use std::process::Command;
use std::path::PathBuf;

const CPPFLAGS: &'static str = "-std=c++14 -flto -O3 -DNDEBUG -ffast-math -fno-builtin-malloc -Wall -Wextra -Wshadow -Wconversion -Wuninitialized -Dalways_inline=";

fn main() {
    // target/{build}/hoard-sys-{hash}/out
    let build_dir = PathBuf::from(std::env::var("OUT_DIR").expect("No OUT_DIR."));
    // target/{build}/hoard-sys-{hash}/out/Hoard
    let hoard_build = build_dir.join("Hoard");
    // target/{build}/hoard-sys-{hash}/out/Hoard/src
    let hoard_src = build_dir.join("Hoard/src");
    // target/{build}/hoard-sys-{hash}/out/Hoard/src/Heap-Layers
    let heaplayers_build = build_dir.join("Hoard/src/Heap-Layers");

    // Project root and submodules
    let this = PathBuf::from(file!()).canonicalize().unwrap();
    let root_dir = this.parent().unwrap();
    let hoard_module = root_dir.join("Hoard");
    let heaplayers_module = root_dir.join("Heap-Layers");

    // Copy Hoard submodule to hoard_build
    if !hoard_build.exists() {
        let mut cmd = Command::new("cp");
        cmd.current_dir(&build_dir).args(&["-r", &hoard_module.to_str().unwrap(), &hoard_build.to_str().unwrap()]);
        run_command(&mut cmd);
        assert!(hoard_build.exists(), "Hoard is not symlinked properly: {:?}", hoard_build);
    }

    // Copy Heap-Layers submodule to heaplayers_build
    if !heaplayers_build.exists() {
        let mut cmd = Command::new("cp");
        cmd.current_dir(&hoard_src).args(&["-r", &heaplayers_module.to_str().unwrap(), &heaplayers_build.to_str().unwrap()]);
        run_command(&mut cmd);
        assert!(heaplayers_build.exists(), "Heap-Layers is not symlinked properly: {:?}", heaplayers_build);
    }

    // Run make in hoard_src
    let mut cmd = Command::new("make");
    cmd.current_dir(&hoard_src).args(&[&get_hoard_build_string(), &format!("CPPFLAGS={}", CPPFLAGS)]);
    run_command(&mut cmd);

    println!("cargo:rustc-link-lib=static=hoard");
    println!("cargo:rustc-link-search=native={}", &hoard_src.to_str().unwrap());
}

fn run_command(cmd: &mut Command) {
    match cmd.status() {
        Ok(ret) => assert!(ret.success(), "{:?} returned non-zero: {:?}", cmd, ret),
        Err(e) => panic!("Failed to run command {:?}: {:?}", cmd, e),
    }
}

fn get_hoard_build_string() -> String {
    use uname::uname;
    match uname() {
        Ok(info) => format!("{}-gcc-{}-static", info.sysname, info.machine),
        Err(e) => panic!("Failed to get uname: {:?}", e),
    }
}