# Copyright 2020 Codethink Limited
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; version 2 of the License.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License along
# with this program; if not, write to the Free Software Foundation, Inc.,
# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

import json
import urllib.error
import urllib.parse
import urllib.request

from . import hosts


class _Gitea:
    '''Run commands on a Gitea instance.'''

    def __init__(self, url, token):
        self._api_url = urllib.parse.urljoin(url, 'api/v1')
        self._api_token = token

    def request(self, method, *path, headers={}, data=None):
        url = self._api_url
        for part in path:
            url = url + '/' + urllib.parse.quote(part, safe='')

        headers = headers.copy()
        headers['Authorization'] = 'token ' + self._api_token

        if data is not None:
            if method == 'GET':
                data = urllib.parse.urlencode(data).encode('ascii')
            elif method in ['POST', 'PATCH']:
                data = json.dumps(data).encode('utf-8')
                headers['Content-Type'] = 'application/json; charset=utf-8'
            else:
                assert isinstance(data, bytes)

        request = urllib.request.Request(url, data=data, headers=headers,
                                         method=method)

        with urllib.request.urlopen(request) as response:
            if response.getcode() == 204:
                return None
            return json.loads(response.read().decode('utf-8'))


class GiteaDownstream(hosts.DownstreamHost):
    @staticmethod
    def add_app_settings(app_settings):
        app_settings.string(
            ['gitea-access-token'],
            'access token for Gitea API access')

    @staticmethod
    def check_app_settings(app_settings):
        app_settings.require('downstream-http-url')
        app_settings.require('gitea-access-token')

    def __init__(self, app_settings):
        self._gitea = _Gitea(app_settings['downstream-http-url'],
                             app_settings['gitea-access-token'])

        # Gitea supports all visibilities for organisations, but
        # repositories can only be private or inherit the visibility
        # of the organisation.  If repository visibility is supposed
        # to be 'internal', assume that the group will be 'internal'
        # rather than making the repository less visible.
        visibility = app_settings['downstream-visibility']
        self._group_vis = 'limited' if visibility == 'internal' else visibility
        self._repo_private = visibility == 'private'

    def prepare_repo(self, repo_path, metadata):
        path_comps = repo_path.split('/')

        # As of Gitea 1.11.5, a 2-level hierarchy must be used:
        # user/organisation and repository.  Deeper hiearchies must be
        # collapsed using a prefixmap.
        if len(path_comps) < 2:
            raise ValueError(
                'cannot create Gitea repository outside an organisation')
        if len(path_comps) > 2:
            raise ValueError('cannot create nested Gitea organisations')

        org_name, repo_name = path_comps
        repo_edit = {}

        try:
            repo = self._gitea.request('GET', 'repos', org_name, repo_name)
        except urllib.error.HTTPError as e:
            if e.code != 404:
                raise

            # Get or create organisation
            try:
                self._gitea.request('GET', 'orgs', org_name)
            except urllib.error.HTTPError as e:
                if e.code != 404:
                    raise
                org_data = {
                    'username':   org_name,
                    'visibility': self._group_vis,
                }
                self._gitea.request('POST', 'orgs', data=org_data)

            # Create repository.  This was under /org, not /orgs,
            # before Gitea 1.11.5 (which supports both).
            repo_create = {
                'auto_init': False,
                'name':      repo_name,
                'private':   self._repo_private,
            }
            repo = self._gitea.request('POST', 'org', org_name, 'repos',
                                       data=repo_create)

            # These can only be turned off after creating the repo
            for feature in ['has_issues', 'has_wiki', 'has_pull_requests']:
                if repo[feature] != False:
                    repo_edit[feature] = False

        # Update repository metadata
        if 'head' in metadata and repo['default_branch'] != metadata['head']:
            repo_edit['default_branch'] = metadata['head']
        if 'description' in metadata \
           and repo['description'] != metadata['description']:
            repo_edit['description'] = metadata['description']
        if repo_edit:
            self._gitea.request('PATCH', 'repos', org_name, repo_name,
                                data=repo_edit)