Block users from using external emoji (Fixes #2)

+ Scan incoming messages for emoji, if they are from an external server they are blocked
+ clippy + fmt

src/discord/commands.rs

@@ -474,11 +474,7 @@ async fn handle_errors(
     match command_result {
         Ok(()) => println!("Successfully processed command '{}'", command_name),
         Err(err) => {
-            let reply_msg = format!(
-                "Command '{}' returned an error. {}",
-                command_name,
-                err.to_string()
-            );
+            let reply_msg = format!("Command '{}' returned an error. {}", command_name, err,);
             println!("{}", reply_msg);
             msg.reply(&ctx.http, reply_msg).await.unwrap();
         }

src/discord/event_handler.rs

@@ -3,6 +3,7 @@ use serenity::client::{Context, EventHandler};
 use serenity::http::AttachmentType;
 use serenity::model::channel::Message;
 use serenity::model::gateway::Ready;
+use serenity::utils::parse_emoji;
 
 use crate::discord::helper::send_webhook_msg_to_player_channels;
 use crate::game::global_data::GlobalData;
@@ -40,6 +41,23 @@ impl EventHandler for Handler {
             let guild = msg.guild(&ctx.cache).await.unwrap();
             let user_msg = msg.content.clone();
 
+            let re = regex::Regex::new(r"<a?:.+:\d+>").unwrap();
+
+            for emoji_cap in re.captures_iter(&user_msg) {
+                if let Some(emoji) = parse_emoji(&emoji_cap[0]) {
+                    if !msg
+                        .guild(&ctx.cache)
+                        .await
+                        .unwrap()
+                        .emojis
+                        .contains_key(&emoji.id)
+                    {
+                        msg.reply(&ctx.http, "Your messages contains custom emojis from outside this guild and has been blocked.").await.unwrap();
+                        return;
+                    }
+                }
+            }
+
             let attachments: Vec<AttachmentType> = msg
                 .attachments
                 .iter()

src/discord/helper.rs

@@ -114,7 +114,6 @@ pub async fn send_webhook_msg(
     msg: &str,
     attachment: Option<Vec<AttachmentType<'_>>>,
 ) -> error::Result<()> {
-
     let webhook = http.get_webhook(webhook_id).await?;
 
     webhook