add /fortune command

requirements.txt

@@ -3,3 +3,4 @@ hikari-arc==1.1.0
 ruff==0.2.0
 pre-commit==3.6.0
 python-dotenv==1.0.1
+fortune-python==1.1.1

src/extensions/fortune.py

@@ -0,0 +1,58 @@
+import arc
+import hikari
+from fortune import fortune
+
+fortune_cmd = arc.GatewayPlugin(name="fortune")
+
+
+@fortune_cmd.include
+@arc.slash_command("fortune", "Send a user a random Fortune!")
+async def fortune_command(
+    ctx: arc.GatewayContext,
+    user: arc.Option[hikari.User, arc.UserParams("A user")] = None,
+) -> None:
+    """Send a user a random Fortune!"""
+
+    # generate fortune
+    fortune_message = fortune()
+    assert len(fortune_message) > 0
+
+    if user is not None:
+        message = f"Dear {user.mention},\n```{fortune_message}```"
+    else:
+        message = f"```{fortune_message}```"
+
+        # do not exceed Discord's 2000 character limit
+    if len(message) > 2000:
+        await ctx.respond(
+            "The generated fortune is too long to send. Please try again.",
+            flags=hikari.MessageFlag.EPHEMERAL,
+        )
+
+    # send fortune in a codeblock
+    await ctx.respond(message)
+
+
+@fortune_cmd.set_error_handler
+async def fortune_error_handler(ctx: arc.GatewayContext, exc: Exception) -> None:
+    user = ctx.get_option("user", arc.OptionType.USER)
+    assert user is not None
+
+    if isinstance(exc, AssertionError):
+        await ctx.respond(
+            "❌ Failed to generate the fortune. Please try again.",
+            flags=hikari.MessageFlag.EPHEMERAL,
+        )
+        return
+    if isinstance(exc, hikari.NotFoundError):
+        await ctx.respond(
+            "❌ Blockbot can't find that user.", flags=hikari.MessageFlag.EPHEMERAL
+        )
+        return
+
+    raise exc
+
+
+@arc.loader
+def loader(client: arc.GatewayClient) -> None:
+    client.add_plugin(fortune_cmd)