# -*- coding: utf-8 -*-
# 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, either version 3 of the License, or
# (at your option) any later version.
#
# 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, see <http://www.gnu.org/licenses/>.
"""
kallithea.lib.middleware.simplehg
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

SimpleHg middleware for handling Mercurial protocol requests (push/clone etc.).
It's implemented with basic auth function

This file was forked by the Kallithea project in July 2014.
Original author and date, and relevant copyright and licensing information is below:
:created_on: Apr 28, 2010
:author: marcink
:copyright: (c) 2013 RhodeCode GmbH, and others.
:license: GPLv3, see LICENSE.md for more details.

"""


import os
import logging
import traceback
import urllib

from webob.exc import HTTPNotFound, HTTPForbidden, HTTPInternalServerError, \
    HTTPNotAcceptable, HTTPBadRequest

from kallithea.lib.utils2 import safe_str, safe_unicode, get_server_url, \
    _set_extras
from kallithea.lib.base import BaseVCSController
from kallithea.lib.utils import make_ui, is_valid_repo
from kallithea.lib.vcs.utils.hgcompat import RepoError, hgweb_mod

log = logging.getLogger(__name__)


def get_header_hgarg(environ):
    """Decode the special Mercurial encoding of big requests over multiple headers.
    >>> get_header_hgarg({})
    ''
    >>> get_header_hgarg({'HTTP_X_HGARG_0': ' ', 'HTTP_X_HGARG_1': 'a','HTTP_X_HGARG_2': '','HTTP_X_HGARG_3': 'b+c %20'})
    'ab+c %20'
    """
    chunks = []
    i = 1
    while True:
        v = environ.get('HTTP_X_HGARG_%d' % i)
        if v is None:
            break
        chunks.append(v)
        i += 1
    return ''.join(chunks)


class SimpleHg(BaseVCSController):

    @classmethod
    def parse_request(cls, environ):
        http_accept = environ.get('HTTP_ACCEPT', '')
        if not http_accept.startswith('application/mercurial'):
            return None
        path_info = environ.get('PATH_INFO', '')
        if not path_info.startswith('/'): # it must!
            return None

        class parsed_request(object):
            repo_name = safe_unicode(path_info[1:].rstrip('/'))

        return parsed_request

    def _handle_request(self, parsed_request, environ, start_response):
        ip_addr = self._get_ip_addr(environ)
        # skip passing error to error controller
        environ['pylons.status_code_redirect'] = True

        # quick check if repo exists...
        if not is_valid_repo(parsed_request.repo_name, self.basepath, 'hg'):
            return HTTPNotFound()(environ, start_response)

        #======================================================================
        # GET ACTION PULL or PUSH
        #======================================================================
        try:
            action = self.__get_action(environ)
        except HTTPBadRequest as e:
            return e(environ, start_response)

        #======================================================================
        # CHECK PERMISSIONS
        #======================================================================
        user, response_app = self._authorize(environ, start_response, action, parsed_request.repo_name, ip_addr)
        if response_app is not None:
            return response_app(environ, start_response)

        # extras are injected into Mercurial UI object and later available
        # in hooks executed by Kallithea
        from kallithea import CONFIG
        server_url = get_server_url(environ)
        extras = {
            'ip': ip_addr,
            'username': user.username,
            'action': action,
            'repository': parsed_request.repo_name,
            'scm': 'hg',
            'config': CONFIG['__file__'],
            'server_url': server_url,
        }
        #======================================================================
        # MERCURIAL REQUEST HANDLING
        #======================================================================
        str_repo_name = safe_str(parsed_request.repo_name)
        repo_path = os.path.join(safe_str(self.basepath), str_repo_name)
        log.debug('Repository path is %s', repo_path)

        log.debug('HOOKS extras is %s', extras)
        baseui = make_ui(repo_path=repo_path)
        _set_extras(extras or {})

        try:
            log.info('%s action on Mercurial repo "%s" by "%s" from %s',
                     action, parsed_request.repo_name, safe_str(user.username), ip_addr)
            environ['REPO_NAME'] = str_repo_name # used by hgweb_mod.hgweb
            app = self.__make_app(repo_path, baseui)
            return app(environ, start_response)
        except Exception:
            log.error(traceback.format_exc())
            return HTTPInternalServerError()(environ, start_response)

    def __make_app(self, repo_name, baseui):
        """
        Make an hgweb wsgi application using baseui.
        """
        return hgweb_mod.hgweb(repo_name, name=repo_name, baseui=baseui)

    def __get_action(self, environ):
        """
        Maps Mercurial request commands into 'pull' or 'push'.

        Raises HTTPBadRequest if the request environment doesn't look like a hg client.
        """
        mapping = {
            # 'batch' is not in this list - it is handled explicitly
            'between': 'pull',
            'branches': 'pull',
            'branchmap': 'pull',
            'capabilities': 'pull',
            'changegroup': 'pull',
            'changegroupsubset': 'pull',
            'changesetdata': 'pull',
            'clonebundles': 'pull',
            'debugwireargs': 'pull',
            'filedata': 'pull',
            'getbundle': 'pull',
            'getlfile': 'pull',
            'heads': 'pull',
            'hello': 'pull',
            'known': 'pull',
            'lheads': 'pull',
            'listkeys': 'pull',
            'lookup': 'pull',
            'manifestdata': 'pull',
            'narrow_widen': 'pull',
            'protocaps': 'pull',
            'statlfile': 'pull',
            'stream_out': 'pull',
            'pushkey': 'push',
            'putlfile': 'push',
            'unbundle': 'push',
            }
        for qry in environ['QUERY_STRING'].split('&'):
            parts = qry.split('=', 1)
            if len(parts) == 2 and parts[0] == 'cmd':
                cmd = parts[1]
                if cmd == 'batch':
                    hgarg = get_header_hgarg(environ)
                    if not hgarg.startswith('cmds='):
                        return 'push' # paranoid and safe
                    for cmd_arg in hgarg[5:].split(';'):
                        cmd, _args = urllib.unquote_plus(cmd_arg).split(' ', 1)
                        op = mapping.get(cmd, 'push')
                        if op != 'pull':
                            assert op == 'push'
                            return 'push'
                    return 'pull'
                return mapping.get(cmd, 'push')

        # Note: the client doesn't get the helpful error message
        raise HTTPBadRequest('Unable to detect pull/push action! Are you using non standard command or client?')