''' Exports create_app. '''

import os
import falcon
import sqlalchemy
import sqlalchemy.orm
import szurubooru.api
import szurubooru.config
import szurubooru.db
import szurubooru.middleware
import szurubooru.services

def _on_auth_error(ex, req, resp, params):
    raise falcon.HTTPForbidden('Authentication error', str(ex))

def _on_integrity_error(ex, req, resp, params):
    raise falcon.HTTPConflict('Integrity violation', ex.args[0])

def create_app():
    ''' Creates a WSGI compatible App object. '''
    config = szurubooru.config.Config()
    root_dir = os.path.dirname(__file__)
    static_dir = os.path.join(root_dir, os.pardir, 'static')

    engine = sqlalchemy.create_engine(
        '{schema}://{user}:{password}@{host}:{port}/{name}'.format(
            schema=config['database']['schema'],
            user=config['database']['user'],
            password=config['database']['pass'],
            host=config['database']['host'],
            port=config['database']['port'],
            name=config['database']['name']))
    session_factory = sqlalchemy.orm.sessionmaker(bind=engine)
    transaction_manager = szurubooru.db.TransactionManager(session_factory)

    # TODO: is there a better way?
    password_service = szurubooru.services.PasswordService(config)
    user_service = szurubooru.services.UserService(
        config, transaction_manager, password_service)
    auth_service = szurubooru.services.AuthService(
        config, user_service, password_service)

    user_list = szurubooru.api.UserListApi(config, auth_service, user_service)
    user = szurubooru.api.UserDetailApi(config, auth_service, user_service)

    app = falcon.API(middleware=[
        szurubooru.middleware.RequireJson(),
        szurubooru.middleware.JsonTranslator(),
        szurubooru.middleware.Authenticator(auth_service),
    ])

    app.add_error_handler(szurubooru.services.AuthError, _on_auth_error)
    app.add_error_handler(szurubooru.services.IntegrityError, _on_integrity_error)

    app.add_route('/users/', user_list)
    app.add_route('/user/{user_name}', user)

    return app