Shell completions and refactors

Output shell completions with `clap_complete`, moving the cli args types into a new file `cli_args.rs`, and add them to the nix package defined in the flake output. Update clap to 4.5.21. Various minor refactors in main.rs, including a removal of `itertools` as a dependency.

Cargo.lock

@@ -53,9 +53,9 @@ dependencies = [
 
 [[package]]
 name = "clap"
-version = "4.5.20"
+version = "4.5.21"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b97f376d85a664d5837dbae44bf546e6477a679ff6610010f17276f686d867e8"
+checksum = "fb3b4b9e5a7c7514dfa52869339ee98b3156b0bfb4e8a77c4ff4babb64b1604f"
 dependencies = [
  "clap_builder",
  "clap_derive",
@@ -63,9 +63,9 @@ dependencies = [
 
 [[package]]
 name = "clap_builder"
-version = "4.5.20"
+version = "4.5.21"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "19bc80abd44e4bed93ca373a0704ccbd1b710dc5749406201bb018272808dc54"
+checksum = "b17a95aa67cc7b5ebd32aa5370189aa0d79069ef1c64ce893bd30fb24bff20ec"
 dependencies = [
  "anstream",
  "anstyle",
@@ -73,6 +73,15 @@ dependencies = [
  "strsim",
 ]
 
+[[package]]
+name = "clap_complete"
+version = "4.5.38"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d9647a559c112175f17cf724dc72d3645680a883c58481332779192b0d8e7a01"
+dependencies = [
+ "clap",
+]
+
 [[package]]
 name = "clap_derive"
 version = "4.5.18"
@@ -97,12 +106,6 @@ version = "1.0.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "5b63caa9aa9397e2d9480a9b13673856c78d8ac123288526c37d7839f2a86990"
 
-[[package]]
-name = "either"
-version = "1.13.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "60b1af1c220855b6ceac025d3f6ecdd2b7c4894bfe9cd9bda4fbb4bc7c0d4cf0"
-
 [[package]]
 name = "heck"
 version = "0.5.0"
@@ -115,15 +118,6 @@ version = "1.70.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7943c866cc5cd64cbc25b2e01621d07fa8eb2a1a23160ee81ce38704e97b8ecf"
 
-[[package]]
-name = "itertools"
-version = "0.13.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "413ee7dfc52ee1a4949ceeb7dbc8a33f2d6c088194d9f922fb8318faf1f01186"
-dependencies = [
- "either",
-]
-
 [[package]]
 name = "proc-macro2"
 version = "1.0.89"
@@ -153,7 +147,7 @@ name = "subtitle-merge"
 version = "0.1.0"
 dependencies = [
  "clap",
- "itertools",
+ "clap_complete",
 ]
 
 [[package]]

Cargo.toml

@@ -4,5 +4,8 @@ version = "0.1.0"
 edition = "2021"
 
 [dependencies]
-clap = { version = "4.5.20", features = ["derive"] }
-itertools = "0.13.0"
+clap = { version = "4.5.21", features = ["derive"] }
+
+[build-dependencies]
+clap = { version = "4.5.21", features = ["derive"] }
+clap_complete = "4.5.38"

build.rs

@@ -0,0 +1,22 @@
+use std::{env, io};
+
+use clap_complete::{generate_to, Shell};
+use cli_args::Args;
+use clap::{CommandFactory, ValueEnum};
+
+mod cli_args {
+    include!("src/cli_args.rs");
+}
+
+fn main() -> io::Result<()> {
+    let Some(outdir) = env::var_os("OUT_DIR") else {
+        return Ok(());
+    };
+    let mut command = Args::command();
+
+    for shell in Shell::value_variants() {
+        generate_to(*shell, &mut command, "subtitle-merge", &outdir)?;
+        // println!("cargo:warning=completion file is generated: {path:?}");
+    }
+    Ok(())
+}

flake.nix

@@ -18,15 +18,24 @@
       overlays.default = final: prev: {
         subtitle-merge = final.rustPlatform.buildRustPackage {
           name = "subtitle-merge";
-          version = "1.0";
+          version = "0.1";
           src = ./.;
           cargoLock.lockFile = ./Cargo.lock;
-          buildInputs = [ final.mkvtoolnix-cli ];
+          buildInputs = builtins.attrValues {
+            inherit (final) installShellFiles mkvtoolnix-cli;
+          };
+
+          postInstall = ''
+            installShellCompletion --cmd subtitle-merge \
+              --bash ./target/release-tmp/build/*/out/subtitle-merge.bash \
+              --fish ./target/release-tmp/build/*/out/subtitle-merge.fish \
+              --zsh ./target/release-tmp/build/*/out/_subtitle-merge
+          '';
         };
       };
 
       packages."${system}" = rec {
-        subtitle-merge = (overlays.default pkgs pkgs).subtitle-merge;
+        inherit (overlays.default pkgs pkgs) subtitle-merge;
         default = subtitle-merge;
       };
     };

src/cli_args.rs

@@ -0,0 +1,25 @@
+use std::path::PathBuf;
+
+use clap::Parser;
+
+#[derive(Parser)]
+pub enum Args {
+    Single(Single),
+    Dir(Dir),
+}
+
+#[derive(Parser)]
+pub struct Single {
+    pub source: PathBuf,
+    #[arg(long)]
+    pub subtitles: Option<PathBuf>,
+    #[arg(long)]
+    pub fonts_dir: Option<PathBuf>,
+    pub output: PathBuf,
+}
+
+#[derive(Parser)]
+pub struct Dir {
+    pub input_dir: PathBuf,
+    pub output_dir: PathBuf,
+}

src/main.rs

@@ -1,36 +1,16 @@
+mod cli_args;
+
 use std::{
     ffi::{OsStr, OsString},
     fs::ReadDir,
     io,
     os::unix::{ffi::OsStrExt, process::CommandExt},
     path::{Path, PathBuf},
-    process::{Command, ExitCode, ExitStatus},
+    process::{Command, ExitCode},
 };
 
 use clap::Parser;
-use itertools::Either;
-
-#[derive(Parser)]
-enum Args {
-    Single(Single),
-    Dir(Dir),
-}
-
-#[derive(Parser)]
-struct Single {
-    source: PathBuf,
-    #[arg(long)]
-    subtitles: Option<PathBuf>,
-    #[arg(long)]
-    fonts_dir: Option<PathBuf>,
-    output: PathBuf,
-}
-
-#[derive(Parser)]
-struct Dir {
-    input_dir: PathBuf,
-    output_dir: PathBuf,
-}
+use cli_args::{Args, Single};
 
 fn find_subs(root: &Path, match_str: &OsStr) -> io::Result<Option<PathBuf>> {
     for entry in root.read_dir()? {
@@ -59,7 +39,10 @@ fn find_subs(root: &Path, match_str: &OsStr) -> io::Result<Option<PathBuf>> {
     Ok(None)
 }
 
-fn find_files(root: &Path, extension: &OsStr) -> impl Iterator<Item = io::Result<PathBuf>> {
+fn find_files(
+    root: &Path,
+    extension: &OsStr,
+) -> io::Result<impl Iterator<Item = io::Result<PathBuf>>> {
     struct FindFonts {
         read_dirs: Vec<ReadDir>,
         extension: OsString,
@@ -74,11 +57,10 @@ fn find_files(root: &Path, extension: &OsStr) -> impl Iterator<Item = io::Result
                     continue;
                 };
                 let entry = match next {
-                    Err(e) => return Some(Err(e)),
                     Ok(entry) => entry,
+                    Err(e) => return Some(Err(e)),
                 };
-                let file_type = entry.file_type();
-                let file_type = match file_type {
+                let file_type = match entry.file_type() {
                     Err(e) => return Some(Err(e)),
                     Ok(file_type) => file_type,
                 };
@@ -101,14 +83,10 @@ fn find_files(root: &Path, extension: &OsStr) -> impl Iterator<Item = io::Result
             }
         }
     }
-
-    match root.read_dir() {
-        Ok(read_dir) => Either::Left(FindFonts {
-            read_dirs: vec![read_dir],
-            extension: extension.to_owned(),
-        }),
-        Err(e) => Either::Right(std::iter::once(Err(e))),
-    }
+    Ok(FindFonts {
+        read_dirs: vec![root.read_dir()?],
+        extension: extension.to_owned(),
+    })
 }
 
 fn convert_single(
@@ -119,18 +97,18 @@ fn convert_single(
         output,
     }: Single,
 ) -> io::Result<Command> {
-    let subtitles = if let Some(subtitles) = subtitles {
-        subtitles
-    } else {
-        find_subs(&source.parent().unwrap(), source.file_stem().unwrap())?.unwrap()
-    };
+    let subtitles = subtitles.map_or_else(|| {
+        find_subs(source.parent().unwrap(), source.file_stem().unwrap())
+            .transpose()
+            .unwrap()
+    }, Ok)?;
     let fonts: Vec<PathBuf> = if let Some(fonts_dir) = fonts_dir {
         fonts_dir
             .read_dir()?
             .map(|r| r.map(|entry| entry.path()))
             .collect::<io::Result<_>>()?
     } else {
-        find_files(source.parent().unwrap(), OsStr::new("ttf")).collect::<io::Result<_>>()?
+        find_files(source.parent().unwrap(), OsStr::new("ttf"))?.collect::<io::Result<_>>()?
     };
 
     let mut command = Command::new("mkvmerge");
@@ -141,7 +119,7 @@ fn convert_single(
     ]);
     for font in fonts {
         command
-            .args(&["--attachment-mime-type", "font/ttf", "--attach-file"])
+            .args(["--attachment-mime-type", "font/ttf", "--attach-file"])
             .arg(font.into_os_string());
     }
     Ok(command)
@@ -155,7 +133,7 @@ fn main() -> io::Result<ExitCode> {
             Err(command.exec())
         }
         Args::Dir(dir) => {
-            let files = find_files(&dir.input_dir, OsStr::new("mkv"));
+            let files = find_files(&dir.input_dir, OsStr::new("mkv"))?;
             let mut commands = Vec::new();
             for file in files {
                 let input_file = file?;