#!/usr/bin/env python
#    Copyright 2013-2016 ARM Limited
#
# 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.
#

"""
This module downloads external dependencies of assets used by Workload Automation.
Works by first downloading a directory index of the assets, then iterating through
it to get assets for the specified workloads.
"""
import sys
import argparse
import logging

from wlauto import Workload
from wlauto.common.resources import File
from wlauto.resource_getters.standard import HttpGetter
from wlauto.utils.log import init_logging

__version__ = '0.1.0'

# Get index.json from this URL
ASSETS_REPO = 'https://github.com/jimboatarm/wa-assets/raw/master/workloads'

logger = logging.getLogger('get_assets')


class RemoteHttpGetter(HttpGetter):
    def __init__(self, base_url, force_download, **kwargs):
        super(RemoteHttpGetter, self).__init__(None, **kwargs)
        self.url = base_url
        self.always_fetch = force_download


class NamedWorkload(Workload):
    def __init__(self, name, **kwargs):
        super(NamedWorkload, self).__init__(None, **kwargs)
        self.name = name


def _instantiate(cls, *args, **kwargs):
    return cls(*args, **kwargs)


def main(args):
    log_level = 1 if args.verbose else 0
    init_logging(log_level)
    logger.debug('Program arguments: {}'.format(vars(args)))
    if args.force:
        logger.info('Force-download of assets requested')

    # Get file index of assets
    getter = _instantiate(RemoteHttpGetter, ASSETS_REPO, args.force)
    getter.index = getter.fetch_index()
    all_assets = dict()
    for k, v in getter.index.iteritems():
        all_assets[str(k)] = [str(asset['path']) for asset in v]

    # Check provided workload arguments
    assets_to_get = set()
    if args.all:
        assets_to_get = set(all_assets)
    elif args.workloads:
        assets_to_get = set(all_assets).intersection(args.workloads)

    if not assets_to_get:
        if args.workloads:
            logger.error('Index does not contain assets for workloads: {}'.format(', '.join(args.workloads)))
        else:
            logger.error('No workloads specified. Provide at least one, or use --all to get them all')
        sys.exit(1)

    # Download files
    for workload in assets_to_get:
        owner = _instantiate(NamedWorkload, workload)
        logger.info('Getting assets for: {}'.format(workload))
        for asset in all_assets[workload]:
            getter.get(File(owner, asset))


if __name__ == '__main__':
    parser = argparse.ArgumentParser(description='''
        Download assets for the specified workloads from a remote server (currently a GitHub repo).
        ''')
    parser.add_argument('workloads', metavar='WORKLOAD', nargs='*',
                        help='One or more workloads whose assets to download (ignored if --all is specified).')
    parser.add_argument('-a', '--all', action='store_true',
                        help='If specified, assets for all workloads found in the index file will be downloaded.')
    parser.add_argument('-f', '--force', action='store_true',
                        help='If specified, always fetch the assets, even if locally cached versions exist.')
    parser.add_argument('-v', '--verbose', action='store_true', help='Enable verbose output')
    sys.exit(main(parser.parse_args()))