from django.core.serializers.json import DjangoJSONEncoder
from django.db import models
from django.utils import timezone


class TrackEvent(models.Model):

    SOURCE_SERVER = 0
    SOURCE_BROWSER = 1
    SOURCE_CHOICES = (
        (SOURCE_SERVER, 'server'),
        (SOURCE_BROWSER, 'browser')
    )

    openid = models.CharField(max_length=64, blank=True, null=True)
    track_id = models.CharField(max_length=128, blank=True, null=True)
    event_type = models.CharField(max_length=255, blank=False, null=False)
    event_body = models.JSONField(default=dict, encoder=DjangoJSONEncoder)
    event_time = models.DateTimeField(default=timezone.now, blank=True)
    user_agent = models.CharField(max_length=255, blank=True, null=True)
    ip = models.CharField(max_length=255, blank=True, null=True)
    pure_url = models.CharField(max_length=255, blank=True, null=True)
    utm_source = models.CharField(max_length=64, blank=True, null=True)
    utm_medium = models.CharField(max_length=64, blank=True, null=True)
    utm_campaign = models.CharField(max_length=64, blank=True, null=True)
    asktug_topic_id = models.IntegerField(blank=True, null=True)
    asktug_post_id = models.IntegerField(blank=True, null=True)
    description = models.TextField(blank=True, null=True)
    source = models.SmallIntegerField(
        blank=True,
        choices=SOURCE_CHOICES,
        default=SOURCE_SERVER)

    class Meta:
        db_table = 'track_events'

    def save(self, *args, **kwargs):
        if self.openid:
            self.openid = str(self.openid)[:64]
        if self.user_agent:
            self.user_agent = str(self.user_agent)[:255]
        if not self.event_time:
            self.event_time = timezone.now()
        super(TrackEvent, self).save(*args, **kwargs)