# -*- coding: utf-8 -*-

import ldap, getpass, pathlib, copy
from ldap.schema.models import ObjectClass
from enum import Flag, auto
import networkx as nx
from typing import Any, Self
from collections.abc import Callable

from .Config import Config as BaseConfig
from .log import *

class Config:
    def __init__(self, external: BaseConfig|None=None):
        self.__external = external
        for attr in ['ldap_uri', 'bind_dn', 'bind_pw', 'base_dn']:
            setattr(self, '_Config__' + attr, None)

    def __get(self, key: str, default: str):
        if not self.__external:
            return default
        return self.__external.value(key, default=default)

    @property
    def ldap_uri(self):
        if self.__ldap_uri is None:
            self.__ldap_uri = self.__get('ldap_uri', default='ldap://ldap.janware.com')
        return self.__ldap_uri
    @ldap_uri.setter
    def ldap_uri(self, rhs):
        self.__ldap_uri = rhs

    @property
    def bind_dn(self):
        if self.__bind_dn is None:
            self.__bind_dn = self.__get('bind_dn', default=f'uid={getpass.getuser()},ou=users,dc=jannet,dc=de')
        return self.__bind_dn
    @bind_dn.setter
    def bind_dn(self, rhs):
        self.__bind_dn = rhs

    @property
    def bind_pw(self):
        if self.__bind_pw is None:
            for key in ['bind_pw', 'password']:
                ret = self.__get(key, default=None)
                if ret is not None:
                    break
            if ret is None:
                ldap_secret_file = self.__get('secret_file', f'{pathlib.Path.home()}/.ldap.secret')
                with open(ldap_secret_file, 'r') as file:
                    ret = file.read()
                file.closed
            ret = ret.strip()
            self.__bind_pw = ret
        return self.__bind_pw
    @bind_pw.setter
    def bind_pw(self, rhs):
        self.__bind_pw = rhs

    @property
    def base_dn(self):
        if self.__base_dn is None:
            self.__base_dn = self.__get('base_dn', default=f'dc=jannet,dc=de')
        return self.__base_dn
    @base_dn.setter
    def base_dn(self, rhs):
        self.__base_dn = rhs

class Connection: # export

    class AttrType(Flag):
        Must = auto()
        May  = auto()

    def __init__(self, conf: Config|BaseConfig|None=None, backtrace=False):
        c = conf if isinstance(conf, Config) else Config(conf)
        ret = ldap.initialize(c.ldap_uri)
        ret.start_tls_s()
        try:
            rr = ret.bind_s(c.bind_dn, c.bind_pw) # method)
        except Exception as e:
            raise Exception(f'Failed to bind to {c.ldap_uri} with dn {c.bind_dn} ({e})')
        self.__ldap = ret
        self.__backtrace = backtrace
        self.__object_classes_by_oid: dict[str, ObjectClass]|None = None
        self.__object_class_tree: nx.Graph|None = None
        self.__object_classes_by_name: dict[str, ObjectClass]|None = None

    @property
    def ldap(self):
        return self.__ldap

    def add(self, attrs: dict[str, bytes], dn: str|None=None):
        if dn is None:
            if not 'dn' in attrs:
                raise Exception('No DN to add an LDAP entry to')
            attrs = copy.deepcopy(attrs)
            del attrs['dn']
        try:
            slog(INFO, f'LDAP: Add [{dn}] -> {attrs}')
            self.__ldap.add_s(dn, ldap.modlist.addModlist(attrs))
        except Exception as e:
            slog(ERR, f'{dn}: Failed to add entry {attrs} ({e})')
            raise

    def delete(self, dn: str, recursive=False, force_existence: bool=False):

        def __walk_cb_delete(conn: Connection, entry, context):
            self.walk(__walk_cb_delete, base=entry[0], scope=ldap.SCOPE_ONELEVEL, context=context)
            self.__ldap.delete_s(entry[0])

        try:
            if recursive:
                self.walk(__walk_cb_delete, dn, scope=ldap.SCOPE_ONELEVEL)
                self.__ldap.delete_s(dn)
            else:
                self.__ldap.delete_s(dn)
        except ldap.NO_SUCH_OBJECT as e:
            if force_existence:
                raise
        except Exception as e:
            slog(ERR, f'Failed to delete {dn} ({e})')
            raise

    def walk(self,
            callback: Callable[[Self, Any, Any], None],
            base: str,
            scope,
            context=None,
            filterstr=None,
            attrlist=None,
            attrsonly=0,
            serverctrls=None,
            clientctrls=None,
            timeout=-1,
            sizelimit=0):

        # TODO: Support ignored arguments
        search_return = self.__ldap.search(base=base,
                                           scope=scope,
                                           filterstr=filterstr,
                                           attrlist=attrlist,
                                           attrsonly=attrsonly)
        while True:
            result_type, result_data = self.__ldap.result(search_return, 0)
            if (result_data == []):
                break
            if result_type != ldap.RES_SEARCH_ENTRY:
                continue
            for entry in result_data:
                try:
                    callback(self, entry, context)
                except Exception as e:
                    msg = f'Exception {e}'
                    if self.__backtrace:
                        slog(ERR, msg)
                        raise
                    slog(WARNING, msg)
                    continue

    def find(self,
            base: str,
            scope,
            filterstr=None,
            attrlist=None,
            attrsonly=0,
            serverctrls=None,
            clientctrls=None,
            timeout=-1,
            sizelimit=0,
            assert_unique=False,
            assert_not_empty=False,
           ):

        def __walk_cb_find(conn: Connection, entry: Any, context: Any):
            result.append(entry)

        def __search():
            return f'{base} -> "{filterstr}"'

        try:
            result: list[Any] = []
            self.walk(__walk_cb_find, base, scope=scope, filterstr=filterstr, attrlist=attrlist)
        except Exception as e:
            slog(ERR, f'Failed search {__search()} ({e})')
            raise
        if assert_not_empty and not result:
            raise Exception(f'Empty result for search {__search()}')
        if assert_unique and len(result) > 1:
            raise Exception(f'Found {len(result)} results for search {__search()}')
        return result

    @property
    def object_classes(self) -> dict[str, ObjectClass]:
    #def object_classes(self):
        if self.__object_classes_by_oid is None:
            res = self.find(base='', scope=ldap.SCOPE_BASE, filterstr='(objectClass=*)', attrlist=['subschemaSubentry'])
            dn = res[0][1]['subschemaSubentry'][0].decode('utf-8') # Usually yields cn=Subschema
            res = self.find(base=dn, scope=ldap.SCOPE_BASE, filterstr='(objectClass=*)', attrlist=['*', '+'])
            subschema_entry = res[0]
            subschema_subentry = ldap.cidict.cidict(subschema_entry[1])
            subschema = ldap.schema.SubSchema(subschema_subentry)
            object_class_oids = subschema.listall(ObjectClass)
            self.__object_classes_by_oid = {
                oid: subschema.get_obj(ObjectClass, oid) for oid in object_class_oids
            }
        return self.__object_classes_by_oid

    @property
    def object_class_by_name(self) -> dict[str, ObjectClass]:
        if self.__object_classes_by_name is None:
            ret: dict[str, ObjectClass] = {}
            self.__object_classes_by_name = ret
            for oid, oc in self.object_classes.items():
                ret[oid] = oc
                for name in oc.names:
                    ret[name] = oc
                    ret[name.lower()] = oc
        return self.__object_classes_by_name

    def __oc_recurse_to_top(self, cur: str|ObjectClass, cb, context):
        cur_oc = cur if isinstance(cur, ObjectClass) else self.object_class_by_name[cur.lower()]
        for s in cur_oc.sup:
            self.__oc_recurse_to_top(s, cb, context)
        cb(cur_oc, context)

    def object_class_path(self, leaf: str|ObjectClass):
        def cb(oc, context):
            ret.append(oc)
        ret: list[str] = []
        self.__oc_recurse_to_top(leaf, cb, None)
        return reversed(ret)

    @property
    def object_class_tree(self) -> nx.Graph:

        if self.__object_class_tree is None:

            def collect(root, attr):
                ret = set()
                def cb(oc, attr):
                    vals = getattr(oc, attr)
                    if vals is None:
                        return
                    for val in vals:
                        ret.add(val)
                self.__oc_recurse_to_top(root, cb, attr)
                return ret

            kind = {
                0: 'STRUCTURAL',
                1: 'ABSTRACT',
                2: 'AUXILIARY'
            }
            ret = nx.DiGraph()
            for oid, oc in self.object_classes.items():
                ret.add_node(
                        oid,
                        oid=oid,
                        name=oc.names[0],
                        kind=kind[oc.kind],
                        must=', '.join(collect(oc, 'must')),
                        may=', '.join(collect(oc, 'may'))
                    )
                for base_class in oc.sup:
                    try:
                        ret.add_edge(oid, self.object_class_by_name[base_class.lower()].oid)
                    except Exception as e:
                        slog(WARNING, f'Failed to add edge {oid}:{oc.names} -> {base_class} ({e})')
            self.__object_class_tree = ret
        return self.__object_class_tree

    def object_class_attrs(self, oc: str|ObjectClass, required: AttrType = AttrType.Must, origins: bool=False) -> dict[str, set[str]]|set[str]:
        all_attrs: set[str] = set()
        attrs_by_origin: dict[str, set[str]] = {}
        for oc in self.object_class_path(oc):
            cur = set()
            if required & self.AttrType.Must:
                cur |= set(oc.must)
            if required & self.AttrType.May:
                cur |= set(oc.may)
            if cur:
                all_attrs |= cur
                attrs_by_origin[oc] = cur
        return attrs_by_origin if origins else all_attrs

    def is_derived_class(self, name, base_candidate):
        #oid = self.object_class_by_name[name].oid
        #base_oid = self.object_class_by_name[base_candidate].oid
        #if base_oid in [oc.oid for oc in self.object_class_path(name)]:
        #    return True
        return nx.has_path(self.object_class_tree, self.object_class_by_name[name.lower()].oid, self.object_class_by_name[base_candidate.lower()].oid)

def default_config() -> Config: # export
    return Config()

def bind(conf: Config|BaseConfig|None=None) -> Connection:
    return Connection(conf)