feat(cli): add completion (#86)

Co-authored-by: sgoudham <sgoudham@gmail.com>

Cargo.toml

@@ -1,7 +1,7 @@
 [package]
 name = "mdbook-catppuccin"
 authors = ["Goudham Suresh <sgoudham@gmail.com>", "winston <hey@winston.sh>"]
-description = "A mdbook preprocessor that exposes the catppuccin flavours as available themes!"
+description = "🎊 Soothing pastel theme for mdBook"
 version = "2.0.1"
 edition = "2021"
 license = "MIT"
@@ -20,6 +20,7 @@ path = "src/lib.rs"
 
 [dependencies]
 clap = { version = "4.4.6", features = ["cargo"] }
+clap_complete = "4.4.4"
 mdbook = { version = "0.4.35", default_features = false }
 env_logger = "0.10.0"
 log = "0.4.20"

src/bin/mdbook-catppuccin.rs

@@ -1,6 +1,10 @@
 use std::{io, process};
 
-use clap::{command, crate_version, Arg, ArgAction, ArgMatches, Command};
+use clap::{
+    command, crate_authors, crate_description, crate_version, value_parser, Arg, ArgAction,
+    ArgMatches, Command,
+};
+use clap_complete::{generate, Generator, Shell};
 use mdbook::errors::Error;
 use mdbook::preprocess::{CmdPreprocessor, Preprocessor};
 use semver::{Version, VersionReq};
@@ -11,6 +15,16 @@ fn main() {
     env_logger::init_from_env(env_logger::Env::default().default_filter_or("info"));
     let matches = make_app().get_matches();
 
+    if let Some(generator) = matches.subcommand_matches("completion") {
+        let generator = generator
+            .get_one::<Shell>("shell")
+            .expect("Shell argument is required");
+        let mut cmd = make_app();
+        eprintln!("Generating completion file for {generator}...");
+        print_completions(*generator, &mut cmd);
+        return;
+    }
+
     let preprocessor = Catppuccin::new();
 
     if let Some(sub_args) = matches.subcommand_matches("supports") {
@@ -23,22 +37,30 @@ fn main() {
     }
 }
 
+fn print_completions<G: Generator>(gen: G, cmd: &mut Command) {
+    generate(gen, cmd, cmd.get_name().to_string(), &mut io::stdout());
+}
+
 pub fn make_app() -> Command {
     command!()
         .name("mdbook-catppuccin")
-        .about("A mdbook preprocessor that implements catppuccin flavours as default themes")
+        .about(crate_description!())
+        .author(crate_authors!())
         .version(crate_version!())
+        .subcommand_required(true)
         .subcommand(
-            Command::new("supports")
-                .arg(Arg::new("renderer").required(true))
+            command!("supports")
+                .arg(
+                    Arg::new("renderer").required(true)
+                )
                 .about("Check whether a renderer is supported by this preprocessor"),
         )
         .subcommand(
-            Command::new("install")
+            command!("install")
                 .arg(
                     Arg::new("dir")
-                        .default_value(".")
-                        .help("Root directory for the book, this should contain the configuration file `book.toml`")
+                    .default_value(".")
+                    .help("Root directory for the book, this should contain the configuration file `book.toml`")
                 )
                 .arg(
                     Arg::new("force")
@@ -49,6 +71,16 @@ pub fn make_app() -> Command {
                 )
                 .about("Install the necessary files needed and update the config to include them"),
         )
+        .subcommand(
+            command!("completion")
+            .arg(
+                Arg::new("shell")
+                .action(ArgAction::Set)
+                .required(true)
+                .value_parser(value_parser!(Shell))
+            )
+            .about("Generate shell completion scripts")
+        )
 }
 
 fn handle_preprocessing(pre: &Catppuccin) -> Result<(), Error> {
@@ -145,7 +177,7 @@ mod install {
 
     fn read_configuration_file(toml_config: &PathBuf) -> (String, Document) {
         info!("Reading configuration file '{}'", toml_config.display());
-        let toml = fs::read_to_string(&toml_config).expect("Can't read configuration file");
+        let toml = fs::read_to_string(toml_config).expect("Can't read configuration file");
         let document = toml
             .parse::<Document>()
             .expect("Configuration is not valid TOML");