add command to list features

Signed-off-by: Jason Volk <jason@zemos.net>

src/admin/server/commands.rs

-use conduit::{utils::time, warn, Err, Result};
+use std::fmt::Write;
+
+use conduit::{info, utils::time, warn, Err, Result};
 use ruma::events::room::message::RoomMessageEventContent;
 
 use crate::services;
@@ -19,6 +21,47 @@ pub(super) async fn show_config(_body: Vec<&str>) -> Result<RoomMessageEventCont
 	Ok(RoomMessageEventContent::text_plain(format!("{}", services().globals.config)))
 }
 
+pub(super) async fn list_features(
+	_body: Vec<&str>, available: bool, enabled: bool, comma: bool,
+) -> Result<RoomMessageEventContent> {
+	let delim = if comma {
+		","
+	} else {
+		" "
+	};
+	if enabled && !available {
+		let features = info::rustc::features().join(delim);
+		let out = format!("```\n{features}\n```");
+		return Ok(RoomMessageEventContent::text_markdown(out));
+	}
+
+	if available && !enabled {
+		let features = info::cargo::features().join(delim);
+		let out = format!("```\n{features}\n```");
+		return Ok(RoomMessageEventContent::text_markdown(out));
+	}
+
+	let mut features = String::new();
+	let enabled = info::rustc::features();
+	let available = info::cargo::features();
+	for feature in available {
+		let active = enabled.contains(&feature.as_str());
+		let emoji = if active {
+			"✅"
+		} else {
+			"❌"
+		};
+		let remark = if active {
+			"[enabled]"
+		} else {
+			""
+		};
+		writeln!(features, "{emoji} {feature} {remark}")?;
+	}
+
+	Ok(RoomMessageEventContent::text_markdown(features))
+}
+
 pub(super) async fn memory_usage(_body: Vec<&str>) -> Result<RoomMessageEventContent> {
 	let services_usage = services().memory_usage().await?;
 	let database_usage = services().db.db.memory_usage()?;

src/admin/server/mod.rs

@@ -14,6 +14,18 @@ pub(super) enum ServerCommand {
 	/// - Show configuration values
 	ShowConfig,
 
+	/// - List the features built into the server
+	ListFeatures {
+		#[arg(short, long)]
+		available: bool,
+
+		#[arg(short, long)]
+		enabled: bool,
+
+		#[arg(short, long)]
+		comma: bool,
+	},
+
 	/// - Print database memory usage statistics
 	MemoryUsage,
 
@@ -54,6 +66,11 @@ pub(super) async fn process(command: ServerCommand, body: Vec<&str>) -> Result<R
 	Ok(match command {
 		ServerCommand::Uptime => uptime(body).await?,
 		ServerCommand::ShowConfig => show_config(body).await?,
+		ServerCommand::ListFeatures {
+			available,
+			enabled,
+			comma,
+		} => list_features(body, available, enabled, comma).await?,
 		ServerCommand::MemoryUsage => memory_usage(body).await?,
 		ServerCommand::ClearCaches => clear_caches(body).await?,
 		ServerCommand::ListBackups => list_backups(body).await?,