use std::{fs::File, io, path::Path};

use clap::{CommandFactory, ValueEnum};
use clap_complete::Shell;
use clap_mangen::Man;

#[path = "src/config.rs"]
mod config;

fn main() {
    // OUT_DIR is where any additional build artifacts are written; Set by Cargo.
    let Some(out_dir) = std::env::var_os("OUT_DIR") else {
        eprintln!("OUT_DIR environment variable not defined.");
        std::process::exit(1);
    };

    std::fs::create_dir_all(&out_dir).unwrap();

    let cmd = config::Config::command();
    let bin_name = cmd.get_bin_name().unwrap_or_else(|| cmd.get_name());

    if let Err(err) = generate_man_page(bin_name, &out_dir) {
        eprintln!("failed to generate man page: {}", err);
    }

    if let Err(err) = generate_completions(bin_name, &out_dir) {
        eprintln!("failed to generate shell completion: {}", err);
    }

    println!("cargo:rerun-if-changed=build.rs");
}

fn generate_man_page<P: AsRef<Path>>(bin_name: &str, out_dir: P) -> Result<(), io::Error> {
    let out_dir = out_dir.as_ref().join("man");
    std::fs::create_dir_all(&out_dir)?;

    let cmd = config::Config::command();

    let mut man_page = out_dir.join(bin_name);
    man_page.set_extension("1");

    let mut file = File::create(&man_page)?;

    Man::new(cmd).render(&mut file)
}

fn generate_completions<P: AsRef<Path>>(bin_name: &str, out_dir: P) -> Result<(), io::Error> {
    let out_dir = out_dir.as_ref().join("completions");
    std::fs::create_dir_all(&out_dir)?;

    let mut cmd = config::Config::command();

    Shell::value_variants().iter().try_for_each(|&shell| {
        clap_complete::generate_to(shell, &mut cmd, bin_name, out_dir.as_path())?;
        Ok(())
    })
}