import hashlib

import pytest

from data import model, database
from storage.basestorage import StoragePaths
from storage.fakestorage import FakeStorage
from storage.distributedstorage import DistributedStorage
from workers.storagereplication import (StorageReplicationWorker, JobException,
                                        WorkerUnhealthyException)

from test.fixtures import *


@pytest.fixture()
def storage_user(app):
  user = model.user.get_user('devtable')
  database.UserRegion.create(user=user,
                             location=database.ImageStorageLocation.get(name='local_us'))
  database.UserRegion.create(user=user,
                             location=database.ImageStorageLocation.get(name='local_eu'))
  return user


@pytest.fixture()
def storage_paths():
  return StoragePaths()


@pytest.fixture()
def replication_worker():
  return StorageReplicationWorker(None)


@pytest.fixture()
def storage():
  return DistributedStorage({'local_us': FakeStorage('local'), 'local_eu': FakeStorage('local')},
                            ['local_us'])


def test_storage_replication_v1(storage_user, storage_paths, replication_worker, storage, app):
  # Add a storage entry with a V1 path.
  v1_storage = model.storage.create_v1_storage('local_us')
  content_path = storage_paths.v1_image_layer_path(v1_storage.uuid)
  storage.put_content(['local_us'], content_path, 'some content')

  # Call replicate on it and verify it replicates.
  replication_worker.replicate_storage(storage_user, v1_storage.uuid, storage)

  # Ensure that the data was replicated to the other "region".
  assert storage.get_content(['local_eu'], content_path) == 'some content'

  locations = model.storage.get_storage_locations(v1_storage.uuid)
  assert len(locations) == 2


def test_storage_replication_cas(storage_user, storage_paths, replication_worker, storage, app):
  # Add a storage entry with a CAS path.
  content_checksum = 'sha256:' + hashlib.sha256('some content').hexdigest()
  cas_storage = database.ImageStorage.create(cas_path=True, content_checksum=content_checksum)

  location = database.ImageStorageLocation.get(name='local_us')
  database.ImageStoragePlacement.create(storage=cas_storage, location=location)

  content_path = storage_paths.blob_path(cas_storage.content_checksum)
  storage.put_content(['local_us'], content_path, 'some content')

  # Call replicate on it and verify it replicates.
  replication_worker.replicate_storage(storage_user, cas_storage.uuid, storage)

  # Ensure that the data was replicated to the other "region".
  assert storage.get_content(['local_eu'], content_path) == 'some content'

  locations = model.storage.get_storage_locations(cas_storage.uuid)
  assert len(locations) == 2


def test_storage_replication_missing_base(storage_user, storage_paths, replication_worker, storage,
                                          app):
  # Add a storage entry with a CAS path.
  content_checksum = 'sha256:' + hashlib.sha256('some content').hexdigest()
  cas_storage = database.ImageStorage.create(cas_path=True, content_checksum=content_checksum)

  location = database.ImageStorageLocation.get(name='local_us')
  database.ImageStoragePlacement.create(storage=cas_storage, location=location)

  # Attempt to replicate storage. This should fail because the layer is missing from the base
  # storage.
  with pytest.raises(JobException):
    replication_worker.replicate_storage(storage_user, cas_storage.uuid, storage,
                                         backoff_check=False)

  # Ensure the storage location count remains 1. This is technically inaccurate, but that's okay
  # as we still require at least one location per storage.
  locations = model.storage.get_storage_locations(cas_storage.uuid)
  assert len(locations) == 1


def test_storage_replication_copy_error(storage_user, storage_paths, replication_worker, storage,
                                        app):
  # Add a storage entry with a CAS path.
  content_checksum = 'sha256:' + hashlib.sha256('some content').hexdigest()
  cas_storage = database.ImageStorage.create(cas_path=True, content_checksum=content_checksum)

  location = database.ImageStorageLocation.get(name='local_us')
  database.ImageStoragePlacement.create(storage=cas_storage, location=location)

  content_path = storage_paths.blob_path(cas_storage.content_checksum)
  storage.put_content(['local_us'], content_path, 'some content')

  # Tell storage to break copying.
  storage.put_content(['local_us'], 'break_copying', 'true')

  # Attempt to replicate storage. This should fail because the write fails.
  with pytest.raises(JobException):
    replication_worker.replicate_storage(storage_user, cas_storage.uuid, storage,
                                         backoff_check=False)

  # Ensure the storage location count remains 1.
  locations = model.storage.get_storage_locations(cas_storage.uuid)
  assert len(locations) == 1


def test_storage_replication_copy_didnot_copy(storage_user, storage_paths, replication_worker,
                                              storage, app):
  # Add a storage entry with a CAS path.
  content_checksum = 'sha256:' + hashlib.sha256('some content').hexdigest()
  cas_storage = database.ImageStorage.create(cas_path=True, content_checksum=content_checksum)

  location = database.ImageStorageLocation.get(name='local_us')
  database.ImageStoragePlacement.create(storage=cas_storage, location=location)

  content_path = storage_paths.blob_path(cas_storage.content_checksum)
  storage.put_content(['local_us'], content_path, 'some content')

  # Tell storage to fake copying (i.e. not actually copy the data).
  storage.put_content(['local_us'], 'fake_copying', 'true')

  # Attempt to replicate storage. This should fail because the copy doesn't actually do the copy.
  with pytest.raises(JobException):
    replication_worker.replicate_storage(storage_user, cas_storage.uuid, storage,
                                         backoff_check=False)

  # Ensure the storage location count remains 1.
  locations = model.storage.get_storage_locations(cas_storage.uuid)
  assert len(locations) == 1


def test_storage_replication_copy_unhandled_exception(storage_user, storage_paths,
                                                      replication_worker, storage, app):
  # Add a storage entry with a CAS path.
  content_checksum = 'sha256:' + hashlib.sha256('some content').hexdigest()
  cas_storage = database.ImageStorage.create(cas_path=True, content_checksum=content_checksum)

  location = database.ImageStorageLocation.get(name='local_us')
  database.ImageStoragePlacement.create(storage=cas_storage, location=location)

  content_path = storage_paths.blob_path(cas_storage.content_checksum)
  storage.put_content(['local_us'], content_path, 'some content')

  # Tell storage to raise an exception when copying.
  storage.put_content(['local_us'], 'except_copying', 'true')

  # Attempt to replicate storage. This should fail because the copy raises an unhandled exception.
  with pytest.raises(WorkerUnhealthyException):
    replication_worker.replicate_storage(storage_user, cas_storage.uuid, storage,
                                         backoff_check=False)

  # Ensure the storage location count remains 1.
  locations = model.storage.get_storage_locations(cas_storage.uuid)
  assert len(locations) == 1