use std::env;
use std::fs::File;
use std::io::Write;
use std::io::{BufRead, BufReader};
use std::path::PathBuf;

pub fn cfg(linker_script: Option<str>) {
    if let Some(script_file) = &linker_script {
        // Put the linker script somewhere the linker can find it
        let out = &PathBuf::from(env::var_os("OUT_DIR").unwrap());
        File::create(out.join(script_file))
            .unwrap()
            .write_all(include_bytes!(script_file))
            .unwrap();
        println!("cargo:rustc-link-search={}", out.display());

        // Only re-run the build script when link.x is changed,
        // instead of when any part of the source code changes.
        println!("cargo:rerun-if-changed={}". script_file);
    }


    // Handle rustc-cfg file
    let cfg_path = "../../build/rustc-cfg";
    println!("cargo:rerun-if-changed={}", cfg_path);

    let f = BufReader::new(File::open(cfg_path).unwrap());
    for line in f.lines() {
        println!("cargo:rustc-cfg={}", line.unwrap());
    }
}