# -*- coding: utf-8 -*-
#
# This file is part of urlwatch (https://thp.io/2008/urlwatch/).
# Copyright (c) 2008-2018 Thomas Perl <m@thp.io>
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
#
# 1. Redistributions of source code must retain the above copyright
#    notice, this list of conditions and the following disclaimer.
# 2. Redistributions in binary form must reproduce the above copyright
#    notice, this list of conditions and the following disclaimer in the
#    documentation and/or other materials provided with the distribution.
# 3. The name of the author may not be used to endorse or promote products
#    derived from this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
# IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
# OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
# IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
# NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
# THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.


import concurrent.futures
import logging

import requests

from .handler import JobState
from .jobs import NotModifiedError

logger = logging.getLogger(__name__)

MAX_WORKERS = 10


def run_parallel(func, items):
    executor = concurrent.futures.ThreadPoolExecutor(max_workers=MAX_WORKERS)
    for future in concurrent.futures.as_completed(executor.submit(func, item) for item in items):
        exception = future.exception()
        if exception is not None:
            raise exception
        yield future.result()


def run_jobs(urlwatcher):
    cache_storage = urlwatcher.cache_storage
    jobs = urlwatcher.jobs
    report = urlwatcher.report

    logger.debug('Processing %d jobs', len(jobs))
    for job_state in run_parallel(lambda job_state: job_state.process(),
                                  (JobState(cache_storage, job) for job in jobs)):
        logger.debug('Job finished: %s', job_state.job)

        if job_state.exception is not None:
            if isinstance(job_state.exception, NotModifiedError):
                logger.info('Job %s has not changed (HTTP 304)', job_state.job)
                report.unchanged(job_state)
            elif isinstance(job_state.exception, requests.exceptions.RequestException):
                # Instead of a full traceback, just show the HTTP error
                job_state.traceback = str(job_state.exception)
                report.error(job_state)
            else:
                report.error(job_state)
        elif job_state.old_data is not None:
            if job_state.old_data.splitlines() != job_state.new_data.splitlines():
                report.changed(job_state)
                job_state.save()
            else:
                report.unchanged(job_state)
        else:
            report.new(job_state)
            job_state.save()
