SNIPPETS: Add base functionality for snippet edit.

bot/cogs/snippets.py

@@ -1,3 +1,5 @@
+from typing import Optional
+
 import discord
 from discord.ext import commands
 from libs.utils import GuildContext
@@ -82,10 +84,44 @@ async def show(self, ctx: GuildContext, name: str):
     async def list(self, ctx, *args):
         await ctx.send("placeholder for snippet list")
 
+    async def edit_prompt_user(self, ctx: GuildContext, name: str):
+        raise NotImplementedError("TODO: Add prompt for editing snippet.")
+
     @commands.guild_only()
     @snippet_cmd.command()
-    async def edit(self, ctx, *args):
-        await ctx.send("placeholder for snippet edit")
+    async def edit(self, ctx: GuildContext, name: str, content: Optional[str]):
+        if content is None:
+            await self.edit_prompt_user(ctx, name)
+            return
+        query = """
+        UPDATE snippets
+        SET content = $3
+        WHERE guild_id = $1 AND name = $2
+        RETURNING name
+        """
+
+        result = await self._bot.pool.fetchrow(query, ctx.guild.id, name, content)
+        if result is None:
+            await ctx.reply(
+                embed=discord.Embed(
+                    title="Oops...",
+                    colour=discord.Colour.red(),
+                    description=f"Cannot edit snippet `{name}` as there is no such "
+                    + "snippet. To create a new snippet with the corresponding "
+                    + f"name, please run `snippet new {name} <snippet text>`.",
+                ),
+                ephemeral=True,
+            )
+        else:
+            await ctx.reply(
+                embed=discord.Embed(
+                    title="Snippet changed",
+                    colour=discord.Colour.green(),
+                    description=f"The contents of snippet {result[0]} has been "
+                    + f"changed to \n\n{content}",
+                ),
+                ephemeral=True,
+            )
 
 
 async def setup(bot: Rodhaj):