import random
import string

from django.db import models
from django.utils import timezone


def generate_code(length):
    return "".join([random.choice(string.ascii_lowercase)
                    for i in range(length)])


class Game(models.Model):
    ACCESS_CODE_LENGTH = 6
    access_code = models.CharField(db_index=True, unique=True,
                                   max_length=ACCESS_CODE_LENGTH)
    game_turn = models.IntegerField(default=0)
    GAME_PHASE_LOBBY = 0
    GAME_PHASE_ACTIVE = 1
    GAME_PHASE_PARLEY = 2
    GAME_PHASE_END = 3
    game_phase = models.IntegerField(default=GAME_PHASE_LOBBY)
    created = models.DateTimeField()
    ended = models.DateTimeField(null=True, default=None)

    # from http://stackoverflow.com/a/11821832
    def save(self, *args, **kwargs):
        # object is being created, thus no primary key field yet
        if not self.pk:
            # Make sure access_code is unique before using it.
            access_code = generate_code(Game.ACCESS_CODE_LENGTH)
            while Game.objects.filter(access_code=access_code).exists():
                access_code = generate_code(Game.ACCESS_CODE_LENGTH)
            self.access_code = access_code
            self.created = timezone.now()
        if self.ended is None and self.game_phase == Game.GAME_PHASE_END:
            self.ended = timezone.now()
        super(Game, self).save(*args, **kwargs)


class Player(models.Model):
    game = models.ForeignKey(Game, on_delete=models.CASCADE, db_index=True)
    name = models.CharField(max_length=80)
    unique_together = (("game", "name"),)