Store command ids on tree

discord/app_commands/tree.py

@@ -161,6 +161,9 @@ class CommandTree(Generic[ClientT]):
         # it's uncommon and N=5 anyway.
         self._context_menus: Dict[Tuple[str, Optional[int], int], ContextMenu] = {}
 
+        self._global_command_ids: Dict[str, int] = {}
+        self._guild_command_ids: Dict[Tuple[str, int], int] = {}
+
     async def fetch_command(self, command_id: int, /, *, guild: Optional[Snowflake] = None) -> AppCommand:
         """|coro|
 
@@ -198,7 +201,9 @@ class CommandTree(Generic[ClientT]):
         else:
             command = await self._http.get_guild_command(self.client.application_id, guild.id, command_id)
 
-        return AppCommand(data=command, state=self._state)
+        res = AppCommand(data=command, state=self._state)
+        self._store_command_id((res, res.id))
+        return res
 
     async def fetch_commands(self, *, guild: Optional[Snowflake] = None) -> List[AppCommand]:
         """|coro|
@@ -238,7 +243,79 @@ class CommandTree(Generic[ClientT]):
         else:
             commands = await self._http.get_guild_commands(self.client.application_id, guild.id)
 
-        return [AppCommand(data=data, state=self._state) for data in commands]
+        res = [AppCommand(data=command, state=self._state) for command in commands]
+        self._store_command_id(*((cmd, cmd.id) for cmd in res))
+        return res
+
+    def get_command_id(
+        self, command: Union[AppCommand, Command, ContextMenu, Group, str], /, *, guild: Optional[Snowflake] = None
+    ) -> Optional[int]:
+        """Gets the command ID for a command.
+
+        Parameters
+        -----------
+        name: Union[:class:`~discord.app_commands.Command`, :class:`~discord.app_commands.ContextMenu`, :class:`~discord.app_commands.Group`, :class:`str`]
+            The name of the command to get the ID for.
+        guild: Optional[:class:`~discord.abc.Snowflake`]
+            The guild to get the command ID for. If not passed then the global command
+            ID is fetched instead.
+
+        Returns
+        --------
+        Optional[:class:`~discord.app_commands.CommandID`]
+            The command ID if found, otherwise ``None``.
+
+            .. note::
+
+                Group commands will return the ID of the root command. Subcommands do not have their own IDs.
+        """
+        name: Optional[str] = None
+
+        if isinstance(command, AppCommand):
+            return command.id
+        elif isinstance(command, (Command, Group)):
+            name = (command.root_parent or command).name
+        elif isinstance(command, ContextMenu):
+            name = command.name
+        elif isinstance(command, str):
+            name = command.split()[0]
+
+        return self._global_command_ids.get(name) if guild is None else self._guild_command_ids.get((name, guild.id))
+
+    def get_command_mention(
+        self, command: Union[AppCommand, Command, ContextMenu, Group, str], /, *, guild: Optional[Snowflake] = None
+    ) -> str | None:
+        """Gets the mention string for a command.
+
+        Parameters
+        -----------
+        command: Union[:class:`~discord.app_commands.Command`, :class:`~discord.app_commands.ContextMenu`, :class:`~discord.app_commands.Group`, :class:`str`]
+            The command to get the mention string for.
+
+        Returns
+        --------
+        Optional[:class:`str`]
+            The mention string for the command if found, otherwise ``None``.
+
+            .. note::
+
+                Remember that groups cannot be mentioned, only with a subcommand.
+        """
+        if isinstance(command, AppCommand):
+            return command.mention
+
+        command_id = self.get_command_id(command, guild=guild)
+        if command_id is None:
+            return None
+
+        if isinstance(command, (Command, Group)):
+            full_name = command.qualified_name
+        elif isinstance(command, ContextMenu):
+            full_name = command.name
+        elif isinstance(command, str):
+            full_name = command
+
+        return f'</{full_name}:{command_id}>'
 
     def copy_global_to(self, *, guild: Snowflake) -> None:
         """Copies all global commands to the specified guild.
@@ -1134,7 +1211,29 @@ class CommandTree(Generic[ClientT]):
                 raise CommandSyncFailure(e, commands) from None
             raise
 
-        return [AppCommand(data=d, state=self._state) for d in data]
+        res = [AppCommand(data=d, state=self._state) for d in data]
+        self._store_command_id(*((cmd, cmd.id) for cmd in res))
+        return res
+
+    def _store_command_id(self, *commands: Tuple[AppCommand | ContextMenu | Command[Any, ..., Any] | Group, int]) -> None:
+        for command, command_id in commands:
+            if isinstance(command, AppCommand):
+                guild_id = command.guild_id
+                if guild_id is None:
+                    self._global_command_ids[command.name] = command_id
+                else:
+                    key = (command.name, guild_id)
+                    self._guild_command_ids[key] = command_id
+            else:
+                guild_ids = command._guild_ids
+                name = (command.root_parent or command).name if not isinstance(command, ContextMenu) else command.name
+
+                if not guild_ids:
+                    self._global_command_ids[name] = command_id
+                else:
+                    for guild_id in guild_ids:
+                        key = (name, guild_id)
+                        self._guild_command_ids[key] = command_id
 
     async def _dispatch_error(self, interaction: Interaction[ClientT], error: AppCommandError, /) -> None:
         command = interaction.command
@@ -1231,6 +1330,8 @@ class CommandTree(Generic[ClientT]):
         if ctx_menu is None:
             raise CommandNotFound(name, [], AppCommandType(type))
 
+        self._store_command_id((ctx_menu, int(data['id'])))
+
         resolved = Namespace._get_resolved_items(interaction, data.get('resolved', {}))
 
         # This is annotated as str | int but realistically this will always be str
@@ -1281,6 +1382,7 @@ class CommandTree(Generic[ClientT]):
             return
 
         command, options = self._get_app_command_options(data)
+        self._store_command_id((command, int(data['id'])))
 
         # Pre-fill the cached slot to prevent re-computation
         interaction._cs_command = command