import datetime

from django.db import models
from django.core.urlresolvers import reverse
import django.utils.http
from django.contrib.sites.models import get_current_site
from django.utils import timezone

QRCODE_API = 'https://chart.googleapis.com/chart?cht=qr&chs={width}x{height}&chl={url}&chld=H'

class URL(models.Model):
    shorturl = models.SlugField(unique=True)
    publishing_schedule = models.TimeField(default=datetime.time(),
            help_text="Default time to publish new URLItems")

    class Meta:
        verbose_name = u"URL Feed"
        verbose_name_plural = u"URL Feeds"

    def qrcode_img (self, size=512) :
        return QRCODE_API.format(
                width=size, height=size,
                url=django.utils.http.urlquote(self.qrcode_url()),
        )

    def qrcode_url (self) :
        return 'HTTP://{domain}{url}'.format(
                domain = get_current_site(None).domain.upper(),
                url = self.get_absolute_url(),
        )

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

    def active_item(self, now=None) :
        """Currently published URLItem."""
        if now is None :
            now = timezone.now()

        try :
            return URLItem.objects.filter(shorturl=self, published__lt=now).order_by('-published')[0]
        except IndexError :
            return None

    def upcoming_item (self, now=None) :
        """Following published URLItem."""
        if now is None :
            now = timezone.now()

        try :
            return URLItem.objects.filter(shorturl=self, published__gt=now).order_by('published')[0]
        except IndexError :
            return None

    def last_item (self) :
        """The last URLItem available."""

        try :
            return URLItem.objects.filter(shorturl=self).order_by('-published')[0]
        except IndexError :
            return None

    def __unicode__ (self) :
        return self.shorturl

class URLImage(models.Model):
    image = models.ImageField(upload_to='qrurls-images')
    title = models.CharField(max_length=1024)
    uploaded = models.DateTimeField(auto_now_add=True)

    class Meta:
        verbose_name = u"URL Image"
        verbose_name_plural = u"URL Images"
        ordering = ['uploaded']

    def get_absolute_url (self) :
        return self.image.url

    def __unicode__ (self) :
        return self.image.name

class URLItem(models.Model):
    shorturl = models.ForeignKey(URL)
    published = models.DateTimeField()

    # either-or
    url = models.URLField(blank=True) # populated from image
    image = models.ForeignKey(URLImage, null=True, blank=True)
    
    class Meta:
        verbose_name = u"URL Item"
        verbose_name_plural = u"URL Items"
        ordering = ['published']

    def get_absolute_url (self) :
        if self.image :
            return reverse('shorturl_image', kwargs=dict(shorturl=self.shorturl, item_id=self.id))
        else :
            return self.url
    
    def published_age (self) :
        now = timezone.now()

        if now > self.published:
            td = now - self.published
        else :
            td = self.published - now

        days, seconds = td.days, td.seconds
        m, s = divmod(seconds, 60)
        h, m = divmod(m, 60)

        return (self.published < now), days, "{h}h {m}m {s}s".format(h=h, m=m, s=s)

    def published_state (self) :
        date = self.published.strftime("%Y-%m-%d")
        published, days, age = self.published_age()

        if published and days :
            return "[{date}]".format(date=date)
        elif published :
            return "[{age}]".format(age=age)
        elif days :
            return "({when})".format(when=date)
        else :
            return "({age})".format(age=age)

    def __unicode__ (self) :
        return u"{published_state} {url}".format(
                published_state=self.published_state(),
                url=self.get_absolute_url(),
        )