"""Base class for notebook tests."""

import os
import sys
import time
import requests
from contextlib import contextmanager
from subprocess import Popen, PIPE
from unittest import TestCase

from IPython.utils.tempdir import TemporaryDirectory

class NotebookTestBase(TestCase):
    """A base class for tests that need a running notebook.
    
    This creates an empty profile in a temp ipython_dir
    and then starts the notebook server with a separate temp notebook_dir.
    """

    port = 12341

    @classmethod
    def wait_until_alive(cls):
        """Wait for the server to be alive"""
        url = 'http://localhost:%i/api/notebooks' % cls.port
        while True:
            try:
                requests.get(url)
            except requests.exceptions.ConnectionError:
                time.sleep(.1)
            else:
                break
    
    @classmethod
    def wait_until_dead(cls):
        """Wait for the server to stop getting requests after shutdown"""
        url = 'http://localhost:%i/api/notebooks' % cls.port
        while True:
            try:
                requests.get(url)
            except requests.exceptions.ConnectionError:
                break
            else:
                time.sleep(.1)
    
    @classmethod
    def setup_class(cls):
        cls.ipython_dir = TemporaryDirectory()
        cls.notebook_dir = TemporaryDirectory()
        notebook_args = [
            sys.executable, '-c',
            'from IPython.html.notebookapp import launch_new_instance; launch_new_instance()',
            '--port=%d' % cls.port,
            '--no-browser',
            '--ipython-dir=%s' % cls.ipython_dir.name,
            '--notebook-dir=%s' % cls.notebook_dir.name,
        ]
        devnull = open(os.devnull, 'w')
        cls.notebook = Popen(notebook_args,
            stdout=devnull,
            stderr=devnull,
        )
        cls.wait_until_alive()

    @classmethod
    def teardown_class(cls):
        cls.notebook.terminate()
        cls.ipython_dir.cleanup()
        cls.notebook_dir.cleanup()
        cls.wait_until_dead()

    @classmethod
    def base_url(cls):
        return 'http://localhost:%i/' % cls.port


@contextmanager
def assert_http_error(status, msg=None):
    try:
        yield
    except requests.HTTPError as e:
        real_status = e.response.status_code
        assert real_status == status, \
                    "Expected status %d, got %d" % (real_status, status)
        if msg:
            assert msg in str(e), e
    else:
        assert False, "Expected HTTP error status"