# Copyright (c) 2012-2016 Seafile Ltd.
# encoding: utf-8
import os
import re
import urllib
import urllib2
import uuid
import logging
import hashlib
import tempfile
import locale
import ConfigParser
import mimetypes
import contextlib
from datetime import datetime
from urlparse import urlparse, urljoin
import json

import ccnet
from constance import config
import seaserv
from seaserv import seafile_api

from django.core.urlresolvers import reverse
from django.core.mail import EmailMessage
from django.shortcuts import render_to_response
from django.template import RequestContext, Context, loader
from django.utils.translation import ugettext as _
from django.http import HttpResponseRedirect, HttpResponse, HttpResponseNotModified
from django.utils.http import urlquote
from django.utils.html import escape
from django.views.static import serve as django_static_serve

from seahub.api2.models import Token, TokenV2
import seahub.settings
from seahub.settings import SITE_NAME, MEDIA_URL, LOGO_PATH
try:
    from seahub.settings import EVENTS_CONFIG_FILE
except ImportError:
    EVENTS_CONFIG_FILE = None
try:
    from seahub.settings import EMAIL_HOST
    IS_EMAIL_CONFIGURED = True
except ImportError:
    IS_EMAIL_CONFIGURED = False
try:
    from seahub.settings import CLOUD_MODE
except ImportError:
    CLOUD_MODE = False
try:
    from seahub.settings import ENABLE_INNER_FILESERVER
except ImportError:
    ENABLE_INNER_FILESERVER = True
try:
    from seahub.settings import CHECK_SHARE_LINK_TRAFFIC
except ImportError:
    CHECK_SHARE_LINK_TRAFFIC = False

def is_cluster_mode():
    cfg = ConfigParser.ConfigParser()
    if 'SEAFILE_CENTRAL_CONF_DIR' in os.environ:
        confdir = os.environ['SEAFILE_CENTRAL_CONF_DIR']
    else:
        confdir = os.environ['SEAFILE_CONF_DIR']
    conf = os.path.join(confdir, 'seafile.conf')
    cfg.read(conf)
    if cfg.has_option('cluster', 'enabled'):
        enabled = cfg.getboolean('cluster', 'enabled')
    else:
        enabled = False

    if enabled:
        logging.debug('cluster mode is enabled')
    else:
        logging.debug('cluster mode is disabled')

    return enabled

CLUSTER_MODE = is_cluster_mode()

try:
    from seahub.settings import OFFICE_CONVERTOR_ROOT
except ImportError:
    OFFICE_CONVERTOR_ROOT = ''
try:
    from seahub.settings import OFFICE_CONVERTOR_NODE
except ImportError:
    OFFICE_CONVERTOR_NODE = False

from seahub.utils.file_types import *
from seahub.utils.htmldiff import HtmlDiff # used in views/files.py

EMPTY_SHA1 = '0000000000000000000000000000000000000000'
MAX_INT = 2147483647

PREVIEW_FILEEXT = {
    TEXT: ('ac', 'am', 'bat', 'c', 'cc', 'cmake', 'cpp', 'cs', 'css', 'diff', 'el', 'h', 'html', 'htm', 'java', 'js', 'json', 'less', 'make', 'org', 'php', 'pl', 'properties', 'py', 'rb', 'scala', 'script', 'sh', 'sql', 'txt', 'text', 'tex', 'vi', 'vim', 'xhtml', 'xml', 'log', 'csv', 'groovy', 'rst', 'patch', 'go'),
    IMAGE: ('gif', 'jpeg', 'jpg', 'png', 'ico', 'bmp'),
    DOCUMENT: ('doc', 'docx', 'ppt', 'pptx'),
    SPREADSHEET: ('xls', 'xlsx', 'ods', 'fods'),
    # SVG: ('svg',),
    PDF: ('pdf',),
    OPENDOCUMENT: ('odt', 'fodt', 'odp', 'fodp'),
    MARKDOWN: ('markdown', 'md'),
    VIDEO: ('mp4', 'ogv', 'webm', 'mov'),
    AUDIO: ('mp3', 'oga', 'ogg'),
    '3D': ('stl', 'obj'),
}

def gen_fileext_type_map():
    """
    Generate previewed file extension and file type relation map.

    """
    d = {}
    for filetype in PREVIEW_FILEEXT.keys():
        for fileext in PREVIEW_FILEEXT.get(filetype):
            d[fileext] = filetype

    return d
FILEEXT_TYPE_MAP = gen_fileext_type_map()

def render_permission_error(request, msg=None, extra_ctx=None):
    """
    Return permisson error page.

    """
    ctx = {}
    ctx['error_msg'] = msg or _('permission error')

    if extra_ctx:
        for k in extra_ctx:
            ctx[k] = extra_ctx[k]

    return render_to_response('error.html', ctx,
                              context_instance=RequestContext(request))

def render_error(request, msg=None, extra_ctx=None):
    """
    Return normal error page.

    """
    ctx = {}
    ctx['error_msg'] = msg or _('Internal error')

    if extra_ctx:
        for k in extra_ctx:
            ctx[k] = extra_ctx[k]

    return render_to_response('error.html', ctx,
                              context_instance=RequestContext(request))

def list_to_string(l):
    """
    Return string of a list.

    """
    return ','.join(l)

def get_fileserver_root():
    """ Construct seafile fileserver address and port.

    Returns:
    	Constructed fileserver root.
    """
    return config.FILE_SERVER_ROOT

def get_inner_fileserver_root():
    """Construct inner seafile fileserver address and port.

    Inner fileserver root allows Seahub access fileserver through local
    address, thus avoiding the overhead of DNS queries, as well as other
    related issues, for example, the server can not ping itself, etc.

    Returns:
    	http://127.0.0.1:<port>
    """

    return seahub.settings.INNER_FILE_SERVER_ROOT

def gen_token(max_length=5):
    """
    Generate a random token.

    """

    return uuid.uuid4().hex[:max_length]

def normalize_cache_key(value, prefix=None, token=None, max_length=200):
    """Returns a cache key consisten of ``value`` and ``prefix`` and ``token``. Cache key
    must not include control characters or whitespace.
    """
    key = value if prefix is None else prefix + value
    key = key if token is None else key + '_' + token
    return urlquote(key)[:max_length]

def get_repo_last_modify(repo):
    """ Get last modification time for a repo.

    If head commit id of a repo is provided, we use that commit as last commit,
    otherwise falls back to getting last commit of a repo which is time
    consuming.
    """
    if repo.head_cmmt_id is not None:
        last_cmmt = seaserv.get_commit(repo.id, repo.version, repo.head_cmmt_id)
    else:
        logger = logging.getLogger(__name__)
        logger.info('[repo %s] head_cmmt_id is missing.' % repo.id)
        last_cmmt = seafile_api.get_commit_list(repo.id, 0, 1)[0]
    return last_cmmt.ctime if last_cmmt else 0

def calculate_repos_last_modify(repo_list):
    """ Get last modification time for repos.
    """
    for repo in repo_list:
        repo.latest_modify = get_repo_last_modify(repo)

def normalize_dir_path(path):
    """Add '/' at the end of directory path if necessary.
    """
    if path[-1] != '/':
        path = path + '/'
    return path

def normalize_file_path(path):
    """Remove '/' at the end of file path if necessary.
    """
    return path.rstrip('/')

# modified from django1.5:/core/validators, and remove the support for single
# quote in email address
email_re = re.compile(
    r"(^[-!#$%&*+/=?^_`{}|~0-9A-Z]+(\.[-!#$%&*+/=?^_`{}|~0-9A-Z]+)*"  # dot-atom
    # quoted-string, see also http://tools.ietf.org/html/rfc2822#section-3.2.5
    r'|^"([\001-\010\013\014\016-\037!#-\[\]-\177]|\\[\001-\011\013\014\016-\177])*"'
    r')@((?:[A-Z0-9](?:[A-Z0-9-]{0,61}[A-Z0-9])?\.)+(?:[A-Z]{2,6}\.?|[A-Z0-9-]{2,}\.?)$)'  # domain
    r'|\[(25[0-5]|2[0-4]\d|[0-1]?\d?\d)(\.(25[0-5]|2[0-4]\d|[0-1]?\d?\d)){3}\]$', re.IGNORECASE)  # literal form, ipv4 address (SMTP 4.1.3)

def is_valid_email(email):
    """A heavy email format validation.
    """
    return True if email_re.match(email) is not None else False

def is_valid_username(username):
    """Check whether username is valid, currently only email can be a username.
    """
    return is_valid_email(username)

def is_ldap_user(user):
    """Check whether user is a LDAP user.
    """
    return user.source == 'LDAP' or user.source == 'LDAPImport'

def check_filename_with_rename(repo_id, parent_dir, filename):
    cmmts = seafile_api.get_commit_list(repo_id, 0, 1)
    latest_commit = cmmts[0] if cmmts else None
    if not latest_commit:
        return ''
    # TODO: what if parrent_dir does not exist?
    dirents = seafile_api.list_dir_by_commit_and_path(repo_id, latest_commit.id,
                                                      parent_dir.encode('utf-8'))

    def no_duplicate(name):
        for dirent in dirents:
            if dirent.obj_name == name:
                return False
        return True

    def make_new_name(filename, i):
        base, ext = os.path.splitext(filename)
        if ext:
            new_base = "%s (%d)" % (base, i)
            return new_base + ext
        else:
            return "%s (%d)" % (filename, i)

    if no_duplicate(filename):
        return filename
    else:
        i = 1
        while True:
            new_name = make_new_name (filename, i)
            if no_duplicate(new_name):
                return new_name
            else:
                i += 1

def get_user_repos(username, org_id=None):
    """
    Get all repos that user can access, including owns, shared, public, and
    repo in groups.
    If ``org_id`` is not None, get org repos that user can access.
    """
    if org_id is None:
        owned_repos = seaserv.list_personal_repos_by_owner(username)
        shared_repos = seafile_api.get_share_in_repo_list(username, -1, -1)
        groups_repos = []
        for group in seaserv.get_personal_groups_by_user(username):
            # TODO: use seafile_api.get_group_repos
            groups_repos += seaserv.get_group_repos(group.id, username)
        if CLOUD_MODE:
            public_repos = []
        else:
            public_repos = seaserv.list_inner_pub_repos(username)

        for r in shared_repos + public_repos:
            # collumn names in shared_repo struct are not same as owned or group
            # repos.
            r.id = r.repo_id
            r.name = r.repo_name
            r.desc = r.repo_desc
            r.last_modify = r.last_modified
    else:
        owned_repos = seafile_api.get_org_owned_repo_list(org_id, username)
        shared_repos = seafile_api.get_org_share_in_repo_list(org_id, username,
                                                              -1, -1)
        groups_repos = []
        for group in seaserv.get_org_groups_by_user(org_id, username):
            groups_repos += seafile_api.get_org_group_repos(org_id, group.id)
        public_repos = seaserv.seafserv_threaded_rpc.list_org_inner_pub_repos(org_id)

        for r in shared_repos + groups_repos + public_repos:
            # collumn names in shared_repo struct are not same as owned
            # repos.
            r.id = r.repo_id
            r.name = r.repo_name
            r.desc = r.repo_desc
            r.last_modify = r.last_modified

    return (owned_repos, shared_repos, groups_repos, public_repos)

def get_file_type_and_ext(filename):
    """
    Return file type and extension if the file can be previewd online,
    otherwise, return unknown type.
    """
    fileExt = os.path.splitext(filename)[1][1:].lower()
    filetype = FILEEXT_TYPE_MAP.get(fileExt)
    if filetype:
        return (filetype, fileExt)
    else:
        return ('Unknown', fileExt)

def get_file_revision_id_size(repo_id, commit_id, path):
    """Given a commit and a file path in that commit, return the seafile id
    and size of the file blob

    """
    repo = seafile_api.get_repo(repo_id)
    dirname  = os.path.dirname(path)
    filename = os.path.basename(path)
    seafdir = seafile_api.list_dir_by_commit_and_path(repo_id, commit_id, dirname)
    for dirent in seafdir:
        if dirent.obj_name == filename:
            file_size = seafile_api.get_file_size(repo.store_id, repo.version,
                                                  dirent.obj_id)
            return dirent.obj_id, file_size

    return None, None

def new_merge_with_no_conflict(commit):
    """Check whether a commit is a new merge, and no conflict.

    Arguments:
    - `commit`:
    """
    if commit.second_parent_id is not None and commit.new_merge is True and \
            commit.conflict is False:
        return True
    else:
        return False

def get_commit_before_new_merge(commit):
    """Traverse parents of ``commit``, and get a commit which is not a new merge.

    Pre-condition: ``commit`` must be a new merge and not conflict.

    Arguments:
    - `commit`:
    """
    assert new_merge_with_no_conflict(commit) is True

    while(new_merge_with_no_conflict(commit)):
        p1 = seaserv.get_commit(commit.repo_id, commit.version, commit.parent_id)
        p2 = seaserv.get_commit(commit.repo_id, commit.version, commit.second_parent_id)
        commit = p1 if p1.ctime > p2.ctime else p2

    assert new_merge_with_no_conflict(commit) is False

    return commit

def gen_inner_file_get_url(token, filename):
    """Generate inner fileserver file url.

    If ``ENABLE_INNER_FILESERVER`` set to False(defaults to True), will
    returns outer fileserver file url.

    Arguments:
    - `token`:
    - `filename`:

    Returns:
    	e.g., http://127.0.0.1:<port>/files/<token>/<filename>
    """
    if ENABLE_INNER_FILESERVER:
        return '%s/files/%s/%s' % (get_inner_fileserver_root(), token,
                                   urlquote(filename))
    else:
        return gen_file_get_url(token, filename)

def get_max_upload_file_size():
    """Get max upload file size from config file, defaults to no limit.

    Returns ``None`` if this value is not set.
    """
    return seaserv.MAX_UPLOAD_FILE_SIZE

def gen_block_get_url(token, blkid):
    """
    Generate fileserver block url.
    Format: http://<domain:port>/blks/<token>/<blkid>
    """
    if blkid:
        return '%s/blks/%s/%s' % (get_fileserver_root(), token, blkid)
    else:
        return '%s/blks/%s/' % (get_fileserver_root(), token)

def gen_file_get_url(token, filename):
    """
    Generate fileserver file url.
    Format: http://<domain:port>/files/<token>/<filename>
    """
    return '%s/files/%s/%s' % (get_fileserver_root(), token, urlquote(filename))

def gen_file_upload_url(token, op):
    return '%s/%s/%s' % (get_fileserver_root(), op, token)

def get_ccnet_server_addr_port():
    """get ccnet server host and port"""
    return seaserv.CCNET_SERVER_ADDR, seaserv.CCNET_SERVER_PORT

def string2list(string):
    """
    Split string contacted with different separators to a list, and remove
    duplicated strings.
    """
    tmp_str = string.replace(';', ',').replace('\n', ',').replace('\r', ',')
    # Remove empty and duplicate strings
    s = set()
    for e in tmp_str.split(','):
        e = e.strip(' ')
        if not e:
            continue
        s.add(e)
    return [ x for x in s ]

def is_org_context(request):
    """An organization context is a virtual private Seafile instance on cloud
    service.

    Arguments:
    - `request`:
    """
    return request.cloud_mode and request.user.org is not None

# events related
if EVENTS_CONFIG_FILE:
    parsed_events_conf = ConfigParser.ConfigParser()
    parsed_events_conf.read(EVENTS_CONFIG_FILE)

    import seafevents

    EVENTS_ENABLED = True
    SeafEventsSession = seafevents.init_db_session_class(EVENTS_CONFIG_FILE)

    @contextlib.contextmanager
    def _get_seafevents_session():
        try:
            session = SeafEventsSession()
            yield session
        finally:
           session.close()

    def _same_events(e1, e2):
        """Two events are equal should follow two rules:
        1. event1.repo_id = event2.repo_id
        2. event1.commit.creator = event2.commit.creator
        3. event1.commit.desc = event2.commit.desc
        """
        if hasattr(e1, 'commit') and hasattr(e2, 'commit'):
            if e1.repo_id == e2.repo_id and \
               e1.commit.desc == e2.commit.desc and \
               e1.commit.creator_name == e2.commit.creator_name:
                return True
        return False

    def _get_events(username, start, count, org_id=None):
        ev_session = SeafEventsSession()

        valid_events = []
        total_used = 0
        try:
            next_start = start
            while True:
                events = _get_events_inner(ev_session, username, next_start,
                                           count, org_id)
                if not events:
                    break

                for e1 in events:
                    duplicate = False
                    for e2 in valid_events:
                        if _same_events(e1, e2): duplicate = True; break

                    new_merge = False
                    if hasattr(e1, 'commit') and e1.commit and \
                       new_merge_with_no_conflict(e1.commit):
                        new_merge = True

                    if not duplicate and not new_merge:
                        valid_events.append(e1)
                    total_used = total_used + 1
                    if len(valid_events) == count:
                        break

                if len(valid_events) == count:
                    break
                next_start = next_start + len(events)
        finally:
            ev_session.close()

        for e in valid_events:            # parse commit description
            if hasattr(e, 'commit'):
                e.commit.converted_cmmt_desc = convert_cmmt_desc_link(e.commit)
                e.commit.more_files = more_files_in_commit(e.commit)
        return valid_events, start + total_used

    def _get_events_inner(ev_session, username, start, limit, org_id=None):
        '''Read events from seafevents database, and remove events that are
        no longer valid

        Return 'limit' events or less than 'limit' events if no more events remain
        '''
        valid_events = []
        next_start = start
        while True:
            if org_id > 0:
                events = seafevents.get_org_user_events(ev_session, org_id,
                                                        username, next_start,
                                                        limit)
            else:
                events = seafevents.get_user_events(ev_session, username,
                                                    next_start, limit)
            if not events:
                break

            for ev in events:
                if ev.etype == 'repo-update':
                    repo = seafile_api.get_repo(ev.repo_id)
                    if not repo:
                        # delete the update event for repo which has been deleted
                        seafevents.delete_event(ev_session, ev.uuid)
                        continue
                    if repo.encrypted:
                        repo.password_set = seafile_api.is_password_set(
                            repo.id, username)
                    ev.repo = repo
                    ev.commit = seaserv.get_commit(repo.id, repo.version, ev.commit_id)

                valid_events.append(ev)
                if len(valid_events) == limit:
                    break

            if len(valid_events) == limit:
                break
            next_start = next_start + len(valid_events)

        return valid_events

    def get_user_events(username, start, count):
        """Return user events list and a new start.

        For example:
        ``get_user_events('foo@example.com', 0, 10)`` returns the first 10
        events.
        ``get_user_events('foo@example.com', 5, 10)`` returns the 6th through
        15th events.
        """
        return _get_events(username, start, count)

    def get_org_user_events(org_id, username, start, count):
        return _get_events(username, start, count, org_id=org_id)

    def get_log_events_by_time(log_type, tstart, tend):
        """Return log events list by start/end timestamp. (If no logs, return 'None')
        """
        with _get_seafevents_session() as session:
            events = seafevents.get_event_log_by_time(session, log_type, tstart, tend)

        return events if events else None

    def generate_file_audit_event_type(e):
        return {
            'file-download-web': ('web', ''),
            'file-download-share-link': ('share-link',''),
            'file-download-api': ('API', e.device),
            'repo-download-sync': ('download-sync', e.device),
            'repo-upload-sync': ('upload-sync', e.device),
        }[e.etype]

    def get_file_audit_events_by_path(email, org_id, repo_id, file_path, start, limit):
        """Return file audit events list by file path. (If no file audit, return 'None')

        For example:
        ``get_file_audit_events_by_path(email, org_id, repo_id, file_path, 0, 10)`` returns the first 10
        events.
        ``get_file_audit_events_by_path(email, org_id, repo_id, file_path, 5, 10)`` returns the 6th through
        15th events.
        """
        with _get_seafevents_session() as session:
            events = seafevents.get_file_audit_events_by_path(session,
                email, org_id, repo_id, file_path, start, limit)

        return events if events else None

    def get_file_audit_events(email, org_id, repo_id, start, limit):
        """Return file audit events list. (If no file audit, return 'None')

        For example:
        ``get_file_audit_events(email, org_id, repo_id, 0, 10)`` returns the first 10
        events.
        ``get_file_audit_events(email, org_id, repo_id, 5, 10)`` returns the 6th through
        15th events.
        """
        with _get_seafevents_session() as session:
            events = seafevents.get_file_audit_events(session, email, org_id, repo_id, start, limit)

        return events if events else None

    def get_file_update_events(email, org_id, repo_id, start, limit):
        """Return file update events list. (If no file update, return 'None')

        For example:
        ``get_file_update_events(email, org_id, repo_id, 0, 10)`` returns the first 10
        events.
        ``get_file_update_events(email, org_id, repo_id, 5, 10)`` returns the 6th through
        15th events.
        """
        with _get_seafevents_session() as session:
            events = seafevents.get_file_update_events(session, email, org_id, repo_id, start, limit)

        return events if events else None

    def get_perm_audit_events(email, org_id, repo_id, start, limit):
        """Return repo perm events list. (If no repo perm, return 'None')

        For example:
        ``get_repo_perm_events(email, org_id, repo_id, 0, 10)`` returns the first 10
        events.
        ``get_repo_perm_events(email, org_id, repo_id, 5, 10)`` returns the 6th through
        15th events.
        """
        with _get_seafevents_session() as session:
            events = seafevents.get_perm_audit_events(session, email, org_id, repo_id, start, limit)

        return events if events else None

    def get_virus_record(repo_id=None, start=-1, limit=-1):
        with _get_seafevents_session() as session:
            r = seafevents.get_virus_record(session, repo_id, start, limit)
        return r if r else []

    def handle_virus_record(vid):
        with _get_seafevents_session() as session:
            return True if seafevents.handle_virus_record(session, vid) == 0 else False

    def get_virus_record_by_id(vid):
        with _get_seafevents_session() as session:
            return seafevents.get_virus_record_by_id(session, vid)
else:
    EVENTS_ENABLED = False
    def get_user_events():
        pass
    def get_log_events_by_time():
        pass
    def get_org_user_events():
        pass
    def generate_file_audit_event_type():
        pass
    def get_file_audit_events_by_path():
        pass
    def get_file_audit_events():
        pass
    def get_file_update_events():
        pass
    def get_perm_audit_events():
        pass
    def get_virus_record():
        pass
    def handle_virus_record():
        pass
    def get_virus_record_by_id(vid):
        pass

def calc_file_path_hash(path, bits=12):
    if isinstance(path, unicode):
        path = path.encode('UTF-8')

    path_hash = hashlib.md5(urllib2.quote(path)).hexdigest()[:bits]

    return path_hash

def get_service_url():
    """Get service url from seaserv.
    """
    return config.SERVICE_URL

def get_server_id():
    """Get server id from seaserv.
    """
    return getattr(seaserv, 'SERVER_ID', '-')

def get_site_scheme_and_netloc():
    """Return a string contains site scheme and network location part from
    service url.

    For example:
    >>> get_site_scheme_and_netloc("https://example.com:8000/seafile/")
    https://example.com:8000

    """
    parse_result = urlparse(get_service_url())
    return "%s://%s" % (parse_result.scheme, parse_result.netloc)

def send_html_email(subject, con_template, con_context, from_email, to_email,
                    reply_to=None):
    """Send HTML email
    """
    base_context = {
        'url_base': get_site_scheme_and_netloc(),
        'site_name': SITE_NAME,
        'media_url': MEDIA_URL,
        'logo_path': LOGO_PATH,
    }
    t = loader.get_template(con_template)
    con_context.update(base_context)

    headers = {}
    if IS_EMAIL_CONFIGURED:
        if reply_to is not None:
            headers['Reply-to'] = reply_to

    msg = EmailMessage(subject, t.render(Context(con_context)), from_email,
                       to_email, headers=headers)
    msg.content_subtype = "html"
    msg.send()

def gen_dir_share_link(token):
    """Generate directory share link.
    """
    return gen_shared_link(token, 'd')

def gen_file_share_link(token):
    """Generate file share link.
    """
    return gen_shared_link(token, 'f')

def gen_shared_link(token, s_type):
    service_url = get_service_url()
    assert service_url is not None

    service_url = service_url.rstrip('/')
    if s_type == 'f':
        return '%s/f/%s/' % (service_url, token)
    else:
        return '%s/d/%s/' % (service_url, token)

def gen_shared_upload_link(token):
    service_url = get_service_url()
    assert service_url is not None

    service_url = service_url.rstrip('/')
    return '%s/u/d/%s/' % (service_url, token)

def show_delete_days(request):
    if request.method == 'GET':
        days_str = request.GET.get('days', '')
    elif request.method == 'POST':
        days_str = request.POST.get('days', '')
    else:
        days_str = ''

    try:
        days = int(days_str)
    except ValueError:
        days = 7

    return days

def is_textual_file(file_type):
    """
    Check whether a file type is a textual file.
    """
    if file_type == TEXT or file_type == MARKDOWN:
        return True
    else:
        return False

def redirect_to_login(request):
    from django.conf import settings
    login_url = settings.LOGIN_URL
    path = urlquote(request.get_full_path())
    tup = login_url, redirect_field_name, path
    return HttpResponseRedirect('%s?%s=%s' % tup)

def mkstemp():
    '''Returns (fd, filepath), the same as tempfile.mkstemp, except the
    filepath is encoded in UTF-8

    '''
    fd, path = tempfile.mkstemp()
    system_encoding = locale.getdefaultlocale()[1]
    if system_encoding is not None:
        path_utf8 = path.decode(system_encoding).encode('UTF-8')
        return fd, path_utf8
    else:
        return fd, path

# File or directory operations
FILE_OP = ('Added or modified', 'Added', 'Modified', 'Renamed', 'Moved',
           'Added directory', 'Renamed directory', 'Moved directory')

OPS = '|'.join(FILE_OP)
CMMT_DESC_PATT = re.compile(r'(%s) "(.*)"\s?(and \d+ more (?:files|directories))?' % OPS)

API_OPS = '|'.join((OPS, 'Deleted', 'Removed'))
API_CMMT_DESC_PATT = r'(%s) "(.*)"\s?(and \d+ more (?:files|directories))?' % API_OPS


def convert_cmmt_desc_link(commit):
    """Wrap file/folder with ``<a></a>`` in commit description.
    """
    repo_id = commit.repo_id
    cmmt_id = commit.id
    conv_link_url = reverse('convert_cmmt_desc_link')

    def link_repl(matchobj):
        op = matchobj.group(1)
        file_or_dir = matchobj.group(2)
        remaining = matchobj.group(3)

        tmp_str = '%s "<a href="%s?repo_id=%s&cmmt_id=%s&nm=%s" class="normal">%s</a>"'
        if remaining:
            return (tmp_str + ' %s') % (op, conv_link_url, repo_id, cmmt_id, urlquote(file_or_dir),
                                        escape(file_or_dir), remaining)
        else:
            return tmp_str % (op, conv_link_url, repo_id, cmmt_id, urlquote(file_or_dir), escape(file_or_dir))

    return re.sub(CMMT_DESC_PATT, link_repl, commit.desc)

def api_tsstr_sec(value):
    """Turn a timestamp to string"""
    try:
        return datetime.fromtimestamp(value).strftime("%Y-%m-%d %H:%M:%S")
    except:
        return datetime.fromtimestamp(value/1000000).strftime("%Y-%m-%d %H:%M:%S")


def api_convert_desc_link(e):
    """Wrap file/folder with ``<a></a>`` in commit description.
    """
    commit = e.commit
    repo_id = commit.repo_id
    cmmt_id = commit.id

    def link_repl(matchobj):
        op = matchobj.group(1)
        file_or_dir = matchobj.group(2)
        remaining = matchobj.group(3)

        tmp_str = '%s "<span class="file-name">%s</span>"'
        if remaining:
            url = reverse('api_repo_history_changes', args=[repo_id])
            e.link = "%s?commit_id=%s" % (url, cmmt_id)
            e.dtime = api_tsstr_sec(commit.props.ctime)
            return (tmp_str + ' %s') % (op, file_or_dir, remaining)
        else:
            diff_result = seafile_api.diff_commits(repo_id, '', cmmt_id)
            if diff_result:
                for d in diff_result:
                    if file_or_dir not in d.name:
                        # skip to next diff_result if file/folder user clicked does not
                        # match the diff_result
                        continue

                    if d.status == 'add' or d.status == 'mod':
                        e.link = "api://repo/%s/files/?p=/%s" % (repo_id, d.name)
                    elif d.status == 'mov':
                        e.link = "api://repo/%s/files/?p=/%s" % (repo_id, d.new_name)
                    elif d.status == 'newdir':
                        e.link = "api://repo/%s/dir/?p=/%s" % (repo_id, d.name)
                    else:
                        continue
            return tmp_str % (op, file_or_dir)
    e.desc = re.sub(API_CMMT_DESC_PATT, link_repl, commit.desc)

MORE_PATT = r'and \d+ more (?:files|directories)'
def more_files_in_commit(commit):
    """Check whether added/deleted/modified more files in commit description.
    """
    return True if re.search(MORE_PATT, commit.desc) else False

# file audit related
FILE_AUDIT_ENABLED = False
if EVENTS_CONFIG_FILE:
    def check_file_audit_enabled():
        enabled = seafevents.is_audit_enabled(parsed_events_conf)

        if enabled:
            logging.debug('file audit: enabled')
        else:
            logging.debug('file audit: not enabled')
        return enabled

    FILE_AUDIT_ENABLED = check_file_audit_enabled()

# office convert related
HAS_OFFICE_CONVERTER = False
if EVENTS_CONFIG_FILE:
    def check_office_converter_enabled():
        enabled = seafevents.is_office_converter_enabled(parsed_events_conf)

        if enabled:
            logging.debug('office converter: enabled')
        else:
            logging.debug('office converter: not enabled')
        return enabled

    def get_office_converter_html_dir():
        return seafevents.get_office_converter_html_dir(parsed_events_conf)

    def get_office_converter_limit():
        return seafevents.get_office_converter_limit(parsed_events_conf)

    HAS_OFFICE_CONVERTER = check_office_converter_enabled()

if HAS_OFFICE_CONVERTER:

    OFFICE_HTML_DIR = get_office_converter_html_dir()
    OFFICE_PREVIEW_MAX_SIZE, OFFICE_PREVIEW_MAX_PAGES = get_office_converter_limit()

    all_doc_types = PREVIEW_FILEEXT[DOCUMENT] + PREVIEW_FILEEXT[OPENDOCUMENT]
    PREVIEW_FILEEXT[DOCUMENT] = all_doc_types
    PREVIEW_FILEEXT.pop(OPENDOCUMENT)

    FILEEXT_TYPE_MAP = gen_fileext_type_map()

    from seafevents.office_converter import OfficeConverterRpcClient
    office_converter_rpc = None

    def _get_office_converter_rpc():
        global office_converter_rpc
        if office_converter_rpc is None:
            pool = ccnet.ClientPool(
                seaserv.CCNET_CONF_PATH,
                central_config_dir=seaserv.SEAFILE_CENTRAL_CONF_DIR
            )
            office_converter_rpc = OfficeConverterRpcClient(pool)

        return office_converter_rpc

    def office_convert_cluster_token(file_id):
        from django.core import signing
        s = '-'.join([file_id, datetime.now().strftime('%Y%m%d')])
        return signing.Signer().sign(s)

    def _office_convert_token_header(file_id):
        return {
            'X-Seafile-Office-Preview-Token': office_convert_cluster_token(file_id),
        }

    def cluster_delegate(delegate_func):
        '''usage:

        @cluster_delegate(funcA)
        def func(*args):
            ...non-cluster logic goes here...

        - In non-cluster mode, this decorator effectively does nothing.
        - In cluster mode, if this node is not the office convert node,
        funcA is called instead of the decorated function itself

        '''
        def decorated(func):
            def real_func(*args, **kwargs):
                cluster_internal = kwargs.pop('cluster_internal', False)
                if CLUSTER_MODE and not OFFICE_CONVERTOR_NODE and not cluster_internal:
                    return delegate_func(*args)
                else:
                    return func(*args)
            return real_func

        return decorated

    def delegate_add_office_convert_task(file_id, doctype, raw_path):
        url = urljoin(OFFICE_CONVERTOR_ROOT, '/office-convert/internal/add-task/')
        data = urllib.urlencode({
            'file_id': file_id,
            'doctype': doctype,
            'raw_path': raw_path,
        })

        headers = _office_convert_token_header(file_id)
        ret = do_urlopen(url, data=data, headers=headers).read()

        return json.loads(ret)

    def delegate_query_office_convert_status(file_id, page):
        url = urljoin(OFFICE_CONVERTOR_ROOT, '/office-convert/internal/status/')
        url += '?file_id=%s&page=%s' % (file_id, page)
        headers = _office_convert_token_header(file_id)
        ret = do_urlopen(url, headers=headers).read()

        return json.loads(ret)

    def delegate_get_office_converted_page(request, repo_id, commit_id, path, static_filename, file_id):
        url = urljoin(OFFICE_CONVERTOR_ROOT,
                      '/office-convert/internal/static/%s/%s%s/%s' % (
                          repo_id, commit_id, urlquote(path), urlquote(static_filename)))
        url += '?file_id=' + file_id
        headers = _office_convert_token_header(file_id)
        timestamp = request.META.get('HTTP_IF_MODIFIED_SINCE')
        if timestamp:
            headers['If-Modified-Since'] = timestamp

        try:
            ret = do_urlopen(url, headers=headers)
            data = ret.read()
        except urllib2.HTTPError, e:
            if timestamp and e.code == 304:
                return HttpResponseNotModified()
            else:
                raise

        content_type = ret.headers.get('content-type', None)
        if content_type is None:
            dummy, ext = os.path.splitext(os.path.basename(path))
            content_type = mimetypes.types_map.get(ext, 'application/octet-stream')

        resp = HttpResponse(data, content_type=content_type)
        if 'last-modified' in ret.headers:
            resp['Last-Modified'] = ret.headers.get('last-modified')

        return resp

    @cluster_delegate(delegate_add_office_convert_task)
    def add_office_convert_task(file_id, doctype, raw_path):
        rpc = _get_office_converter_rpc()
        d = rpc.add_task(file_id, doctype, raw_path)
        return {
            'exists': False,
        }

    @cluster_delegate(delegate_query_office_convert_status)
    def query_office_convert_status(file_id, page):
        rpc = _get_office_converter_rpc()
        d = rpc.query_convert_status(file_id, page)
        ret = {}
        if d.error:
            ret['error'] = d.error
            ret['status'] = 'ERROR'
        else:
            ret['success'] = True
            ret['status'] = d.status
            ret['info'] = d.info
        return ret

    @cluster_delegate(delegate_get_office_converted_page)
    def get_office_converted_page(request, repo_id, commit_id, path, static_filename, file_id):
        return django_static_serve(request,
                                   os.path.join(file_id, static_filename),
                                   document_root=OFFICE_HTML_DIR)

    def prepare_converted_html(raw_path, obj_id, doctype, ret_dict):
        try:
            add_office_convert_task(obj_id, doctype, raw_path)
        except:
            logging.exception('failed to add_office_convert_task:')
            return _(u'Internal error')
        return None

# search realted
HAS_FILE_SEARCH = False
if EVENTS_CONFIG_FILE:
    def check_search_enabled():
        enabled = False
        if hasattr(seafevents, 'is_search_enabled'):
            enabled = seafevents.is_search_enabled(parsed_events_conf)

            if enabled:
                logging.debug('search: enabled')
            else:
                logging.debug('search: not enabled')
        return enabled

    HAS_FILE_SEARCH = check_search_enabled()

TRAFFIC_STATS_ENABLED = False
if EVENTS_CONFIG_FILE and hasattr(seafevents, 'get_user_traffic_stat'):
    TRAFFIC_STATS_ENABLED = True
    def get_user_traffic_stat(username):
        session = SeafEventsSession()
        try:
            stat = seafevents.get_user_traffic_stat(session, username)
        finally:
            session.close()
        return stat

    def get_user_traffic_list(month, start=0, limit=25):
        session = SeafEventsSession()
        try:
            stat = seafevents.get_user_traffic_list(session, month, start, limit)
        finally:
            session.close()
        return stat

else:
    def get_user_traffic_stat(username):
        pass
    def get_user_traffic_list():
        pass

def user_traffic_over_limit(username):
    """Return ``True`` if user traffic over the limit, otherwise ``False``.
    """
    if not CHECK_SHARE_LINK_TRAFFIC:
        return False

    from seahub_extra.plan.models import UserPlan
    from seahub_extra.plan.settings import PLAN
    up = UserPlan.objects.get_valid_plan_by_user(username)
    plan = 'Free' if up is None else up.plan_type
    traffic_limit = int(PLAN[plan]['share_link_traffic']) * 1024 * 1024 * 1024

    try:
        stat = get_user_traffic_stat(username)
    except Exception as e:
        logger = logging.getLogger(__name__)
        logger.error('Failed to get user traffic stat: %s' % username,
                     exc_info=True)
        return True

    if stat is None:            # No traffic record yet
        return False

    month_traffic = stat['file_view'] + stat['file_download'] + stat['dir_download']
    return True if month_traffic >= traffic_limit else False

def is_user_password_strong(password):
    """Return ``True`` if user's password is STRONG, otherwise ``False``.
       STRONG means password has at least USER_PASSWORD_STRENGTH_LEVEL(3) types of the bellow:
       num, upper letter, lower letter, other symbols
    """

    if len(password) < config.USER_PASSWORD_MIN_LENGTH:
        return False
    else:
        num = 0
        for letter in password:
            # get ascii dec
            # bitwise OR
            num |= get_char_mode(ord(letter))

        if calculate_bitwise(num) < config.USER_PASSWORD_STRENGTH_LEVEL:
            return False
        else:
            return True

def get_char_mode(n):
    """Return different num according to the type of given letter:
       '1': num,
       '2': upper_letter,
       '4': lower_letter,
       '8': other symbols
    """
    if (n >= 48 and n <= 57): #nums
        return 1;
    if (n >= 65 and n <= 90): #uppers
        return 2;
    if (n >= 97 and n <= 122): #lowers
        return 4;
    else:
        return 8;

def calculate_bitwise(num):
    """Return different level according to the given num:
    """
    level = 0
    for i in range(4):
        # bitwise AND
        if (num&1):
            level += 1
        # Right logical shift
        num = num >> 1
    return level

def do_md5(s):
    if isinstance(s, unicode):
        s = s.encode('UTF-8')
    return hashlib.md5(s).hexdigest()

def do_urlopen(url, data=None, headers=None):
    headers = headers or {}
    req = urllib2.Request(url, data=data, headers=headers)
    ret = urllib2.urlopen(req)
    return ret

def is_pro_version():
    if seahub.settings.DEBUG:
        if hasattr(seahub.settings, 'IS_PRO_VERSION') \
            and seahub.settings.IS_PRO_VERSION:
            return True
    if EVENTS_CONFIG_FILE:
        return True
    else:
        return False

def clear_token(username):
    '''
    clear web api and repo sync token
    when delete/inactive an user
    '''
    Token.objects.filter(user = username).delete()
    TokenV2.objects.filter(user = username).delete()
    seafile_api.delete_repo_tokens_by_email(username)

def send_perm_audit_msg(etype, from_user, to, repo_id, path, perm):
    """Send repo permission audit msg.

    Arguments:
    - `etype`: add/modify/delete-repo-perm
    - `from_user`: email
    - `to`: email or group_id or all(public)
    - `repo_id`: origin repo id
    - `path`: dir path
    - `perm`: r or rw
    """
    msg = 'perm-update\t%s\t%s\t%s\t%s\t%s\t%s' % \
        (etype, from_user, to, repo_id, path, perm)
    msg_utf8 = msg.encode('utf-8')

    try:
        seaserv.send_message('seahub.stats', msg_utf8)
    except Exception as e:
        logger.error("Error when sending perm-audit-%s message: %s" %
                     (etype, str(e)))

def get_origin_repo_info(repo_id):
    repo = seafile_api.get_repo(repo_id)
    if repo.origin_repo_id is not None:
        origin_repo_id = repo.origin_repo_id
        origin_path = repo.origin_path
        return (origin_repo_id, origin_path)

    return (None, None)

def within_time_range(d1, d2, maxdiff_seconds):
    '''Return true if two datetime.datetime object differs less than the given seconds'''
    delta = d2 - d1 if d2 > d1 else d1 - d2
    # delta.total_seconds() is only available in python 2.7+
    diff = (delta.microseconds + (delta.seconds + delta.days*24*3600) * 1e6) / 1e6
    return diff < maxdiff_seconds

def is_org_repo_creation_allowed(request):
    """Whether or not allow a user create  organization library.
    """
    if request.user.is_staff:
        return True
    else:
        return config.ENABLE_USER_CREATE_ORG_REPO

def get_system_admins():
    db_users = seaserv.get_emailusers('DB', -1, -1)
    ldpa_imported_users = seaserv.get_emailusers('LDAPImport', -1, -1)

    admins = []
    for user in db_users + ldpa_imported_users:
        if user.is_staff:
            admins.append(user)

    return admins

def is_windows_operating_system(request):
    if not request.META.has_key('HTTP_USER_AGENT'):
        return False

    if 'windows' in request.META['HTTP_USER_AGENT'].lower():
        return True
    else:
        return False
