"""Machinery for testing Jupyter kernels via the messaging protocol.
"""

from unittest import TestCase, SkipTest
try:                  # Python 3
    from queue import Empty
except ImportError:   # Python 2
    from Queue import Empty

from jupyter_client.manager import start_new_kernel
from .messagespec import validate_message, MimeBundle

TIMEOUT = 15

__version__ = '0.2.2'

class KernelTests(TestCase):
    kernel_name = ""

    @classmethod
    def setUpClass(cls):
        cls.km, cls.kc = start_new_kernel(kernel_name=cls.kernel_name)

    @classmethod
    def tearDownClass(cls):
        cls.kc.stop_channels()
        cls.km.shutdown_kernel()

    def flush_channels(self):
        for channel in (self.kc.shell_channel, self.kc.iopub_channel):
            while True:
                try:
                    msg = channel.get_msg(block=True, timeout=0.1)
                except Empty:
                    break
                else:
                    validate_message(msg)

    language_name = ""
    file_extension = ""

    def test_kernel_info(self):
        self.flush_channels()

        msg_id = self.kc.kernel_info()
        reply = self.kc.get_shell_msg(timeout=TIMEOUT)
        validate_message(reply, 'kernel_info_reply', msg_id)

        if self.language_name:
            self.assertEqual(reply['content']['language_info']['name'],
                             self.language_name)
        if self.file_extension:
            self.assertEqual(reply['content']['language_info']['file_extension'],
                             self.file_extension)
            self.assertTrue(reply['content']['language_info']['file_extension'].startswith("."))



    def execute_helper(self, code, timeout=TIMEOUT,
                       silent=False, store_history=True):
        msg_id = self.kc.execute(code=code, silent=silent,
                                 store_history=store_history)

        reply = self.kc.get_shell_msg(timeout=timeout)
        validate_message(reply, 'execute_reply', msg_id)

        busy_msg = self.kc.iopub_channel.get_msg(timeout=1)
        validate_message(busy_msg, 'status', msg_id)
        self.assertEqual(busy_msg['content']['execution_state'], 'busy')

        output_msgs = []
        while True:
            msg = self.kc.iopub_channel.get_msg(timeout=0.1)
            validate_message(msg, msg['msg_type'], msg_id)
            if msg['msg_type'] == 'status':
                self.assertEqual(msg['content']['execution_state'], 'idle')
                break
            elif msg['msg_type'] == 'execute_input':
                self.assertEqual(msg['content']['code'], code)
                continue
            output_msgs.append(msg)

        return reply, output_msgs

    code_hello_world = ""

    def test_execute_stdout(self):
        if not self.code_hello_world:
            raise SkipTest

        self.flush_channels()
        reply, output_msgs = self.execute_helper(code=self.code_hello_world)

        self.assertEqual(reply['content']['status'], 'ok')

        self.assertGreaterEqual(len(output_msgs), 1)
        self.assertEqual(output_msgs[0]['msg_type'], 'stream')
        self.assertEqual(output_msgs[0]['content']['name'], 'stdout')
        self.assertIn('hello, world', output_msgs[0]['content']['text'])

    code_stderr = ""

    def test_execute_stderr(self):
        if not self.code_stderr:
            raise SkipTest

        self.flush_channels()
        reply, output_msgs = self.execute_helper(code=self.code_stderr)

        self.assertEqual(reply['content']['status'], 'ok')

        self.assertGreaterEqual(len(output_msgs), 1)
        self.assertEqual(output_msgs[0]['msg_type'], 'stream')
        self.assertEqual(output_msgs[0]['content']['name'], 'stderr')

    completion_samples = []

    def test_completion(self):
        if not self.completion_samples:
            raise SkipTest

        for sample in self.completion_samples:
            with self.subTest(text=sample['text']):
                msg_id = self.kc.complete(sample['text'])
                reply = self.kc.get_shell_msg()
                validate_message(reply, 'complete_reply', msg_id)
                if 'matches' in sample:
                    self.assertEqual(set(reply['content']['matches']),
                                     set(sample['matches']))

    complete_code_samples = []
    incomplete_code_samples = []
    invalid_code_samples = []

    def check_is_complete(self, sample, status):
        msg_id = self.kc.is_complete(sample)
        reply = self.kc.get_shell_msg()
        validate_message(reply, 'is_complete_reply', msg_id)
        if reply['content']['status'] != status:
            msg = "For code sample\n  {!r}\nExpected {!r}, got {!r}."
            raise AssertionError(msg.format(sample, status,
                                            reply['content']['status']))

    def test_is_complete(self):
        if not (self.complete_code_samples
                or self.incomplete_code_samples
                or self.invalid_code_samples):
            raise SkipTest

        self.flush_channels()

        with self.subTest(status="complete"):
            for sample in self.complete_code_samples:
                self.check_is_complete(sample, 'complete')

        with self.subTest(status="incomplete"):
            for sample in self.incomplete_code_samples:
                self.check_is_complete(sample, 'incomplete')

        with self.subTest(status="invalid"):
            for sample in self.invalid_code_samples:
                self.check_is_complete(sample, 'invalid')

    code_page_something = ""

    def test_pager(self):
        if not self.code_page_something:
            raise SkipTest

        self.flush_channels()

        reply, output_msgs = self.execute_helper(self.code_page_something)
        self.assertEqual(reply['content']['status'],  'ok')
        payloads = reply['content']['payload']
        self.assertEqual(len(payloads), 1)
        self.assertEqual(payloads[0]['source'], 'page')
        mimebundle = payloads[0]['data']
        # Validate the mimebundle
        MimeBundle().data = mimebundle
        self.assertIn('text/plain', mimebundle)

    code_generate_error = ""

    def test_error(self):
        if not self.code_generate_error:
            raise SkipTest

        self.flush_channels()

        reply, output_msgs = self.execute_helper(self.code_generate_error)
        self.assertEqual(reply['content']['status'], 'error')
        self.assertEqual(len(output_msgs), 1)
        self.assertEqual(output_msgs[0]['msg_type'], 'error')

    code_execute_result = []

    def test_execute_result(self):
        if not self.code_execute_result:
            raise SkipTest

        for sample in self.code_execute_result:
            with self.subTest(code=sample['code']):
                self.flush_channels()

                reply, output_msgs = self.execute_helper(sample['code'])

                self.assertEqual(reply['content']['status'], 'ok')

                self.assertGreaterEqual(len(output_msgs), 1)
                self.assertEqual(output_msgs[0]['msg_type'], 'execute_result')
                self.assertIn('text/plain', output_msgs[0]['content']['data'])
                self.assertEqual(output_msgs[0]['content']['data']['text/plain'],
                                 sample['result'])

    code_display_data = []

    def test_display_data(self):
        if not self.code_display_data:
            raise SkipTest

        for sample in self.code_display_data:
            with self.subTest(code=sample['code']):
                self.flush_channels()
                reply, output_msgs = self.execute_helper(sample['code'])

                self.assertEqual(reply['content']['status'], 'ok')

                self.assertGreaterEqual(len(output_msgs), 1)
                self.assertEqual(output_msgs[0]['msg_type'], 'display_data')
                self.assertIn(sample['mime'], output_msgs[0]['content']['data'])

    # this should match one of the values in code_execute_result
    code_history_pattern = ""
    supported_history_operations = ()

    def history_helper(self, execute_first, timeout=TIMEOUT, **histargs):
        self.flush_channels()

        for code in execute_first:
            reply, output_msgs = self.execute_helper(code)

        self.flush_channels()
        msg_id = self.kc.history(**histargs)

        reply = self.kc.get_shell_msg(timeout=timeout)
        validate_message(reply, 'history_reply', msg_id)

        return reply

    def test_history(self):
        if not self.code_execute_result:
            raise SkipTest

        codes = [s['code'] for s in self.code_execute_result]
        results = [s['result'] for s in self.code_execute_result]
        n = len(codes)

        session = start = None

        with self.subTest(hist_access_type="tail"):
            if 'tail' not in self.supported_history_operations:
                raise SkipTest
            reply = self.history_helper(codes, output=False, raw=True,
                                        hist_access_type="tail", n=n)
            self.assertEqual(len(reply['content']['history']), n)
            self.assertEqual(len(reply['content']['history'][0]), 3)
            self.assertEqual(codes, [h[2] for h in reply['content']['history']])

            session, start = reply['content']['history'][0][0:2]
            with self.subTest(output=True):
                reply = self.history_helper(codes, output=True, raw=True,
                                            hist_access_type="tail", n=n)
                self.assertEqual(len(reply['content']['history'][0][2]), 2)

        with self.subTest(hist_access_type="range"):
            if 'range' not in self.supported_history_operations:
                raise SkipTest
            if session is None:
                raise SkipTest
            reply = self.history_helper(codes, output=False, raw=True,
                                        hist_access_type="range",
                                        session=session, start=start,
                                        stop=start+1)
            self.assertEqual(len(reply['content']['history']), 1)
            self.assertEqual(reply['content']['history'][0][0], session)
            self.assertEqual(reply['content']['history'][0][1], start)

        with self.subTest(hist_access_type="search"):
            if not self.code_history_pattern:
                raise SkipTest
            if 'search' not in self.supported_history_operations:
                raise SkipTest

            with self.subTest(subsearch="normal"):
                reply = self.history_helper(codes, output=False, raw=True,
                                            hist_access_type="search",
                                            pattern=self.code_history_pattern)
                self.assertGreaterEqual(len(reply['content']['history']), 1)
            with self.subTest(subsearch="unique"):
                reply = self.history_helper(codes, output=False, raw=True,
                                            hist_access_type="search",
                                            pattern=self.code_history_pattern,
                                            unique=True)
                self.assertEqual(len(reply['content']['history']), 1)
            with self.subTest(subsearch="n"):
                reply = self.history_helper(codes, output=False, raw=True,
                                            hist_access_type="search",
                                            pattern=self.code_history_pattern,
                                            n=3)
                self.assertEqual(len(reply['content']['history']), 3)

    code_inspect_sample = ""

    def test_inspect(self):
        if not self.code_inspect_sample:
            raise SkipTest

        self.flush_channels()
        msg_id = self.kc.inspect(self.code_inspect_sample)
        reply = self.kc.get_shell_msg(timeout=TIMEOUT)
        validate_message(reply, 'inspect_reply', msg_id)

        self.assertEqual(reply['content']['status'], 'ok')
        self.assertTrue(reply['content']['found'])
        self.assertGreaterEqual(len(reply['content']['data']), 1)

    code_clear_output = ""

    def test_clear_output(self):
        if not self.code_clear_output:
            raise SkipTest

        self.flush_channels()
        reply, output_msgs = self.execute_helper(code=self.code_clear_output)

        self.assertEqual(reply['content']['status'], 'ok')

        self.assertGreaterEqual(len(output_msgs), 1)
        self.assertEqual(output_msgs[0]['msg_type'], 'clear_output')
