from os import environ
from pathlib import Path
from contextlib import contextmanager
from tempfile import TemporaryDirectory
from textwrap import dedent
import pytest

from sanic import Sanic


@contextmanager
def temp_path():
    """ a simple cross platform replacement for NamedTemporaryFile """
    with TemporaryDirectory() as td:
        yield Path(td, 'file')


def test_load_from_object(app):
    class Config:
        not_for_config = 'should not be used'
        CONFIG_VALUE = 'should be used'

    app.config.from_object(Config)
    assert 'CONFIG_VALUE' in app.config
    assert app.config.CONFIG_VALUE == 'should be used'
    assert 'not_for_config' not in app.config


def test_auto_load_env():
    environ["SANIC_TEST_ANSWER"] = "42"
    app = Sanic()
    assert app.config.TEST_ANSWER == 42
    del environ["SANIC_TEST_ANSWER"]


def test_dont_load_env():
    environ["SANIC_TEST_ANSWER"] = "42"
    app = Sanic(load_env=False)
    assert getattr(app.config, 'TEST_ANSWER', None) is None
    del environ["SANIC_TEST_ANSWER"]


def test_load_env_prefix():
    environ["MYAPP_TEST_ANSWER"] = "42"
    app = Sanic(load_env='MYAPP_')
    assert app.config.TEST_ANSWER == 42
    del environ["MYAPP_TEST_ANSWER"]


def test_load_from_file(app):
    config = dedent("""
    VALUE = 'some value'
    condition = 1 == 1
    if condition:
        CONDITIONAL = 'should be set'
    """)
    with temp_path() as config_path:
        config_path.write_text(config)
        app.config.from_pyfile(str(config_path))
        assert 'VALUE' in app.config
        assert app.config.VALUE == 'some value'
        assert 'CONDITIONAL' in app.config
        assert app.config.CONDITIONAL == 'should be set'
        assert 'condition' not in app.config


def test_load_from_missing_file(app):
    with pytest.raises(IOError):
        app.config.from_pyfile('non-existent file')


def test_load_from_envvar(app):
    config = "VALUE = 'some value'"
    with temp_path() as config_path:
        config_path.write_text(config)
        environ['APP_CONFIG'] = str(config_path)
        app.config.from_envvar('APP_CONFIG')
        assert 'VALUE' in app.config
        assert app.config.VALUE == 'some value'


def test_load_from_missing_envvar(app):
    with pytest.raises(RuntimeError):
        app.config.from_envvar('non-existent variable')


def test_overwrite_exisiting_config(app):
    app.config.DEFAULT = 1
    class Config:
        DEFAULT = 2

    app.config.from_object(Config)
    assert app.config.DEFAULT == 2


def test_missing_config(app):
    with pytest.raises(AttributeError):
        app.config.NON_EXISTENT