feat(completion): add completion command

src/action/completion.rs

@@ -0,0 +1,37 @@
+use crate::cli::Cli;
+use clap::{Command, CommandFactory};
+use clap_complete::{generator::generate, Generator, Shell};
+
+#[derive(Debug, clap::Args)]
+pub struct CompletionArgs {
+    #[arg(name = "shell", long = "shell", short)]
+    shell: String,
+}
+
+fn get_command() -> Command {
+    Cli::command()
+}
+
+fn print_completions<G: Generator>(gen: G, cmd: &mut Command) {
+    generate(gen, cmd, cmd.get_name().to_string(), &mut std::io::stdout());
+}
+
+fn get_shell_by_name(shell_name: &str) -> Option<Shell> {
+    match shell_name {
+        "zsh" => Some(Shell::Zsh),
+        "bash" => Some(Shell::Bash),
+        "fish" => Some(Shell::Fish),
+        "powershell" => Some(Shell::PowerShell),
+        "elvish" => Some(Shell::Elvish),
+        _ => None,
+    }
+}
+
+pub fn completion(args: CompletionArgs) {
+    if let Some(shell) = get_shell_by_name(&args.shell) {
+        let mut cmd = get_command();
+        print_completions(shell, &mut cmd);
+    } else {
+        eprintln!("No such shell was found: {}", &args.shell);
+    }
+}

src/action/mod.rs

@@ -3,6 +3,7 @@ use crate::QuartzResult;
 use crate::{cli::Cmd, Ctx};
 
 pub mod body;
+pub mod completion;
 pub mod config;
 pub mod cookie;
 pub mod env;
@@ -39,6 +40,7 @@ pub async fn cmd(ctx: &mut Ctx, command: Cmd) -> QuartzResult {
         Cmd::Var { command } => action::var::cmd(ctx, command)?,
         Cmd::Env { command } => action::env::cmd(ctx, command)?,
         Cmd::Config { command } => action::config::cmd(ctx, command)?,
+        Cmd::Completion(args) => action::completion::completion(args),
     };
 
     Ok(())

src/cli.rs

@@ -92,6 +92,11 @@ pub enum Cmd {
         #[command(subcommand)]
         command: ConfigCmd,
     },
+    #[command(
+        name = "completion",
+        about = "outputs a completion script for a given shell"
+    )]
+    Completion(action::completion::CompletionArgs),
 }
 
 #[derive(Debug, Subcommand)]

src/lib.rs

@@ -1,5 +1,6 @@
 pub mod action;
 pub mod cli;
+pub mod completion;
 pub mod config;
 pub mod cookie;
 pub mod endpoint;