feat(cli): Generate man page

Cargo.toml

@@ -31,6 +31,9 @@ unic-langid = "0.9"
   version = "4.3"
   features = [ "derive", "wrap_help" ]
 
+  [build-dependencies.clap_mangen]
+  version = "0.2"
+
   [dependencies.git2]
   version = "0.17"
   default-features = false

build.rs

@@ -1,6 +1,7 @@
 use clap::Command;
 use clap_complete::generator::generate_to;
 use clap_complete::shells::{Bash, Elvish, Fish, PowerShell, Zsh};
+use clap_mangen::Man;
 use std::{collections, env, fs};
 use vergen::EmitBuilder;
 
@@ -16,9 +17,29 @@ fn main() {
     };
     builder.emit().expect("Unable to generate the cargo keys!");
     pass_on_configure_details();
+    generate_manpage();
     generate_shell_completions();
 }
 
+/// Generate man page
+fn generate_manpage() {
+    let out_dir = match env::var_os("OUT_DIR") {
+        None => return,
+        Some(out_dir) => out_dir,
+    };
+    let manpage_dir = path::Path::new(&out_dir);
+    fs::create_dir_all(manpage_dir).expect("Unable to create directory for generated manpages");
+    let bin_name: &str = "casile";
+    let cli = Command::new("casile");
+    let cli = Cli::augment_args(cli);
+    let man = Man::new(cli);
+    let mut buffer: Vec<u8> = Default::default();
+    man.render(&mut buffer)
+        .expect("Unable to render man page to UTF-8 string");
+    fs::write(manpage_dir.join(format!("{bin_name}.1")), buffer)
+        .expect("Unable to write manepage to file");
+}
+
 /// Generate shell completion files from CLI interface
 fn generate_shell_completions() {
     let out_dir = match env::var_os("OUT_DIR") {