# Copyright (C) 2016-2023 RhodeCode GmbH
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License, version 3
# (only), as published by the Free Software Foundation.
#
# 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 Affero General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
#
# This program is dual-licensed. If you wish to learn more about the
# RhodeCode Enterprise Edition, including its added features, Support services,
# and proprietary license terms, please see https://rhodecode.com/licenses/

import os
import re
import logging
import datetime
from sqlalchemy import Table

from rhodecode.lib.api_utils import call_service_api
from rhodecode.lib.utils2 import AttributeDict
from rhodecode.lib.vcs.exceptions import ImproperlyConfiguredError

from .hg import MercurialServer
from .git import GitServer
from .svn import SubversionServer
log = logging.getLogger(__name__)


class SshWrapper(object):
    hg_cmd_pat  = re.compile(r'^hg\s+\-R\s+(\S+)\s+serve\s+\-\-stdio$')
    git_cmd_pat = re.compile(r'^git-(receive-pack|upload-pack)\s\'[/]?(\S+?)(|\.git)\'$')
    svn_cmd_pat = re.compile(r'^svnserve -t')

    def __init__(self, command, connection_info, mode,
                 user, user_id, key_id: int, shell, ini_path: str, settings, env):
        self.command = command
        self.connection_info = connection_info
        self.mode = mode
        self.username = user
        self.user_id = user_id
        self.key_id = key_id
        self.shell = shell
        self.ini_path = ini_path
        self.env = env
        self.settings = settings
        self.server_impl = None

    def update_key_access_time(self, key_id):
        from rhodecode.model.meta import raw_query_executor, Base

        table = Table('user_ssh_keys', Base.metadata, autoload=False)
        atime = datetime.datetime.utcnow()
        stmt = (
            table.update()
            .where(table.c.ssh_key_id == key_id)
            .values(accessed_on=atime)
            # no MySQL Support for .returning :((
            #.returning(table.c.accessed_on, table.c.ssh_key_fingerprint)
        )

        res_count = None
        with raw_query_executor() as session:
            result = session.execute(stmt)
            if result.rowcount:
                res_count = result.rowcount

        if res_count:
            log.debug('Update key id:`%s` access time', key_id)

    def get_user(self, user_id):
        user = AttributeDict()
        # lazy load db imports
        from rhodecode.model.db import User
        dbuser = User.get(user_id)
        if not dbuser:
            return None
        user.user_id = dbuser.user_id
        user.username = dbuser.username
        user.auth_user = dbuser.AuthUser()
        return user

    def get_connection_info(self):
        """
        connection_info

        Identifies the client and server ends of the connection.
        The variable contains four space-separated values: client IP address,
        client port number, server IP address, and server port number.
        """
        conn = dict(
            client_ip=None,
            client_port=None,
            server_ip=None,
            server_port=None,
        )

        info = self.connection_info.split(' ')
        if len(info) == 4:
            conn['client_ip'] = info[0]
            conn['client_port'] = info[1]
            conn['server_ip'] = info[2]
            conn['server_port'] = info[3]

        return conn

    def maybe_translate_repo_uid(self, repo_name):
        _org_name = repo_name
        if _org_name.startswith('_'):
            # remove format of _ID/subrepo
            _org_name = _org_name.split('/', 1)[0]

        if repo_name.startswith('_'):
            from rhodecode.model.repo import RepoModel
            org_repo_name = repo_name
            log.debug('translating UID repo %s', org_repo_name)
            by_id_match = RepoModel().get_repo_by_id(repo_name)
            if by_id_match:
                repo_name = by_id_match.repo_name
                log.debug('translation of UID repo %s got `%s`', org_repo_name, repo_name)

        return repo_name, _org_name

    def get_repo_details(self, mode):
        vcs_type = mode if mode in ['svn', 'hg', 'git'] else None
        repo_name = None

        hg_match = self.hg_cmd_pat.match(self.command)
        if hg_match is not None:
            vcs_type = 'hg'
            repo_id = hg_match.group(1).strip('/')
            repo_name, org_name = self.maybe_translate_repo_uid(repo_id)
            return vcs_type, repo_name, mode

        git_match = self.git_cmd_pat.match(self.command)
        if git_match is not None:
            mode = git_match.group(1)
            vcs_type = 'git'
            repo_id = git_match.group(2).strip('/')
            repo_name, org_name = self.maybe_translate_repo_uid(repo_id)
            return vcs_type, repo_name, mode

        svn_match = self.svn_cmd_pat.match(self.command)
        if svn_match is not None:
            vcs_type = 'svn'
            # Repo name should be extracted from the input stream, we're unable to
            # extract it at this point in execution
            return vcs_type, repo_name, mode

        return vcs_type, repo_name, mode

    def serve(self, vcs, repo, mode, user, permissions, branch_permissions):
        # TODO: remove this once we have .ini defined access path...
        from rhodecode.model.scm import ScmModel

        store = ScmModel().repos_path

        check_branch_perms = False
        detect_force_push = False

        if branch_permissions:
            check_branch_perms = True
            detect_force_push = True

        log.debug(
            'VCS detected:`%s` mode: `%s` repo_name: %s, branch_permission_checks:%s',
            vcs, mode, repo, check_branch_perms)

        # detect if we have to check branch permissions
        extras = {
            'detect_force_push': detect_force_push,
            'check_branch_perms': check_branch_perms,
            'config': self.ini_path
        }

        if vcs == 'hg':
            server = MercurialServer(
                store=store, ini_path=self.ini_path,
                repo_name=repo, user=user,
                user_permissions=permissions, settings=self.settings, env=self.env)
            self.server_impl = server
            return server.run(tunnel_extras=extras)

        elif vcs == 'git':
            server = GitServer(
                store=store, ini_path=self.ini_path,
                repo_name=repo, repo_mode=mode, user=user,
                user_permissions=permissions, settings=self.settings, env=self.env)
            self.server_impl = server
            return server.run(tunnel_extras=extras)

        elif vcs == 'svn':
            server = SubversionServer(
                store=store, ini_path=self.ini_path,
                repo_name=None, user=user,
                user_permissions=permissions, settings=self.settings, env=self.env)
            self.server_impl = server
            return server.run(tunnel_extras=extras)

        else:
            raise Exception(f'Unrecognised VCS: {vcs}')

    def wrap(self):
        mode = self.mode
        username = self.username
        user_id = self.user_id
        key_id = self.key_id
        shell = self.shell

        scm_detected, scm_repo, scm_mode = self.get_repo_details(mode)

        log.debug(
            'Mode: `%s` User: `name:%s : id:%s` Shell: `%s` SSH Command: `\"%s\"` '
            'SCM_DETECTED: `%s` SCM Mode: `%s` SCM Repo: `%s`',
            mode, username, user_id, shell, self.command,
            scm_detected, scm_mode, scm_repo)

        log.debug('SSH Connection info %s', self.get_connection_info())

        # update last access time for this key
        if key_id:
            self.update_key_access_time(key_id)

        if shell and self.command is None:
            log.info('Dropping to shell, no command given and shell is allowed')
            os.execl('/bin/bash', '-l')
            exit_code = 1

        elif scm_detected:
            user = self.get_user(user_id)
            if not user:
                log.warning('User with id %s not found', user_id)
                exit_code = -1
                return exit_code

            auth_user = user.auth_user
            permissions = auth_user.permissions['repositories']
            repo_branch_permissions = auth_user.get_branch_permissions(scm_repo)
            try:
                exit_code, is_updated = self.serve(
                    scm_detected, scm_repo, scm_mode, user, permissions,
                    repo_branch_permissions)
            except Exception:
                log.exception('Error occurred during execution of SshWrapper')
                exit_code = -1

        elif self.command is None and shell is False:
            log.error('No Command given.')
            exit_code = -1

        else:
            log.error('Unhandled Command: "%s" Aborting.', self.command)
            exit_code = -1

        return exit_code


class SshWrapperStandalone(SshWrapper):
    """
    New version of SshWrapper designed to be depended only on service API
    """
    repos_path = None
    service_api_host: str
    service_api_token: str
    api_url: str

    def __init__(self, command, connection_info, mode,
                 user, user_id, key_id: int, shell, ini_path: str, settings, env):

        # validate our settings for making a standalone calls
        try:
            self.service_api_host = settings['app.service_api.host']
            self.service_api_token = settings['app.service_api.token']
        except KeyError:
            raise ImproperlyConfiguredError(
                "app.service_api.host or app.service_api.token are missing. "
                "Please ensure that app.service_api.host and app.service_api.token are "
                "defined inside of .ini configuration file."
            )

        try:
            self.api_url = settings['rhodecode.api.url']
        except KeyError:
            raise ImproperlyConfiguredError(
                "rhodecode.api.url is missing. "
                "Please ensure that rhodecode.api.url is "
                "defined inside of .ini configuration file."
            )

        super(SshWrapperStandalone, self).__init__(
            command, connection_info, mode, user, user_id, key_id, shell, ini_path, settings, env)

    @staticmethod
    def parse_user_related_data(user_data):
        user = AttributeDict()
        user.user_id = user_data['user_id']
        user.username = user_data['username']
        user.repo_permissions = user_data['repo_permissions']
        user.branch_permissions = user_data['branch_permissions']
        return user

    def wrap(self):
        mode = self.mode
        username = self.username
        user_id = self.user_id
        shell = self.shell

        scm_detected, scm_repo, scm_mode = self.get_repo_details(mode)

        log.debug(
            'Mode: `%s` User: `name:%s : id:%s` Shell: `%s` SSH Command: `\"%s\"` '
            'SCM_DETECTED: `%s` SCM Mode: `%s` SCM Repo: `%s`',
            mode, username, user_id, shell, self.command,
            scm_detected, scm_mode, scm_repo)

        log.debug('SSH Connection info %s', self.get_connection_info())

        if shell and self.command is None:
            log.info('Dropping to shell, no command given and shell is allowed')
            os.execl('/bin/bash', '-l')
            exit_code = 1

        elif scm_detected:
            data = call_service_api(self.service_api_host, self.service_api_token, self.api_url, {
                "method": "service_get_data_for_ssh_wrapper",
                "args": {"user_id": user_id, "repo_name": scm_repo, "key_id": self.key_id}
            })
            user = self.parse_user_related_data(data)
            if not user:
                log.warning('User with id %s not found', user_id)
                exit_code = -1
                return exit_code
            self.repos_path = data['repos_path']
            permissions = user.repo_permissions
            repo_branch_permissions = user.branch_permissions
            try:
                exit_code, is_updated = self.serve(
                    scm_detected, scm_repo, scm_mode, user, permissions,
                    repo_branch_permissions)
            except Exception:
                log.exception('Error occurred during execution of SshWrapper')
                exit_code = -1

        elif self.command is None and shell is False:
            log.error('No Command given.')
            exit_code = -1

        else:
            log.error('Unhandled Command: "%s" Aborting.', self.command)
            exit_code = -1

        return exit_code

    def maybe_translate_repo_uid(self, repo_name):
        _org_name = repo_name
        if _org_name.startswith('_'):
            _org_name = _org_name.split('/', 1)[0]

        if repo_name.startswith('_'):
            org_repo_name = repo_name
            log.debug('translating UID repo %s', org_repo_name)
            by_id_match = call_service_api(self.service_api_host, self.service_api_token, self.api_url, {
                'method': 'service_get_repo_name_by_id',
                "args": {"repo_id": repo_name}
            })
            if by_id_match:
                repo_name = by_id_match['repo_name']
                log.debug('translation of UID repo %s got `%s`', org_repo_name, repo_name)

        return repo_name, _org_name

    def serve(self, vcs, repo, mode, user, permissions, branch_permissions):
        store = self.repos_path

        check_branch_perms = False
        detect_force_push = False

        if branch_permissions:
            check_branch_perms = True
            detect_force_push = True

        log.debug(
            'VCS detected:`%s` mode: `%s` repo_name: %s, branch_permission_checks:%s',
            vcs, mode, repo, check_branch_perms)

        # detect if we have to check branch permissions
        extras = {
            'detect_force_push': detect_force_push,
            'check_branch_perms': check_branch_perms,
            'config': self.ini_path
        }

        match vcs:
            case 'hg':
                server = MercurialServer(
                    store=store, ini_path=self.ini_path,
                    repo_name=repo, user=user,
                    user_permissions=permissions, settings=self.settings, env=self.env)
            case 'git':
                server = GitServer(
                    store=store, ini_path=self.ini_path,
                    repo_name=repo, repo_mode=mode, user=user,
                    user_permissions=permissions, settings=self.settings, env=self.env)
            case 'svn':
                server = SubversionServer(
                    store=store, ini_path=self.ini_path,
                    repo_name=None, user=user,
                    user_permissions=permissions, settings=self.settings, env=self.env)
            case _:
                raise Exception(f'Unrecognised VCS: {vcs}')
        self.server_impl = server
        return server.run(tunnel_extras=extras)