"""
Models for the downloads application.
"""
import os

import datetime
from django.db import models
from django.contrib.auth.models import User
from django.template.defaultfilters import filesizeformat

from core.markup import site_markup


class Category(models.Model):
    """Downloads belong to categories."""
    title = models.CharField(max_length=64)
    description = models.TextField(blank=True)
    count = models.IntegerField(default=0, blank=True)

    class Meta:
        verbose_name_plural = 'Categories'
        ordering = ('title', )

    def __unicode__(self):
        return self.title


def download_path(instance, filename):
    """
    Creates a path for a download. Uses the current date to avoid filename
    clashes. Uses the current microsecond also to make the directory name
    harder to guess.
    """
    now = datetime.datetime.now()
    parts = ['downloads']
    parts.extend([str(p) for p in (now.year, now.month, now.day, now.microsecond)])
    parts.append(filename)
    return os.path.join(*parts)


class PublicDownloadManager(models.Manager):
    """The manager for all public downloads."""
    def get_query_set(self):
        return super(PublicDownloadManager, self).get_query_set().filter(
                is_public=True).select_related()


class DownloadBase(models.Model):
    """Abstract model to collect common download fields."""
    title = models.CharField(max_length=128)
    category = models.ForeignKey(Category)
    description = models.TextField()
    html = models.TextField(blank=True)
    file = models.FileField(upload_to=download_path)
    user = models.ForeignKey(User)
    date_added = models.DateTimeField()
    ip_address = models.IPAddressField('IP Address')

    class Meta:
        abstract = True

    def size(self):
        return filesizeformat(self.file.size)


class PendingDownload(DownloadBase):
    """This model represents pending downloads created by users. These pending
    downloads must be approved by an admin before they turn into "real"
    Downloads and are visible on site.
    """
    class Meta:
        ordering = ('date_added', )

    def __unicode__(self):
        return self.title

    def save(self, *args, **kwargs):
        if not self.pk:
            self.date_added = datetime.datetime.now()
        self.html = site_markup(self.description)
        super(PendingDownload, self).save(*args, **kwargs)


class Download(DownloadBase):
    """Model to represent a download."""
    hits = models.IntegerField(default=0)
    average_score = models.FloatField(default=0.0)
    total_votes = models.IntegerField(default=0)
    is_public = models.BooleanField(default=False, db_index=True)

    # Managers:
    objects = models.Manager()
    public_objects = PublicDownloadManager()

    def __unicode__(self):
        return self.title

    @models.permalink
    def get_absolute_url(self):
        return ('downloads-details', [str(self.id)])

    def save(self, *args, **kwargs):
        self.html = site_markup(self.description)
        super(Download, self).save(*args, **kwargs)

    def vote(self, vote_value):
        """receives a vote_value and updates internal score accordingly"""
        total_score = self.average_score * self.total_votes
        total_score += vote_value
        self.total_votes += 1
        self.average_score = total_score / self.total_votes
        return self.average_score


class AllowedExtensionManager(models.Manager):
    def get_extension_list(self):
        return self.values_list('extension', flat=True)


class AllowedExtension(models.Model):
    """Model to represent the list of allowed file extensions."""
    extension = models.CharField(max_length=8)

    objects = AllowedExtensionManager()

    def __unicode__(self):
        return self.extension

    class Meta:
        ordering = ('extension', )


class VoteRecord(models.Model):
    """Model to record the date that a user voted on a download."""
    download = models.ForeignKey(Download)
    user = models.ForeignKey(User)
    vote_date = models.DateTimeField(auto_now_add=True)

    def __unicode__(self):
        return u"%s voted on '%s' on %s" % (
                self.user.username, 
                self.download.title, 
                self.vote_date.strftime('%b %d, %Y %H:%M:%S'))

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