use std::env;
use std::error::Error;
use std::path::PathBuf;

fn main() -> Result<(), Box<dyn Error>> {
    // heavily inspired from EmbarkStudios/rust-gpu/examples/runners/wgpu/build.rs
    println!("cargo:rerun-if-changed=build.rs");
    println!("cargo:rerun-if-env-changed=CARGO_CFG_TARGET_OS");
    println!("cargo:rerun-if-env-changed=CARGO_CFG_TARGET_ARCH");
    // While OUT_DIR is set for both build.rs and compiling the crate, PROFILE is only set in
    // build.rs. So, export it to crate compilation as well.
    let profile = env::var("PROFILE").unwrap();
    println!("cargo:rustc-env=PROFILE={}", profile);
    let mut dir = PathBuf::from(env::var_os("OUT_DIR").unwrap());
    println!("OUT_DIR: {:?}", dir);
    // recover the directory from which this was invoked
    while !dir.ends_with("target") {
        dir.pop();
    }
    assert!(dir.pop());

    if dir.ends_with("spirv_backend_runner") {
        // being run from this dir
        assert!(
            dir.pop()
            && dir.ends_with("spirv")
            && dir.pop()
            && dir.ends_with("sim")
            && dir.pop()
            && dir.ends_with("src")
            && dir.pop()
        );
    } // else already at the top-level dir

    let target_dir = dir.join("target/spirv_backend_builder");
    let manifest_path = dir.join("crates/spirv_backend_builder/Cargo.toml");
    println!("target_dir: {:?}", target_dir);
    println!("manifest_path: {:?}", manifest_path);

    let status = std::process::Command::new("cargo")
        .args([
            "run",
            "--release",
            "--manifest-path",
        ])
        .arg(manifest_path)
        .arg("--target-dir")
        .arg(target_dir)
        .stdout(std::process::Stdio::inherit())
        .stderr(std::process::Stdio::inherit())
        .status()?;

    if !status.success() {
        if let Some(code) = status.code() {
            std::process::exit(code);
        } else {
            std::process::exit(1);
        }
    }
    Ok(())
}