from aergia.aergia import Aergia
import yappi
import unittest


class AergiaUnitTestCase(unittest.TestCase):

    interval = 0.01
    Aergia = Aergia(interval)
    # yappi is a singleton

    def setUp(self):
        self.Aergia.clear()

        yappi.stop()
        yappi.clear_stats()
        yappi.set_clock_type('wall')
        yappi.set_context_id_callback(None)
        yappi.set_context_name_callback(None)
        yappi.set_tag_callback(None)

    def assert_reasonable_delay(self, func_name, time_expected, samples):
        '''Compares the results reported by Aergia for FUNC_NAME
        with time_expected.'''
        samples_actual = self.aergia_extract_values_by_func(samples, func_name)
        time_actual = self.aergia_expected_time(samples_actual)
        self.assert_roughly_equal(time_actual, time_expected)

    def assert_similar_delay(self, func_name, yappi_stats, aergia_samples):
        '''Compares the results reported by Aergia for FUNC_NAME
        with yappi.'''
        time_yappi = self.yappi_extract_values_by_func(yappi_stats, func_name)

        samples_aergia = self.aergia_extract_values_by_func(
            aergia_samples, func_name)
        time_aergia = self.aergia_expected_time(samples_aergia)

        self.assert_roughly_equal(time_aergia, time_yappi)

    def assert_roughly_equal(self, v1, v2):
        '''Throws an exception if values V1 and V2 are not within 0.035
        seconds of each other. This number is influenced by instrumentation
        overhead, sampling inconsistency, etc.'''
        a = abs(v1 - v2)
        self.assertTrue(a <= .035, f'{v1} (actual) not roughly {v2} (expected)')

    def aergia_expected_time(self, total_samples):
        '''Given TOTAL_SAMPLES, returns the total time, using the
        sampling interval.'''
        return total_samples * self.interval

    def aergia_extract_values_by_func(self, samples, func_name):
        '''Returns the total number of samples for function name, given an
        Aergia SAMPLES object.'''
        return sum(
            value for key, value in samples.items()
            if key.func == func_name
        )

    def yappi_extract_values_by_func(self, stats, func_name):
        '''Returns the total number of samples for function name, given a
        yappi stats object.'''
        for s in stats:
            if s.name == func_name:
                return s.ttot