from django.utils.translation import get_language
from django.conf import settings
from django.db import models
import os


class Element(models.Model):
    parent = models.ForeignKey(
        'Element',
        on_delete=models.CASCADE,
        null=True,
        blank=True,
        limit_choices_to={'parent': None}
    )
    link = models.CharField(max_length=512, blank=True)
    new_window = models.BooleanField(default=False)
    add_locale = models.BooleanField(default=False)
    icon = models.FilePathField(
        path='navbar/static/navbar/icons',
        match=".png",
        null=True,
        blank=True
    )
    weight = models.PositiveSmallIntegerField()

    def icon_path(self):
        return os.path.join('navbar/icons', os.path.basename(self.icon))

    def children(self):
        return sorted(
            list(Element.objects.filter(parent=self.id).order_by('weight')) +
            list(
                ElementSeparator.objects.filter(parent=self.id)
                .order_by('weight')
            ),
            key=lambda c: c.weight
        )

    def description(self):
        lang = get_language()
        if lang is None:
            lang = settings.LANGUAGE_CODE
        return ElementDescription.objects.filter(
            element=self.id,
            language=lang
        ).first()

    def localized_link(self):
        link = self.link
        desc = self.description()
        if desc.link_override:
            link = desc.link_override
        return link

    def __str__(self):
        desc = self.description()
        return desc.short_name if desc is not None else self.link


class ElementDescription(models.Model):
    element = models.ForeignKey(Element, on_delete=models.CASCADE)
    language = models.CharField(max_length=10, choices=settings.LANGUAGES)
    short_name = models.CharField(max_length=32)
    full_name = models.CharField(max_length=64, blank=True)
    description = models.CharField(max_length=512, blank=True)
    link_override = models.CharField(max_length=512, blank=True)

    def is_separator(self):
        return False


class ElementSeparator(models.Model):
    parent = models.ForeignKey(
        Element,
        on_delete=models.CASCADE,
        limit_choices_to={'parent': None}
    )
    weight = models.PositiveSmallIntegerField()

    def is_separator(self):
        return True

    def __str__(self):
        return '{} ({})'.format(self.parent, self.weight)