from contextlib import contextmanager
import os

from alembic.command import upgrade
from alembic.config import Config
from flask_migrate import Migrate, MigrateCommand
from flask_script import Manager
import boto3
import pytest
import sqlalchemy

from app import create_app, db


@pytest.fixture(scope='session')
def notify_api():
    app = create_app()

    # deattach server-error error handlers - error_handler_spec looks like:
    #   {'blueprint_name': {
    #       status_code: [error_handlers],
    #       None: { ExceptionClass: error_handler }
    # }}
    for error_handlers in app.error_handler_spec.values():
        error_handlers.pop(500, None)
        if None in error_handlers:
            error_handlers[None] = {
                exc_class: error_handler
                for exc_class, error_handler in error_handlers[None].items()
                if exc_class != Exception
            }
            if error_handlers[None] == []:
                error_handlers.pop(None)

    ctx = app.app_context()
    ctx.push()

    yield app

    ctx.pop()


@pytest.fixture(scope='function')
def client(notify_api):
    with notify_api.test_request_context(), notify_api.test_client() as client:
        yield client


def create_test_db(database_uri):
    # get the
    db_uri_parts = database_uri.split('/')
    postgres_db_uri = '/'.join(db_uri_parts[:-1] + ['postgres'])

    postgres_db = sqlalchemy.create_engine(
        postgres_db_uri,
        echo=False,
        isolation_level='AUTOCOMMIT',
        client_encoding='utf8'
    )
    try:
        result = postgres_db.execute(sqlalchemy.sql.text('CREATE DATABASE {}'.format(db_uri_parts[-1])))
        result.close()
    except sqlalchemy.exc.ProgrammingError:
        # database "test_notification_api_master" already exists
        pass
    finally:
        postgres_db.dispose()


@pytest.fixture(scope='session')
def notify_db(notify_api, worker_id):
    assert 'test_notification_api' in db.engine.url.database, 'dont run tests against main db'

    # create a database for this worker thread -
    from flask import current_app
    current_app.config['SQLALCHEMY_DATABASE_URI'] += '_{}'.format(worker_id)
    create_test_db(current_app.config['SQLALCHEMY_DATABASE_URI'])

    Migrate(notify_api, db)
    Manager(db, MigrateCommand)
    BASE_DIR = os.path.dirname(os.path.dirname(__file__))
    ALEMBIC_CONFIG = os.path.join(BASE_DIR, 'migrations')
    config = Config(ALEMBIC_CONFIG + '/alembic.ini')
    config.set_main_option("script_location", ALEMBIC_CONFIG)

    with notify_api.app_context():
        upgrade(config, 'head')

    yield db

    db.session.remove()
    db.get_engine(notify_api).dispose()


@pytest.fixture(scope='function')
def notify_db_session(notify_db):
    yield notify_db

    notify_db.session.remove()
    for tbl in reversed(notify_db.metadata.sorted_tables):
        if tbl.name not in ["provider_details",
                            "key_types",
                            "branding_type",
                            "job_status",
                            "provider_details_history",
                            "template_process_type",
                            "dvla_organisation",
                            "notification_status_types",
                            "service_permission_types",
                            "auth_type"]:
            notify_db.engine.execute(tbl.delete())
    notify_db.session.commit()


@pytest.fixture
def os_environ():
    """
    clear os.environ, and restore it after the test runs
    """
    # for use whenever you expect code to edit environment variables
    old_env = os.environ.copy()

    class EnvironDict(dict):
        def __setitem__(self, key, value):
            assert type(value) == str
            super().__setitem__(key, value)

    os.environ = EnvironDict()
    yield
    os.environ = old_env


@pytest.fixture(scope='function')
def sqs_client_conn():
    boto3.setup_default_session(region_name='eu-west-1')
    return boto3.resource('sqs')


def pytest_generate_tests(metafunc):
    # Copied from https://gist.github.com/pfctdayelise/5719730
    idparametrize = getattr(metafunc.function, 'idparametrize', None)
    if idparametrize:
        argnames, testdata = idparametrize.args
        ids, argvalues = zip(*sorted(testdata.items()))
        metafunc.parametrize(argnames, argvalues, ids=ids)


@contextmanager
def set_config(app, name, value):
    old_val = app.config.get(name)
    app.config[name] = value
    yield
    app.config[name] = old_val


@contextmanager
def set_config_values(app, dict):
    old_values = {}

    for key in dict:
        old_values[key] = app.config.get(key)
        app.config[key] = dict[key]

    yield

    for key in dict:
        app.config[key] = old_values[key]