from typing import Tuple

from django.contrib.auth import get_user_model
from django.db import models
from django.db.models import CASCADE
from django.urls import reverse

User = get_user_model()


class StoryRound(models.Model):
    name = models.CharField(max_length=256)
    participants = models.ManyToManyField(User)  # for ordering add: through='Participant'
    created = models.DateTimeField(auto_now_add=True)
    number_of_rounds = models.IntegerField()
    current_turn = models.IntegerField(default=0, blank=True)

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

    def get_next_story_part(self, user: User) -> 'StoryPart':
        return StoryPart.objects.get(
            part_of__part_of_round=self,
            turn_number=self.current_turn,
            user=user
        )

    def next_round_ready(self) -> bool:
        for story in self.story_set.all():
            if not story.parts.get(turn_number=self.current_turn).finished:
                return False
        return True

    def advance_to_next_turn_and_get_status_and_round_number(self) -> Tuple[str, int]:
        if self.current_turn+1 == self.number_of_rounds:
            return 'finished', self.current_turn
        self.current_turn += 1
        self.save()

        return 'ongoing', self.current_turn


#class Participant(models.Model):
#    user = models.ForeignKey(User, on_delete=CASCADE)
#    story_round = models.ForeignKey(StoryRound, on_delete=CASCADE)
#    order_by = models.IntegerField()


class Story(models.Model):
    name = models.CharField(max_length=256, null=True, blank=True)
    created = models.DateTimeField(auto_now_add=True)
    part_of_round = models.ForeignKey(StoryRound, on_delete=CASCADE)
    started_by = models.ForeignKey(User, on_delete=CASCADE)
    finished = models.BooleanField(default=False)

    def get_first_unfinished_part(self):
        if self.finished:
            return None

        first_part = StoryPart.objects.get(part_of_id=self.pk, previous_part__isnull=True)

        last_unfinished_part = first_part
        while last_unfinished_part.finished:
            last_unfinished_part = StoryPart.objects.get(previous_part=last_unfinished_part)

        return last_unfinished_part


class StoryPart(models.Model):
    user = models.ForeignKey(User, on_delete=CASCADE)
    previous_part = models.ForeignKey('StoryPart', on_delete=CASCADE, null=True, blank=True)
    text = models.TextField(null=True, blank=True)
    part_of = models.ForeignKey('Story', on_delete=CASCADE, related_name='parts')
    turn_number = models.IntegerField()

    @property
    def finished(self):
        return bool(self.text)