use bindgen::MacroTypeVariation;
use std::env;
use std::path::PathBuf;

fn main() {
    if cfg!(feature = "link") {
        println!("cargo::rustc-check-cfg=cfg(pam_impl, values(\"linux-pam\",\"openpam\"))");
        let common_builder = bindgen::Builder::default()
            .merge_extern_blocks(true)
            .parse_callbacks(Box::new(bindgen::CargoCallbacks::new()))
            .blocklist_type("pam_handle")
            .blocklist_type("pam_conv")
            .allowlist_var(".*")
            .allowlist_function("pam_start")
            .allowlist_function("pam_[gs]et_item")
            .allowlist_function("pam_get_user")
            .allowlist_function("pam_get_authtok")
            .allowlist_function("pam_end")
            .dynamic_link_require_all(true)
            .default_macro_constant_type(MacroTypeVariation::Signed);

        let linux_builder = common_builder.clone().header_contents(
            "linux-pam.h",
            r#"
                #include <security/_pam_types.h>
                #include <security/pam_appl.h>
                #include <security/pam_ext.h>
                #include <security/pam_modules.h>
                "#,
        );
        let openpam_builder = common_builder.clone().header_contents(
            "openpam.h",
            r#"
                #include <security/openpam.h>
                #include <security/pam_appl.h>
                #include <security/pam_constants.h>
                #include <security/pam_types.h>
                "#,
        );

        let (pam_impl, bindings) = {
            let bb = linux_builder.generate();
            bb.as_ref().unwrap();
            if let Ok(bindings) = bb {
                ("linux-pam", bindings)
            } else if let Ok(bindings) = openpam_builder.generate() {
                ("openpam", bindings)
            } else {
                panic!("unrecognized PAM implementation")
            }
        };
        println!("cargo::rustc-cfg=pam_impl={pam_impl:?}");
        let out_path = PathBuf::from(env::var("OUT_DIR").unwrap());
        bindings
            .write_to_file(out_path.join("bindings.rs"))
            .unwrap();
    }
}