import os
from contextlib import contextmanager

import pytest
import sqlalchemy
from alembic.command import upgrade
from alembic.config import Config
from flask import Flask

from app import create_app, db
from app.dao.provider_details_dao import get_provider_details_by_identifier


@pytest.fixture(scope='session')
def notify_app():
    app = Flask('test')
    create_app(app)
    return app


@pytest.fixture(scope='session')
def notify_api(notify_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 notify_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 = notify_app.app_context()
    ctx.push()

    yield notify_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):
    """
    Manages the connection to the database. Generally this shouldn't be used, instead you should use the
    `notify_db_session` fixture which also cleans up any data you've got left over after your test run.
    """
    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'])

    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 sms_providers(_notify_db):
    """
    In production we randomly choose which provider to use based on their priority. To guarantee tests run the same each
    time, make sure we always choose sns. You'll need to override them in your tests if you wish to do something
    different.
    """
    get_provider_details_by_identifier('sns').priority = 100


@pytest.fixture(scope='function')
def notify_db_session(_notify_db, sms_providers):
    """
    This fixture clears down all non static data after your test run. It yields the sqlalchemy session variable
    so you can manually add, commit, etc if needed.

    `notify_db_session.commit()`
    """
    yield _notify_db.session

    _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",
                            "notifications_all_time_view",
                            "notification_status_types",
                            "organisation_types",
                            "service_permission_types",
                            "auth_type",
                            "invite_status_type",
                            "service_callback_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()
    os.environ.clear()

    yield

    # clear afterwards in case anything extra was added to the environment during the test
    os.environ.clear()
    for k, v in old_env.items():
        os.environ[k] = v


def pytest_generate_tests(metafunc):
    # Copied from https://gist.github.com/pfctdayelise/5719730
    idparametrize = metafunc.definition.get_closest_marker('idparametrize')
    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
    try:
        yield
    finally:
        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]

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


class Matcher:
    def __init__(self, description, key):
        self.description = description
        self.key = key

    def __eq__(self, other):
        return self.key(other)

    def __repr__(self):
        return '<Matcher: {}>'.format(self.description)
