import os
import shutil

import pytest

from peewee import OperationalError

from data.database import configure, User, read_only_config
from data.readreplica import ReadOnlyModeException
from test.testconfig import FakeTransaction
from test.fixtures import *


@pytest.mark.skipif(bool(os.environ.get('TEST_DATABASE_URI')), reason='Testing requires SQLite')
def test_readreplica(init_db_path, tmpdir_factory):
  primary_file = str(tmpdir_factory.mktemp("data").join("primary.db"))
  replica_file = str(tmpdir_factory.mktemp("data").join("replica.db"))

  # Copy the initialized database to two different locations.
  shutil.copy2(init_db_path, primary_file)
  shutil.copy2(init_db_path, replica_file)

  db_config = {
    'DB_URI': 'sqlite:///{0}'.format(primary_file),
    'DB_READ_REPLICAS': [
      {'DB_URI': 'sqlite:///{0}'.format(replica_file)},
    ],
    "DB_CONNECTION_ARGS": {
      'threadlocals': True,
      'autorollback': True,
    },
    "DB_TRANSACTION_FACTORY": lambda x: FakeTransaction(),
    "FOR_TESTING": True,
    "DATABASE_SECRET_KEY": "anothercrazykey!",
  }

  # Initialize the DB with the primary and the replica.
  configure(db_config)
  assert not read_only_config.obj.is_readonly
  assert read_only_config.obj.read_replicas

  # Ensure we can read the data.
  devtable_user = User.get(username='devtable')
  assert devtable_user.username == 'devtable'

  # Configure with a bad primary. Reading should still work since we're hitting the replica.
  db_config['DB_URI'] = 'sqlite:///does/not/exist'
  configure(db_config)

  assert not read_only_config.obj.is_readonly
  assert read_only_config.obj.read_replicas

  devtable_user = User.get(username='devtable')
  assert devtable_user.username == 'devtable'

  # Try to change some data. This should fail because the primary is broken.
  with pytest.raises(OperationalError):
    devtable_user.email = 'newlychanged'
    devtable_user.save()

  # Fix the primary and try again.
  db_config['DB_URI'] = 'sqlite:///{0}'.format(primary_file)
  configure(db_config)

  assert not read_only_config.obj.is_readonly
  assert read_only_config.obj.read_replicas

  devtable_user.email = 'newlychanged'
  devtable_user.save()

  # Mark the system as readonly.
  db_config['DB_URI'] = 'sqlite:///{0}'.format(primary_file)
  db_config['REGISTRY_STATE'] = 'readonly'
  configure(db_config)

  assert read_only_config.obj.is_readonly
  assert read_only_config.obj.read_replicas

  # Ensure all write operations raise a readonly mode exception.
  with pytest.raises(ReadOnlyModeException):
    devtable_user.email = 'newlychanged2'
    devtable_user.save()

  with pytest.raises(ReadOnlyModeException):
    User.create(username='foo')

  with pytest.raises(ReadOnlyModeException):
    User.delete().where(User.username == 'foo').execute()

  with pytest.raises(ReadOnlyModeException):
    User.update(username='bar').where(User.username == 'foo').execute()

  # Reset the config on the DB, so we don't mess up other tests.
  configure({
    'DB_URI': 'sqlite:///{0}'.format(primary_file),
    "DB_CONNECTION_ARGS": {
      'threadlocals': True,
      'autorollback': True,
    },
    "DB_TRANSACTION_FACTORY": lambda x: FakeTransaction(),
    "DATABASE_SECRET_KEY": "anothercrazykey!",
  })