# -*- coding: utf-8 -*-
# Copyright 2012 Google Inc. All Rights Reserved.
#
# 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.
"""Implementation of website configuration command for buckets."""

from __future__ import absolute_import
from __future__ import print_function
from __future__ import division
from __future__ import unicode_literals

import sys

from apitools.base.py import encoding

from gslib import metrics
from gslib.command import Command
from gslib.command_argument import CommandArgument
from gslib.cs_api_map import ApiSelector
from gslib.exception import CommandException
from gslib.exception import NO_URLS_MATCHED_TARGET
from gslib.help_provider import CreateHelpText
from gslib.third_party.storage_apitools import storage_v1_messages as apitools_messages
from gslib.utils.constants import NO_MAX

_SET_SYNOPSIS = """
  gsutil web set [-m <main_page_suffix>] [-e <error_page>] gs://<bucket_name>...
"""

_GET_SYNOPSIS = """
  gsutil web get gs://<bucket_name>
"""

_SYNOPSIS = _SET_SYNOPSIS + _GET_SYNOPSIS.lstrip('\n')

_SET_DESCRIPTION = """
<B>SET</B>
  The "gsutil web set" command allows you to configure or disable
  Website Configuration on your bucket(s). The "set" sub-command has the
  following options (leave both options blank to disable):

<B>SET OPTIONS</B>
  -m <index.html>      Specifies the object name to serve when a bucket
                       listing is requested via the CNAME alias to
                       c.storage.googleapis.com.

  -e <404.html>        Specifies the error page to serve when a request is made
                       for a non-existent object via the CNAME alias to
                       c.storage.googleapis.com.

"""

_GET_DESCRIPTION = """
<B>GET</B>
  The "gsutil web get" command retrieves the web semantics configuration for
  a bucket and displays a JSON representation of the configuration.

  In Google Cloud Storage, this would look like the following:

    {
      "notFoundPage": "404.html",
      "mainPageSuffix": "index.html"
    }

"""

_DESCRIPTION = """
  The Website Configuration feature enables you to configure a Google Cloud
  Storage bucket to behave like a static website. This means requests made via a
  domain-named bucket aliased using a Domain Name System "CNAME" to
  c.storage.googleapis.com works like any other website. For example, a GET request to the
  bucket serves the configured "main" page instead of the usual bucket
  listing and a GET request for a non-existent object serves the configured error
  page.

  For example, suppose your company's domain name is ``example.com``. You could set
  up a website bucket as follows:

  1. Create a bucket called ``www.example.com`` (see the "DOMAIN NAMED BUCKETS"
     section of "gsutil help naming" for details about creating such buckets).

  2. Create index.html and 404.html files and upload them to the bucket.

  3. Configure the bucket to have website behavior using the command:

       gsutil web set -m index.html -e 404.html gs://www.example.com

  4. Add a DNS CNAME record for ``www.example.com`` pointing to
     ``c.storage.googleapis.com`` (ask your DNS administrator for help with this).

  Now if you open a browser and navigate to ``http://www.example.com``, it
  displays the main page instead of the default bucket listing.
  
  NOTE: It can take time for DNS updates to propagate because of caching used
  by the DNS, so it may take up to a day for the domain-named bucket website to
  work after you create the CNAME DNS record.

  Additional notes:

  1. Because the main page is only served when a bucket listing request is made
     via the CNAME alias, you can continue to use "gsutil ls" to list the bucket
     and get the normal bucket listing (rather than the main page).

  2. The main_page_suffix applies to each subdirectory of the bucket. For
     example, with the main_page_suffix configured to be index.html, a GET
     request for ``http://www.example.com`` retrieves
     ``http://www.example.com/index.html`` but shows ``http://www.example.com`` as
     the URL to the requester, and a GET request for
     ``http://www.example.com/photos`` retrieves
     ``http://www.example.com/photos/index.html`` but shows ``http://www.example.com/photos``
     as the URL to the requester.

  3. There is just one 404.html page. For example, a GET request for
     ``http://www.example.com/photos/missing`` retrieves
     ``http://www.example.com/404.html``, not
     ``http://www.example.com/photos/404.html``.

  4. For additional details, see 
     `Hosting a static website <https://cloud.google.com/storage/docs/website-configuration>`_.

  The web command has two sub-commands:
""" + _SET_DESCRIPTION + _GET_DESCRIPTION

_DETAILED_HELP_TEXT = CreateHelpText(_SYNOPSIS, _DESCRIPTION)

_get_help_text = CreateHelpText(_GET_SYNOPSIS, _GET_DESCRIPTION)
_set_help_text = CreateHelpText(_SET_SYNOPSIS, _SET_DESCRIPTION)


class WebCommand(Command):
  """Implementation of gsutil web command."""

  # Command specification. See base class for documentation.
  command_spec = Command.CreateCommandSpec(
      'web',
      command_name_aliases=['setwebcfg', 'getwebcfg'],
      usage_synopsis=_SYNOPSIS,
      min_args=2,
      max_args=NO_MAX,
      supported_sub_args='m:e:',
      file_url_ok=False,
      provider_url_ok=False,
      urls_start_arg=1,
      gs_api_support=[ApiSelector.XML, ApiSelector.JSON],
      gs_default_api=ApiSelector.JSON,
      argparse_arguments={
          'set': [CommandArgument.MakeZeroOrMoreCloudBucketURLsArgument()],
          'get': [CommandArgument.MakeNCloudBucketURLsArgument(1)],
      },
  )
  # Help specification. See help_provider.py for documentation.
  help_spec = Command.HelpSpec(
      help_name='web',
      help_name_aliases=['getwebcfg', 'setwebcfg'],
      help_type='command_help',
      help_one_line_summary=(
          'Set a main page and/or error page for one or more buckets'),
      help_text=_DETAILED_HELP_TEXT,
      subcommand_help_text={
          'get': _get_help_text,
          'set': _set_help_text,
      },
  )

  def _GetWeb(self):
    """Gets website configuration for a bucket."""
    bucket_url, bucket_metadata = self.GetSingleBucketUrlFromArg(
        self.args[0], bucket_fields=['website'])

    if bucket_url.scheme == 's3':
      sys.stdout.write(
          self.gsutil_api.XmlPassThroughGetWebsite(bucket_url,
                                                   provider=bucket_url.scheme))
    else:
      if bucket_metadata.website and (bucket_metadata.website.mainPageSuffix or
                                      bucket_metadata.website.notFoundPage):
        sys.stdout.write(
            str(encoding.MessageToJson(bucket_metadata.website)) + '\n')
      else:
        sys.stdout.write('%s has no website configuration.\n' % bucket_url)

    return 0

  def _SetWeb(self):
    """Sets website configuration for a bucket."""
    main_page_suffix = None
    error_page = None
    if self.sub_opts:
      for o, a in self.sub_opts:
        if o == '-m':
          main_page_suffix = a
        elif o == '-e':
          error_page = a

    url_args = self.args

    website = apitools_messages.Bucket.WebsiteValue(
        mainPageSuffix=main_page_suffix, notFoundPage=error_page)

    # Iterate over URLs, expanding wildcards and setting the website
    # configuration on each.
    some_matched = False
    for url_str in url_args:
      bucket_iter = self.GetBucketUrlIterFromArg(url_str, bucket_fields=['id'])
      for blr in bucket_iter:
        url = blr.storage_url
        some_matched = True
        self.logger.info('Setting website configuration on %s...', blr)
        bucket_metadata = apitools_messages.Bucket(website=website)
        self.gsutil_api.PatchBucket(url.bucket_name,
                                    bucket_metadata,
                                    provider=url.scheme,
                                    fields=['id'])
    if not some_matched:
      raise CommandException(NO_URLS_MATCHED_TARGET % list(url_args))
    return 0

  def RunCommand(self):
    """Command entry point for the web command."""
    action_subcommand = self.args.pop(0)
    self.ParseSubOpts(check_args=True)
    if action_subcommand == 'get':
      func = self._GetWeb
    elif action_subcommand == 'set':
      func = self._SetWeb
    else:
      raise CommandException(
          ('Invalid subcommand "%s" for the %s command.\n'
           'See "gsutil help web".') % (action_subcommand, self.command_name))

    # Commands with both suboptions and subcommands need to reparse for
    # suboptions, so we log again.
    metrics.LogCommandParams(subcommands=[action_subcommand],
                             sub_opts=self.sub_opts)
    return func()
