evennia/src/typeclasses/models.py

"""
This is the *abstract* django models for many of the database objects
in Evennia. A django abstract (obs, not the same as a Python metaclass!) is
a model which is not actually created in the database, but which only exists
for other models to inherit from, to avoid code duplication. Any model can
import and inherit from these classes.

Attributes are database objects stored on other objects. The implementing
class needs to supply a ForeignKey field attr_object pointing to the kind
of object being mapped. Attributes storing iterables actually store special
types of iterables named PackedList/PackedDict respectively. These make
sure to save changes to them to database - this is criticial in order to
allow for obj.db.mylist[2] = data. Also, all dbobjects are saved as
dbrefs but are also aggressively cached.

TypedObjects are objects 'decorated' with a typeclass - that is, the typeclass
(which is a normal Python class implementing some special tricks with its
get/set attribute methods, allows for the creation of all sorts of different
objects all with the same database object underneath. Usually attributes are
used to permanently store things not hard-coded as field on the database object.
The admin should usually not have to deal directly  with the database object
layer.

This module also contains the Managers for the respective models; inherit from
these to create custom managers.

"""

import sys
import re
import traceback
import weakref
from importlib import import_module

from django.db import models
from django.core.exceptions import ObjectDoesNotExist
from django.conf import settings
from django.utils.encoding import smart_str

from src.utils.idmapper.models import SharedMemoryModel
from src.server.caches import get_prop_cache, set_prop_cache
#from src.server.caches import set_attr_cache

#from src.server.caches import call_ndb_hooks
#from src.server.models import ServerConfig
from src.typeclasses import managers
from src.locks.lockhandler import LockHandler
#from src.utils import logger
from django.db.models.base import ModelBase
from src.utils.utils import (
    make_iter, is_iter, to_str, inherits_from, lazy_property)
from src.utils.dbserialize import to_pickle, from_pickle
from src.utils.picklefield import PickledObjectField

__all__ = ("Attribute", "TypeNick", "TypedObject")

TICKER_HANDLER = None

_PERMISSION_HIERARCHY = [p.lower() for p in settings.PERMISSION_HIERARCHY]
_TYPECLASS_AGGRESSIVE_CACHE = settings.TYPECLASS_AGGRESSIVE_CACHE

_GA = object.__getattribute__
_SA = object.__setattr__
_DA = object.__delattr__


#------------------------------------------------------------
#
#   Attributes
#
#------------------------------------------------------------

class Attribute(SharedMemoryModel):
    """
    Abstract django model.

    Attributes are things that are specific to different types of objects. For
    example, a drink container needs to store its fill level, whereas an exit
    needs to store its open/closed/locked/unlocked state. These are done via
    attributes, rather than making different classes for each object type and
    storing them directly. The added benefit is that we can add/remove
    attributes on the fly as we like.
    The Attribute class defines the following properties:
      key - primary identifier
      lock_storage - perm strings
      obj - which object the attribute is defined on
      date_created - when the attribute was created.
      value - the data stored in the attribute, in pickled form
              using wrappers to be able to store/retrieve models.
      strvalue - string-only data. This data is not pickled and is
                 thus faster to search for in the database.
      category - optional character string for grouping the Attribute

    """

    #
    # Attribute Database Model setup
    #
    # These database fields are all set using their corresponding properties,
    # named same as the field, but withtout the db_* prefix.
    db_key = models.CharField('key', max_length=255, db_index=True)
    db_value = PickledObjectField(
        'value', null=True,
        help_text="The data returned when the attribute is accessed. Must be "
                  "written as a Python literal if editing through the admin "
                  "interface. Attribute values which are not Python literals "
                  "cannot be edited through the admin interface.")
    db_strvalue = models.TextField(
        'strvalue', null=True, blank=True,
        help_text="String-specific storage for quick look-up")
    db_category = models.CharField(
        'category', max_length=128, db_index=True, blank=True, null=True,
        help_text="Optional categorization of attribute.")
    # Lock storage
    db_lock_storage = models.TextField(
        'locks', blank=True,
        help_text="Lockstrings for this object are stored here.")
    db_model = models.CharField(
        'model', max_length=32, db_index=True, blank=True, null=True,
        help_text="Which model of object this attribute is attached to (A "
                  "natural key like objects.dbobject). You should not change "
                  "this value unless you know what you are doing.")
    # subclass of Attribute (None or nick)
    db_attrtype = models.CharField(
        'attrtype', max_length=16, db_index=True, blank=True, null=True,
        help_text="Subclass of Attribute (None or nick)")
    # time stamp
    db_date_created = models.DateTimeField(
        'date_created', editable=False, auto_now_add=True)

    # Database manager
    #objects = managers.AttributeManager()

    @lazy_property
    def locks(self):
        return LockHandler(self)

    class Meta:
        "Define Django meta options"
        verbose_name = "Evennia Attribute"

    # read-only wrappers
    key = property(lambda self: self.db_key)
    strvalue = property(lambda self: self.db_strvalue)
    category = property(lambda self: self.db_category)
    model = property(lambda self: self.db_model)
    attrtype = property(lambda self: self.db_attrtype)
    date_created = property(lambda self: self.db_date_created)

    def __lock_storage_get(self):
        return self.db_lock_storage
    def __lock_storage_set(self, value):
        self.db_lock_storage = value
        self.save(update_fields=["db_lock_storage"])
    def __lock_storage_del(self):
        self.db_lock_storage = ""
        self.save(update_fields=["db_lock_storage"])
    lock_storage = property(__lock_storage_get, __lock_storage_set, __lock_storage_del)

    # Wrapper properties to easily set database fields. These are
    # @property decorators that allows to access these fields using
    # normal python operations (without having to remember to save()
    # etc). So e.g. a property 'attr' has a get/set/del decorator
    # defined that allows the user to do self.attr = value,
    # value = self.attr and del self.attr respectively (where self
    # is the object in question).

    # value property (wraps db_value)
    #@property
    def __value_get(self):
        """
        Getter. Allows for value = self.value.
        We cannot cache here since it makes certain cases (such
        as storing a dbobj which is then deleted elsewhere) out-of-sync.
        The overhead of unpickling seems hard to avoid.
        """
        return from_pickle(self.db_value, db_obj=self)

    #@value.setter
    def __value_set(self, new_value):
        """
        Setter. Allows for self.value = value. We cannot cache here,
        see self.__value_get.
        """
        self.db_value = to_pickle(new_value)
        self.save(update_fields=["db_value"])

    #@value.deleter
    def __value_del(self):
        "Deleter. Allows for del attr.value. This removes the entire attribute."
        self.delete()
    value = property(__value_get, __value_set, __value_del)

    #
    #
    # Attribute methods
    #
    #

    def __str__(self):
        return smart_str("%s(%s)" % (_GA(self, "db_key"), _GA(self, "id")))

    def __unicode__(self):
        return u"%s(%s)" % (_GA(self, "db_key"), _GA(self, "id"))

    def access(self, accessing_obj, access_type='read', default=False, **kwargs):
        """
        Determines if another object has permission to access.
        accessing_obj - object trying to access this one
        access_type - type of access sought
        default - what to return if no lock of access_type was found
        **kwargs - passed to at_access hook along with result.
        """
        result = self.locks.check(accessing_obj, access_type=access_type, default=default)
        #self.at_access(result, **kwargs)
        return result


#
# Handlers making use of the Attribute model
#

class AttributeHandler(object):
    """
    Handler for adding Attributes to the object.
    """
    _m2m_fieldname = "db_attributes"
    _attrcreate = "attrcreate"
    _attredit = "attredit"
    _attrread = "attrread"
    _attrtype = None

    def __init__(self, obj):
        "Initialize handler"
        self.obj = obj
        self._objid = obj.id
        self._model = to_str(obj.__class__.__name__.lower())
        self._cache = None

    def _recache(self):
        "Cache all attributes of this object"
        query = {"%s__id" % self._model : self._objid,
                 "attribute__db_attrtype" : self._attrtype}
        attrs = [conn.attribute for conn in getattr(self.obj, self._m2m_fieldname).through.objects.filter(**query)]
        self._cache = dict(("%s-%s" % (to_str(attr.db_key).lower(),
                                       attr.db_category.lower() if conn.attribute.db_category else None),
                            attr) for attr in attrs)

    def has(self, key, category=None):
        """
        Checks if the given Attribute (or list of Attributes) exists on
        the object.

        If an iterable is given, returns list of booleans.
        """
        if self._cache is None or not _TYPECLASS_AGGRESSIVE_CACHE:
            self._recache()
        key = [k.strip().lower() for k in make_iter(key) if k]
        category = category.strip().lower() if category is not None else None
        searchkeys = ["%s-%s" % (k, category) for k in make_iter(key)]
        ret = [self._cache.get(skey) for skey in searchkeys if skey in self._cache]
        return ret[0] if len(ret) == 1 else ret

    def get(self, key=None, category=None, default=None, return_obj=False,
            strattr=False, raise_exception=False, accessing_obj=None,
            default_access=True, not_found_none=False):
        """
        Returns the value of the given Attribute or list of Attributes.
        strattr will cause the string-only value field instead of the normal
        pickled field data. Use to get back values from Attributes added with
        the strattr keyword.
        If return_obj=True, return the matching Attribute object
        instead. Returns default if no matches (or [ ] if key was a list
        with no matches). If raise_exception=True, failure to find a
        match will raise AttributeError instead.

        If accessing_obj is given, its "attrread" permission lock will be
        checked before displaying each looked-after Attribute. If no
        accessing_obj is given, no check will be done.
        """

        class RetDefault(object):
            "Holds default values"
            def __init__(self):
                self.value = default
                self.strvalue = str(default) if default is not None else None

        if self._cache is None or not _TYPECLASS_AGGRESSIVE_CACHE:
            self._recache()
        ret = []
        key = [k.strip().lower() for k in make_iter(key) if k]
        category = category.strip().lower() if category is not None else None
        #print "cache:", self._cache.keys(), key
        if not key:
            # return all with matching category (or no category)
            catkey = "-%s" % category if category is not None else None
            ret = [attr for key, attr in self._cache.items() if key and key.endswith(catkey)]
        else:
            for searchkey in ("%s-%s" % (k, category) for k in key):
                attr_obj = self._cache.get(searchkey)
                if attr_obj:
                    ret.append(attr_obj)
                else:
                    if raise_exception:
                        raise AttributeError
                    else:
                        ret.append(RetDefault())
        if accessing_obj:
            # check 'attrread' locks
            ret = [attr for attr in ret if attr.access(accessing_obj, self._attrread, default=default_access)]
        if strattr:
            ret = ret if return_obj else [attr.strvalue for attr in ret if attr]
        else:
            ret = ret if return_obj else [attr.value for attr in ret if attr]
        if not ret:
            return ret if len(key) > 1 else default
        return ret[0] if len(ret)==1 else ret


    def add(self, key, value, category=None, lockstring="",
            strattr=False, accessing_obj=None, default_access=True):
        """
        Add attribute to object, with optional lockstring.

        If strattr is set, the db_strvalue field will be used (no pickling).
        Use the get() method with the strattr keyword to get it back.

        If accessing_obj is given, self.obj's  'attrcreate' lock access
        will be checked against it. If no accessing_obj is given, no check
        will be done.
        """
        if accessing_obj and not self.obj.access(accessing_obj,
                                      self._attrcreate, default=default_access):
            # check create access
            return
        if self._cache is None:
            self._recache()
        if not key:
            return

        category = category.strip().lower() if category is not None else None
        keystr = key.strip().lower()
        cachekey = "%s-%s" % (keystr, category)
        attr_obj = self._cache.get(cachekey)

        if attr_obj:
            # update an existing attribute object
            if strattr:
                # store as a simple string (will not notify OOB handlers)
                attr_obj.db_strvalue = value
                attr_obj.save(update_fields=["db_strvalue"])
            else:
                # store normally (this will also notify OOB handlers)
                attr_obj.value = value
        else:
            # create a new Attribute (no OOB handlers can be notified)
            kwargs = {"db_key" : keystr, "db_category" : category,
                      "db_model" : self._model, "db_attrtype" : self._attrtype,
                      "db_value" : None if strattr else to_pickle(value),
                      "db_strvalue" : value if strattr else None}
            new_attr = Attribute(**kwargs)
            new_attr.save()
            getattr(self.obj, self._m2m_fieldname).add(new_attr)
            self._cache[cachekey] = new_attr


    def batch_add(self, key, value, category=None, lockstring="",
            strattr=False, accessing_obj=None, default_access=True):
        """
        Batch-version of add(). This is more efficient than
        repeat-calling add.

        key and value must be sequences of the same length, each
        representing a key-value pair.

        """
        if accessing_obj and not self.obj.access(accessing_obj,
                                      self._attrcreate, default=default_access):
            # check create access
            return
        if self._cache is None:
            self._recache()
        if not key:
            return

        keys, values= make_iter(key), make_iter(value)

        if len(keys) != len(values):
            raise RuntimeError("AttributeHandler.add(): key and value of different length: %s vs %s" % key, value)
        category = category.strip().lower() if category is not None else None
        new_attrobjs = []
        for ikey, keystr in enumerate(keys):
            keystr = keystr.strip().lower()
            new_value = values[ikey]
            cachekey = "%s-%s" % (keystr, category)
            attr_obj = self._cache.get(cachekey)

            if attr_obj:
                # update an existing attribute object
                if strattr:
                    # store as a simple string (will not notify OOB handlers)
                    attr_obj.db_strvalue = new_value
                    attr_obj.save(update_fields=["db_strvalue"])
                else:
                    # store normally (this will also notify OOB handlers)
                    attr_obj.value = new_value
            else:
                # create a new Attribute (no OOB handlers can be notified)
                kwargs = {"db_key" : keystr, "db_category" : category,
                          "db_attrtype" : self._attrtype,
                          "db_value" : None if strattr else to_pickle(new_value),
                          "db_strvalue" : value if strattr else None}
                new_attr = Attribute(**kwargs)
                new_attr.save()
                new_attrobjs.append(new_attr)
        if new_attrobjs:
            # Add new objects to m2m field all at once
            getattr(self.obj, self._m2m_fieldname).add(*new_attrobjs)
            self._recache()


    def remove(self, key, raise_exception=False, category=None,
               accessing_obj=None, default_access=True):
        """Remove attribute or a list of attributes from object.

        If accessing_obj is given, will check against the 'attredit' lock.
        If not given, this check is skipped.
        """
        if self._cache is None or not _TYPECLASS_AGGRESSIVE_CACHE:
            self._recache()
        key = [k.strip().lower() for k in make_iter(key) if k]
        category = category.strip().lower() if category is not None else None
        for searchstr in ("%s-%s" % (k, category) for k in key):
            attr_obj = self._cache.get(searchstr)
            if attr_obj:
                if not (accessing_obj and not attr_obj.access(accessing_obj,
                        self._attredit, default=default_access)):
                    attr_obj.delete()
            elif not attr_obj and raise_exception:
                raise AttributeError
        self._recache()

    def clear(self, category=None, accessing_obj=None, default_access=True):
        """
        Remove all Attributes on this object. If accessing_obj is
        given, check the 'attredit' lock on each Attribute before
        continuing. If not given, skip check.
        """
        if self._cache is None or not _TYPECLASS_AGGRESSIVE_CACHE:
            self._recache()
        if accessing_obj:
            [attr.delete() for attr in self._cache.values()
             if attr.access(accessing_obj, self._attredit, default=default_access)]
        else:
            [attr.delete() for attr in self._cache.values()]
        self._recache()

    def all(self, accessing_obj=None, default_access=True):
        """
        Return all Attribute objects on this object.

        If accessing_obj is given, check the "attrread" lock on
        each attribute before returning them. If not given, this
        check is skipped.
        """
        if self._cache is None or not _TYPECLASS_AGGRESSIVE_CACHE:
            self._recache()
        attrs = sorted(self._cache.values(), key=lambda o: o.id)
        if accessing_obj:
            return [attr for attr in attrs
                    if attr.access(accessing_obj, self._attredit, default=default_access)]
        else:
            return attrs


class NickHandler(AttributeHandler):
    """
    Handles the addition and removal of Nicks
    (uses Attributes' strvalue and category fields)

    Nicks are stored as Attributes
    with categories nick_<nicktype>
    """
    _attrtype = "nick"

    def has(self, key, category="inputline"):
        return super(NickHandler, self).has(key, category=category)

    def get(self, key=None, category="inputline", **kwargs):
        "Get the replacement value matching the given key and category"
        return super(NickHandler, self).get(key=key, category=category, strattr=True, **kwargs)

    def add(self, key, replacement, category="inputline", **kwargs):
        "Add a new nick"
        super(NickHandler, self).add(key, replacement, category=category, strattr=True, **kwargs)

    def remove(self, key, category="inputline", **kwargs):
        "Remove Nick with matching category"
        super(NickHandler, self).remove(key, category=category, **kwargs)

    def nickreplace(self, raw_string, categories=("inputline", "channel"), include_player=True):
        "Replace entries in raw_string with nick replacement"
        raw_string
        obj_nicks, player_nicks = [], []
        for category in make_iter(categories):
            obj_nicks.extend([n for n in make_iter(self.get(category=category, return_obj=True)) if n])
        if include_player and self.obj.has_player:
            for category in make_iter(categories):
                player_nicks.extend([n for n in make_iter(self.obj.player.nicks.get(category=category, return_obj=True)) if n])
        for nick in obj_nicks + player_nicks:
            # make a case-insensitive match here
            match = re.match(re.escape(nick.db_key), raw_string, re.IGNORECASE)
            if match:
                raw_string = raw_string.replace(match.group(), nick.db_strvalue, 1)
                break
        return raw_string


class NAttributeHandler(object):
    """
    This stand-alone handler manages non-database saving.
    It is similar to AttributeHandler and is used
    by the .ndb handler in the same way as .db does
    for the AttributeHandler.
    """
    def __init__(self, obj):
        "initialized on the object"
        self._store = {}
        self.obj = weakref.proxy(obj)

    def has(self, key):
        "Check if object has this attribute or not"
        return key in self._store

    def get(self, key):
        "Returns named key value"
        return self._store.get(key, None)

    def add(self, key, value):
        "Add new key and value"
        self._store[key] = value
        self.obj.set_recache_protection()

    def remove(self, key):
        "Remove key from storage"
        if key in self._store:
            del self._store[key]
        self.obj.set_recache_protection(self._store)

    def clear(self):
        "Remove all nattributes from handler"
        self._store = {}

    def all(self, return_tuples=False):
        "List all keys or (keys, values) stored, except _keys"
        if return_tuples:
            return [(key, value) for (key, value) in self._store.items() if not key.startswith("_")]
        return [key for key in self._store if not key.startswith("_")]


#------------------------------------------------------------
#
# Tags
#
#------------------------------------------------------------

class Tag(models.Model):
    """
    Tags are quick markers for objects in-game. An typeobject
    can have any number of tags, stored via its db_tags property.
    Tagging similar objects will make it easier to quickly locate the
    group later (such as when implementing zones). The main advantage
    of tagging as opposed to using Attributes is speed; a tag is very
    limited in what data it can hold, and the tag key+category is
    indexed for efficient lookup in the database. Tags are shared between
    objects - a new tag is only created if the key+category combination
    did not previously exist, making them unsuitable for storing
    object-related data (for this a full Attribute
    should be used).
    The 'db_data' field is intended as a documentation
    field for the tag itself, such as to document what this tag+category
    stands for and display that in a web interface or similar.

    The main default use for Tags is to implement Aliases for objects.
    this uses the 'aliases' tag category, which is also checked by the
    default search functions of Evennia to allow quick searches by alias.
    """
    db_key = models.CharField('key', max_length=255, null=True,
                              help_text="tag identifier", db_index=True)
    db_category = models.CharField('category', max_length=64, null=True,
                                   help_text="tag category", db_index=True)
    db_data = models.TextField('data', null=True, blank=True,
                               help_text="optional data field with extra information. This is not searched for.")
    # this is "objectdb" etc. Required behind the scenes
    db_model = models.CharField('model', max_length=32, null=True, help_text="database model to Tag", db_index=True)
    # this is None, alias or permission
    db_tagtype = models.CharField('tagtype', max_length=16, null=True, help_text="overall type of Tag", db_index=True)

    class Meta:
        "Define Django meta options"
        verbose_name = "Tag"
        unique_together = (('db_key', 'db_category', 'db_tagtype'),)
        index_together = (('db_key', 'db_category', 'db_tagtype'),)

    def __unicode__(self):
        return u"%s" % self.db_key

    def __str__(self):
        return str(self.db_key)


#
# Handlers making use of the Tags model
#

class TagHandler(object):
    """
    Generic tag-handler. Accessed via TypedObject.tags.
    """
    _m2m_fieldname = "db_tags"
    _tagtype = None

    def __init__(self, obj):
        """
        Tags are stored internally in the TypedObject.db_tags m2m field
        with an tag.db_model based on the obj the taghandler is stored on
        and with a tagtype given by self.handlertype
        """
        self.obj = obj
        self._objid = obj.id
        self._model = obj.__class__.__name__.lower()
        self._cache = None

    def _recache(self):
        "Cache all tags of this object"
        query = {"%s__id" % self._model : self._objid,
                 "tag__db_tagtype" : self._tagtype}
        tagobjs = [conn.tag for conn in getattr(self.obj, self._m2m_fieldname).through.objects.filter(**query)]
        self._cache = dict(("%s-%s" % (to_str(tagobj.db_key).lower(),
                                       tagobj.db_category.lower() if tagobj.db_category else None),
                            tagobj) for tagobj in tagobjs)

    def add(self, tag=None, category=None, data=None):
        "Add a new tag to the handler. Tag is a string or a list of strings."
        if not tag:
            return
        for tagstr in make_iter(tag):
            if not tagstr:
                continue
            tagstr = tagstr.strip().lower()
            category = category.strip().lower() if category is not None else None
            data = str(data) if data is not None else None
            # this will only create tag if no matches existed beforehand (it
            # will overload data on an existing tag since that is not
            # considered part of making the tag unique)
            tagobj = self.obj.__class__.objects.create_tag(key=tagstr, category=category, data=data,
                                            tagtype=self._tagtype)
            getattr(self.obj, self._m2m_fieldname).add(tagobj)
            if self._cache is None:
                self._recache()
            cachestring = "%s-%s" % (tagstr, category)
            self._cache[cachestring] = tagobj

    def get(self, key, category="", return_tagobj=False):
        """
        Get the tag for the given key or list of tags. If
        return_data=True, return the matching Tag objects instead.
        Returns a single tag if a unique match, otherwise a list
        """
        if self._cache is None or not _TYPECLASS_AGGRESSIVE_CACHE:
            self._recache()
        ret = []
        category = category.strip().lower() if category is not None else None
        searchkey = ["%s-%s" % (key.strip().lower(), category) if key is not None else None for key in make_iter(key)]
        ret = [val for val in (self._cache.get(keystr) for keystr in searchkey) if val]
        ret = [to_str(tag.db_data) for tag in ret] if return_tagobj else ret
        return ret[0] if len(ret) == 1 else ret

    def remove(self, key, category=None):
        "Remove a tag from the handler based ond key and category."
        for key in make_iter(key):
            if not (key or key.strip()):  # we don't allow empty tags
                continue
            tagstr = key.strip().lower()
            category = category.strip().lower() if category is not None else None

            # This does not delete the tag object itself. Maybe it should do
            # that when no objects reference the tag anymore (how to check)?
            tagobj = self.obj.db_tags.filter(db_key=tagstr, db_category=category)
            if tagobj:
                getattr(self.obj, self._m2m_fieldname).remove(tagobj[0])
        self._recache()

    def clear(self):
        "Remove all tags from the handler"
        getattr(self.obj, self._m2m_fieldname).clear()
        self._recache()

    def all(self, category=None, return_key_and_category=False):
        """
        Get all tags in this handler.
        If category is given, return only Tags with this category.  If
        return_keys_and_categories is set, return a list of tuples [(key, category), ...]
        """
        if self._cache is None or not _TYPECLASS_AGGRESSIVE_CACHE:
            self._recache()
        if category:
            category = category.strip().lower() if category is not None else None
            matches = [tag for tag in self._cache.values() if tag.db_category == category]
        else:
            matches = self._cache.values()

        if matches:
            matches = sorted(matches, key=lambda o: o.id)
            if return_key_and_category:
                # return tuple (key, category)
                return [(to_str(p.db_key), to_str(p.db_category)) for p in matches]
            else:
                return [to_str(p.db_key) for p in matches]
        return []

    def __str__(self):
        return ",".join(self.all())

    def __unicode(self):
        return u",".join(self.all())


class AliasHandler(TagHandler):
    _tagtype = "alias"


class PermissionHandler(TagHandler):
    _tagtype = "permission"


#------------------------------------------------------------
#
# Typed Objects
#
#------------------------------------------------------------


#
# Meta class for typeclasses
#

# django patch imports
import copy
from django.apps import apps
from django.db.models.base import subclass_exception
import warnings
from django.db.models.options import Options
from django.utils.deprecation import RemovedInDjango19Warning
from django.core.exceptions import MultipleObjectsReturned, FieldError
from django.apps.config import MODELS_MODULE_NAME
from django.db.models.fields.related import OneToOneField
#/ django patch imports

from src.utils.idmapper.base import SharedMemoryModelBase

class TypeclassBase(SharedMemoryModelBase):
    """
    Metaclass which should be set for the root of model proxies
    that don't define any new fields, like Object, Script etc.
    """
    def __new__(cls, name, bases, attrs):
        """
        We must define our Typeclasses as proxies. We also store the path
        directly on the class, this is useful for managers.
        """
        # typeclass proxy setup
        if "Meta" in attrs:
            attrs["Meta"].proxy = True
        else:
            class Meta:
                proxy = True
            attrs["Meta"] = Meta


        # patch start - django multi-inheritance
        # this is a copy of django.db.models.base.__new__
        # with a few lines (marked patch below) changed
        # as per https://code.djangoproject.com/ticket/11560

        super_new = super(ModelBase, cls).__new__

        # Also ensure initialization is only performed for subclasses of Model
        # (excluding Model class itself).
        parents = [b for b in bases if isinstance(b, ModelBase)]
        if not parents:
            return super_new(cls, name, bases, attrs)

        # Create the class.
        module = attrs.pop('__module__')
        new_class = super_new(cls, name, bases, {'__module__': module})
        attr_meta = attrs.pop('Meta', None)
        abstract = getattr(attr_meta, 'abstract', False)
        if not attr_meta:
            meta = getattr(new_class, 'Meta', None)
        else:
            meta = attr_meta
        base_meta = getattr(new_class, '_meta', None)

        # Look for an application configuration to attach the model to.
        app_config = apps.get_containing_app_config(module)

        if getattr(meta, 'app_label', None) is None:

            if app_config is None:
                # If the model is imported before the configuration for its
                # application is created (#21719), or isn't in an installed
                # application (#21680), use the legacy logic to figure out the
                # app_label by looking one level up from the package or module
                # named 'models'. If no such package or module exists, fall
                # back to looking one level up from the module this model is
                # defined in.

                # For 'django.contrib.sites.models', this would be 'sites'.
                # For 'geo.models.places' this would be 'geo'.

                msg = (
                    "Model class %s.%s doesn't declare an explicit app_label "
                    "and either isn't in an application in INSTALLED_APPS or "
                    "else was imported before its application was loaded. " %
                    (module, name))
                if abstract:
                    msg += "Its app_label will be set to None in Django 1.9."
                else:
                    msg += "This will no longer be supported in Django 1.9."
                warnings.warn(msg, RemovedInDjango19Warning, stacklevel=2)

                model_module = sys.modules[new_class.__module__]
                package_components = model_module.__name__.split('.')
                package_components.reverse()  # find the last occurrence of 'models'
                try:
                    app_label_index = package_components.index(MODELS_MODULE_NAME) + 1
                except ValueError:
                    app_label_index = 1
                kwargs = {"app_label": package_components[app_label_index]}

            else:
                kwargs = {"app_label": app_config.label}

        else:
            kwargs = {}

        new_class.add_to_class('_meta', Options(meta, **kwargs))
        if not abstract:
            new_class.add_to_class(
                'DoesNotExist',
                subclass_exception(
                    str('DoesNotExist'),
                    tuple(x.DoesNotExist for x in parents if hasattr(x, '_meta') and not x._meta.abstract) or (ObjectDoesNotExist,),
                    module,
                    attached_to=new_class))
            new_class.add_to_class(
                'MultipleObjectsReturned',
                subclass_exception(
                    str('MultipleObjectsReturned'),
                    tuple(x.MultipleObjectsReturned for x in parents if hasattr(x, '_meta') and not x._meta.abstract) or (MultipleObjectsReturned,),
                    module,
                    attached_to=new_class))
            if base_meta and not base_meta.abstract:
                # Non-abstract child classes inherit some attributes from their
                # non-abstract parent (unless an ABC comes before it in the
                # method resolution order).
                if not hasattr(meta, 'ordering'):
                    new_class._meta.ordering = base_meta.ordering
                if not hasattr(meta, 'get_latest_by'):
                    new_class._meta.get_latest_by = base_meta.get_latest_by

        is_proxy = new_class._meta.proxy

        # If the model is a proxy, ensure that the base class
        # hasn't been swapped out.
        if is_proxy and base_meta and base_meta.swapped:
            raise TypeError("%s cannot proxy the swapped model '%s'." % (name, base_meta.swapped))

        if getattr(new_class, '_default_manager', None):
            if not is_proxy:
                # Multi-table inheritance doesn't inherit default manager from
                # parents.
                new_class._default_manager = None
                new_class._base_manager = None
            else:
                # Proxy classes do inherit parent's default manager, if none is
                # set explicitly.
                new_class._default_manager = new_class._default_manager._copy_to_model(new_class)
                new_class._base_manager = new_class._base_manager._copy_to_model(new_class)

        # Add all attributes to the class.
        for obj_name, obj in attrs.items():
            new_class.add_to_class(obj_name, obj)

        # All the fields of any type declared on this model
        new_fields = (
            new_class._meta.local_fields +
            new_class._meta.local_many_to_many +
            new_class._meta.virtual_fields
        )
        field_names = set(f.name for f in new_fields)

        # Basic setup for proxy models.
        if is_proxy:
            base = None
            for parent in [kls for kls in parents if hasattr(kls, '_meta')]:
                if parent._meta.abstract:
                    if parent._meta.fields:
                        raise TypeError("Abstract base class containing model fields not permitted for proxy model '%s'." % name)
                    else:
                        continue
                #if base is not None:                              # patch
                while parent._meta.proxy:                          # patch
                    parent = parent._meta.proxy_for_model          # patch
                if base is not None and base is not parent:        # patch
                    raise TypeError("Proxy model '%s' has more than one non-abstract model base class." % name)
                else:
                    base = parent
            if base is None:
                raise TypeError("Proxy model '%s' has no non-abstract model base class." % name)
            new_class._meta.setup_proxy(base)
            new_class._meta.concrete_model = base._meta.concrete_model
        else:
            new_class._meta.concrete_model = new_class

        # Collect the parent links for multi-table inheritance.
        parent_links = {}
        for base in reversed([new_class] + parents):
            # Conceptually equivalent to `if base is Model`.
            if not hasattr(base, '_meta'):
                continue
            # Skip concrete parent classes.
            if base != new_class and not base._meta.abstract:
                continue
            # Locate OneToOneField instances.
            for field in base._meta.local_fields:
                if isinstance(field, OneToOneField):
                    parent_links[field.rel.to] = field

        # Do the appropriate setup for any model parents.
        for base in parents:
            original_base = base
            if not hasattr(base, '_meta'):
                # Things without _meta aren't functional models, so they're
                # uninteresting parents.
                continue

            parent_fields = base._meta.local_fields + base._meta.local_many_to_many
            # Check for clashes between locally declared fields and those
            # on the base classes (we cannot handle shadowed fields at the
            # moment).
            for field in parent_fields:
                if field.name in field_names:
                    raise FieldError(
                        'Local field %r in class %r clashes '
                        'with field of similar name from '
                        'base class %r' % (field.name, name, base.__name__)
                    )
            if not base._meta.abstract:
                # Concrete classes...
                base = base._meta.concrete_model
                if base in parent_links:
                    field = parent_links[base]
                elif not is_proxy:
                    attr_name = '%s_ptr' % base._meta.model_name
                    field = OneToOneField(base, name=attr_name,
                            auto_created=True, parent_link=True)
                    # Only add the ptr field if it's not already present;
                    # e.g. migrations will already have it specified
                    if not hasattr(new_class, attr_name):
                        new_class.add_to_class(attr_name, field)
                else:
                    field = None
                new_class._meta.parents[base] = field
            else:
                # .. and abstract ones.
                for field in parent_fields:
                    new_class.add_to_class(field.name, copy.deepcopy(field))

                # Pass any non-abstract parent classes onto child.
                new_class._meta.parents.update(base._meta.parents)

            # Inherit managers from the abstract base classes.
            new_class.copy_managers(base._meta.abstract_managers)

            # Proxy models inherit the non-abstract managers from their base,
            # unless they have redefined any of them.
            if is_proxy:
                new_class.copy_managers(original_base._meta.concrete_managers)

            # Inherit virtual fields (like GenericForeignKey) from the parent
            # class
            for field in base._meta.virtual_fields:
                if base._meta.abstract and field.name in field_names:
                    raise FieldError(
                        'Local field %r in class %r clashes '
                        'with field of similar name from '
                        'abstract base class %r' % (field.name, name, base.__name__)
                    )
                new_class.add_to_class(field.name, copy.deepcopy(field))

        if abstract:
            # Abstract base models can't be instantiated and don't appear in
            # the list of models for an app. We do the final setup for them a
            # little differently from normal models.
            attr_meta.abstract = False
            new_class.Meta = attr_meta
            return new_class

        new_class._prepare()
        new_class._meta.apps.register_model(new_class._meta.app_label, new_class)
        return new_class

        # /patch end



#
# Main TypedObject abstraction
#


class TypedObject(SharedMemoryModel):
    """
    Abstract Django model.

    This is the basis for a typed object. It also contains all the
    mechanics for managing connected attributes.

    The TypedObject has the following properties:
      key - main name
      name - alias for key
      typeclass_path - the path to the decorating typeclass
      typeclass - auto-linked typeclass
      date_created - time stamp of object creation
      permissions - perm strings
      dbref - #id of object
      db - persistent attribute storage
      ndb - non-persistent attribute storage

    """

    #
    # TypedObject Database Model setup
    #
    #
    # These databse fields are all accessed and set using their corresponding
    # properties, named same as the field, but without the db_* prefix
    # (no separate save() call is needed)

    # Main identifier of the object, for searching. Is accessed with self.key
    # or self.name
    db_key = models.CharField('key', max_length=255, db_index=True)
    # This is the python path to the type class this object is tied to the
    # typeclass is what defines what kind of Object this is)
    db_typeclass_path = models.CharField('typeclass', max_length=255, null=True,
            help_text="this defines what 'type' of entity this is. This variable holds a Python path to a module with a valid Evennia Typeclass.")
    # Creation date. This is not changed once the object is created.
    db_date_created = models.DateTimeField('creation date', editable=False, auto_now_add=True)
    # Permissions (access these through the 'permissions' property)
    #db_permissions = models.CharField('permissions', max_length=255, blank=True,
    #     help_text="a comma-separated list of text strings checked by
    # in-game locks. They are often used for hierarchies, such as letting a Player have permission 'Wizards', 'Builders' etc. Character objects use 'Players' by default. Most other objects don't have any permissions.")
    # Lock storage
    db_lock_storage = models.TextField('locks', blank=True,
            help_text="locks limit access to an entity. A lock is defined as a 'lock string' on the form 'type:lockfunctions', defining what functionality is locked and how to determine access. Not defining a lock means no access is granted.")
    # many2many relationships
    db_attributes = models.ManyToManyField(Attribute, null=True,
            help_text='attributes on this object. An attribute can hold any pickle-able python object (see docs for special cases).')
    db_tags = models.ManyToManyField(Tag, null=True,
            help_text='tags on this object. Tags are simple string markers to identify, group and alias objects.')

    # Database manager
    objects = managers.TypedObjectManager()

    # quick on-object typeclass cache for speed
    _cached_typeclass = None

    # typeclass mechanism

    def _import_class(self, path):
        path, clsname = path.rsplit(".", 1)
        mod = import_module(path)
        return getattr(mod, clsname)

    def __init__(self, *args, **kwargs):
        typeclass_path = kwargs.pop("typeclass", None)
        super(TypedObject, self).__init__(*args, **kwargs)
        if typeclass_path:
            self.__class__ = self._import_class(typeclass_path)
            self.db_typclass_path = typeclass_path
        elif self.db_typeclass_path:
            self.__class__ = self._import_class(self.db_typeclass_path)
        else:
            self.db_typeclass_path = "%s.%s" % (self.__module__, self.__class__.__name__)

    # initialize all handlers in a lazy fashion
    @lazy_property
    def attributes(self):
        return AttributeHandler(self)

    @lazy_property
    def locks(self):
        return LockHandler(self)

    @lazy_property
    def tags(self):
        return TagHandler(self)

    @lazy_property
    def aliases(self):
        return AliasHandler(self)

    @lazy_property
    def permissions(self):
        return PermissionHandler(self)

    @lazy_property
    def nattributes(self):
        return NAttributeHandler(self)


    class Meta:
        """
        Django setup info.
        """
        abstract = True
        verbose_name = "Evennia Database Object"
        ordering = ['-db_date_created', 'id', 'db_typeclass_path', 'db_key']

    # wrapper
    # Wrapper properties to easily set database fields. These are
    # @property decorators that allows to access these fields using
    # normal python operations (without having to remember to save()
    # etc). So e.g. a property 'attr' has a get/set/del decorator
    # defined that allows the user to do self.attr = value,
    # value = self.attr and del self.attr respectively (where self
    # is the object in question).

    # name property (alias to self.key)
    def __name_get(self):
        return self.key

    def __name_set(self, value):
        self.key = value

    def __name_del(self):
        raise Exception("Cannot delete name")
    name = property(__name_get, __name_set, __name_del)

    #
    #
    # TypedObject main class methods and properties
    #
    #

    _typeclass_paths = settings.OBJECT_TYPECLASS_PATHS

    def __eq__(self, other):
        return other and hasattr(other, 'dbid') and self.dbid == other.dbid

    def __str__(self):
        return smart_str("%s" % _GA(self, "db_key"))

    def __unicode__(self):
        return u"%s" % _GA(self, "db_key")

    #@property
    def __dbid_get(self):
        """
        Caches and returns the unique id of the object.
        Use this instead of self.id, which is not cached.
        """
        dbid = get_prop_cache(self, "_dbid")
        if not dbid:
            dbid = _GA(self, "id")
            set_prop_cache(self, "_dbid", dbid)
        return dbid

    def __dbid_set(self, value):
        raise Exception("dbid cannot be set!")

    def __dbid_del(self):
        raise Exception("dbid cannot be deleted!")
    dbid = property(__dbid_get, __dbid_set, __dbid_del)

    #@property
    def __dbref_get(self):
        """
        Returns the object's dbref on the form #NN.
        """
        return "#%s" % _GA(self, "_TypedObject__dbid_get")()

    def __dbref_set(self):
        raise Exception("dbref cannot be set!")

    def __dbref_del(self):
        raise Exception("dbref cannot be deleted!")
    dbref = property(__dbref_get, __dbref_set, __dbref_del)

    #
    # Object manipulation methods
    #

    def swap_typeclass(self, new_typeclass, clean_attributes=False,
                       run_start_hooks=True, no_default=True):
        """
        This performs an in-situ swap of the typeclass. This means
        that in-game, this object will suddenly be something else.
        Player will not be affected. To 'move' a player to a different
        object entirely (while retaining this object's type), use
        self.player.swap_object().

        Note that this might be an error prone operation if the
        old/new typeclass was heavily customized - your code
        might expect one and not the other, so be careful to
        bug test your code if using this feature! Often its easiest
        to create a new object and just swap the player over to
        that one instead.

        Arguments:
        new_typeclass (path/classobj) - type to switch to
        clean_attributes (bool/list) - will delete all attributes
                           stored on this object (but not any
                           of the database fields such as name or
                           location). You can't get attributes back,
                           but this is often the safest bet to make
                           sure nothing in the new typeclass clashes
                           with the old one. If you supply a list,
                           only those named attributes will be cleared.
        no_default - if this is active, the swapper will not allow for
                     swapping to a default typeclass in case the given
                     one fails for some reason. Instead the old one
                     will be preserved.
        Returns:
          boolean True/False depending on if the swap worked or not.

        """
        if callable(new_typeclass):
            # this is an actual class object - build the path
            cls = new_typeclass
            new_typeclass = "%s.%s" % (cls.__module__, cls.__name__)
        else:
            new_typeclass = "%s" % to_str(new_typeclass)

        # Try to set the new path
        # this will automatically save to database
        old_typeclass_path = self.typeclass_path

        if inherits_from(self, "src.scripts.models.ScriptDB"):
            if self.interval > 0:
                raise RuntimeError("Cannot use swap_typeclass on time-dependent " \
                                   "Script '%s'.\nStop and start a new Script of the " \
                                   "right type instead." % self.key)

        _SA(self, "typeclass_path", new_typeclass.strip())
        # this will automatically use a default class if
        # there is an error with the given typeclass.
        new_typeclass = self.typeclass
        if self.typeclass_path != new_typeclass.path and no_default:
            # something went wrong; the default was loaded instead,
            # and we don't allow that; instead we return to previous.
            _SA(self, "typeclass_path", old_typeclass_path)
            return False

        if clean_attributes:
            # Clean out old attributes
            if is_iter(clean_attributes):
                for attr in clean_attributes:
                    self.attributes.remove(attr)
                for nattr in clean_attributes:
                    if hasattr(self.ndb, nattr):
                        self.nattributes.remove(nattr)
            else:
                #print "deleting attrs ..."
                self.attributes.clear()
                self.nattributes.clear()

        if run_start_hooks:
            # run hooks for this new typeclass
            if inherits_from(self, "src.objects.models.ObjectDB"):
                new_typeclass.basetype_setup()
                new_typeclass.at_object_creation()
            elif inherits_from(self, "src.players.models.PlayerDB"):
                new_typeclass.basetype_setup()
                new_typeclass.at_player_creation()
            elif inherits_from(self, "src.scripts.models.ScriptDB"):
                new_typeclass.at_script_creation()
                new_typeclass.start()
            elif inherits_from(self, "src.channels.models.Channel"):
                # channels do no initial setup
                pass

        return True

    #
    # Lock / permission methods
    #

    def access(self, accessing_obj, access_type='read', default=False, **kwargs):
        """
        Determines if another object has permission to access.
        accessing_obj - object trying to access this one
        access_type - type of access sought
        default - what to return if no lock of access_type was found
        **kwargs - this is ignored, but is there to make the api consistent with the
                   object-typeclass method access, which use it to feed to its hook methods.
        """
        return self.locks.check(accessing_obj, access_type=access_type, default=default)

    def check_permstring(self, permstring):
        """
        This explicitly checks if we hold particular permission without
        involving any locks. It does -not- trigger the at_access hook.
        """
        if hasattr(self, "player"):
            if self.player and self.player.is_superuser:
                return True
        else:
            if self.is_superuser:
                return True

        if not permstring:
            return False
        perm = permstring.lower()
        perms = [p.lower() for p in self.permissions.all()]
        if perm in perms:
            # simplest case - we have a direct match
            return True
        if perm in _PERMISSION_HIERARCHY:
            # check if we have a higher hierarchy position
            ppos = _PERMISSION_HIERARCHY.index(perm)
            return any(True for hpos, hperm in enumerate(_PERMISSION_HIERARCHY)
                       if hperm in perms and hpos > ppos)
        return False

    #
    # Deletion methods
    #

    def _deleted(self, *args, **kwargs):
        "Scrambling method for already deleted objects"
        raise ObjectDoesNotExist("This object was already deleted!")

    _is_deleted = False # this is checked by db_* wrappers

    def delete(self):
        "Cleaning up handlers on the typeclass level"
        global TICKER_HANDLER
        if not TICKER_HANDLER:
            from src.scripts.tickerhandler import TICKER_HANDLER
        TICKER_HANDLER.remove(self) # removes objects' all ticker subscriptions
        _GA(self, "permissions").clear()
        _GA(self, "attributes").clear()
        _GA(self, "aliases").clear()
        if hasattr(self, "nicks"):
            _GA(self, "nicks").clear()
        _SA(self, "_cached_typeclass", None)
        _GA(self, "flush_from_cache")()

        # scrambling properties
        self.delete = self._deleted
        self._is_deleted = True
        super(TypedObject, self).delete()

    #
    # Memory management
    #

    def flush_from_cache(self):
        """
        Flush this object instance from cache, forcing an object reload.
        Note that this will kill all temporary attributes on this object
         since it will be recreated as a new Typeclass instance.
        """
        self.__class__.flush_cached_instance(self)

    #
    # Attribute storage
    #

    #@property db
    def __db_get(self):
        """
        Attribute handler wrapper. Allows for the syntax
           obj.db.attrname = value
             and
           value = obj.db.attrname
             and
           del obj.db.attrname
             and
           all_attr = obj.db.all() (unless there is an attribute
                      named 'all', in which case that will be returned instead).
        """
        try:
            return self._db_holder
        except AttributeError:
            class DbHolder(object):
                "Holder for allowing property access of attributes"
                def __init__(self, obj):
                    _SA(self, "attrhandler", _GA(obj, "attributes"))

                def __getattribute__(self, attrname):
                    if attrname == 'all':
                        # we allow to overload our default .all
                        attr = _GA(self, "attrhandler").get("all")
                        if attr:
                            return attr
                        return _GA(self, 'all')
                    return _GA(self, "attrhandler").get(attrname)

                def __setattr__(self, attrname, value):
                    _GA(self, "attrhandler").add(attrname, value)

                def __delattr__(self, attrname):
                    _GA(self, "attrhandler").remove(attrname)

                def get_all(self):
                    return _GA(self, "attrhandler").all()
                all = property(get_all)
            self._db_holder = DbHolder(self)
            return self._db_holder

    #@db.setter
    def __db_set(self, value):
        "Stop accidentally replacing the db object"
        string = "Cannot assign directly to db object! "
        string += "Use db.attr=value instead."
        raise Exception(string)

    #@db.deleter
    def __db_del(self):
        "Stop accidental deletion."
        raise Exception("Cannot delete the db object!")
    db = property(__db_get, __db_set, __db_del)

    #
    # Non-persistent (ndb) storage
    #

    #@property ndb
    def __ndb_get(self):
        """
        A non-attr_obj store (ndb: NonDataBase). Everything stored
        to this is guaranteed to be cleared when a server is shutdown.
        Syntax is same as for the _get_db_holder() method and
        property, e.g. obj.ndb.attr = value etc.
        """
        try:
            return self._ndb_holder
        except AttributeError:
            class NDbHolder(object):
                "Holder for allowing property access of attributes"
                def __init__(self, obj):
                    _SA(self, "nattrhandler", _GA(obj, "nattributes"))

                def __getattribute__(self, attrname):
                    if attrname == 'all':
                        # we allow to overload our default .all
                        attr = _GA(self, "nattrhandler").get("all")
                        if attr:
                            return attr
                        return _GA(self, 'all')
                    return _GA(self, "nattrhandler").get(attrname)

                def __setattr__(self, attrname, value):
                    _GA(self, "nattrhandler").add(attrname, value)

                def __delattr__(self, attrname):
                    _GA(self, "nattrhandler").remove(attrname)

                def get_all(self):
                    return _GA(self, "nattrhandler").all()
                all = property(get_all)
            self._ndb_holder = NDbHolder(self)
            return self._ndb_holder

    #@db.setter
    def __ndb_set(self, value):
        "Stop accidentally replacing the ndb object"
        string = "Cannot assign directly to ndb object! "
        string += "Use ndb.attr=value instead."
        raise Exception(string)

    #@db.deleter
    def __ndb_del(self):
        "Stop accidental deletion."
        raise Exception("Cannot delete the ndb object!")
    ndb = property(__ndb_get, __ndb_set, __ndb_del)