from django.db import models
from django.conf import settings
from datetime import datetime

class TimeEntry(models.Model):
    user = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE, related_name='time_entries')
    date = models.DateField()
    start_time = models.TimeField(null=True, blank=True)
    end_time = models.TimeField(null=True, blank=True)
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)
    
    class Meta:
        ordering = ['-date', '-start_time']
        unique_together = ['user', 'date', 'start_time']
    
    def __str__(self):
        return f"{self.user.username} - {self.date} ({self.start_time} to {self.end_time})"

    @property
    def duration(self):
        """Calculate duration in hours"""
        if self.start_time and self.end_time:
            start = datetime.combine(self.date, self.start_time)
            end = datetime.combine(self.date, self.end_time)
            return (end - start).total_seconds() / 3600
        return None

    @property
    def day_of_week(self):
        """Get day of week as string"""
        return self.date.strftime('%A')