'''Test runner and result class for the regression test suite.

'''

import functools
import io
import sys
import time
import traceback
import unittest

import xml.etree.ElementTree as ET

from datetime import datetime

class RegressionTestResult(unittest.TextTestResult):

    def __init__(self, stream, descriptions, verbosity):
        super().__init__(stream=stream, descriptions=descriptions,
                         verbosity=2 if verbosity else 0)
        self.buffer = True
        self.__suite = ET.Element('testsuite')
        self.__suite.set('start', datetime.utcnow().isoformat(' '))

        self.__e = None
        self.__start_time = None

    @classmethod
    def __getId(cls, test):
        try:
            test_id = test.id
        except AttributeError:
            return str(test)
        try:
            return test_id()
        except TypeError:
            return str(test_id)
        return repr(test)

    def startTest(self, test):
        super().startTest(test)
        self.__e = e = ET.SubElement(self.__suite, 'testcase')
        self.__start_time = time.perf_counter()

    def _add_result(self, test, capture=False, **args):
        e = self.__e
        self.__e = None
        if e is None:
            return
        e.set('name', args.pop('name', self.__getId(test)))
        e.set('status', args.pop('status', 'run'))
        e.set('result', args.pop('result', 'completed'))
        if self.__start_time:
            e.set('time', f'{time.perf_counter() - self.__start_time:0.6f}')

        if capture:
            if self._stdout_buffer is not None:
                stdout = self._stdout_buffer.getvalue().rstrip()
                ET.SubElement(e, 'system-out').text = stdout
            if self._stderr_buffer is not None:
                stderr = self._stderr_buffer.getvalue().rstrip()
                ET.SubElement(e, 'system-err').text = stderr

        for k, v in args.items():
            if not k or not v:
                continue
            e2 = ET.SubElement(e, k)
            if hasattr(v, 'items'):
                for k2, v2 in v.items():
                    if k2:
                        e2.set(k2, str(v2))
                    else:
                        e2.text = str(v2)
            else:
                e2.text = str(v)

    @classmethod
    def __makeErrorDict(cls, err_type, err_value, err_tb):
        if isinstance(err_type, type):
            if err_type.__module__ == 'builtins':
                typename = err_type.__name__
            else:
                typename = f'{err_type.__module__}.{err_type.__name__}'
        else:
            typename = repr(err_type)

        msg = traceback.format_exception(err_type, err_value, None)
        tb = traceback.format_exception(err_type, err_value, err_tb)

        return {
            'type': typename,
            'message': ''.join(msg),
            '': ''.join(tb),
        }

    def addError(self, test, err):
        self._add_result(test, True, error=self.__makeErrorDict(*err))
        super().addError(test, err)

    def addExpectedFailure(self, test, err):
        self._add_result(test, True, output=self.__makeErrorDict(*err))
        super().addExpectedFailure(test, err)

    def addFailure(self, test, err):
        self._add_result(test, True, failure=self.__makeErrorDict(*err))
        super().addFailure(test, err)

    def addSkip(self, test, reason):
        self._add_result(test, skipped=reason)
        super().addSkip(test, reason)

    def addSuccess(self, test):
        self._add_result(test)
        super().addSuccess(test)

    def addUnexpectedSuccess(self, test):
        self._add_result(test, outcome='UNEXPECTED_SUCCESS')
        super().addUnexpectedSuccess(test)

    def get_xml_element(self):
        e = self.__suite
        e.set('tests', str(self.testsRun))
        e.set('errors', str(len(self.errors)))
        e.set('failures', str(len(self.failures)))
        return e

class QuietRegressionTestRunner:
    def __init__(self, stream, buffer=False):
        self.result = RegressionTestResult(stream, None, 0)
        self.result.buffer = buffer

    def run(self, test):
        test(self.result)
        return self.result

def get_test_runner_class(verbosity, buffer=False):
    if verbosity:
        return functools.partial(unittest.TextTestRunner,
                                 resultclass=RegressionTestResult,
                                 buffer=buffer,
                                 verbosity=verbosity)
    return functools.partial(QuietRegressionTestRunner, buffer=buffer)

def get_test_runner(stream, verbosity, capture_output=False):
    return get_test_runner_class(verbosity, capture_output)(stream)

if __name__ == '__main__':
    class TestTests(unittest.TestCase):
        def test_pass(self):
            pass

        def test_pass_slow(self):
            time.sleep(1.0)

        def test_fail(self):
            print('stdout', file=sys.stdout)
            print('stderr', file=sys.stderr)
            self.fail('failure message')

        def test_error(self):
            print('stdout', file=sys.stdout)
            print('stderr', file=sys.stderr)
            raise RuntimeError('error message')

    suite = unittest.TestSuite()
    suite.addTest(unittest.makeSuite(TestTests))
    stream = io.StringIO()
    runner_cls = get_test_runner_class(sum(a == '-v' for a in sys.argv))
    runner = runner_cls(sys.stdout)
    result = runner.run(suite)
    print('Output:', stream.getvalue())
    print('XML: ', end='')
    for s in ET.tostringlist(result.get_xml_element()):
        print(s.decode(), end='')
    print()