from django.db import models
from django.db.models import UniqueConstraint
from django.utils.text import slugify
from django.utils.translation import gettext_lazy as _
from wagtail.models import Page

from vbv_lernwelt.core.model_utils import find_available_slug
from vbv_lernwelt.core.models import User


class Course(models.Model):
    title = models.CharField(_("Titel"), max_length=255)
    category_name = models.CharField(
        _("Kategorie-Name"), max_length=255, default="Kategorie"
    )

    class Meta:
        verbose_name = _("Lehrgang")

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


class CourseCategory(models.Model):
    # Die Handlungsfelder im "Versicherungsvermittler/in"
    title = models.CharField(_("Titel"), max_length=255, blank=True)
    course = models.ForeignKey("course.Course", on_delete=models.CASCADE)
    general = models.BooleanField(_("Allgemein"), default=False)

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


class CoursePage(Page):
    content_panels = Page.content_panels
    subpage_types = ["learnpath.LearningPath", "media_library.MediaLibraryPage"]
    course = models.ForeignKey("course.Course", on_delete=models.PROTECT)

    class Meta:
        verbose_name = _("Lehrgang-Seite")

    def full_clean(self, *args, **kwargs):
        self.slug = find_available_slug(slugify(self.title, allow_unicode=True))
        super(CoursePage, self).full_clean(*args, **kwargs)

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


class CourseCompletion(models.Model):
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

    user = models.ForeignKey(User, on_delete=models.CASCADE)

    # page can logically be a LearningContent or a PerformanceCriteria for now
    page_key = models.UUIDField()
    page_type = models.CharField(max_length=255, default="", blank=True)
    page_slug = models.CharField(max_length=255, default="", blank=True)

    course = models.ForeignKey("course.Course", on_delete=models.CASCADE)

    completion_status = models.CharField(
        max_length=255,
        choices=[
            ("unknown", "unknown"),
            ("success", "success"),
            ("fail", "fail"),
        ],
        default="unknown",
    )
    additional_json_data = models.JSONField(default=dict)

    class Meta:
        constraints = [
            UniqueConstraint(
                fields=[
                    "user",
                    "page_key",
                ],
                name="course_completion_unique_user_page_key",
            )
        ]


class CourseSession(models.Model):
    """
    Die Durchführung eines Kurses
    Benutzer die an eine CourseSession gehängt sind können diesen Lehrgang sehen
    Das anhängen kann via CourseSessionUser oder "Schulklasse (TODO)" geschehen
    """

    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

    course = models.ForeignKey("course.Course", on_delete=models.CASCADE)
    title = models.TextField()

    start_date = models.DateField(null=True, blank=True)
    end_date = models.DateField(null=True, blank=True)

    additional_json_data = models.JSONField(default=dict)


class CourseSessionUser(models.Model):
    """
    Ein Benutzer der an einer CourseSession teilnimmt
    """

    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

    course_session = models.ForeignKey("course.CourseSession", on_delete=models.CASCADE)
    user = models.ForeignKey(User, on_delete=models.CASCADE)

    class Meta:
        constraints = [
            UniqueConstraint(
                fields=[
                    "course_session",
                    "user",
                ],
                name="course_session_user_unique_course_session_user",
            )
        ]