# Create your models here.

from django.db import models
from modelcluster.fields import ParentalKey
from wagtail.admin.edit_handlers import FieldPanel, StreamFieldPanel, InlinePanel
from wagtail.core.blocks import StreamBlock
from wagtail.core.fields import StreamField
from wagtail.core.models import Page, Orderable
from django.utils.text import slugify


from vbv_lernwelt.learnpath.models_learning_unit_content import WebBasedTrainingBlock, VideoBlock


class LearningPath(Page):
    # PageChooserPanel('related_page', 'demo.PublisherPage'),

    content_panels = Page.content_panels + [
        InlinePanel('topics', label="Topics"),
    ]

    subpage_types = ['learnpath.Circle']

    class Meta:
        verbose_name = "Learning Path"

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


class Topic(Orderable):
    title = models.TextField(default='')
    is_visible = models.BooleanField(default=True)

    learning_path = ParentalKey('learnpath.LearningPath',
                                null=True,
                                blank=True,
                                on_delete=models.CASCADE,
                                related_name='topics',
                                )

    panels = [FieldPanel('title'),
              FieldPanel('is_visible'),
              ]

    # content_panels = Page.content_panels + [
    #     FieldPanel('is_visible', classname="full"),
    #     PageChooserPanel('learning_path',  'learnpath.LearningPath'),
    # ]

    # parent_page_types = ['learnpath.LearningPath']
    # subpage_types = ['learnpath.Circle']
    def full_clean(self, *args, **kwargs):
        self.slug = find_available_slug(Topic, slugify(self.title, allow_unicode=True))
        super(Topic, self).full_clean(*args, **kwargs)


    class Meta:
        verbose_name = "Topic"

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


class Circle(Page, Orderable):
    description = models.TextField(default="", blank=True)
    goals = models.TextField(default="", blank=True)
    topic = models.ForeignKey(
        'learnpath.Topic',
        null=True,
        blank=True,
        on_delete=models.SET_NULL,
        related_name='circles'
    )

    parent_page_types = ['learnpath.Learningpath']
    subpage_types = ['learnpath.LearningUnit']

    content_panels = Page.content_panels + [
        FieldPanel('description'),
        FieldPanel('topic'),
        FieldPanel('goals'),
        InlinePanel('learning_sequences', label="Learning Sequences"),
    ]

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

    class Meta:
        verbose_name = "Circle"



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


IN_CIRCLE = 'INCIRCLE'
START = 'START'
END = 'END'

LEARNING_SEQUENCE_CATEGORIES = [
    (IN_CIRCLE, 'In Circle'),
    (START, 'Start'),
    (END, 'End')
]


class LearningSequence(Orderable):
    # TODO: How to do a icon choice field?
    title = models.CharField(max_length=256, default='')
    category = models.CharField(max_length=16, choices=LEARNING_SEQUENCE_CATEGORIES, default=IN_CIRCLE)

    circle = ParentalKey(
        'learnpath.Circle',
        null=True,
        blank=True,
        on_delete=models.CASCADE,
        related_name='learning_sequences',
    )

    panels = [FieldPanel('title'), FieldPanel('category')]

    class Meta:
        verbose_name = "Learning Sequence"

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


class LearningUnit(Page, Orderable):
    # TODO: Review model architecture, is the stream fiel the right thing here?
    parent_page_types = ['learnpath.Circle']
    learning_sequence = models.ForeignKey(
        'learnpath.LearningSequence',
        null=True,
        blank=True,
        on_delete=models.CASCADE,
        related_name='learning_units'
    )

    content_blocks = [
        ('web_based_training', WebBasedTrainingBlock()),
        ('video', VideoBlock()),
    ]

    contents = StreamField(StreamBlock(content_blocks),
                           null=True, blank=True, min_num=1, max_num=1)

    content_panels = [
        FieldPanel('title', classname="full title"),
        StreamFieldPanel('contents'),
        FieldPanel('learning_sequence')
    ]

    subpage_types = []

    class Meta:
        verbose_name = "Learning Unit"

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

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


def find_available_slug(model, requested_slug, ignore_page_id=None):
    """
    Finds an available slug within the specified parent.

    If the requested slug is not available, this adds a number on the end, for example:

     - 'requested-slug'
     - 'requested-slug-1'
     - 'requested-slug-2'

    And so on, until an available slug is found.

    The `ignore_page_id` keyword argument is useful for when you are updating a page,
    you can pass the page being updated here so the page's current slug is not
    treated as in use by another page.
    """

    # TODO: In comparison ot wagtails own function, I look for the same model  instead of the parent
    pages = model.objects.filter(slug__startswith=requested_slug)

    if ignore_page_id:
        pages = pages.exclude(id=ignore_page_id)

    existing_slugs = set(pages.values_list("slug", flat=True))
    slug = requested_slug
    number = 1


    while slug in existing_slugs:
        slug = requested_slug + "-" + str(number)
        number += 1

    return slug