evennia/evennia/prototypes/prototypes.py

"""

Handling storage of prototypes, both database-based ones (DBPrototypes) and those defined in modules
(Read-only prototypes). Also contains utility functions, formatters and manager functions.

"""

import hashlib
import time
from ast import literal_eval
from django.conf import settings
from django.db.models import Q, Subquery
from django.core.paginator import Paginator
from evennia.scripts.scripts import DefaultScript
from evennia.objects.models import ObjectDB
from evennia.typeclasses.attributes import Attribute
from evennia.utils.create import create_script
from evennia.utils.evmore import EvMore
from evennia.utils.utils import (
    all_from_module,
    make_iter,
    is_iter,
    dbid_to_obj,
    callables_from_module,
    get_all_typeclasses,
    to_str,
    dbref,
    justify,
    class_from_module,
)
from evennia.locks.lockhandler import validate_lockstring, check_lockstring
from evennia.utils import logger
from evennia.utils.funcparser import FuncParser
from evennia.utils import dbserialize
from evennia.utils.evtable import EvTable


_MODULE_PROTOTYPE_MODULES = {}
_MODULE_PROTOTYPES = {}
_PROTOTYPE_META_NAMES = (
    "prototype_key",
    "prototype_desc",
    "prototype_tags",
    "prototype_locks",
    "prototype_parent",
)
_PROTOTYPE_RESERVED_KEYS = _PROTOTYPE_META_NAMES + (
    "key",
    "aliases",
    "typeclass",
    "location",
    "home",
    "destination",
    "permissions",
    "locks",
    "exec",
    "tags",
    "attrs",
)
PROTOTYPE_TAG_CATEGORY = "from_prototype"
_PROTOTYPE_TAG_META_CATEGORY = "db_prototype"

_PROTOTYPE_FALLBACK_LOCK = "spawn:all();edit:all()"


# the protfunc parser
FUNC_PARSER = FuncParser(settings.PROT_FUNC_MODULES)


class PermissionError(RuntimeError):
    pass


class ValidationError(RuntimeError):
    """
    Raised on prototype validation errors
    """

    pass


def homogenize_prototype(prototype, custom_keys=None):
    """
    Homogenize the more free-form prototype supported pre Evennia 0.7 into the stricter form.


    Args:
        prototype (dict): Prototype.
        custom_keys (list, optional): Custom keys which should not be interpreted as attrs, beyond
            the default reserved keys.

    Returns:
        homogenized (dict): Prototype where all non-identified keys grouped as attributes and other
            homogenizations like adding missing prototype_keys and setting a default typeclass.

    """
    if not prototype or not isinstance(prototype, dict):
        return {}

    reserved = _PROTOTYPE_RESERVED_KEYS + (custom_keys or ())

    # correct cases of setting None for certain values
    for protkey in prototype:
        if prototype[protkey] is None:
            if protkey in ("attrs", "tags", "prototype_tags"):
                prototype[protkey] = []
            elif protkey in ("prototype_key", "prototype_desc"):
                prototype[protkey] = ""

    attrs = list(prototype.get("attrs", []))  # break reference
    tags = make_iter(prototype.get("tags", []))
    homogenized_tags = []

    homogenized = {}
    for key, val in prototype.items():
        if key in reserved:
            if key == "tags":
                for tag in tags:
                    if not is_iter(tag):
                        homogenized_tags.append((tag, None, None))
                    else:
                        homogenized_tags.append(tag)
            else:
                homogenized[key] = val
        else:
            # unassigned keys -> attrs
            attrs.append((key, val, None, ""))
    if attrs:
        homogenized["attrs"] = attrs
    if homogenized_tags:
        homogenized["tags"] = homogenized_tags

    # add required missing parts that had defaults before

    homogenized["prototype_key"] = homogenized.get(
        "prototype_key",
        # assign a random hash as key
        "prototype-{}".format(hashlib.md5(bytes(str(time.time()), "utf-8")).hexdigest()[:7]),
    )
    homogenized["prototype_tags"] = homogenized.get("prototype_tags", [])
    homogenized["prototype_locks"] = homogenized.get("prototype_lock", _PROTOTYPE_FALLBACK_LOCK)
    homogenized["prototype_desc"] = homogenized.get("prototype_desc", "")
    if "typeclass" not in prototype and "prototype_parent" not in prototype:
        homogenized["typeclass"] = settings.BASE_OBJECT_TYPECLASS

    return homogenized


# module-based prototypes

def load_module_prototypes():
    """
    This is called by `evennia.__init__` as Evennia initializes. It's important
    to do this late so as to not interfere with evennia initialization.

    """
    for mod in settings.PROTOTYPE_MODULES:
        # to remove a default prototype, override it with an empty dict.
        # internally we store as (key, desc, locks, tags, prototype_dict)
        prots = []
        for variable_name, prot in all_from_module(mod).items():
            if isinstance(prot, dict):
                if "prototype_key" not in prot:
                    prot["prototype_key"] = variable_name.lower()
                prots.append((prot["prototype_key"], homogenize_prototype(prot)))
        # assign module path to each prototype_key for easy reference
        _MODULE_PROTOTYPE_MODULES.update({prototype_key.lower(): mod for prototype_key, _ in prots})
        # make sure the prototype contains all meta info
        for prototype_key, prot in prots:
            actual_prot_key = prot.get("prototype_key", prototype_key).lower()
            prot.update(
                {
                    "prototype_key": actual_prot_key,
                    "prototype_desc": prot["prototype_desc"] if "prototype_desc" in prot else mod,
                    "prototype_locks": (
                        prot["prototype_locks"]
                        if "prototype_locks" in prot
                        else "use:all();edit:false()"
                    ),
                    "prototype_tags": list(
                        set(list(make_iter(prot.get("prototype_tags", []))) + ["module"])
                    ),
                }
            )
            _MODULE_PROTOTYPES[actual_prot_key] = prot


# Db-based prototypes


class DbPrototype(DefaultScript):
    """
    This stores a single prototype, in an Attribute `prototype`.
    """

    def at_script_creation(self):
        self.key = "empty prototype"  # prototype_key
        self.desc = "A prototype"  # prototype_desc (.tags are used for prototype_tags)
        self.db.prototype = {}  # actual prototype

    @property
    def prototype(self):
        "Make sure to decouple from db!"
        return dbserialize.deserialize(self.attributes.get("prototype", {}))

    @prototype.setter
    def prototype(self, prototype):
        self.attributes.add("prototype", prototype)


# Prototype manager functions


def save_prototype(prototype):
    """
    Create/Store a prototype persistently.

    Args:
        prototype (dict): The prototype to save. A `prototype_key` key is
            required.

    Returns:
        prototype (dict or None): The prototype stored using the given kwargs, None if deleting.

    Raises:
        prototypes.ValidationError: If prototype does not validate.

    Note:
        No edit/spawn locks will be checked here - if this function is called the caller
        is expected to have valid permissions.

    """
    in_prototype = prototype
    in_prototype = homogenize_prototype(in_prototype)

    def _to_batchtuple(inp, *args):
        "build tuple suitable for batch-creation"
        if is_iter(inp):
            # already a tuple/list, use as-is
            return inp
        return (inp,) + args

    prototype_key = in_prototype.get("prototype_key")
    if not prototype_key:
        raise ValidationError("Prototype requires a prototype_key")

    prototype_key = str(prototype_key).lower()

    # we can't edit a prototype defined in a module
    if prototype_key in _MODULE_PROTOTYPES:
        mod = _MODULE_PROTOTYPE_MODULES.get(prototype_key, "N/A")
        raise PermissionError(
            "{} is a read-only prototype " "(defined as code in {}).".format(prototype_key, mod)
        )

    # make sure meta properties are included with defaults
    in_prototype["prototype_desc"] = in_prototype.get(
        "prototype_desc", prototype.get("prototype_desc", "")
    )
    prototype_locks = in_prototype.get(
        "prototype_locks", prototype.get("prototype_locks", _PROTOTYPE_FALLBACK_LOCK)
    )
    is_valid, err = validate_lockstring(prototype_locks)
    if not is_valid:
        raise ValidationError("Lock error: {}".format(err))
    in_prototype["prototype_locks"] = prototype_locks

    prototype_tags = [
        _to_batchtuple(tag, _PROTOTYPE_TAG_META_CATEGORY)
        for tag in make_iter(
            in_prototype.get("prototype_tags", prototype.get("prototype_tags", []))
        )
    ]
    in_prototype["prototype_tags"] = prototype_tags

    stored_prototype = DbPrototype.objects.filter(db_key=prototype_key)
    if stored_prototype:
        # edit existing prototype
        stored_prototype = stored_prototype[0]
        stored_prototype.desc = in_prototype["prototype_desc"]
        if prototype_tags:
            stored_prototype.tags.clear(category=PROTOTYPE_TAG_CATEGORY)
            stored_prototype.tags.batch_add(*in_prototype["prototype_tags"])
        stored_prototype.locks.add(in_prototype["prototype_locks"])
        stored_prototype.attributes.add("prototype", in_prototype)
    else:
        # create a new prototype
        stored_prototype = create_script(
            DbPrototype,
            key=prototype_key,
            desc=in_prototype["prototype_desc"],
            persistent=True,
            locks=prototype_locks,
            tags=in_prototype["prototype_tags"],
            attributes=[("prototype", in_prototype)],
        )
    return stored_prototype.prototype


create_prototype = save_prototype  # alias


def delete_prototype(prototype_key, caller=None):
    """
    Delete a stored prototype

    Args:
        key (str): The persistent prototype to delete.
        caller (Account or Object, optionsl): Caller aiming to delete a prototype.
            Note that no locks will be checked if`caller` is not passed.
    Returns:
        success (bool): If deletion worked or not.
    Raises:
        PermissionError: If 'edit' lock was not passed or deletion failed for some other reason.

    """
    if prototype_key in _MODULE_PROTOTYPES:
        mod = _MODULE_PROTOTYPE_MODULES.get(prototype_key.lower(), "N/A")
        raise PermissionError(
            "{} is a read-only prototype " "(defined as code in {}).".format(prototype_key, mod)
        )

    stored_prototype = DbPrototype.objects.filter(db_key__iexact=prototype_key)

    if not stored_prototype:
        raise PermissionError("Prototype {} was not found.".format(prototype_key))

    stored_prototype = stored_prototype[0]
    if caller:
        if not stored_prototype.access(caller, "edit"):
            raise PermissionError(
                "{} needs explicit 'edit' permissions to "
                "delete prototype {}.".format(caller, prototype_key)
            )
    stored_prototype.delete()
    return True


def search_prototype(key=None, tags=None, require_single=False, return_iterators=False):
    """
    Find prototypes based on key and/or tags, or all prototypes.

    Keyword Args:
        key (str): An exact or partial key to query for.
        tags (str or list): Tag key or keys to query for. These
            will always be applied with the 'db_protototype'
            tag category.
        require_single (bool): If set, raise KeyError if the result
            was not found or if there are multiple matches.
        return_iterators (bool): Optimized return for large numbers of db-prototypes.
            If set, separate returns of module based prototypes and paginate
            the db-prototype return.

    Return:
        matches (list): Default return, all found prototype dicts. Empty list if
            no match was found. Note that if neither `key` nor `tags`
            were given, *all* available prototypes will be returned.
        list, queryset: If `return_iterators` are found, this is a list of
            module-based prototypes followed by a *paginated* queryset of
            db-prototypes.

    Raises:
        KeyError: If `require_single` is True and there are 0 or >1 matches.

    Note:
        The available prototypes is a combination of those supplied in
        PROTOTYPE_MODULES and those stored in the database. Note that if
        tags are given and the prototype has no tags defined, it will not
        be found as a match.

    """
    # search module prototypes

    mod_matches = {}
    if tags:
        # use tags to limit selection
        tagset = set(tags)
        mod_matches = {
            prototype_key: prototype
            for prototype_key, prototype in _MODULE_PROTOTYPES.items()
            if tagset.intersection(prototype.get("prototype_tags", []))
        }
    else:
        mod_matches = _MODULE_PROTOTYPES

    if key:
        if key in mod_matches:
            # exact match
            module_prototypes = [mod_matches[key]]
        else:
            # fuzzy matching
            module_prototypes = [
                prototype
                for prototype_key, prototype in mod_matches.items()
                if key in prototype_key
            ]
    else:
        module_prototypes = [match for match in mod_matches.values()]

    # search db-stored prototypes

    if tags:
        # exact match on tag(s)
        tags = make_iter(tags)
        tag_categories = ["db_prototype" for _ in tags]
        db_matches = DbPrototype.objects.get_by_tag(tags, tag_categories)
    else:
        db_matches = DbPrototype.objects.all()

    if key:
        # exact or partial match on key
        exact_match = db_matches.filter(Q(db_key__iexact=key)).order_by("db_key")
        if not exact_match:
            # try with partial match instead
            db_matches = db_matches.filter(Q(db_key__icontains=key)).order_by("db_key")
        else:
            db_matches = exact_match

    # convert to prototype
    db_ids = db_matches.values_list("id", flat=True)
    db_matches = (
        Attribute.objects.filter(scriptdb__pk__in=db_ids, db_key="prototype")
        .values_list("db_value", flat=True)
        .order_by("scriptdb__db_key")
    )
    if key and require_single:
        nmodules = len(module_prototypes)
        ndbprots = db_matches.count()
        if nmodules + ndbprots != 1:
            raise KeyError(f"Found {nmodules + ndbprots} matching prototypes.")

    if return_iterators:
        # trying to get the entire set of prototypes - we must paginate
        # the result instead of trying to fetch the entire set at once
        return db_matches, module_prototypes
    else:
        # full fetch, no pagination (compatibility mode)
        return list(db_matches) + module_prototypes


def search_objects_with_prototype(prototype_key):
    """
    Retrieve all object instances created by a given prototype.

    Args:
        prototype_key (str): The exact (and unique) prototype identifier to query for.

    Returns:
        matches (Queryset): All matching objects spawned from this prototype.

    """
    return ObjectDB.objects.get_by_tag(key=prototype_key, category=PROTOTYPE_TAG_CATEGORY)


class PrototypeEvMore(EvMore):
    """
    Listing 1000+ prototypes can be very slow. So we customize EvMore to
    display an EvTable per paginated page rather than to try creating an
    EvTable for the entire dataset and then paginate it.
    """

    def __init__(self, caller, *args, session=None, **kwargs):
        """Store some extra properties on the EvMore class"""
        self.show_non_use = kwargs.pop("show_non_use", False)
        self.show_non_edit = kwargs.pop("show_non_edit", False)
        super().__init__(caller, *args, session=session, **kwargs)

    def init_pages(self, inp):
        """
        This will be initialized with a tuple (mod_prototype_list, paginated_db_query)
        and we must handle these separately since they cannot be paginated in the same
        way. We will build the prototypes so that the db-prototypes come first (they
        are likely the most volatile), followed by the mod-prototypes.
        """
        dbprot_query, modprot_list = inp
        # set the number of entries per page to half the reported height of the screen
        # to account for long descs etc
        dbprot_paged = Paginator(dbprot_query, max(1, int(self.height / 2)))

        # we separate the different types of data, so we track how many pages there are
        # of each.
        n_mod = len(modprot_list)
        self._npages_mod = n_mod // self.height + (0 if n_mod % self.height == 0 else 1)
        self._db_count = dbprot_paged.count
        self._npages_db = dbprot_paged.num_pages if self._db_count > 0 else 0
        # total number of pages
        self._npages = self._npages_mod + self._npages_db
        self._data = (dbprot_paged, modprot_list)
        self._paginator = self.prototype_paginator

    def prototype_paginator(self, pageno):
        """
        The listing is separated in db/mod prototypes, so we need to figure out which
        one to pick based on the page number. Also, pageno starts from 0.
        """
        dbprot_pages, modprot_list = self._data

        if self._db_count and pageno < self._npages_db:
            return dbprot_pages.page(pageno + 1)
        else:
            # get the correct slice, adjusted for the db-prototypes
            pageno = max(0, pageno - self._npages_db)
            return modprot_list[pageno * self.height : pageno * self.height + self.height]

    def page_formatter(self, page):
        """Input is a queryset page from django.Paginator"""
        caller = self._caller

        # get use-permissions of readonly attributes (edit is always False)
        display_tuples = []

        table = EvTable(
            "|wKey|n",
            "|wSpawn/Edit|n",
            "|wTags|n",
            "|wDesc|n",
            border="tablecols",
            crop=True,
            width=self.width,
        )

        for prototype in page:
            lock_use = caller.locks.check_lockstring(
                caller, prototype.get("prototype_locks", ""), access_type="spawn", default=True
            )
            if not self.show_non_use and not lock_use:
                continue
            if prototype.get("prototype_key", "") in _MODULE_PROTOTYPES:
                lock_edit = False
            else:
                lock_edit = caller.locks.check_lockstring(
                    caller, prototype.get("prototype_locks", ""), access_type="edit", default=True
                )
            if not self.show_non_edit and not lock_edit:
                continue
            ptags = []
            for ptag in prototype.get("prototype_tags", []):
                if is_iter(ptag):
                    if len(ptag) > 1:
                        ptags.append("{}".format(ptag[0]))
                    else:
                        ptags.append(ptag[0])
                else:
                    ptags.append(str(ptag))

            table.add_row(
                prototype.get("prototype_key", "<unset>"),
                "{}/{}".format("Y" if lock_use else "N", "Y" if lock_edit else "N"),
                ", ".join(list(set(ptags))),
                prototype.get("prototype_desc", "<unset>"),
            )

        return str(table)


def list_prototypes(
    caller, key=None, tags=None, show_non_use=False, show_non_edit=True, session=None
):
    """
    Collate a list of found prototypes based on search criteria and access.

    Args:
        caller (Account or Object): The object requesting the list.
        key (str, optional): Exact or partial prototype key to query for.
        tags (str or list, optional): Tag key or keys to query for.
        show_non_use (bool, optional): Show also prototypes the caller may not use.
        show_non_edit (bool, optional): Show also prototypes the caller may not edit.
        session (Session, optional): If given, this is used for display formatting.
    Returns:
        PrototypeEvMore: An EvMore subclass optimized for prototype listings.
        None: If no matches were found. In this case the caller has already been notified.

    """
    # this allows us to pass lists of empty strings
    tags = [tag for tag in make_iter(tags) if tag]

    dbprot_query, modprot_list = search_prototype(key, tags, return_iterators=True)

    if not dbprot_query and not modprot_list:
        caller.msg("No prototypes found.", session=session)
        return None

    # get specific prototype (one value or exception)
    return PrototypeEvMore(
        caller,
        (dbprot_query, modprot_list),
        session=session,
        show_non_use=show_non_use,
        show_non_edit=show_non_edit,
    )


def validate_prototype(
    prototype, protkey=None, protparents=None, is_prototype_base=True, strict=True, _flags=None
):
    """
    Run validation on a prototype, checking for inifinite regress.

    Args:
        prototype (dict): Prototype to validate.
        protkey (str, optional): The name of the prototype definition. If not given, the prototype
            dict needs to have the `prototype_key` field set.
        protpartents (dict, optional): The available prototype parent library. If
            note given this will be determined from settings/database.
        is_prototype_base (bool, optional): We are trying to create a new object *based on this
            object*. This means we can't allow 'mixin'-style prototypes without typeclass/parent
            etc.
        strict (bool, optional): If unset, don't require needed keys, only check against infinite
            recursion etc.
        _flags (dict, optional): Internal work dict that should not be set externally.
    Raises:
        RuntimeError: If prototype has invalid structure.
        RuntimeWarning: If prototype has issues that would make it unsuitable to build an object
            with (it may still be useful as a mix-in prototype).

    """
    assert isinstance(prototype, dict)

    if _flags is None:
        _flags = {"visited": [], "depth": 0, "typeclass": False, "errors": [], "warnings": []}

    if not protparents:
        protparents = {
            prototype.get("prototype_key", "").lower(): prototype
            for prototype in search_prototype()
        }

    protkey = protkey and protkey.lower() or prototype.get("prototype_key", None)

    if strict and not bool(protkey):
        _flags["errors"].append("Prototype lacks a `prototype_key`.")
        protkey = "[UNSET]"

    typeclass = prototype.get("typeclass")
    prototype_parent = prototype.get("prototype_parent", [])

    if strict and not (typeclass or prototype_parent):
        if is_prototype_base:
            _flags["errors"].append(
                "Prototype {} requires `typeclass` " "or 'prototype_parent'.".format(protkey)
            )
        else:
            _flags["warnings"].append(
                "Prototype {} can only be used as a mixin since it lacks "
                "a typeclass or a prototype_parent.".format(protkey)
            )

    if strict and typeclass:
        try:
            class_from_module(typeclass)
        except ImportError as err:
            _flags["errors"].append(
                "{}: Prototype {} is based on typeclass {}, which could not be imported!".format(
                    err, protkey, typeclass
                )
            )

    # recursively traverese prototype_parent chain

    for protstring in make_iter(prototype_parent):
        protstring = protstring.lower()
        if protkey is not None and protstring == protkey:
            _flags["errors"].append("Prototype {} tries to parent itself.".format(protkey))
        protparent = protparents.get(protstring)
        if not protparent:
            _flags["errors"].append(
                "Prototype {}'s prototype_parent '{}' was not found.".format(protkey, protstring)
            )
        if id(prototype) in _flags["visited"]:
            _flags["errors"].append(
                "{} has infinite nesting of prototypes.".format(protkey or prototype)
            )

        if _flags["errors"]:
            raise RuntimeError("Error: " + "\nError: ".join(_flags["errors"]))
        _flags["visited"].append(id(prototype))
        _flags["depth"] += 1
        validate_prototype(
            protparent, protstring, protparents, is_prototype_base=is_prototype_base, _flags=_flags
        )
        _flags["visited"].pop()
        _flags["depth"] -= 1

    if typeclass and not _flags["typeclass"]:
        _flags["typeclass"] = typeclass

    # if we get back to the current level without a typeclass it's an error.
    if strict and is_prototype_base and _flags["depth"] <= 0 and not _flags["typeclass"]:
        _flags["errors"].append(
            "Prototype {} has no `typeclass` defined anywhere in its parent\n "
            "chain. Add `typeclass`, or a `prototype_parent` pointing to a "
            "prototype with a typeclass.".format(protkey)
        )

    if _flags["depth"] <= 0:
        if _flags["errors"]:
            raise RuntimeError("Error: " + "\nError: ".join(_flags["errors"]))
        if _flags["warnings"]:
            raise RuntimeWarning("Warning: " + "\nWarning: ".join(_flags["warnings"]))

    # make sure prototype_locks are set to defaults
    prototype_locks = [
        lstring.split(":", 1)
        for lstring in prototype.get("prototype_locks", "").split(";")
        if ":" in lstring
    ]
    locktypes = [tup[0].strip() for tup in prototype_locks]
    if "spawn" not in locktypes:
        prototype_locks.append(("spawn", "all()"))
    if "edit" not in locktypes:
        prototype_locks.append(("edit", "all()"))
    prototype_locks = ";".join(":".join(tup) for tup in prototype_locks)
    prototype["prototype_locks"] = prototype_locks


def protfunc_parser(value, available_functions=None, testing=False, stacktrace=False, caller=None, **kwargs):
    """
    Parse a prototype value string for a protfunc and process it.

    Available protfuncs are specified as callables in one of the modules of
    `settings.PROTFUNC_MODULES`, or specified on the command line.

    Args:
        value (any): The value to test for a parseable protfunc. Only strings will be parsed for
            protfuncs, all other types are returned as-is.
        available_functions (dict, optional): Mapping of name:protfunction to use for this parsing.
            If not set, use default sources.
        stacktrace (bool, optional): If set, print the stack parsing process of the protfunc-parser.

    Keyword Args:
        session (Session): Passed to protfunc. Session of the entity spawning the prototype.
        protototype (dict): Passed to protfunc. The dict this protfunc is a part of.
        current_key(str): Passed to protfunc. The key in the prototype that will hold this value.
        caller (Object or Account): This is necessary for certain protfuncs that perform object
            searches and have to check permissions.
        any (any): Passed on to the protfunc.

    Returns:
        any: A structure to replace the string on the prototype leve.  Note
        that FunctionParser functions $funcname(*args, **kwargs) can return any
        data type to insert into the prototype.

    """
    if not isinstance(value, str):
        return value

    result = FUNC_PARSER.parse(value, raise_errors=True, return_str=False, caller=caller, **kwargs)

    return result


# Various prototype utilities


def format_available_protfuncs():
    """
    Get all protfuncs in a pretty-formatted form.

    Args:
        clr (str, optional): What coloration tag to use.
    """
    out = []
    for protfunc_name, protfunc in FUNC_PARSER.callables.items():
        out.append(
            "- |c${name}|n - |W{docs}".format(
                name=protfunc_name, docs=protfunc.__doc__.strip().replace("\n", "")
            )
        )
    return justify("\n".join(out), indent=8)


def prototype_to_str(prototype):
    """
    Format a prototype to a nice string representation.

    Args:
        prototype (dict): The prototype.
    """

    prototype = homogenize_prototype(prototype)

    header = """
|cprototype-key:|n {prototype_key}, |c-tags:|n {prototype_tags}, |c-locks:|n {prototype_locks}|n
|c-desc|n: {prototype_desc}
|cprototype-parent:|n {prototype_parent}
    \n""".format(
        prototype_key=prototype.get("prototype_key", "|r[UNSET](required)|n"),
        prototype_tags=prototype.get("prototype_tags", "|wNone|n"),
        prototype_locks=prototype.get("prototype_locks", "|wNone|n"),
        prototype_desc=prototype.get("prototype_desc", "|wNone|n"),
        prototype_parent=prototype.get("prototype_parent", "|wNone|n"),
    )
    key = aliases = attrs = tags = locks = permissions = location = home = destination = ""
    if "key" in prototype:
        key = prototype["key"]
        key = "|ckey:|n {key}".format(key=key)
    if "aliases" in prototype:
        aliases = prototype["aliases"]
        aliases = "|caliases:|n {aliases}".format(aliases=", ".join(aliases))
    if "attrs" in prototype:
        attrs = prototype["attrs"]
        out = []
        for (attrkey, value, category, locks) in attrs:
            locks = ", ".join(lock for lock in locks if lock)
            category = "|ccategory:|n {}".format(category) if category else ""
            cat_locks = ""
            if category or locks:
                cat_locks = " (|ccategory:|n {category}, ".format(
                    category=category if category else "|wNone|n"
                )
            out.append(
                "{attrkey}{cat_locks} |c=|n {value}".format(
                    attrkey=attrkey,
                    cat_locks=cat_locks,
                    locks=locks if locks else "|wNone|n",
                    value=value,
                )
            )
        attrs = "|cattrs:|n\n {attrs}".format(attrs="\n ".join(out))
    if "tags" in prototype:
        tags = prototype["tags"]
        out = []
        for (tagkey, category, data) in tags:
            out.append(
                "{tagkey} (category: {category}{dat})".format(
                    tagkey=tagkey, category=category, dat=", data: {}".format(data) if data else ""
                )
            )
        tags = "|ctags:|n\n {tags}".format(tags=", ".join(out))
    if "locks" in prototype:
        locks = prototype["locks"]
        locks = "|clocks:|n\n {locks}".format(locks=locks)
    if "permissions" in prototype:
        permissions = prototype["permissions"]
        permissions = "|cpermissions:|n {perms}".format(perms=", ".join(permissions))
    if "location" in prototype:
        location = prototype["location"]
        location = "|clocation:|n {location}".format(location=location)
    if "home" in prototype:
        home = prototype["home"]
        home = "|chome:|n {home}".format(home=home)
    if "destination" in prototype:
        destination = prototype["destination"]
        destination = "|cdestination:|n {destination}".format(destination=destination)

    body = "\n".join(
        part
        for part in (key, aliases, attrs, tags, locks, permissions, location, home, destination)
        if part
    )

    return header.lstrip() + body.strip()


def check_permission(prototype_key, action, default=True):
    """
    Helper function to check access to actions on given prototype.

    Args:
        prototype_key (str): The prototype to affect.
        action (str): One of "spawn" or "edit".
        default (str): If action is unknown or prototype has no locks

    Returns:
        passes (bool): If permission for action is granted or not.

    """
    if action == "edit":
        if prototype_key in _MODULE_PROTOTYPES:
            mod = _MODULE_PROTOTYPE_MODULES.get(prototype_key, "N/A")
            logger.log_err(
                "{} is a read-only prototype " "(defined as code in {}).".format(prototype_key, mod)
            )
            return False

    prototype = search_prototype(key=prototype_key)
    if not prototype:
        logger.log_err("Prototype {} not found.".format(prototype_key))
        return False

    lockstring = prototype.get("prototype_locks")

    if lockstring:
        return check_lockstring(None, lockstring, default=default, access_type=action)
    return default


def init_spawn_value(value, validator=None, caller=None):
    """
    Analyze the prototype value and produce a value useful at the point of spawning.

    Args:
        value (any): This can be:
            callable - will be called as callable()
            (callable, (args,)) - will be called as callable(*args)
            other - will be assigned depending on the variable type
            validator (callable, optional): If given, this will be called with the value to
                check and guarantee the outcome is of a given type.
            caller (Object or Account): This is necessary for certain protfuncs that perform object
                searches and have to check permissions.

    Returns:
        any (any): The (potentially pre-processed value to use for this prototype key)

    """
    validator = validator if validator else lambda o: o
    if callable(value):
        value = validator(value())
    elif value and isinstance(value, (list, tuple)) and callable(value[0]):
        # a structure (callable, (args, ))
        args = value[1:]
        value = validator(value[0](*make_iter(args)))
    else:
        value = validator(value)
    result = protfunc_parser(value, caller=caller)
    if result != value:
        return validator(result)
    return result


def value_to_obj_or_any(value):
    "Convert value(s) to Object if possible, otherwise keep original value"
    stype = type(value)
    if is_iter(value):
        if stype == dict:
            return {
                value_to_obj_or_any(key): value_to_obj_or_any(val) for key, val in value.items()
            }
        else:
            return stype([value_to_obj_or_any(val) for val in value])
    obj = dbid_to_obj(value, ObjectDB)
    return obj if obj is not None else value


def value_to_obj(value, force=True):
    "Always convert value(s) to Object, or None"
    stype = type(value)
    if is_iter(value):
        if stype == dict:
            return {value_to_obj_or_any(key): value_to_obj_or_any(val) for key, val in value.iter()}
        else:
            return stype([value_to_obj_or_any(val) for val in value])
    return dbid_to_obj(value, ObjectDB)