import string
import logging

from random import SystemRandom
from datetime import datetime
from peewee import *
from peewee import create_model_tables

from app import app


logger = logging.getLogger(__name__)
db = app.config['DB_DRIVER'](app.config['DB_NAME'],
                             **app.config['DB_CONNECTION_ARGS'])


def close_db(exc):
  if not db.is_closed():
    logger.debug('Disconnecting from database.')
    db.close()


app.teardown_request(close_db)


class BaseModel(Model):
  class Meta:
    database = db


class User(BaseModel):
  username = CharField(unique=True, index=True)
  password_hash = CharField(null=True)
  email = CharField(unique=True, index=True)
  verified = BooleanField(default=False)
  stripe_id = CharField(index=True, null=True)


class LoginService(BaseModel):
  name = CharField(unique=True, index=True)


class FederatedLogin(BaseModel):
  user = ForeignKeyField(User, index=True)
  service = ForeignKeyField(LoginService, index=True)
  service_ident = CharField()

  class Meta:
    database = db
    indexes = (
      # create a unique index on service and the local service id
      (('service', 'service_ident'), True),

      # a user may only have one federated login per service
      (('service', 'user'), True),
    )


class Visibility(BaseModel):
  name = CharField(index=True)


class Repository(BaseModel):
  namespace = CharField()
  name = CharField()
  visibility = ForeignKeyField(Visibility)
  description = TextField(null=True)

  class Meta:
    database = db
    indexes = (
      # create a unique index on namespace and name
      (('namespace', 'name'), True),
    )


class Role(BaseModel):
  name = CharField(index=True)


class RepositoryPermission(BaseModel):
  user = ForeignKeyField(User, index=True)
  repository = ForeignKeyField(Repository, index=True)
  role = ForeignKeyField(Role)

  class Meta:
    database = db
    indexes = (
      (('user', 'repository'), True),
    )


def random_string_generator(length=16):
  def random_string():
    random = SystemRandom()
    return ''.join([random.choice(string.ascii_uppercase + string.digits)
                   for x in range(length)])
  return random_string


class AccessToken(BaseModel):
  code = CharField(default=random_string_generator(), unique=True, index=True)
  user = ForeignKeyField(User, null=True)
  repository = ForeignKeyField(Repository)
  created = DateTimeField(default=datetime.now)


class EmailConfirmation(BaseModel):
  code = CharField(default=random_string_generator(), unique=True, index=True)
  user = ForeignKeyField(User)
  pw_reset = BooleanField(default=False)
  email_confirm = BooleanField(default=False)
  created = DateTimeField(default=datetime.now)


class Image(BaseModel):
  # This class is intentionally denormalized. Even though images are supposed
  # to be globally unique we can't treat them as such for permissions and
  # security reasons. So rather than Repository <-> Image being many to many
  # each image now belongs to exactly one repository.
  docker_image_id = CharField()
  checksum = CharField(null=True)
  created = DateTimeField(null=True)
  comment = TextField(null=True)
  repository = ForeignKeyField(Repository)

  # '/' separated list of ancestory ids, e.g. /1/2/6/7/10/
  ancestors = CharField(index=True, default='/', max_length=64535)

  class Meta:
    database = db
    indexes = (
      # we don't really want duplicates
      (('repository', 'docker_image_id'), True),
    )


class RepositoryTag(BaseModel):
  name = CharField()
  image = ForeignKeyField(Image)
  repository = ForeignKeyField(Repository)

  class Meta:
    database = db
    indexes = (
      (('repository', 'name'), True),
    )


def initialize_db():
  create_model_tables([User, Repository, Image, AccessToken, Role,
                       RepositoryPermission, Visibility, RepositoryTag,
                       EmailConfirmation, FederatedLogin, LoginService])
  Role.create(name='admin')
  Role.create(name='write')
  Role.create(name='read')
  Visibility.create(name='public')
  Visibility.create(name='private')
  LoginService.create(name='github')