# -*- coding: utf-8 -*-
"""
@file run_tests.py
@brief provides a class to collect test information and a method to loop over each test and execute them.

@par History
     - Brian Helgans, Dec 11 2019, initial version
"""
import os
import multiprocessing
from Sample_Execution.exceptions import AlgorithmExecutionError

class Test:
    """ a test consists of variables which will eventually populate the environment for a run, and an optional summary. A run method is expected to be appended to thes object after instantiation."""

    def __init__(self):
        '''
        Creates an empty test.
        '''
        self.dictionary = dict()
        """Dict[str : str]. An empty dictionary (key:value) that will later hold all the settings necessary for the test. """
        self.summary = None

    def update(self, a_dictionary):
        '''
        Updates the test dictionary which will be used to set the environment.
        :param a_dictionary: used to set the environment later
        :type a_dictionary: dict
        '''
        self.dictionary.update(a_dictionary)

    def set_env(self):
        '''
        sets the environment right before a run.
        '''
        os.environ.update(self.dictionary)
    
    # a run method will be needed for run_tests.
    #run()
        #run.schedule()


def run_tests(tests):
    '''
    Iterates over a list of tests. All tests must have a run method.
    :param tests: list of tests
    :type tests: list[Test]
    '''
    #save the environment. We want to reset to this after each test.
    old_environ = os.environ.copy()

    #loop over all day tests.
    for test in tests:

        #consider setting this inside a context manager in case we decide to catch and recover from exceptions.
        test.set_env()

        #this just separates things for human readability. It's not really an event so it's not logged with the logger.
        line = "{:{fill}^120}".format("",fill="-")
        print(line)
        print("{0:{fill}^120}".format(" Starting a new test: "+str(test.run.testname)+" ",fill="-"))
        print(line)

        #sometimes the test comes with a summary
        if test.summary is not None:
            print("Test Summary: " + test.summary)
        
        
        test.run.schedule()
        os.environ.clear()
        os.environ.update(old_environ)

def run_test_subprocess(test):

    test.set_env()
    test.run.schedule()
    
    
def run_tests_in_parallel(tests, max_processes):
    
    with multiprocessing.Pool(int(max_processes)) as pool:
        res = pool.map_async(run_test_subprocess,tests)
        pool.close()
        pool.join()
        if not res.successful():
            raise AlgorithmExecutionError(message="Failure in a job")