Add dynamic shell completions

More of an experiment, but I stumbled upon this when trying to make shell
completions suggest existing marks, and I just had to add it

Cargo.toml

@@ -19,6 +19,7 @@ exclude = ["images/*"]
 
 git2 = { version= "0.19", features = [ "vendored-openssl" ] }
 clap = { version = "4.5", features = ["cargo", "derive"] }
+clap_complete = { version = "4.5", features = [ "unstable-dynamic" ] }
 serde_derive = "1.0"
 serde = "1.0"
 error-stack = "0.5"
@@ -31,7 +32,6 @@ dirs = "5.0"
 nucleo = "0.5.0"
 ratatui = { version = "0.29", features = ["serde"] }
 crossterm = "0.28"
-clap_complete = "4.5"
 
 [lib]
 name = "tms"

README.md

@@ -209,3 +209,20 @@ session switch. This can be configured with settings like this.
 bind -r '(' switch-client -p\; refresh-client -S
 bind -r ')' switch-client -n\; refresh-client -S
 ```
+
+## Shell completions
+
+### Bash
+```bash
+echo "source <(COMPLETE=bash tms)" >> ~/.bashrc
+```
+
+### Zsh
+```zsh
+echo "source <(COMPLETE=zsh tms) >> ~/.zshrc"
+```
+
+### Fish
+```fish
+echo "COMPLETE=fish tms | source" >> ~/.config/fish/config.fish
+```

flake.nix

@@ -65,6 +65,12 @@
             cargoDeps = final.rustPlatform.importCargoLock {
               lockFile = self + "/Cargo.lock";
             };
+            postInstall = final.lib.optionalString (final.stdenv.buildPlatform.canExecute final.stdenv.hostPlatform) ''
+              installShellCompletion --cmd tms \
+                --bash <(COMPLETE=bash $out/bin/tms) \
+                --fish <(COMPLETE=fish $out/bin/tms) \
+                --zsh <(COMPLETE=zsh $out/bin/tms)
+            '';
           });
         };
 

src/cli.rs

@@ -15,8 +15,7 @@ use crate::{
     tmux::Tmux,
     Result, TmsError,
 };
-use clap::{Args, Command, CommandFactory, Parser, Subcommand};
-use clap_complete::{generate, Generator, Shell};
+use clap::{Args, Parser, Subcommand};
 use error_stack::ResultExt;
 use git2::{build::RepoBuilder, FetchOptions, RemoteCallbacks, Repository};
 use ratatui::style::Color;
@@ -25,8 +24,6 @@ use ratatui::style::Color;
 #[command(author, version)]
 ///Scan for all git folders in specified directorires, select one and open it as a new tmux session
 pub struct Cli {
-    #[arg(long = "generate", value_enum)]
-    generator: Option<Shell>,
     #[command(subcommand)]
     command: Option<CliCommand>,
 }
@@ -154,12 +151,6 @@ pub struct OpenSessionCommand {
 
 impl Cli {
     pub fn handle_sub_commands(&self, tmux: &Tmux) -> Result<SubCommandGiven> {
-        if let Some(generator) = self.generator {
-            let mut cmd = Cli::command();
-            print_completions(generator, &mut cmd);
-            return Ok(SubCommandGiven::Yes);
-        }
-
         // Get the configuration from the config file
         let config = Config::new().change_context(TmsError::ConfigError)?;
 
@@ -771,19 +762,6 @@ fn open_session_command(args: &OpenSessionCommand, config: Config, tmux: &Tmux)
     }
 }
 
-fn print_completions<G: Generator>(gen: G, cmd: &mut Command) {
-    let name = if let Ok(exe) = std::env::current_exe() {
-        if let Some(exe) = exe.file_name() {
-            exe.to_string_lossy().to_string()
-        } else {
-            cmd.get_name().to_string()
-        }
-    } else {
-        cmd.get_name().to_string()
-    };
-    generate(gen, cmd, name, &mut std::io::stdout());
-}
-
 pub enum SubCommandGiven {
     Yes,
     No(Box<Config>),

src/main.rs

@@ -1,4 +1,7 @@
-use clap::Parser;
+use std::env;
+
+use clap::{CommandFactory, Parser};
+use clap_complete::CompleteEnv;
 use error_stack::Report;
 
 use tms::{
@@ -18,6 +21,21 @@ fn main() -> Result<()> {
     #[cfg(any(not(debug_assertions), test))]
     Report::install_debug_hook::<std::panic::Location>(|_value, _context| {});
 
+    let bin_name = std::env::current_exe()
+        .ok()
+        .and_then(|exe| exe.file_name().map(|exe| exe.to_string_lossy().to_string()))
+        .unwrap_or("tms".into());
+    match CompleteEnv::with_factory(Cli::command)
+        .bin(bin_name)
+        .try_complete(env::args_os(), None)
+    {
+        Ok(true) => return Ok(()),
+        Err(e) => {
+            panic!("failed to generate completions: {e}");
+        }
+        Ok(false) => {}
+    };
+
     // Use CLAP to parse the command line arguments
     let cli_args = Cli::parse();
 

src/marks.rs

@@ -1,6 +1,7 @@
 use std::{env::current_dir, path::PathBuf};
 
 use clap::{Args, Subcommand};
+use clap_complete::{ArgValueCandidates, CompletionCandidate};
 use error_stack::ResultExt;
 
 use crate::{
@@ -14,6 +15,7 @@ use crate::{
 #[derive(Debug, Args)]
 #[clap(args_conflicts_with_subcommands = true)]
 pub struct MarksCommand {
+    #[arg(add  = ArgValueCandidates::new(get_completion_candidates))]
     /// The index of the mark to open
     index: Option<usize>,
     #[command(subcommand)]
@@ -43,20 +45,33 @@ pub struct MarksSetCommand {
 
 #[derive(Debug, Args)]
 pub struct MarksOpenCommand {
+    #[arg(add  = ArgValueCandidates::new(get_completion_candidates))]
     /// The index of the mark to open
     index: usize,
 }
 
 #[derive(Debug, Args)]
 #[group(required = true, multiple = false)]
 pub struct MarksDeleteCommand {
+    #[arg(add  = ArgValueCandidates::new(get_completion_candidates))]
     /// Index of mark to delete
     index: Option<usize>,
     #[arg(long, short)]
     /// Delete all items
     all: bool,
 }
 
+fn get_completion_candidates() -> Vec<CompletionCandidate> {
+    let config = Config::new().unwrap_or_default();
+    let marks = get_marks(&config).unwrap_or_default();
+    marks
+        .iter()
+        .map(|(index, session)| {
+            CompletionCandidate::new(index.to_string()).help(Some(session.name.clone().into()))
+        })
+        .collect::<Vec<_>>()
+}
+
 pub fn marks_command(args: &MarksCommand, config: Config, tmux: &Tmux) -> Result<()> {
     match (&args.cmd, args.index) {
         (None, None) => list(config),