From 90b604a850d44c7b53159f9b747576ea46b4b5c9 Mon Sep 17 00:00:00 2001
From: Caleb Maclennan <caleb@alerque.com>
Date: Thu, 21 Sep 2023 16:34:58 +0300
Subject: [PATCH] feat(cli): Generate man page

---
 Cargo.lock | 17 +++++++++++++++++
 Cargo.toml |  3 +++
 build.rs   | 21 +++++++++++++++++++++
 3 files changed, 41 insertions(+)

diff --git a/Cargo.lock b/Cargo.lock
index 7c3f7cee..d42fdd81 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -177,6 +177,7 @@ dependencies = [
  "assert_cmd",
  "clap",
  "clap_complete",
+ "clap_mangen",
  "colored",
  "config",
  "fluent",
@@ -262,6 +263,16 @@ version = "0.5.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "2da6da31387c7e4ef160ffab6d5e7f00c42626fe39aea70a7b0f1773f7dd6c1b"
 
+[[package]]
+name = "clap_mangen"
+version = "0.2.14"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b44f35c514163027542f7147797ff930523eea288e03642727348ef1a9666f6b"
+dependencies = [
+ "clap",
+ "roff",
+]
+
 [[package]]
 name = "clru"
 version = "0.6.1"
@@ -1720,6 +1731,12 @@ dependencies = [
  "syn 1.0.109",
 ]
 
+[[package]]
+name = "roff"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b833d8d034ea094b1ea68aa6d5c740e0d04bad9d16568d08ba6f76823a114316"
+
 [[package]]
 name = "rust-embed"
 version = "6.8.1"
diff --git a/Cargo.toml b/Cargo.toml
index 17e1061a..2b2e4b37 100644
--- a/Cargo.toml
+++ b/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
diff --git a/build.rs b/build.rs
index c0e6c306..9caab759 100644
--- a/build.rs
+++ b/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") {