import os

from cachetools import lru_cache

import pytest
import shutil
from flask import Flask, jsonify
from flask_login import LoginManager
from peewee import SqliteDatabase, savepoint, InternalError

from app import app as application
from data import model
from data.database import close_db_filter, db, configure
from data.model.user import LoginWrappedDBUser
from endpoints.api import api_bp
from endpoints.appr import appr_bp
from endpoints.web import web

from initdb import initialize_database, populate_database

from path_converters import APIRepositoryPathConverter, RegexConverter, RepositoryPathConverter
from test.testconfig import FakeTransaction

@pytest.fixture(scope="session")
@lru_cache(maxsize=1) # Important! pytest is calling this multiple times (despite it being session)
def init_db_path(tmpdir_factory):
  """ Creates a new database and appropriate configuration. Note that the initial database
      is created *once* per session. In the non-full-db-test case, the database_uri fixture
      makes a copy of the SQLite database file on disk and passes a new copy to each test.
  """
  if os.environ.get('TEST_DATABASE_URI'):
    return _init_db_path_real_db(os.environ.get('TEST_DATABASE_URI'))

  return _init_db_path_sqlite(tmpdir_factory)

def _init_db_path_real_db(db_uri):
  """ Initializes a real database for testing by populating it from scratch. Note that this does
      *not* add the tables (merely data). Callers must have migrated the database before calling
      the test suite.
  """
  configure({
    "DB_URI": db_uri,
    "DB_CONNECTION_ARGS": {
      'threadlocals': True,
      'autorollback': True,
    },
    "DB_TRANSACTION_FACTORY": _create_transaction,
  })

  populate_database()
  return db_uri

def _init_db_path_sqlite(tmpdir_factory):
  """ Initializes a SQLite database for testing by populating it from scratch and placing it into
      a temp directory file.
  """
  sqlitedbfile = str(tmpdir_factory.mktemp("data").join("test.db"))
  sqlitedb = 'sqlite:///{0}'.format(sqlitedbfile)
  conf = {"TESTING": True,
          "DEBUG": True,
          "DB_URI": sqlitedb}
  os.environ['DB_URI'] = str(sqlitedb)
  db.initialize(SqliteDatabase(sqlitedbfile))
  application.config.update(conf)
  application.config.update({"DB_URI": sqlitedb})
  initialize_database()

  db.obj.execute_sql('PRAGMA foreign_keys = ON;')

  populate_database()
  close_db_filter(None)
  return str(sqlitedbfile)


@pytest.fixture()
def database_uri(monkeypatch, init_db_path, sqlitedb_file):
  """ Returns the database URI to use for testing. In the SQLite case, a new, distinct copy of
      the SQLite database is created by copying the initialized database file (sqlitedb_file)
      on a per-test basis. In the non-SQLite case, a reference to the existing database URI is
      returned.
  """
  if os.environ.get('TEST_DATABASE_URI'):
    db_uri = os.environ['TEST_DATABASE_URI']
    monkeypatch.setenv("DB_URI", db_uri)
    return db_uri

  # Copy the golden database file to a new path.
  shutil.copy2(init_db_path, sqlitedb_file)

  # Monkeypatch the DB_URI.
  db_path = 'sqlite:///{0}'.format(sqlitedb_file)
  monkeypatch.setenv("DB_URI", db_path)
  return db_path


@pytest.fixture()
def sqlitedb_file(tmpdir):
  """ Returns the path at which the initialized, golden SQLite database file will be placed. """
  test_db_file = tmpdir.mkdir("quaydb").join("test.db")
  return str(test_db_file)

def _create_transaction(db):
  return FakeTransaction()

@pytest.fixture()
def appconfig(database_uri):
  """ Returns application configuration for testing that references the proper database URI. """
  conf = {
    "TESTING": True,
    "DEBUG": True,
    "DB_URI": database_uri,
    "SECRET_KEY": 'superdupersecret!!!1',
    "DB_CONNECTION_ARGS": {
      'threadlocals': True,
      'autorollback': True,
    },
    "DB_TRANSACTION_FACTORY": _create_transaction,
  }
  return conf

@pytest.fixture()
def initialized_db(appconfig):
  """ Configures the database for the database found in the appconfig. """

  # Configure the database.
  configure(appconfig)

  # If under a test *real* database, setup a savepoint.
  under_test_real_database = bool(os.environ.get('TEST_DATABASE_URI'))
  if under_test_real_database:
    test_savepoint = savepoint(db)
    test_savepoint.__enter__()

    yield # Run the test.

    try:
      test_savepoint.__exit__(None, None, None)
    except InternalError:
      # If postgres fails with an exception (like IntegrityError) mid-transaction, it terminates
      # it immediately, so when we go to remove the savepoint, it complains. We can safely ignore
      # this case.
      pass
  else:
    yield

@pytest.fixture()
def app(appconfig, initialized_db):
  """ Used by pytest-flask plugin to inject a custom app instance for testing. """
  app = Flask(__name__)
  login_manager = LoginManager(app)

  @app.errorhandler(model.DataModelException)
  def handle_dme(ex):
    response = jsonify({'message': ex.message})
    response.status_code = 400
    return response

  @login_manager.user_loader
  def load_user(user_uuid):
    return LoginWrappedDBUser(user_uuid)

  app.url_map.converters['regex'] = RegexConverter
  app.url_map.converters['apirepopath'] = APIRepositoryPathConverter
  app.url_map.converters['repopath'] = RepositoryPathConverter

  app.register_blueprint(api_bp, url_prefix='/api')
  app.register_blueprint(appr_bp, url_prefix='/cnr')
  app.register_blueprint(web, url_prefix='/')

  app.config.update(appconfig)
  return app