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


class User(models.Model):
  name = models.TextField(verbose_name='Имя')
  email = models.TextField(verbose_name='Почта')

  def __str__(self):
    return f'{self.name}'


class Activity(models.Model):
  type = models.TextField()

  def __str__(self):
    return f'{self.type}'


class ActivityLog(models.Model):
  user = models.ForeignKey(User, on_delete=models.CASCADE, verbose_name='Пользователь')
  activity = models.ForeignKey(Activity, on_delete=models.CASCADE, verbose_name='Тип активности')

  start_time = models.DateTimeField(verbose_name='Момент начала')
  end_time = models.DateTimeField(verbose_name='Момент окончания')
  logged_at = models.DateTimeField(auto_now_add=True)

  def clean(self):
    if self.start_time >= self.end_time:
      raise ValidationError(f'Illegal times: {self}')

    for other_activity in ActivityLog.objects.filter(user=self.user).exclude(id=self.id):
      l = max(self.start_time, other_activity.start_time)
      r = min(self.end_time, other_activity.end_time)
      if r > l:
        raise ValidationError(f'Intersects with another activity: \n{self}\n{other_activity}\n{l}, {r}')

  def __str__(self):
    return f'ActivityLog[{self.user}, {self.activity}] {self.start_time}-{self.end_time} ({self.end_time - self.start_time})'