from django.db import models

import datetime
import os, errno

import settings
import groups.models
from util.misc import log_and_ignore_failures, mkdir_p

class FYSM(models.Model):
    group = models.ForeignKey(groups.models.Group)
    display_name = models.CharField(max_length=50)
    year = models.IntegerField()
    website = models.URLField()
    join_url = models.URLField(help_text="If you have a specific web page for students interested in joining your group, you can link to it here. If you leave this blank it will default to your website.")
    contact_email = models.EmailField(help_text="Give an address for students interested in joining the group to email (e.g., an officers list)")
    description = models.TextField(help_text="Explain in about three or four sentences what your group does and why incoming freshmen should get involved.")
    logo = models.ImageField(upload_to='fysm/logos', blank=True, )
    tags = models.CharField(max_length=100, blank=True, help_text="Specify some free-form, comma-delimited tags for your group", )
    categories = models.ManyToManyField('FYSMCategory', blank=True, help_text="Put your group into whichever of our categories seem applicable.", )
    join_preview = models.ForeignKey('PagePreview', null=True, )

    def save(self, *args, **kwargs):
        if self.join_preview is None or self.join_url != self.join_preview.url:
            self.join_preview = PagePreview.allocate_page_preview(
                filename='fysm/%d/group%d'%(self.year, self.group.pk, ),
                url=self.join_url,
            )
        super(FYSM, self).save(*args, **kwargs) # Call the "real" save() method.

    class Meta:
        verbose_name = "FYSM submission"

class FYSMCategory(models.Model):
    name = models.CharField(max_length=10)
    slug = models.SlugField()
    blurb = models.TextField()

    def __str__(self, ):
        return self.name

    class Meta:
        verbose_name = "FYSM category"
        verbose_name_plural = "FYSM categories"

class FYSMView(models.Model):
    when = models.DateTimeField(default=datetime.datetime.now)
    fysm = models.ForeignKey(FYSM, null=True, blank=True, )
    year = models.IntegerField(null=True, blank=True, )
    page = models.CharField(max_length=20, blank=True, )
    referer = models.URLField(verify_exists=False, null=True, )
    user_agent = models.CharField(max_length=255)
    source_ip = models.IPAddressField()
    source_user = models.CharField(max_length=30, blank=True, )

    @staticmethod
    @log_and_ignore_failures(logfile=settings.LOGFILE)
    def record_metric(request, fysm=None, year=None, page=None, ):
        record = FYSMView()
        record.fysm = fysm
        record.year = year
        record.page = page
        if 'HTTP_REFERER' in request.META:
            record.referer = request.META['HTTP_REFERER']
        record.user_agent = request.META['HTTP_USER_AGENT']
        record.source_ip = request.META['REMOTE_ADDR']
        record.source_user = request.user.username
        record.save()

class PagePreview(models.Model):
    update_time = models.DateTimeField(default=datetime.datetime.utcfromtimestamp(0))
    url = models.URLField()
    image = models.ImageField(upload_to='page-previews', blank=True, )

    @classmethod
    def allocate_page_preview(cls, filename, url, ):
        preview = PagePreview()
        preview.update_time = datetime.datetime.utcfromtimestamp(0) # Never updated
        preview.url = url
        preview.image = 'page-previews/%s.png' % (filename, )
        image_filename = os.path.join(settings.MEDIA_ROOT, preview.image.name)
        mkdir_p(os.path.dirname(image_filename))
        try:
            os.symlink('no-preview.png', image_filename)
        except OSError as exc:
            if exc.errno == errno.EEXIST:
                pass
            else: raise
        preview.save()
        return preview

    def update_preview(self, ):
        pass

    @classmethod
    def previews_needing_updates(cls, interval=None, ):
        if interval is None:
            interval = datetime.timedelta(days=1)
        before = datetime.datetime.now() - interval
        return cls.objects.filter(update_time__le=before)