use std::{ env, fs, io };
use std::process::Command;

fn main() {
    let manifest_dir = env::var("CARGO_MANIFEST_DIR").unwrap();
    let out_dir = env::var("OUT_DIR").unwrap();

    let lua_src_dir = format!("{}/libs/src/lua", manifest_dir);
    let bin_dst_dir = out_dir;

    let make_platform = match &env::var("CARGO_CFG_TARGET_FAMILY").unwrap()[..] {
        "unix" => "posix",
        "windows" => "mingw",
        _ => panic!("Unknown target family")
    };

    let make_result = Command::new("make")
        .arg(make_platform)
        .current_dir(&lua_src_dir)
        .output()
        .unwrap();

    if !make_result.status.success() {
        panic!("Error building Lua: {}, stdout: {}, stderr: {}",
               make_result.status,
               String::from_utf8_lossy(&make_result.stdout),
               String::from_utf8_lossy(&make_result.stderr));
    }

    copy_archive_to_bin(&lua_src_dir, &bin_dst_dir)
        .expect("Error copying `liblua.a` file");

    delete_intermediate_build_files(&lua_src_dir)
        .expect("Something went wrong deleting and moving intermediate build files");
}

fn copy_archive_to_bin(src: &str, dst: &str) -> io::Result<()> {
    fs::create_dir_all(dst)?;
    let lib_lua_src_file = format!("{}/liblua.a", src);
    let lib_lua_dst_file = format!("{}/liblua.a", dst);
    fs::copy(lib_lua_src_file, lib_lua_dst_file)?;
    Ok(())
}

fn delete_intermediate_build_files(dir: &str) -> io::Result<()> {
    let o_files = fs::read_dir(dir)?
        .filter_map(Result::ok)
        .map(|file| file.path())
        .filter(|path| path.extension().is_some())
        .filter(|path| path.extension().unwrap() == "o");

    for o_file in o_files {
        fs::remove_file(o_file)?;
    }

    fs::remove_file(format!("{}/liblua.a", dir))?;
    fs::remove_file(format!("{}/lua", dir))?;
    fs::remove_file(format!("{}/luac", dir))?;

    Ok(())
}