// Resolve the active sysroot (from the pinned rust-toolchain.toml) and
// teach the linker where to find librustc_driver.dylib at build + run time.
// Without this, the binary links but crashes at startup with "dyld: Library
// not loaded: librustc_driver-*.dylib" — rustc_driver lives under
// $sysroot/lib, not /usr/local/lib.

use std::process::Command;

fn main() {
    println!("cargo:rerun-if-changed=build.rs");
    println!("cargo:rerun-if-changed=rust-toolchain.toml");

    let out = Command::new("rustc")
        .arg("--print")
        .arg("sysroot")
        .output()
        .expect("failed to invoke rustc --print sysroot");
    if !out.status.success() {
        panic!("rustc --print sysroot exited non-zero");
    }
    let sysroot = String::from_utf8(out.stdout).expect("non-utf8 sysroot");
    let sysroot = sysroot.trim();
    let libdir = format!("{}/lib", sysroot);

    let version = Command::new("rustc")
        .arg("-Vv")
        .output()
        .expect("failed to invoke rustc -Vv");
    if !version.status.success() {
        panic!("rustc -Vv exited non-zero");
    }
    let version = String::from_utf8(version.stdout).expect("non-utf8 rustc version");
    for (key, prefix) in [
        ("FOLD_RUST_ANALYZER_RELEASE", "release: "),
        ("FOLD_RUST_ANALYZER_COMMIT", "commit-hash: "),
        ("FOLD_RUST_ANALYZER_HOST", "host: "),
    ] {
        let value = version
            .lines()
            .find_map(|line| line.strip_prefix(prefix))
            .unwrap_or("unknown");
        println!("cargo:rustc-env={}={}", key, value);
    }

    println!("cargo:rustc-link-search=native={}", libdir);
    // macOS dyld: rpath via -Wl,-rpath; Linux: -Wl,-rpath plus
    // -Wl,--enable-new-dtags. The double-link-arg form works on both.
    println!("cargo:rustc-link-arg=-Wl,-rpath,{}", libdir);
}