# Copyright (c) 2009-2016 Hewlett Packard Enterprise Development LP
#
# Redistribution and use of this software in source and binary forms,
# with or without modification, are permitted provided that the following
# conditions are met:
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#   Redistributions of source code must retain the above copyright notice,
#   this list of conditions and the following disclaimer.
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#   Redistributions in binary form must reproduce the above copyright
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#   documentation and/or other materials provided with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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import multiprocessing
import os.path
import sys

from requestbuilder import Arg
from requestbuilder.exceptions import ArgumentError
from requestbuilder.mixins import FileTransferProgressBarMixin
import six

from euca2ools.bundle.util import open_pipe_fileobjs
from euca2ools.bundle.util import waitpid_in_thread
from euca2ools.commands.bundle.downloadbundle import DownloadBundle
from euca2ools.commands.bundle.mixins import BundleDownloadingMixin
from euca2ools.commands.bundle.unbundlestream import UnbundleStream
from euca2ools.commands.s3 import S3Request


class DownloadAndUnbundle(S3Request, FileTransferProgressBarMixin,
                          BundleDownloadingMixin):
    DESCRIPTION = ('Download and unbundle a bundled image from the cloud\n\n '
                   'The key used to unbundle the image must match a '
                   'certificate that was used to bundle it.')
    ARGS = [Arg('-d', '--destination', dest='dest', metavar='(FILE | DIR)',
                default=".", help='''where to place the unbundled image
                (default: current directory)'''),
            Arg('-k', '--privatekey',
                help='''file containing the private key to decrypt the bundle
                with.  This must match a certificate used when bundling the
                image.''')]

    # noinspection PyExceptionInherit
    def configure(self):
        S3Request.configure(self)

        # The private key could be the user's or the cloud's.  In the config
        # this is a user-level option.
        if not self.args.get('privatekey'):
            config_privatekey = self.config.get_user_option('private-key')
            if self.args.get('userregion'):
                self.args['privatekey'] = config_privatekey
            elif 'EC2_PRIVATE_KEY' in os.environ:
                self.args['privatekey'] = os.getenv('EC2_PRIVATE_KEY')
            elif config_privatekey:
                self.args['privatekey'] = config_privatekey
            else:
                raise ArgumentError(
                    'missing private key; please supply one with -k')
        self.args['privatekey'] = os.path.expanduser(os.path.expandvars(
            self.args['privatekey']))
        if not os.path.exists(self.args['privatekey']):
            raise ArgumentError("private key file '{0}' does not exist"
                                .format(self.args['privatekey']))
        if not os.path.isfile(self.args['privatekey']):
            raise ArgumentError("private key file '{0}' is not a file"
                                .format(self.args['privatekey']))
        self.log.debug('private key: %s', self.args['privatekey'])

    def __open_dest(self, manifest):
        if self.args['dest'] == '-':
            self.args['dest'] = sys.stdout
            self.args['show_progress'] = False
        elif isinstance(self.args['dest'], six.string_types):
            if os.path.isdir(self.args['dest']):
                image_filename = os.path.join(self.args['dest'],
                                              manifest.image_name)
            else:
                image_filename = self.args['dest']
            self.args['dest'] = open(image_filename, 'w')
            return image_filename
        # Otherwise we assume it's a file object

    def main(self):
        manifest = self.fetch_manifest(
            self.service, privkey_filename=self.args['privatekey'])
        download_out_r, download_out_w = open_pipe_fileobjs()
        try:
            self.__create_download_pipeline(download_out_w)
        finally:
            download_out_w.close()
        image_filename = self.__open_dest(manifest)
        unbundlestream = UnbundleStream.from_other(
            self, source=download_out_r, dest=self.args['dest'],
            enc_key=manifest.enc_key, enc_iv=manifest.enc_iv,
            image_size=manifest.image_size, sha1_digest=manifest.image_digest,
            show_progress=self.args.get('show_progress', False))
        unbundlestream.main()
        return image_filename

    def __create_download_pipeline(self, outfile):
        downloadbundle = DownloadBundle.from_other(
            self, dest=outfile, bucket=self.args['bucket'],
            manifest=self.args.get('manifest'),
            local_manifest=self.args.get('local_manifest'),
            show_progress=False)
        downloadbundle_p = multiprocessing.Process(target=downloadbundle.main)
        downloadbundle_p.start()
        waitpid_in_thread(downloadbundle_p.pid)
        outfile.close()

    def print_result(self, image_filename):
        if (image_filename and
                self.args['dest'].fileno() != sys.stdout.fileno()):
            print 'Wrote', image_filename
