Add commands for editing aliases (#5108)

* [Alias] Added alias edit and alias global edit

* Comment and whitespace only changes

* Docstring fix

* Remove more whitespace

* Add `the` before some English purists make a PR for this...

Co-authored-by: npc203 <npc203@users.noreply.github.com>
Co-authored-by: jack1142 <6032823+jack1142@users.noreply.github.com>

redbot/cogs/alias/alias.py

@@ -338,6 +338,75 @@ class Alias(commands.Cog):
             )
         )
 
+    @checks.mod_or_permissions(manage_guild=True)
+    @alias.command(name="edit")
+    @commands.guild_only()
+    async def _edit_alias(self, ctx: commands.Context, alias_name: str, *, command):
+        """Edit an existing alias in this server."""
+        # region Alias Add Validity Checking
+        alias = await self._aliases.get_alias(ctx.guild, alias_name)
+        if not alias:
+            await ctx.send(
+                _("The alias with the name {name} does not exist.").format(name=alias_name)
+            )
+            return
+
+        given_command_exists = self.bot.get_command(command.split(maxsplit=1)[0]) is not None
+        if not given_command_exists:
+            await ctx.send(_("You attempted to edit an alias to a command that doesn't exist."))
+            return
+        # endregion
+
+        # So we figured it is a valid alias and the command exists
+        # we can go ahead editing the command
+        try:
+            if await self._aliases.edit_alias(ctx, alias_name, command):
+                await ctx.send(
+                    _("The alias with the trigger `{name}` has been edited sucessfully.").format(
+                        name=alias_name
+                    )
+                )
+            else:
+                # This part should technically never be reached...
+                await ctx.send(
+                    _("Alias with the name `{name}` was not found.").format(name=alias_name)
+                )
+        except ArgParseError as e:
+            return await ctx.send(" ".join(e.args))
+
+    @checks.is_owner()
+    @global_.command(name="edit")
+    async def _edit_global_alias(self, ctx: commands.Context, alias_name: str, *, command):
+        """Edit an existing global alias."""
+        # region Alias Add Validity Checking
+        alias = await self._aliases.get_alias(None, alias_name)
+        if not alias:
+            await ctx.send(
+                _("The alias with the name {name} does not exist.").format(name=alias_name)
+            )
+            return
+
+        given_command_exists = self.bot.get_command(command.split(maxsplit=1)[0]) is not None
+        if not given_command_exists:
+            await ctx.send(_("You attempted to edit an alias to a command that doesn't exist."))
+            return
+        # endregion
+
+        try:
+            if await self._aliases.edit_alias(ctx, alias_name, command, global_=True):
+                await ctx.send(
+                    _("The alias with the trigger `{name}` has been edited sucessfully.").format(
+                        name=alias_name
+                    )
+                )
+            else:
+                # This part should technically never be reached...
+                await ctx.send(
+                    _("Alias with the name `{name}` was not found.").format(name=alias_name)
+                )
+        except ArgParseError as e:
+            return await ctx.send(" ".join(e.args))
+
     @alias.command(name="help")
     async def _help_alias(self, ctx: commands.Context, alias_name: str):
         """Try to execute help for the base command of the alias."""

redbot/cogs/alias/alias_entry.py

@@ -187,9 +187,10 @@ class AliasCache:
 
         return None
 
-    async def add_alias(
-        self, ctx: commands.Context, alias_name: str, command: str, global_: bool = False
-    ) -> AliasEntry:
+    @staticmethod
+    def format_command_for_alias(command: str) -> str:
+        # This was present in add_alias previously
+        # Made this into a separate method so as to reuse the same code in edit_alias
         indices = findall(r"{(\d*)}", command)
         if indices:
             try:
@@ -206,6 +207,12 @@ class AliasCache:
                     + ", ".join(str(i + low) for i in gaps)
                 )
             command = command.format(*(f"{{{i}}}" for i in range(-low, high + low + 1)))
+        return command
+
+    async def add_alias(
+        self, ctx: commands.Context, alias_name: str, command: str, global_: bool = False
+    ) -> AliasEntry:
+        command = self.format_command_for_alias(command)
 
         if global_:
             alias = AliasEntry(alias_name, command, ctx.author.id, None)
@@ -225,6 +232,32 @@ class AliasCache:
 
         return alias
 
+    async def edit_alias(
+        self, ctx: commands.Context, alias_name: str, command: str, global_: bool = False
+    ) -> bool:
+        command = self.format_command_for_alias(command)
+
+        if global_:
+            settings = self.config
+        else:
+            settings = self.config.guild(ctx.guild)
+
+        async with settings.entries() as aliases:
+            for index, alias in enumerate(aliases):
+                if alias["name"] == alias_name:
+                    alias_edited = AliasEntry.from_json(alias)
+                    alias_edited.command = command
+                    aliases[index] = alias_edited.to_json()
+
+                    if self._cache_enabled:
+                        if global_:
+                            self._aliases[None][alias_edited.name] = alias_edited
+                        else:
+                            self._aliases[ctx.guild.id][alias_edited.name] = alias_edited
+                    return True
+
+        return False
+
     async def delete_alias(
         self, ctx: commands.Context, alias_name: str, global_: bool = False
     ) -> bool: