//! Build script generating the header for the `servicepoint` C library.
//!
//! When the environment variable `SERVICEPOINT_HEADER_OUT` is set, the header is copied there from
//! the out directory. This can be used to use the build script as a command line tool from other
//! build tools.

use std::{env, fs};

fn main() {
    let crate_dir = env::var("CARGO_MANIFEST_DIR").unwrap();
    let is_recursive = env::var("SERVICEPOINT_IS_BUILDING")
        .unwrap_or("".to_string())
        == "true";
    unsafe {
        env::set_var("SERVICEPOINT_IS_BUILDING", "true");
    }

    println!("cargo::rerun-if-changed={crate_dir}/src");
    println!("cargo::rerun-if-changed={crate_dir}/build.rs");
    println!("cargo::rerun-if-changed={crate_dir}/Cargo.toml");
    println!("cargo::rerun-if-changed={crate_dir}/Cargo.lock");
    println!("cargo::rerun-if-changed={crate_dir}/cbindgen.toml");
    println!("cargo::rerun-if-env-changed=SERVICEPOINT_HEADER_OUT");

    let config =
        cbindgen::Config::from_file(crate_dir.clone() + "/cbindgen.toml")
            .unwrap();

    let output_dir = &env::var("OUT_DIR").unwrap();
    let header_file = output_dir.clone() + "/servicepoint.h";

    let bindings = cbindgen::generate_with_config(crate_dir, config)
        .expect("Servicepoint header could not be generated");

    bindings.write_to_file(&header_file);
    println!("cargo:include={output_dir}");

    if is_recursive {
        return;
    }

    if let Ok(header_out) = env::var("SERVICEPOINT_HEADER_OUT") {
        if !fs::exists(&header_out).unwrap() {
            panic!(
                "SERVICEPOINT_HEADER_OUT is not set to an existing directory"
            );
        }

        let header_copy = header_out + "/servicepoint.h";

        println!("cargo:warning=Copying header to {header_copy}");
        fs::copy(header_file, &header_copy)
            .expect("header could not be copied to SERVICEPOINT_HEADER_OUT");
        println!("cargo::rerun-if-changed={header_copy}");
    }
}