vtt/src/ttfrog/schema.py

from __future__ import annotations

from datetime import datetime
from enum import StrEnum
from typing import List

from grung.types import (
    BackReference,
    Collection,
    DateTime,
    Dict,
    Field,
    Password,
    Pointer,
    Record,
    TextFilePointer,
    Timestamp,
)
from tinydb import where


class Permissions(StrEnum):
    READ = "r"
    WRITE = "w"
    DELETE = "d"


class Page(Record):
    """
    A page in the wiki. Just about everything in the databse is either a Page or a subclass of a Page.
    """

    @classmethod
    def fields(cls):
        # fmt: off
        return [
            *super().fields(),
            Field("uri", unique=True),                 # The URI for the page, relative to the app's VIEW_URI
            Field("name"),                             # The portion of the URI after the last /
            TextFilePointer("body", extension='.md'),  # The main content blob of the page
            Collection("members", Page),               # The pages that exist below this page's URI
            BackReference("parent", value_type=Page),  # The page that exists above this page's URI
            Pointer("author", value_type=User),        # The last user to touch the page.
            DateTime("created"),                       # When the page was created
            Timestamp("last_modified"),                # The last time the page was modified.
            Dict("acl"),
        ]

    # fmt: on

    def before_insert(self, db):
        """
        Make the following adjustments before saving this record:
          * Derive the URI from the hierarchy of the parent.
        """
        if not self.name:
            raise Exception("Must provide a name")

        super().before_insert(db)

        now = datetime.utcnow()
        if not self.doc_id and self.created < now:
            self.created = now

        self.uri = (self.parent.uri + "/" if self.parent and self.parent.uri != "/" else "") + self.name

    def after_insert(self, db):
        """
        After saving this record, ensure that any page in the members collection is updated with the
        correct URI. This ensures that if a page is moved from one collection to another, the URI is updated.
        """
        super().after_insert(db)
        if not hasattr(self, "members"):
            return
        for child in self.members:
            obj = BackReference.dereference(child, db)
            obj.uri = f"{self.uri}/{obj.name}"
            child = db.save(obj)

    def add_member(self, child: Record):
        from ttfrog import app

        app.check_state()
        self.members = list(set(self.members + [app.db.save(child)]))
        app.db.save(self)
        return self.get_child(child)

    def get_child(self, obj: Record):
        for page in self.members:
            if page[page._metadata.primary_key] == obj[obj._metadata.primary_key]:
                return page
        return None

    def set_permissions(self, entity: Entity, permissions: List) -> str:
        from ttfrog import app

        app.check_state()

        perms = "".join(permissions)
        self.acl[entity.reference] = perms
        app.db.save(self)
        return perms

    def get_acl_for_entity(self, entity) -> (str, str | None):
        """
        Search upward through the page hierarchy looking for one with an ACL that either
        has a grant for the entity we care about, or at least one group in which the entity is a member.
        """
        from ttfrog import app

        app.check_state()

        def find_acl(obj):
            if hasattr(obj, "acl"):
                if entity.reference in obj.acl:
                    return {entity.reference: obj.acl[entity.reference]}

                group_grants = {}
                for ref, grant in obj.acl.items():
                    (table_name, pkey, pval) = ref.split("::")
                    if table_name == "Group":
                        group = app.db.Group.get(where(pkey) == pval, recurse=False)
                        if entity.reference in group.members:
                            group_grants[ref] = grant
                if group_grants:
                    return group_grants

            if hasattr(obj, "parent"):
                return find_acl(obj.parent)
            return {"": ""}

        return find_acl(self)


class Entity(Page):
    @classmethod
    def fields(cls):
        inherited = [field for field in super().fields() if field.name not in ("members", "uid")]
        return inherited + [
            Field("name", primary_key=True),
        ]

    def has_permission(self, record: Record, requested: str) -> bool | None:
        for entity, grants in record.get_acl_for_entity(self).items():
            if requested in grants:
                return True
        return False

    def can_read(self, record: Record):
        return self.has_permission(record, Permissions.READ)

    def can_write(self, record: Record):
        return self.has_permission(record, Permissions.WRITE)

    def can_delete(self, record: Record):
        return self.has_permission(record, Permissions.DELETE)


class User(Entity):
    """
    A website user, editable as a wiki page.
    """

    @classmethod
    def fields(cls):
        return super().fields() + [
            Field("email", unique=True),
            Password("password"),
        ]

    def check_credentials(self, username: str, password: str) -> bool:
        return username == self.name and self._metadata.fields["password"].compare(password, self.password)


class Group(Entity):
    """
    A set of users, editable as a wiki page.
    """

    @classmethod
    def fields(cls):
        return super().fields() + [Collection("members", Entity)]


class NPC(Page):
    """
    An NPC, editable as a wiki page.
    """