from django.db import models
from django.utils.translation import gettext_lazy as _
from wagtail import blocks
from wagtail.admin.panels import FieldPanel
from wagtail.documents.blocks import DocumentChooserBlock
from wagtail.snippets.models import register_snippet


class VisualisationType(models.TextChoices):
    LEARNING_MEDIA = 'LearningMedia', _('Lernmedien')
    LINK = 'Link', _('Links')
    ANKER = 'Anker', _('Verankerung')
    CROSSREFERENCE = 'CrossReference', _('Querverweise')


@register_snippet
class MediaLibraryContent(models.Model):
    title = models.TextField()
    description = models.TextField()
    link_display_text = models.CharField(max_length=255)
    # TODO: Revisions only work with wagtail 4.0, can not migrate since wagtail localize is not ready yet.
    # _revisions = GenericRelation("wagtailcore.Revision", related_query_name="media_library_content")

    panels = [
        FieldPanel('title'),
        FieldPanel('description'),
        FieldPanel('link_display_text'),
    ]

    @property
    def revisions(self):
        return self._revisions


class AnkerBlock(blocks.PageChooserBlock):
    """
    Verankerung im Lernpfad. Link to a Learning Content.
    """
    page_type = 'learnpath.LearningUnit'


class LinkBlock(blocks.StructBlock):
    title = blocks.TextBlock(blank=False, null=False)
    description = blocks.TextBlock(default='')
    link_display_text = blocks.CharBlock(max_length=255, default='Link öffnen')
    url = blocks.URLBlock()


class CrossReferenceBlock(blocks.StructBlock):
    title = models.TextField(blank=False, null=False)
    description = blocks.TextBlock(default='')
    link_display_text = blocks.CharBlock(max_length=255, default='Link öffnen')
    category = blocks.PageChooserBlock(page_type='media_library.Category')


class ContentCollection(blocks.StructBlock):
    """
    Lernmedien, Links, Querverweise, Verankerung
    """
    title = blocks.TextBlock()
    collection_type = blocks.MultipleChoiceBlock(choices=VisualisationType.choices,
                                                 max_length=20,
                                                 default=VisualisationType.LEARNING_MEDIA)
    contents = blocks.StreamBlock([('Links', LinkBlock()),
                                   ('Documents', DocumentChooserBlock()),
                                   ('Ankers', AnkerBlock()),
                                   ('CrossReference', CrossReferenceBlock())
                                   ])

    class Meta:
        icon = 'link'