# Authors: Rob Crittenden <rcritten@redhat.com>
#
# Copyright (C) 2007  Red Hat
# see file 'COPYING' for use and warranty information
#
# 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/>.
#

import ldap
from ipalib.request import context
from ipaserver import ipaldap
from ipalib import errors
from ipalib import api

def convert_entry(ent):
    entry = dict(ent.data)
    entry['dn'] = ent.dn
    # For now convert single entry lists to a string for the ui.
    # TODO: we need to deal with multi-values better
    for key,value in entry.iteritems():
        if isinstance(value,list) or isinstance(value,tuple):
            if len(value) == 0:
                entry[key] = ''
            elif len(value) == 1:
                entry[key] = value[0]
    return entry

def convert_scalar_values(orig_dict):
    """LDAP update dicts expect all values to be a list (except for dn).
       This method converts single entries to a list."""
    new_dict={}
    for (k,v) in orig_dict.iteritems():
        if not isinstance(v, list) and k != 'dn':
            v = [v]
        new_dict[k] = v

    return new_dict

def generate_match_filters(search_fields, criteria_words):
    """Generates a search filter based on a list of words and a list
       of fields to search against.

       Returns a tuple of two filters: (exact_match, partial_match)"""

    # construct search pattern for a single word
    # (|(f1=word)(f2=word)...)
    search_pattern = "(|"
    for field in search_fields:
        search_pattern += "(" + field + "=%(match)s)"
    search_pattern += ")"
    gen_search_pattern = lambda word: search_pattern % {'match':word}

    # construct the giant match for all words
    exact_match_filter = "(&"
    partial_match_filter = "(|"
    for word in criteria_words:
        exact_match_filter += gen_search_pattern(word)
        partial_match_filter += gen_search_pattern("*%s*" % word)
    exact_match_filter += ")"
    partial_match_filter += ")"

    return (exact_match_filter, partial_match_filter)

# TODO: rethink the get_entry vs get_list API calls.
#       they currently restrict the data coming back without
#       restricting scope.  For now adding a get_base/sub_entry()
#       calls, but the API isn't great.
def get_entry (base, scope, searchfilter, sattrs=None):
    """Get a specific entry (with a parametized scope).
       Return as a dict of values.
       Multi-valued fields are represented as lists.
    """
    ent=""

    ent = context.ldap.conn.getEntry(base, scope, searchfilter, sattrs)

    return convert_entry(ent)

def get_base_entry (base, searchfilter, sattrs=None):
    """Get a specific entry (with a scope of BASE).
       Return as a dict of values.
       Multi-valued fields are represented as lists.
    """
    return get_entry(base, ldap.SCOPE_BASE, searchfilter, sattrs)

def get_sub_entry (base, searchfilter, sattrs=None):
    """Get a specific entry (with a scope of SUB).
       Return as a dict of values.
       Multi-valued fields are represented as lists.
    """
    return get_entry(base, ldap.SCOPE_SUBTREE, searchfilter, sattrs)

def get_one_entry (base, searchfilter, sattrs=None):
    """Get the children of an entry (with a scope of ONE).
       Return as a list of dict of values.
       Multi-valued fields are represented as lists.
    """
    return get_list(base, searchfilter, sattrs, ldap.SCOPE_ONELEVEL)

def get_list (base, searchfilter, sattrs=None, scope=ldap.SCOPE_SUBTREE):
    """Gets a list of entries. Each is converted to a dict of values.
       Multi-valued fields are represented as lists.
    """
    entries = []

    entries = context.ldap.conn.getList(base, scope, searchfilter, sattrs)

    return map(convert_entry, entries)

def has_nsaccountlock(dn):
    """Check to see if an entry has the nsaccountlock attribute.
       This attribute is provided by the Class of Service plugin so
       doing a search isn't enough. It is provided by the two
       entries cn=inactivated and cn=activated. So if the entry has
       the attribute and isn't in either cn=activated or cn=inactivated
       then the attribute must be in the entry itself.

       Returns True or False
    """
    # First get the entry. If it doesn't have nsaccountlock at all we
    # can exit early.
    entry = get_entry_by_dn(dn, ['dn', 'nsaccountlock', 'memberof'])
    if not entry.get('nsaccountlock'):
        return False

    # Now look to see if they are in activated or inactivated
    # entry is a member
    memberof = entry.get('memberof')
    if isinstance(memberof, basestring):
        memberof = [memberof]
    for m in memberof:
        inactivated = m.find("cn=inactivated")
        activated = m.find("cn=activated")
        # if they are in either group that means that the nsaccountlock
        # value comes from there, otherwise it must be in this entry.
        if inactivated >= 0 or activated >= 0:
            return False

    return True

# General searches

def get_entry_by_dn (dn, sattrs=None):
    """Get a specific entry. Return as a dict of values.
       Multi-valued fields are represented as lists.
    """
    searchfilter = "(objectClass=*)"
    api.log.info("IPA: get_entry_by_dn '%s'" % dn)
    return get_base_entry(dn, searchfilter, sattrs)

def get_entry_by_cn (cn, sattrs):
    """Get a specific entry by cn. Return as a dict of values.
       Multi-valued fields are represented as lists.
    """
    api.log.info("IPA: get_entry_by_cn '%s'" % cn)
#    cn = self.__safe_filter(cn)
    searchfilter = "(cn=%s)" % cn
    return get_sub_entry("cn=accounts," + api.env.basedn, searchfilter, sattrs)

def get_user_by_uid(uid, sattrs):
    """Get a specific user's entry."""
    # FIXME: should accept a container to look in
#    uid = self.__safe_filter(uid)
    searchfilter = "(&(uid=%s)(objectclass=posixAccount))" % uid

    return get_sub_entry("cn=accounts," + api.env.basedn, searchfilter, sattrs)

# User support

def entry_exists(dn):
    """Return True if the entry exists, False otherwise."""
    try:
        get_base_entry(dn, "objectclass=*", ['dn','objectclass'])
        return True
    except errors.NotFound:
        return False

def get_user_by_uid (uid, sattrs):
    """Get a specific user's entry. Return as a dict of values.
       Multi-valued fields are represented as lists.
    """

    if not isinstance(uid,basestring) or len(uid) == 0:
        raise SyntaxError("uid is not a string")
#        raise ipaerror.gen_exception(ipaerror.INPUT_INVALID_PARAMETER)
    if sattrs is not None and not isinstance(sattrs,list):
        raise SyntaxError("sattrs is not a list")
#        raise ipaerror.gen_exception(ipaerror.INPUT_INVALID_PARAMETER)
    api.log.info("IPA: get_user_by_uid '%s'" % uid)
#    uid = self.__safe_filter(uid)
    searchfilter = "(uid=" + uid + ")"
    return get_sub_entry("cn=accounts," + api.env.basedn, searchfilter, sattrs)

def uid_too_long(uid):
    """Verify that the new uid is within the limits we set. This is a
       very narrow test.

       Returns True if it is longer than allowed
               False otherwise
    """
    if not isinstance(uid,basestring) or len(uid) == 0:
        # It is bad, but not too long
        return False
    api.log.debug("IPA: __uid_too_long(%s)" % uid)
    try:
        config = get_ipa_config()
        maxlen = int(config.get('ipamaxusernamelength', 0))
        if maxlen > 0 and len(uid) > maxlen:
            return True
    except Exception, e:
        api.log.debug("There was a problem " + str(e))
        pass

    return False

def update_entry (entry, remove_keys=[]):
    """Update an LDAP entry

       entry is a dict
       remove_keys is a list of attributes to remove from this entry

       This refreshes the record from LDAP in order to obtain the list of
       attributes that has changed. It only retrieves the attributes that
       are in the update so attributes aren't inadvertantly lost.
    """
    assert type(remove_keys) is list
    attrs = entry.keys()
    o = get_base_entry(entry['dn'], "objectclass=*", attrs + remove_keys)
    oldentry = convert_scalar_values(o)
    newentry = convert_scalar_values(entry)

    # Should be able to get this from either the old or new entry
    # but just in case someone has decided to try changing it, use the
    # original
    try:
        moddn = oldentry['dn']
    except KeyError, e:
        # FIXME: return a missing DN error message
        raise e

    return context.ldap.conn.updateEntry(moddn, oldentry, newentry)

def add_entry(entry):
    """Add a new entry"""
    return context.ldap.conn.addEntry(entry)

def delete_entry(dn):
    """Remove an entry"""
    return context.ldap.conn.deleteEntry(dn)

# FIXME, get time and search limit from cn=ipaconfig
def search(base, filter, attributes, timelimit=1, sizelimit=3000, scope=ldap.SCOPE_SUBTREE):
    """Perform an LDAP query"""
    try:
        timelimit = float(timelimit)
        results = context.ldap.conn.getListAsync(base, scope,
            filter, attributes, 0, None, None, timelimit, sizelimit)
    except ldap.NO_SUCH_OBJECT:
        raise errors.NotFound(reason=filter)

    counter = results[0]
    entries = [counter]
    for r in results[1:]:
        entries.append(convert_entry(r))

    return entries

def uniq_list(x):
    """Return a unique list, preserving order and ignoring case"""
    myset = {}
    return [myset.setdefault(e.lower(),e) for e in x if e.lower() not in myset]

def get_schema():
    """Retrieves the current LDAP schema from the LDAP server."""

    schema_entry = get_base_entry("", "objectclass=*", ['dn','subschemasubentry'])
    schema_cn = schema_entry.get('subschemasubentry')
    schema = get_base_entry(schema_cn, "objectclass=*", ['*'])

    return schema

def get_objectclasses():
    """Returns a list of available objectclasses that the LDAP
       server supports. This parses out the syntax, attributes, etc
       and JUST returns a lower-case list of the names."""

    schema = get_schema()

    objectclasses = schema.get('objectclasses')

    # Convert this list into something more readable
    result = []
    for i in range(len(objectclasses)):
        oc = objectclasses[i].lower().split(" ")
        result.append(oc[3].replace("'",""))

    return result

def get_ipa_config():
    """Retrieve the IPA configuration"""
    searchfilter = "cn=ipaconfig"
    try:
        config = get_sub_entry("cn=etc," + api.env.basedn, searchfilter)
    except ldap.NO_SUCH_OBJECT:
        # FIXME
        raise errors.NotFound(reason="IPA configuration cannot be loaded")

    return config

def modify_password(dn, oldpass, newpass):
    return context.ldap.conn.modifyPassword(dn, oldpass, newpass)

def mark_entry_active (dn):
    """Mark an entry as active in LDAP."""

    # This can be tricky. The entry itself can be marked inactive
    # by being in the inactivated group. It can also be inactivated by
    # being the member of an inactive group.
    #
    # First we try to remove the entry from the inactivated group. Then
    # if it is still inactive we have to add it to the activated group
    # which will override the group membership.

    res = ""
    # First, check the entry status
    entry = get_entry_by_dn(dn, ['dn', 'nsAccountlock'])

    if entry.get('nsaccountlock', 'false').lower() == "false":
        api.log.debug("IPA: already active")
        raise errors.AlreadyActive()

    if has_nsaccountlock(dn):
        api.log.debug("IPA: appears to have the nsaccountlock attribute")
        raise errors.HasNSAccountLock()

    group = get_entry_by_cn("inactivated", None)
    try:
        remove_member_from_group(entry.get('dn'), group.get('dn'))
    except errors.NotGroupMember:
        # Perhaps the user is there as a result of group membership
        pass

    # Now they aren't a member of inactivated directly, what is the status
    # now?
    entry = get_entry_by_dn(dn, ['dn', 'nsAccountlock'])

    if entry.get('nsaccountlock', 'false').lower() == "false":
        # great, we're done
        api.log.debug("IPA: removing from inactivated did it.")
        return True

    # So still inactive, add them to activated
    group = get_entry_by_cn("activated", None)
    res = add_member_to_group(dn, group.get('dn'))
    api.log.debug("IPA: added to activated.")

    return res

def mark_entry_inactive (dn):
    """Mark an entry as inactive in LDAP."""

    entry = get_entry_by_dn(dn, ['dn', 'nsAccountlock', 'memberOf'])

    if entry.get('nsaccountlock', 'false').lower() == "true":
        api.log.debug("IPA: already marked as inactive")
        raise errors.AlreadyInactive()

    if has_nsaccountlock(dn):
        api.log.debug("IPA: appears to have the nsaccountlock attribute")
        raise errors.HasNSAccountLock()

    # First see if they are in the activated group as this will override
    # the our inactivation.
    group = get_entry_by_cn("activated", None)
    try:
        remove_member_from_group(dn, group.get('dn'))
    except errors.NotGroupMember:
        # this is fine, they may not be explicitly in this group
        pass

    # Now add them to inactivated
    group = get_entry_by_cn("inactivated", None)
    res = add_member_to_group(dn, group.get('dn'))

    return res

def add_member_to_group(member_dn, group_dn, memberattr='member'):
    """
    Add a member to an existing group.
    """
    api.log.info("IPA: add_member_to_group '%s' to '%s'" % (member_dn, group_dn))
    if member_dn.lower() == group_dn.lower():
        # You can't add a group to itself
        raise errors.RecursiveGroup()

    group = get_entry_by_dn(group_dn, None)
    if group is None:
        raise errors.NotFound(reason="cannot find group %s" % group_dn)

    # check to make sure member_dn exists
    member_entry = get_base_entry(member_dn, "(objectClass=*)", ['dn','objectclass'])
    if not member_entry:
        raise errors.NotFound(reason="cannot find member %s" % member_dn)

    # Add the new member to the group member attribute
    members = group.get(memberattr, [])
    if isinstance(members, basestring):
        members = [members]
    members.append(member_dn)
    group[memberattr] = members

    return update_entry(group)

def remove_member_from_group(member_dn, group_dn, memberattr='member'):
    """Remove a member_dn from an existing group."""

    group = get_entry_by_dn(group_dn, None)
    if group is None:
        raise errors.NotFound(reason="cannot find group %s" % group_dn)
    """
    if group.get('cn') == "admins":
        member = get_entry_by_dn(member_dn, ['dn','uid'])
        if member.get('uid') == "admin":
            raise ipaerror.gen_exception(ipaerror.INPUT_ADMIN_REQUIRED_IN_ADMINS)
    """
    api.log.info("IPA: remove_member_from_group '%s' from '%s'" % (member_dn, group_dn))

    members = group.get(memberattr, False)
    if not members:
        raise errors.NotGroupMember()

    if isinstance(members,basestring):
        members = [members]
    for i in range(len(members)):
        members[i] = ipaldap.IPAdmin.normalizeDN(members[i])
    try:
        members.remove(member_dn)
    except ValueError:
        raise errors.NotGroupMember()
    except Exception, e:
        raise e

    group[memberattr] = members

    return update_entry(group)