from django.db import models
from wagtail import blocks
from wagtail.admin.panels import FieldPanel
from wagtail.documents.blocks import DocumentChooserBlock
from wagtail.snippets.models import register_snippet


@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 AnchorBlock(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.MediaCategoryPage")


class MediaContentCollection(blocks.StructBlock):
    """
    Lernmedien, Links, Querverweise, Verankerung
    """

    title = blocks.TextBlock()
    contents = blocks.StreamBlock(
        [
            ("Links", LinkBlock()),
            ("Documents", DocumentChooserBlock()),
            ("Ankers", AnchorBlock()),
            ("CrossReference", CrossReferenceBlock()),
        ]
    )

    class Meta:
        icon = "link"