name="Kurs-Name")
    code = models.CharField(max_length=50, unique=True, verbose_name="Kurs-Code")  # z.B. "PROG-101"
    description = models.TextField(blank=True, verbose_name="Beschreibung")

    tutor = models.ForeignKey(
        User,
        on_delete=models.SET_NULL,
        null=True,
        blank=True,
        verbose_name="Tutor",
        related_name="courses_as_tutor"
    )

    is_active = models.BooleanField(default=True, verbose_name="Aktiv")
    created_at = models.DateTimeField(auto_now_add=True)

    class Meta:
        ordering = ['name']
        verbose_name = "Kurs"
        verbose_name_plural = "Kurse"

    def __str__(self):
        if self.tutor:
            return f"{self.code} - {self.name} (Tutor: {self.tutor.username})"
        return f"{self.code} - {self.name}"


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"),
    ]

    MATERIAL_CHOICES = [
        ("learning_sprint", "Learning Sprint"),
        ("ilse", "Intensive Live Session"),
        ("video", "Video"),
        ("exercise", "Übungsaufgabe"),
        ("solution", "Musterlösung"),
        ("slides", "Präsentationsfolien"),
        ("other", "Sonstiges"),
    ]

    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")
    material = models.CharField(max_length=20, choices=MATERIAL_CHOICES, default="script")

    answer = models.TextField(
        blank=True,
        null=True,
        verbose_name="Antwort/Lösung",
        help_text="Beschreibung der Lösung (erforderlich bei Status 'Gelöst')"
    )
    answered_at = models.DateTimeField(
        blank=True,
        null=True,
        verbose_name="Beantwortet am"
    )

    course = models.ForeignKey(
        Course,
        on_delete=models.CASCADE,
        verbose_name="Kurs",
        related_name="tickets"
    )
    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"]


class FAQ(models.Model):
    """Einfaches FAQ Model"""
    question = models.CharField(max_length=300, verbose_name="Frage")
    answer = models.TextField(verbose_name="Antwort")
    order = models.IntegerField(default=0, verbose_name="Reihenfolge")
    is_active = models.BooleanField(default=True, verbose_name="Aktiv")

    class Meta:
        ordering = ['order', 'question']
        verbose_name = "FAQ"
        verbose_name_plural = "FAQs"

    def __str__(self):
        return self.question