ax-runtime 0.6.0

use std::{env, fs, io::Result, path::PathBuf};

const LINKER_TEMPLATE_NAME: &str = "runtime.ld";
const FINAL_LINKER_SCRIPT_NAME: &str = "linker.x";
const EXT_LINKER_SCRIPT_NAME: &str = "runtime.x";

fn main() -> Result<()> {
    println!("cargo:rerun-if-changed={LINKER_TEMPLATE_NAME}");
    println!("cargo:rerun-if-env-changed=CARGO_FEATURE_EXT_LD");
    println!("cargo:rerun-if-env-changed=DWARF");

    let out_dir = PathBuf::from(env::var("OUT_DIR").unwrap());
    let ld_content = fs::read_to_string(LINKER_TEMPLATE_NAME)?.replace("%DWARF%", dwarf_sections());
    let linker_script_name = if env::var_os("CARGO_FEATURE_EXT_LD").is_some() {
        EXT_LINKER_SCRIPT_NAME
    } else {
        FINAL_LINKER_SCRIPT_NAME
    };
    let linker_path = out_dir.join(linker_script_name);

    fs::write(&linker_path, &ld_content)?;
    println!("cargo:rustc-link-search={}", out_dir.display());

    Ok(())
}

fn dwarf_sections() -> &'static str {
    if env_truthy("DWARF") {
        r#"debug_abbrev : { . += SIZEOF(.debug_abbrev); }
    debug_addr : { . += SIZEOF(.debug_addr); }
    debug_aranges : { . += SIZEOF(.debug_aranges); }
    debug_info : { . += SIZEOF(.debug_info); }
    debug_line : { . += SIZEOF(.debug_line); }
    debug_line_str : { . += SIZEOF(.debug_line_str); }
    debug_ranges : { . += SIZEOF(.debug_ranges); }
    debug_rnglists : { . += SIZEOF(.debug_rnglists); }
    debug_str : { . += SIZEOF(.debug_str); }
    debug_str_offsets : { . += SIZEOF(.debug_str_offsets); }"#
    } else {
        ""
    }
}

fn env_truthy(key: &str) -> bool {
    env::var(key).is_ok_and(|value| {
        matches!(
            value.trim().to_ascii_lowercase().as_str(),
            "y" | "yes" | "1" | "true" | "on"
        )
    })
}