nix: add clap completions

Cargo.lock

@@ -201,6 +201,15 @@ dependencies = [
  "terminal_size",
 ]
 
+[[package]]
+name = "clap_complete"
+version = "4.5.65"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "430b4dc2b5e3861848de79627b2bedc9f3342c7da5173a14eaa5d0f8dc18ae5d"
+dependencies = [
+ "clap",
+]
+
 [[package]]
 name = "clap_derive"
 version = "4.5.49"
@@ -815,6 +824,7 @@ dependencies = [
  "bytes",
  "chrono",
  "clap",
+ "clap_complete",
  "futures-util",
  "nix",
  "sd-notify",

Cargo.toml

@@ -30,6 +30,7 @@ sd-notify = "0.4.5"
 serde_json = "1.0.148"
 uucore = { version = "0.5.0", features = ["utmpx"] }
 zlink = { version = "0.2.0", features = ["introspection"] }
+clap_complete = "4.5.65"
 
 [lib]
 name = "roowho2_lib"

nix/package.nix

@@ -2,6 +2,7 @@
   lib
 , rustPlatform
 , stdenv
+, buildPackages
 , installShellFiles
 , versionCheckHook
 
@@ -20,6 +21,21 @@ rustPlatform.buildRustPackage {
 
   RUSTFLAGS = "-Zhigher-ranked-assumptions";
 
+  nativeBuildInputs = [ installShellFiles ];
+  postInstall = let
+    emulator = stdenv.hostPlatform.emulator buildPackages;
+    installShellCompletions = lib.mapCartesianProduct ({ shell, command }: ''
+      (
+        export PATH="$out/bin:$PATH"
+        "${emulator}" "${command}" --completions=${shell} > "$TMP/${command}.${shell}"
+      )
+      installShellCompletion "--${shell}" --cmd "${command}" "$TMP/${command}.${shell}"
+    '') {
+      shell = [ "bash" "zsh" "fish" ];
+      command = [ "rwho" "ruptime" ];
+    };
+  in lib.concatStringsSep "\n" installShellCompletions;
+
   meta = with lib; {
     license = licenses.mit;
     platforms = platforms.linux ++ platforms.darwin;

src/bin/ruptime.rs

@@ -1,6 +1,7 @@
 use anyhow::Context;
 use chrono::{Duration, Utc};
-use clap::Parser;
+use clap::{CommandFactory, Parser};
+use clap_complete::{Shell, generate};
 
 use roowho2_lib::{proto::WhodStatusUpdate, server::varlink_api::RwhodClientProxy};
 
@@ -44,12 +45,27 @@ pub struct Args {
     /// Output in JSON format
     #[arg(long, short)]
     json: bool,
+
+    /// Generate shell completion scripts for the specified shell
+    /// and print them to stdout.
+    #[arg(long, value_enum, hide = true)]
+    completions: Option<Shell>,
 }
 
 #[tokio::main]
 async fn main() -> anyhow::Result<()> {
     let args = Args::parse();
 
+    if let Some(shell) = args.completions {
+        generate(
+            shell,
+            &mut Args::command(),
+            "ruptime",
+            &mut std::io::stdout(),
+        );
+        return Ok(());
+    }
+
     let mut conn = zlink::unix::connect("/run/roowho2/roowho2.varlink")
         .await
         .expect("Failed to connect to rwhod server");

src/bin/rwho.rs

@@ -1,5 +1,6 @@
 use anyhow::Context;
-use clap::Parser;
+use clap::{CommandFactory, Parser};
+use clap_complete::{Shell, generate};
 use roowho2_lib::{proto::WhodUserEntry, server::varlink_api::RwhodClientProxy};
 
 /// Check who is logged in on local machines.
@@ -29,12 +30,27 @@ pub struct Args {
     /// Output in JSON format
     #[arg(long, short)]
     json: bool,
+
+    /// Generate shell completion scripts for the specified shell
+    /// and print them to stdout.
+    #[arg(long, value_enum, hide = true)]
+    completions: Option<Shell>,
 }
 
 #[tokio::main]
 async fn main() -> anyhow::Result<()> {
     let args = Args::parse();
 
+    if let Some(shell) = args.completions {
+        generate(
+            shell,
+            &mut Args::command(),
+            "rwho",
+            &mut std::io::stdout(),
+        );
+        return Ok(());
+    }
+
     let mut conn = zlink::unix::connect("/run/roowho2/roowho2.varlink")
         .await
         .expect("Failed to connect to rwhod server");