# -*- 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.utils
~~~~~~~~~~~~~~~~~~~

Utilities library for Kallithea

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 18, 2010
:author: marcink
:copyright: (c) 2013 RhodeCode GmbH, and others.
:license: GPLv3, see LICENSE.md for more details.
"""

import datetime
import logging
import os
import re
import sys
import traceback
from distutils.version import StrictVersion

import beaker.cache
import mercurial.config
import mercurial.ui
from tg.i18n import ugettext as _

import kallithea.config.conf
from kallithea.lib.exceptions import HgsubversionImportError
from kallithea.lib.utils2 import ascii_bytes, aslist, get_current_authuser, safe_bytes, safe_str
from kallithea.lib.vcs.backends.git.repository import GitRepository
from kallithea.lib.vcs.backends.hg.repository import MercurialRepository
from kallithea.lib.vcs.conf import settings
from kallithea.lib.vcs.exceptions import RepositoryError, VCSError
from kallithea.lib.vcs.utils.fakemod import create_module
from kallithea.lib.vcs.utils.helpers import get_scm
from kallithea.model import meta
from kallithea.model.db import RepoGroup, Repository, Setting, Ui, User, UserGroup, UserLog


log = logging.getLogger(__name__)

REMOVED_REPO_PAT = re.compile(r'rm__\d{8}_\d{6}_\d{6}_.*')


#==============================================================================
# PERM DECORATOR HELPERS FOR EXTRACTING NAMES FOR PERM CHECKS
#==============================================================================
def get_repo_slug(request):
    _repo = request.environ['pylons.routes_dict'].get('repo_name')
    if _repo:
        _repo = _repo.rstrip('/')
    return _repo


def get_repo_group_slug(request):
    _group = request.environ['pylons.routes_dict'].get('group_name')
    if _group:
        _group = _group.rstrip('/')
    return _group


def get_user_group_slug(request):
    _group = request.environ['pylons.routes_dict'].get('id')
    _group = UserGroup.get(_group)
    if _group:
        return _group.users_group_name
    return None


def _get_permanent_id(s):
    """Helper for decoding stable URLs with repo ID. For a string like '_123'
    return 123.
    """
    by_id_match = re.match(r'^_(\d+)$', s)
    if by_id_match is None:
        return None
    return int(by_id_match.group(1))


def fix_repo_id_name(path):
    """
    Rewrite repo_name for _<ID> permanent URLs.

    Given a path, if the first path element is like _<ID>, return the path with
    this part expanded to the corresponding full repo name, else return the
    provided path.
    """
    first, rest = path, ''
    if '/' in path:
        first, rest_ = path.split('/', 1)
        rest = '/' + rest_
    repo_id = _get_permanent_id(first)
    if repo_id is not None:
        repo = Repository.get(repo_id)
        if repo is not None:
            return repo.repo_name + rest
    return path


def action_logger(user, action, repo, ipaddr='', commit=False):
    """
    Action logger for various actions made by users

    :param user: user that made this action, can be a unique username string or
        object containing user_id attribute
    :param action: action to log, should be on of predefined unique actions for
        easy translations
    :param repo: string name of repository or object containing repo_id,
        that action was made on
    :param ipaddr: optional IP address from what the action was made

    """

    # if we don't get explicit IP address try to get one from registered user
    # in tmpl context var
    if not ipaddr:
        ipaddr = getattr(get_current_authuser(), 'ip_addr', '')

    if getattr(user, 'user_id', None):
        user_obj = User.get(user.user_id)
    elif isinstance(user, str):
        user_obj = User.get_by_username(user)
    else:
        raise Exception('You have to provide a user object or a username')

    if getattr(repo, 'repo_id', None):
        repo_obj = Repository.get(repo.repo_id)
        repo_name = repo_obj.repo_name
    elif isinstance(repo, str):
        repo_name = repo.lstrip('/')
        repo_obj = Repository.get_by_repo_name(repo_name)
    else:
        repo_obj = None
        repo_name = u''

    user_log = UserLog()
    user_log.user_id = user_obj.user_id
    user_log.username = user_obj.username
    user_log.action = action

    user_log.repository = repo_obj
    user_log.repository_name = repo_name

    user_log.action_date = datetime.datetime.now()
    user_log.user_ip = ipaddr
    meta.Session().add(user_log)

    log.info('Logging action:%s on %s by user:%s ip:%s',
             action, repo, user_obj, ipaddr)
    if commit:
        meta.Session().commit()


def get_filesystem_repos(path):
    """
    Scans given path for repos and return (name,(type,path)) tuple

    :param path: path to scan for repositories
    :param recursive: recursive search and return names with subdirs in front
    """

    # remove ending slash for better results
    path = path.rstrip(os.sep)
    log.debug('now scanning in %s', path)

    def isdir(*n):
        return os.path.isdir(os.path.join(*n))

    for root, dirs, _files in os.walk(path):
        recurse_dirs = []
        for subdir in dirs:
            # skip removed repos
            if REMOVED_REPO_PAT.match(subdir):
                continue

            # skip .<something> dirs TODO: rly? then we should prevent creating them ...
            if subdir.startswith('.'):
                continue

            cur_path = os.path.join(root, subdir)
            if isdir(cur_path, '.git'):
                log.warning('ignoring non-bare Git repo: %s', cur_path)
                continue

            if (isdir(cur_path, '.hg') or
                isdir(cur_path, '.svn') or
                isdir(cur_path, 'objects') and (isdir(cur_path, 'refs') or
                                                os.path.isfile(os.path.join(cur_path, 'packed-refs')))):

                if not os.access(cur_path, os.R_OK) or not os.access(cur_path, os.X_OK):
                    log.warning('ignoring repo path without access: %s', cur_path)
                    continue

                if not os.access(cur_path, os.W_OK):
                    log.warning('repo path without write access: %s', cur_path)

                try:
                    scm_info = get_scm(cur_path)
                    assert cur_path.startswith(path)
                    repo_path = cur_path[len(path) + 1:]
                    yield repo_path, scm_info
                    continue # no recursion
                except VCSError:
                    # We should perhaps ignore such broken repos, but especially
                    # the bare git detection is unreliable so we dive into it
                    pass

            recurse_dirs.append(subdir)

        dirs[:] = recurse_dirs


def is_valid_repo_uri(repo_type, url, ui):
    """Check if the url seems like a valid remote repo location - raise an Exception if any problems"""
    if repo_type == 'hg':
        if url.startswith('http') or url.startswith('ssh'):
            # initially check if it's at least the proper URL
            # or does it pass basic auth
            MercurialRepository._check_url(url, ui)
        elif url.startswith('svn+http'):
            try:
                from hgsubversion.svnrepo import svnremoterepo
            except ImportError:
                raise HgsubversionImportError(_('Unable to activate hgsubversion support. '
                                                'The "hgsubversion" library is missing'))
            svnremoterepo(ui, url).svn.uuid
        elif url.startswith('git+http'):
            raise NotImplementedError()
        else:
            raise Exception('URI %s not allowed' % (url,))

    elif repo_type == 'git':
        if url.startswith('http') or url.startswith('git'):
            # initially check if it's at least the proper URL
            # or does it pass basic auth
            GitRepository._check_url(url)
        elif url.startswith('svn+http'):
            raise NotImplementedError()
        elif url.startswith('hg+http'):
            raise NotImplementedError()
        else:
            raise Exception('URI %s not allowed' % (url))


def is_valid_repo(repo_name, base_path, scm=None):
    """
    Returns True if given path is a valid repository False otherwise.
    If scm param is given also compare if given scm is the same as expected
    from scm parameter

    :param repo_name:
    :param base_path:
    :param scm:

    :return True: if given path is a valid repository
    """
    # TODO: paranoid security checks?
    full_path = os.path.join(base_path, repo_name)

    try:
        scm_ = get_scm(full_path)
        if scm:
            return scm_[0] == scm
        return True
    except VCSError:
        return False


def is_valid_repo_group(repo_group_name, base_path, skip_path_check=False):
    """
    Returns True if given path is a repository group False otherwise

    :param repo_name:
    :param base_path:
    """
    full_path = os.path.join(base_path, repo_group_name)

    # check if it's not a repo
    if is_valid_repo(repo_group_name, base_path):
        return False

    try:
        # we need to check bare git repos at higher level
        # since we might match branches/hooks/info/objects or possible
        # other things inside bare git repo
        get_scm(os.path.dirname(full_path))
        return False
    except VCSError:
        pass

    # check if it's a valid path
    if skip_path_check or os.path.isdir(full_path):
        return True

    return False


# propagated from mercurial documentation
ui_sections = ['alias', 'auth',
                'decode/encode', 'defaults',
                'diff', 'email',
                'extensions', 'format',
                'merge-patterns', 'merge-tools',
                'hooks', 'http_proxy',
                'smtp', 'patch',
                'paths', 'profiling',
                'server', 'trusted',
                'ui', 'web', ]


def make_ui(repo_path=None):
    """
    Create an Mercurial 'ui' object based on database Ui settings, possibly
    augmenting with content from a hgrc file.
    """
    baseui = mercurial.ui.ui()

    # clean the baseui object
    baseui._ocfg = mercurial.config.config()
    baseui._ucfg = mercurial.config.config()
    baseui._tcfg = mercurial.config.config()

    sa = meta.Session()
    for ui_ in sa.query(Ui).all():
        if ui_.ui_active:
            log.debug('config from db: [%s] %s=%r', ui_.ui_section,
                      ui_.ui_key, ui_.ui_value)
            baseui.setconfig(ascii_bytes(ui_.ui_section), ascii_bytes(ui_.ui_key),
                             b'' if ui_.ui_value is None else safe_bytes(ui_.ui_value))

    # force set push_ssl requirement to False, Kallithea handles that
    baseui.setconfig(b'web', b'push_ssl', False)
    baseui.setconfig(b'web', b'allow_push', b'*')
    # prevent interactive questions for ssh password / passphrase
    ssh = baseui.config(b'ui', b'ssh', default=b'ssh')
    baseui.setconfig(b'ui', b'ssh', b'%s -oBatchMode=yes -oIdentitiesOnly=yes' % ssh)
    # push / pull hooks
    baseui.setconfig(b'hooks', b'changegroup.kallithea_log_push_action', b'python:kallithea.lib.hooks.log_push_action')
    baseui.setconfig(b'hooks', b'outgoing.kallithea_log_pull_action', b'python:kallithea.lib.hooks.log_pull_action')

    if repo_path is not None:
        hgrc_path = os.path.join(repo_path, '.hg', 'hgrc')
        if os.path.isfile(hgrc_path):
            log.debug('reading hgrc from %s', hgrc_path)
            cfg = mercurial.config.config()
            cfg.read(safe_bytes(hgrc_path))
            for section in ui_sections:
                for k, v in cfg.items(section):
                    log.debug('config from file: [%s] %s=%s', section, k, v)
                    baseui.setconfig(ascii_bytes(section), ascii_bytes(k), safe_bytes(v))
        else:
            log.debug('hgrc file is not present at %s, skipping...', hgrc_path)

    return baseui


def set_app_settings(config):
    """
    Updates app config with new settings from database

    :param config:
    """
    hgsettings = Setting.get_app_settings()
    for k, v in hgsettings.items():
        config[k] = v


def set_vcs_config(config):
    """
    Patch VCS config with some Kallithea specific stuff

    :param config: kallithea.CONFIG
    """
    settings.BACKENDS = {
        'hg': 'kallithea.lib.vcs.backends.hg.MercurialRepository',
        'git': 'kallithea.lib.vcs.backends.git.GitRepository',
    }

    settings.GIT_EXECUTABLE_PATH = config.get('git_path', 'git')
    settings.GIT_REV_FILTER = config.get('git_rev_filter', '--all').strip()
    settings.DEFAULT_ENCODINGS = aslist(config.get('default_encoding',
                                                        'utf-8'), sep=',')


def set_indexer_config(config):
    """
    Update Whoosh index mapping

    :param config: kallithea.CONFIG
    """
    log.debug('adding extra into INDEX_EXTENSIONS')
    kallithea.config.conf.INDEX_EXTENSIONS.extend(re.split(r'\s+', config.get('index.extensions', '')))

    log.debug('adding extra into INDEX_FILENAMES')
    kallithea.config.conf.INDEX_FILENAMES.extend(re.split(r'\s+', config.get('index.filenames', '')))


def map_groups(path):
    """
    Given a full path to a repository, create all nested groups that this
    repo is inside. This function creates parent-child relationships between
    groups and creates default perms for all new groups.

    :param paths: full path to repository
    """
    from kallithea.model.repo_group import RepoGroupModel
    sa = meta.Session()
    groups = path.split(Repository.url_sep())
    parent = None
    group = None

    # last element is repo in nested groups structure
    groups = groups[:-1]
    rgm = RepoGroupModel()
    owner = User.get_first_admin()
    for lvl, group_name in enumerate(groups):
        group_name = u'/'.join(groups[:lvl] + [group_name])
        group = RepoGroup.get_by_group_name(group_name)
        desc = '%s group' % group_name

        # skip folders that are now removed repos
        if REMOVED_REPO_PAT.match(group_name):
            break

        if group is None:
            log.debug('creating group level: %s group_name: %s',
                      lvl, group_name)
            group = RepoGroup(group_name, parent)
            group.group_description = desc
            group.owner = owner
            sa.add(group)
            rgm._create_default_perms(group)
            sa.flush()

        parent = group
    return group


def repo2db_mapper(initial_repo_dict, remove_obsolete=False,
                   install_git_hooks=False, user=None, overwrite_git_hooks=False):
    """
    maps all repos given in initial_repo_dict, non existing repositories
    are created, if remove_obsolete is True it also check for db entries
    that are not in initial_repo_dict and removes them.

    :param initial_repo_dict: mapping with repositories found by scanning methods
    :param remove_obsolete: check for obsolete entries in database
    :param install_git_hooks: if this is True, also check and install git hook
        for a repo if missing
    :param overwrite_git_hooks: if this is True, overwrite any existing git hooks
        that may be encountered (even if user-deployed)
    """
    from kallithea.model.repo import RepoModel
    from kallithea.model.scm import ScmModel
    sa = meta.Session()
    repo_model = RepoModel()
    if user is None:
        user = User.get_first_admin()
    added = []

    # creation defaults
    defs = Setting.get_default_repo_settings(strip_prefix=True)
    enable_statistics = defs.get('repo_enable_statistics')
    enable_downloads = defs.get('repo_enable_downloads')
    private = defs.get('repo_private')

    for name, repo in initial_repo_dict.items():
        group = map_groups(name)
        db_repo = repo_model.get_by_repo_name(name)
        # found repo that is on filesystem not in Kallithea database
        if not db_repo:
            log.info('repository %s not found, creating now', name)
            added.append(name)
            desc = (repo.description
                    if repo.description != 'unknown'
                    else '%s repository' % name)

            new_repo = repo_model._create_repo(
                repo_name=name,
                repo_type=repo.alias,
                description=desc,
                repo_group=getattr(group, 'group_id', None),
                owner=user,
                enable_downloads=enable_downloads,
                enable_statistics=enable_statistics,
                private=private,
                state=Repository.STATE_CREATED
            )
            sa.commit()
            # we added that repo just now, and make sure it has githook
            # installed, and updated server info
            if new_repo.repo_type == 'git':
                git_repo = new_repo.scm_instance
                ScmModel().install_git_hooks(git_repo)
                # update repository server-info
                log.debug('Running update server info')
                git_repo._update_server_info()
            new_repo.update_changeset_cache()
        elif install_git_hooks:
            if db_repo.repo_type == 'git':
                ScmModel().install_git_hooks(db_repo.scm_instance, force_create=overwrite_git_hooks)

    removed = []
    # remove from database those repositories that are not in the filesystem
    for repo in sa.query(Repository).all():
        if repo.repo_name not in initial_repo_dict:
            if remove_obsolete:
                log.debug("Removing non-existing repository found in db `%s`",
                          repo.repo_name)
                try:
                    RepoModel().delete(repo, forks='detach', fs_remove=False)
                    sa.commit()
                except Exception:
                    #don't hold further removals on error
                    log.error(traceback.format_exc())
                    sa.rollback()
            removed.append(repo.repo_name)
    return added, removed


def load_rcextensions(root_path):
    path = os.path.join(root_path, 'rcextensions', '__init__.py')
    if os.path.isfile(path):
        rcext = create_module('rc', path)
        EXT = kallithea.EXTENSIONS = rcext
        log.debug('Found rcextensions now loading %s...', rcext)

        # Additional mappings that are not present in the pygments lexers
        kallithea.config.conf.LANGUAGES_EXTENSIONS_MAP.update(getattr(EXT, 'EXTRA_MAPPINGS', {}))

        # OVERRIDE OUR EXTENSIONS FROM RC-EXTENSIONS (if present)

        if getattr(EXT, 'INDEX_EXTENSIONS', []):
            log.debug('settings custom INDEX_EXTENSIONS')
            kallithea.config.conf.INDEX_EXTENSIONS = getattr(EXT, 'INDEX_EXTENSIONS', [])

        # ADDITIONAL MAPPINGS
        log.debug('adding extra into INDEX_EXTENSIONS')
        kallithea.config.conf.INDEX_EXTENSIONS.extend(getattr(EXT, 'EXTRA_INDEX_EXTENSIONS', []))

        # auto check if the module is not missing any data, set to default if is
        # this will help autoupdate new feature of rcext module
        #from kallithea.config import rcextensions
        #for k in dir(rcextensions):
        #    if not k.startswith('_') and not hasattr(EXT, k):
        #        setattr(EXT, k, getattr(rcextensions, k))


#==============================================================================
# MISC
#==============================================================================

git_req_ver = StrictVersion('1.7.4')

def check_git_version():
    """
    Checks what version of git is installed on the system, and raise a system exit
    if it's too old for Kallithea to work properly.
    """
    if 'git' not in kallithea.BACKENDS:
        return None

    if not settings.GIT_EXECUTABLE_PATH:
        log.warning('No git executable configured - check "git_path" in the ini file.')
        return None

    try:
        stdout, stderr = GitRepository._run_git_command(['--version'])
    except RepositoryError as e:
        # message will already have been logged as error
        log.warning('No working git executable found - check "git_path" in the ini file.')
        return None

    if stderr:
        log.warning('Error/stderr from "%s --version":\n%s', settings.GIT_EXECUTABLE_PATH, safe_str(stderr))

    if not stdout:
        log.warning('No working git executable found - check "git_path" in the ini file.')
        return None

    output = safe_str(stdout).strip()
    m = re.search(r"\d+.\d+.\d+", output)
    if m:
        ver = StrictVersion(m.group(0))
        log.debug('Git executable: "%s", version %s (parsed from: "%s")',
                  settings.GIT_EXECUTABLE_PATH, ver, output)
        if ver < git_req_ver:
            log.error('Kallithea detected %s version %s, which is too old '
                      'for the system to function properly. '
                      'Please upgrade to version %s or later. '
                      'If you strictly need Mercurial repositories, you can '
                      'clear the "git_path" setting in the ini file.',
                      settings.GIT_EXECUTABLE_PATH, ver, git_req_ver)
            log.error("Terminating ...")
            sys.exit(1)
    else:
        ver = StrictVersion('0.0.0')
        log.warning('Error finding version number in "%s --version" stdout:\n%s',
                    settings.GIT_EXECUTABLE_PATH, output)

    return ver


#===============================================================================
# CACHE RELATED METHODS
#===============================================================================

def conditional_cache(region, prefix, condition, func):
    """

    Conditional caching function use like::
        def _c(arg):
            #heavy computation function
            return data

        # depending from condition the compute is wrapped in cache or not
        compute = conditional_cache('short_term', 'cache_desc', condition=True, func=func)
        return compute(arg)

    :param region: name of cache region
    :param prefix: cache region prefix
    :param condition: condition for cache to be triggered, and return data cached
    :param func: wrapped heavy function to compute

    """
    wrapped = func
    if condition:
        log.debug('conditional_cache: True, wrapping call of '
                  'func: %s into %s region cache' % (region, func))
        wrapped = beaker.cache._cache_decorate((prefix,), None, None, region)(func)

    return wrapped