"""Example of dependency injection in Python.

Alternative injections definition style #1.
"""

import logging
import sqlite3

import boto.s3.connection

import example.main
import example.services

import dependency_injector.containers as containers
import dependency_injector.providers as providers


class Platform(containers.DeclarativeContainer):
    """IoC container of platform service providers."""

    logger = providers.Singleton(logging.Logger) \
        .add_kwargs(name='example')

    database = providers.Singleton(sqlite3.connect) \
        .add_args(':memory:')

    s3 = providers.Singleton(boto.s3.connection.S3Connection) \
        .add_kwargs(aws_access_key_id='KEY',
                    aws_secret_access_key='SECRET')


class Services(containers.DeclarativeContainer):
    """IoC container of business service providers."""

    users = providers.Factory(example.services.UsersService) \
        .add_kwargs(logger=Platform.logger,
                    db=Platform.database)

    auth = providers.Factory(example.services.AuthService) \
        .add_kwargs(logger=Platform.logger,
                    db=Platform.database,
                    token_ttl=3600)

    photos = providers.Factory(example.services.PhotosService) \
        .add_kwargs(logger=Platform.logger,
                    db=Platform.database,
                    s3=Platform.s3)


class Application(containers.DeclarativeContainer):
    """IoC container of application component providers."""

    main = providers.Callable(example.main.main) \
        .add_kwargs(users_service=Services.users,
                    auth_service=Services.auth,
                    photos_service=Services.photos)