Add prefix customization command

src/database/models.rs

@@ -253,6 +253,36 @@ impl Server {
         }
     }
 
+    pub async fn get_or_create_by_id(
+        id: u64,
+        session: &Session,
+        http: &Client,
+    ) -> Result<Self, DatabaseOrDiscordError> {
+        let server = Server::get_by_id(id, session)
+            .await
+            .map_err(DatabaseOrDiscordError::Database)?;
+
+        if let Some(server) = server {
+            Ok(server)
+        } else {
+            let server: Server = http
+                .guild(Id::new(id))
+                .await
+                .map_err(DatabaseOrDiscordError::Discord)?
+                .model()
+                .await
+                .map_err(|_| DatabaseOrDiscordError::DiscordDeserializationFailed)?
+                .into();
+
+            server
+                .insert(session)
+                .await
+                .map_err(DatabaseOrDiscordError::Database)?;
+
+            Ok(server)
+        }
+    }
+
     pub async fn insert(&self, session: &Session) -> Result<(), DatabaseError> {
         session
             .query_unpaged(

src/framework/commands/arguments.rs

@@ -31,6 +31,10 @@ impl FromArguments for String {
     }
 }
 
+/// Consumes the entire remaining string as a single argument. If no string is remaining, it
+/// returns an empty string.
+///
+/// Parsing this argument type never fails.
 pub struct GreedyString(pub String);
 
 impl FromArguments for GreedyString {

src/framework/commands/mod.rs

@@ -20,6 +20,9 @@ pub enum CommandError {
 
     #[error("A database operation failed due to an inconsistent state")]
     DatabaseInconsistentState,
+
+    #[error("The command was used in DMs, but it can only be used in servers")]
+    ServerCommandRunInDMs,
 }
 
 #[async_trait]
@@ -66,7 +69,10 @@ pub fn get_command_parts<'a>(prefix: &str, message: &'a str) -> Option<CommandPa
         .to_ascii_lowercase()
         .starts_with(&prefix.to_ascii_lowercase())
     {
-        let message = message_trimmed_start.split_at(prefix.len()).1.trim_ascii_start();
+        let message = message_trimmed_start
+            .split_at(prefix.len())
+            .1
+            .trim_ascii_start();
 
         match message.split_once(" ") {
             Some((name, args)) => Some(CommandParts::new(name, args)),

src/framework/commands/runner.rs

@@ -32,7 +32,10 @@ impl<T: Send + Sync + 'static> OnMessageHandler<T> for CommandRunner {
 
                 if let Some(command) = command {
                     command
-                        .execute(CommandContext::new(event, rt.clone(), &prefixes[0]), parts.args)
+                        .execute(
+                            CommandContext::new(event, rt.clone(), &prefixes[0]),
+                            parts.args,
+                        )
                         .await?;
 
                     break;

src/groups/servers/commands.rs

@@ -0,0 +1,83 @@
+use async_trait::async_trait;
+
+use crate::{
+    constants::DEFAULT_PREFIX,
+    database::models::Server,
+    discord::sanitizing::SanitizeDiscordMarkdown,
+    framework::commands::{
+        Command, CommandError,
+        arguments::{Argument, GreedyString, ParseArguments},
+        context::CommandContext,
+    },
+    state::State,
+};
+
+#[derive(Debug)]
+pub struct PrefixCommand;
+
+#[async_trait]
+impl Command<State> for PrefixCommand {
+    fn name(&self) -> &'static str {
+        "prefix"
+    }
+
+    fn aliases(&self) -> &'static [&'static str] {
+        &["p"]
+    }
+
+    fn description(&self) -> &'static str {
+        "Sets the command prefix for the server."
+    }
+
+    fn arguments(&self) -> &'static [Argument] {
+        &[Argument {
+            name: "prefix",
+            is_optional: true,
+            is_greedy: true,
+        }]
+    }
+
+    async fn execute(
+        &self,
+        ctx: CommandContext<'_, State>,
+        args: &str,
+    ) -> Result<(), CommandError> {
+        let prefix: GreedyString = ParseArguments::parse(args).unwrap();
+        let mut prefix = prefix.trim();
+
+        let mut server = Server::get_or_create_by_id(
+            ctx.event
+                .guild_id
+                .ok_or(CommandError::ServerCommandRunInDMs)?
+                .get(),
+            &ctx.rt.state.db,
+            &ctx.rt.http,
+        )
+        .await
+        .inspect_err(|e| log::error!("Failed to get or create server: {e}"))
+        .map_err(|_| CommandError::DatabaseQueryFailed)?;
+
+        if prefix.is_empty() {
+            prefix = DEFAULT_PREFIX;
+        }
+
+        server.prefix = prefix.to_string();
+        server
+            .upsert(&ctx.rt.state.db)
+            .await
+            .map_err(|_| CommandError::DatabaseQueryFailed)?;
+
+        ctx.send()
+            .content(format!(
+                "✅ Prefix updated! Run `{}help` to see the new prefix.",
+                prefix.sanitize(false)
+            ))
+            .await
+            .map_err(|e| {
+                log::error!("Failed to send prefix update message: {e}");
+                CommandError::MessageSendingFailed
+            })?;
+
+        Ok(())
+    }
+}

src/groups/servers/mod.rs

@@ -1,6 +1,7 @@
-//! Adding, updating, and removing servers from the database.
+//! Syncing servers with the database and server configuration commands.
 //!
 //! This sub-module is responsible for registering servers in the database, updating them when they
 //! update, and removing them when they get deleted or Payphone is kicked.
 
+pub mod commands;
 pub mod events;

src/main.rs

@@ -116,18 +116,26 @@ use tower_http::services::ServeDir;
 use twilight_gateway::Intents;
 
 use crate::{
-    cli::{Args, Commands}, constants::DEFAULT_PREFIX, database::models::Server, framework::{
+    cli::{Args, Commands},
+    constants::DEFAULT_PREFIX,
+    database::models::Server,
+    framework::{
         bot::{Bot, PrefixGetter},
         runtime::Runtime,
-    }, groups::{
+    },
+    groups::{
         about::{commands::HelpCommand, components::HelpGoBackButton},
         calls::{
             commands::{CallCommand, HangupCommand, SkipCommand},
             events::MessageRedirector,
         },
         gateway::events::{ReadyHandler, ReconnectHandler},
-        servers::events::{ServerCreateHandler, ServerDeleteHandler, ServerUpdateHandler},
+        servers::{
-    }, state::State
+            commands::PrefixCommand,
+            events::{ServerCreateHandler, ServerDeleteHandler, ServerUpdateHandler},
+        },
+    },
+    state::State,
 };
 
 mod cli;
@@ -217,6 +225,7 @@ async fn start(token: String, database_addr: String) {
         .command(CallCommand::new())
         .command(SkipCommand)
         .command(HangupCommand)
+        .command(PrefixCommand)
         .component(HelpGoBackButton)
         .on_ready(ReadyHandler)
         .on_reconnect(ReconnectHandler)