#! /usr/bin/env python
# -*- coding: utf-8 -*-

#   COPYRIGHT NOTICE STARTS HERE

#   Copyright 2019 © Samsung Electronics Co., Ltd.
#
#   Licensed under the Apache License, Version 2.0 (the "License");
#   you may not use this file except in compliance with the License.
#   You may obtain a copy of the License at
#
#       http://www.apache.org/licenses/LICENSE-2.0
#
#   Unless required by applicable law or agreed to in writing, software
#   distributed under the License is distributed on an "AS IS" BASIS,
#   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
#   See the License for the specific language governing permissions and
#   limitations under the License.

#   COPYRIGHT NOTICE ENDS HERE


import progressbar
import concurrent.futures
from distutils.spawn import find_executable

progressbar.streams.wrap_stdout()
progressbar.streams.wrap_stderr()


def load_list(item_list):
    """
    Parse list with items to be downloaded.
    :param item_list: File with list of items (1 line per item)
    :return: set of items from file
    """
    with open(item_list, 'r') as f:
        return {item for item in (line.strip() for line in f) if item}


def init_progress(items_name):
    progress_widgets = ['Downloading {}: '.format(items_name),
                        progressbar.Bar(), ' ',
                        progressbar.Percentage(), ' ',
                        '(', progressbar.SimpleProgress(), ')']

    progress = progressbar.ProgressBar(widgets=progress_widgets,
                                       poll_rate=1.0,
                                       redirect_stdout=True)
    return progress


def start_progress(progress, target_count, skipping, log):
    log_skipping(skipping, log)
    log.info("Initializing download. Takes a while.")

    progress.max_value = target_count
    progress.start()
    progress.update(len(skipping))


def log_skipping(skipping_iterable, logger):
    for skipped in skipping_iterable:
        logger.info('Skipping: {}'.format(skipped))


def run_concurrent(workers, progress, fn, iterable, *args):
    with concurrent.futures.ThreadPoolExecutor(max_workers=workers) as executor:
        futures = [executor.submit(fn, item, *args) for item in iterable]
        error_count = 0
        for future in concurrent.futures.as_completed(futures):
            error = future.exception()
            if error:
                error_count += 1
                progress.update()
            else:
                progress.update(progress.value +1)
    return error_count


def finish_progress(progress, error_count, log):
    progress.finish(dirty=error_count > 0)
    log.info('Download ended. Elapsed time {}'.format(progress.data()['time_elapsed']))

def check_tool(name):
    return find_executable(name)