import re
import secrets
from django.conf import settings
from django.db import models
from django.urls import reverse

TAG_RE = re.compile(r'(?<!\w)#([\wäöüÄÖÜß-]+)')
LINK_RE = re.compile(r'\[\[(todo|note|link|journal)?:?(\d+)\]\]', re.I)


class Tag(models.Model):
    name = models.SlugField(max_length=80, unique=True, allow_unicode=True)

    class Meta:
        ordering = ['name']

    def __str__(self):
        return f'#{self.name}'


class Item(models.Model):
    class Kind(models.TextChoices):
        TODO = 'todo', 'Aufgabe'
        NOTE = 'note', 'Notiz'
        LINK = 'link', 'Link'
        JOURNAL = 'journal', 'Journal'

    class Visibility(models.TextChoices):
        PRIVATE = 'private', 'Privat'
        PUBLIC = 'public', 'Öffentlich'

    owner = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE, related_name='items')
    kind = models.CharField(max_length=10, choices=Kind.choices, default=Kind.NOTE)
    content = models.TextField()
    comment = models.TextField(blank=True)
    visibility = models.CharField(max_length=10, choices=Visibility.choices, default=Visibility.PRIVATE)
    kanban_status = models.CharField(max_length=20, default='inbox', choices=[
        ('inbox', 'Eingang'),
        ('todo', 'Todo'),
        ('progress', 'In Progress'),
        ('done', 'Erledigt'),
    ])
    is_done = models.BooleanField(default=False)
    completed_at = models.DateTimeField(blank=True, null=True)
    due_at = models.DateTimeField(blank=True, null=True)
    url = models.URLField(blank=True)
    tags = models.ManyToManyField(Tag, blank=True, related_name='items')
    linked_items = models.ManyToManyField('self', blank=True, symmetrical=False, related_name='backlinks')
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

    class Meta:
        ordering = ['-created_at']

    def __str__(self):
        return self.content[:80]

    def get_absolute_url(self):
        return reverse('item_detail', args=[self.pk])

    def sync_metadata(self):
        tag_names = {m.group(1).lower() for m in TAG_RE.finditer(self.content)}
        tags = [Tag.objects.get_or_create(name=name)[0] for name in tag_names]
        self.tags.set(tags)
        ids = [int(m.group(2)) for m in LINK_RE.finditer(f'{self.content}\n{self.comment}')]
        self.linked_items.set(Item.objects.filter(id__in=ids).exclude(id=self.id))


class Kanban(models.Model):
    owner = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE, related_name='kanbans')
    name = models.CharField(max_length=120)
    tag = models.ForeignKey(Tag, on_delete=models.CASCADE, related_name='kanbans')
    created_at = models.DateTimeField(auto_now_add=True)

    class Meta:
        ordering = ['name']
        unique_together = [('owner', 'tag')]

    def __str__(self):
        return self.name


class UserPreference(models.Model):
    user = models.OneToOneField(settings.AUTH_USER_MODEL, on_delete=models.CASCADE, related_name='preferences')
    show_notes = models.BooleanField(default=True)
    show_open_todos = models.BooleanField(default=True)
    show_done_todos = models.BooleanField(default=False)
    show_links = models.BooleanField(default=True)
    show_journal = models.BooleanField(default=False)
    overview_lines = models.PositiveSmallIntegerField(default=4)

    def __str__(self):
        return f'Einstellungen {self.user}'


class ApiKey(models.Model):
    owner = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE, related_name='api_keys')
    name = models.CharField(max_length=120, default='API Key')
    token = models.CharField(max_length=80, unique=True, editable=False)
    tags = models.ManyToManyField(Tag, blank=True, related_name='api_keys')
    created_at = models.DateTimeField(auto_now_add=True)
    is_active = models.BooleanField(default=True)

    class Meta:
        ordering = ['-created_at']

    def save(self, *args, **kwargs):
        if not self.token:
            self.token = secrets.token_urlsafe(32)
        super().save(*args, **kwargs)

    def __str__(self):
        return self.name


class Attachment(models.Model):
    item = models.ForeignKey(Item, on_delete=models.CASCADE, related_name='attachments')
    file = models.FileField(upload_to='attachments/%Y/%m/')
    uploaded_at = models.DateTimeField(auto_now_add=True)

    def __str__(self):
        return self.file.name