from django.db import models
from django.core.exceptions import ValidationError


class Training(models.Model):
    date = models.DateField()
    start_time = models.TimeField()
    end_time = models.TimeField()
    club = models.ForeignKey('clubs.Club', on_delete=models.CASCADE, related_name='trainings', null=True, blank=True)
    location = models.ForeignKey('locations.Location', on_delete=models.SET_NULL, null=True, blank=True, related_name='trainings')
    trainers = models.ManyToManyField('trainers.Trainer', related_name='trainings', blank=True)
    template = models.ForeignKey('templates.TrainingTemplate', on_delete=models.SET_NULL, null=True, blank=True, related_name='trainings')
    group = models.CharField(max_length=20, choices=[
        ('kids', 'Kids'),
        ('youth', 'Youth'),
        ('adults', 'Adults'),
        ('all', 'All'),
    ], default='all')
    notes = models.TextField(blank=True)
    is_completed = models.BooleanField(default=False)
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

    class Meta:
        ordering = ['-date', '-start_time']
        indexes = [
            models.Index(fields=['date']),
            models.Index(fields=['group']),
            models.Index(fields=['club']),
        ]

    def __str__(self):
        return f"{self.date} - {self.get_group_display()}"

    def clean(self):
        if self.start_time and self.end_time and self.end_time <= self.start_time:
            raise ValidationError({'end_time': 'End time must be greater than start time.'})

    def save(self, *args, **kwargs):
        self.full_clean()
        super().save(*args, **kwargs)


class Attendance(models.Model):
    training = models.ForeignKey(Training, on_delete=models.CASCADE, related_name='attendances')
    wrestler = models.ForeignKey('wrestlers.Wrestler', on_delete=models.CASCADE, related_name='attendances')
    created_at = models.DateTimeField(auto_now_add=True)

    class Meta:
        unique_together = ['training', 'wrestler']

    def __str__(self):
        return f"{self.wrestler} - {self.training.date}"


class TrainingExercise(models.Model):
    training = models.ForeignKey(Training, on_delete=models.CASCADE, related_name='training_exercises')
    exercise = models.ForeignKey('exercises.Exercise', on_delete=models.CASCADE, related_name='training_exercises')
    reps = models.PositiveIntegerField(null=True, blank=True)
    time_minutes = models.PositiveIntegerField(null=True, blank=True)
    order = models.IntegerField(default=0)

    class Meta:
        ordering = ['order', 'id']
        unique_together = ['training', 'exercise']

    def __str__(self):
        return f"{self.training} - {self.exercise.name}"