"""
This module defines the structure and properties of documents.
"""

from django.db import models
from closuretree.models import ClosureModel
from simple_history.models import HistoricalRecords

from jci.models import Standard


class Audience(ClosureModel):
    name = models.CharField(max_length=50)
    parent = models.ForeignKey('self', related_name='children', null=True, blank=True)

    def __str__(self):
        return self.name

    class Meta:
        ordering = ('name',)


class Site(models.Model):
    name = models.CharField(max_length=50)

    def __str__(self):
        return self.name

    class Meta:
        ordering = ['name']


class Structure(ClosureModel):
    name = models.CharField(max_length=50)
    acronym = models.CharField(max_length=20, null=True, blank=True)
    parent = models.ForeignKey('self', related_name='children', null=True, blank=True)

    def __str__(self):
        return self.name


class DocumentType(models.Model):
    name = models.CharField(max_length=50)
    level = models.IntegerField()
    template = models.FileField(upload_to='documents_templates/', null=True, blank=True)

    def __str__(self):
        return self.name

    class Meta:
        ordering = ['level']


class Document(models.Model):
    audiences = models.ManyToManyField(Audience)
    sites = models.ManyToManyField(Site)
    standards = models.ManyToManyField(Standard, related_name='documents')
    structures = models.ManyToManyField(Structure)
    title = models.CharField(max_length=255)
    overview = models.TextField(blank=True, null=True)
    type = models.ForeignKey(DocumentType, null=True)
    created_at = models.DateTimeField(auto_now_add=True)
    revised_at = models.DateTimeField(null=True, blank=True)
    history = HistoricalRecords()

    @property
    def last_published_version(self):
        try:
            return self.versions.filter(published__isnull=False).first().revisions.first()
        except Version.DoesNotExist:
            return 'None'
        except Exception:
            return 'None'

    @property
    def last_working_version(self):
        try:
            return self.versions.filter(published__isnull=True).first().revisions.first()
        except Version.DoesNotExist:
            return 'None'

    def __str__(self):
        return self.title

    def update_version(self, document):
        pass

    def publish(self):
        pass


class Version(models.Model):
    document = models.ForeignKey(Document, related_name='versions')
    major = models.PositiveIntegerField()
    published = models.OneToOneField('Revision', related_name='published_version+', null=True, blank=True)

    class Meta:
        unique_together = ('document', 'major')

    @property
    def status(self):
        return 'Published' if self.published else 'Draft'

    def __str__(self):
        return '{} v{} ({})'.format(self.document, self.major, self.status)

    def publish(self):
        pass


class Revision(models.Model):
    revision = models.FileField(upload_to='revisions/')
    created_at = models.DateTimeField(auto_now_add=True)
    version = models.ForeignKey(Version, related_name='revisions')
    minor = models.PositiveIntegerField()

    class Meta:
        ordering = ('-minor',)

    def __str__(self):
        return '{} rev {}'.format(self.version, self.minor)