from datetime import datetime
from django.db import models
from django.urls import reverse
from accounts.models import Student
from django.db.models.signals import post_save
from django.dispatch import receiver

class Code(models.Model):
    student = models.ForeignKey(Student, on_delete=models.CASCADE)
    station_number = models.IntegerField()

    created = models.DateTimeField(auto_now_add=True)
    modified = models.DateTimeField(auto_now=True)

    def qr_code_str(self):
        return f'{self.student.student_number}:{self.station_number}'

    def get_absolute_url(self):
        return reverse('code-detail', kwargs={'pk': self.pk})

    def __str__(self):
        return f'{self.student.student_number}:{self.station_number}'

class Period(models.Model):
    student = models.ForeignKey(Student, on_delete=models.CASCADE)
    clocked_in = models.DateTimeField()
    clocked_out = models.DateTimeField(blank=True, null=True)
    station_number = models.IntegerField()
    duration = models.DurationField(blank=True, null=True)

    created = models.DateTimeField(auto_now_add=True)
    modified = models.DateTimeField(auto_now=True)

    class Meta:
        ordering = ['-clocked_in']

    @property
    def p_duration(self):
        return round((self.clocked_out - self.clocked_in).seconds / 3600, 2)

    def get_absolute_url(self):
        return reverse('period-detail', kwargs={'pk': self.pk})

    def __str__(self):
        return f'{self.clocked_in}: {self.student.user.first_name} {self.student.user.last_name}'

    def save(self, *args, **kwargs):
        if self.clocked_out != None:
            self.duration = self.clocked_out - self.clocked_in
        super(Period, self).save(*args, **kwargs)

@receiver(post_save, sender=Period)
def auto_clockin_student(sender, instance, created, **kwargs):
    if created:
        instance.student.is_clocked_in = True
        instance.student.current_period_id = instance.pk
        instance.student.save()