#!/usr/bin/env python3

import argparse
import shutil
from subprocess import call, Popen, PIPE
import sys
import os

def query_yes_no(question, default=None):
    """
    Queries the user for a decision.
    """

    if default is None:
        prompt = ' [y/n]'
    elif default.lower() == 'yes':
        prompt = ' [Y/n]'
    elif default.lower() == 'no':
        prompt = ' [y/N]'
    else:
        raise ValueError('Invalid default answer {}'.format(default))

    while True:
        print(question, prompt, end='')
        choice = input().lower()
        if 'yes'.find(choice) == 0:
            return True
        elif 'no'.find(choice) == 0:
            return False

def create_dir(filename):
    """
    Create the directory denoted by filename, if it doesn't exists. Ask for its
    removal if it exists.
    """
    try:
        os.makedirs(filename)
    except FileExistsError:
        pass
    return True

class cd:
    """Context manager for changing the current working directory"""
    def __init__(self, newPath):
        self.newPath = os.path.expanduser(newPath)

    def __enter__(self):
        self.savedPath = os.getcwd()
        os.chdir(self.newPath)

    def __exit__(self, etype, value, traceback):
        os.chdir(self.savedPath)

def main():
    parser = argparse.ArgumentParser('Build and run experiments.')
    parser.add_argument('path', type=str, default='.', nargs='?',
                        help='Base path of the experiments')

    args = parser.parse_args()

    with cd(args.path):
        result = call(['make', '-j10'])
        if result is not 0 and result is not 2:
            print('Failed building the experiments!', file=sys.stderr)
            sys.exit(1)

        if not create_dir('results'):
            sys.exit(1)

        for experiment in os.listdir():
            if experiment == 'results' or not os.path.isdir(experiment):
                continue
            if experiment.isdigit():
                continue
            experiment_file = os.path.join('results', experiment + '.out')
            if os.path.exists(experiment_file):
                continue

            with open(experiment_file, 'w') as of:
                with cd(experiment):
                    try:
                        p = Popen(['./' + experiment], stdout=of)
                        p.wait()
                    except Exception as e:
                        print(e)
                        print('Failed running experiment: {}'.format(experiment),
                              file=sys.stderr)
                        sys.exit(1)
            if os.stat(experiment_file).st_size == 0:
                print('Removing file after failed experiment.', file=sys.stderr)
                os.remove(experiment_file)
                shutil.rmtree(experiment)

if __name__ == '__main__':
    main()