use std::path::{Path, PathBuf};

fn main() {
    println!("cargo:rerun-if-changed=liburing");

    // configure liburing
    let liburing = out_dir().join("liburing");
    if liburing.exists() {
        std::fs::remove_dir_all(&liburing).unwrap();
    }
    let readonly_liburing = manifest().join("liburing");
    std::process::Command::new("cp")
        .arg("--recursive")
        .arg(&readonly_liburing)
        .arg(&liburing)
        .status()
        .unwrap();
    std::process::Command::new("sh")
        .arg("-c")
        .arg(format!(
            "cd {} && ./configure --cc=clang --cxx=clang++ --use-libc",
            path_to_string(&liburing)
        ))
        .status()
        .unwrap();

    // build liburing-ffi.a
    let src = liburing.join("src");
    if lto_enabled() {
        std::process::Command::new("make")
            .arg("-C")
            .arg(&src)
            .arg("liburing-ffi.a")
            .arg("CFLAGS=-g -O3 -Wall -Wextra -fno-stack-protector -flto=thin")
            .status()
            .unwrap();
    } else {
        std::process::Command::new("make")
            .arg("-C")
            .arg(&src)
            .arg("liburing-ffi.a")
            .arg("CFLAGS=-g -O3 -Wall -Wextra -fno-stack-protector")
            .status()
            .unwrap();
    }
    std::fs::copy(src.join("liburing-ffi.a"), src.join("libminiring.a")).unwrap();
    println!("cargo:rustc-link-search={}", path_to_string(&src));
    println!("cargo:rustc-link-lib=miniring");

    // generate headers.rs
    let include = src.join("include");
    std::fs::copy(src.join("ffi.c"), include.join("wrapper.h")).unwrap();
    bindgen::builder()
        .header(path_to_string(include.join("wrapper.h")))
        .allowlist_file(path_to_string(include.join("liburing.h")))
        .allowlist_file(path_to_string(include.join("liburing/io_uring.h")))
        .anon_fields_prefix("anonymous")
        .default_enum_style(bindgen::EnumVariation::ModuleConsts)
        .default_non_copy_union_style(bindgen::NonCopyUnionStyle::ManuallyDrop)
        .derive_copy(true)
        .derive_debug(true)
        .derive_default(false)
        .explicit_padding(true)
        .layout_tests(true)
        .merge_extern_blocks(true)
        .sort_semantically(true)
        .use_core()
        .generate()
        .unwrap()
        .write_to_file(include.join("headers.rs"))
        .unwrap();
}

fn manifest() -> PathBuf {
    std::path::Path::new(&std::env::var("CARGO_MANIFEST_DIR").unwrap())
        .canonicalize()
        .unwrap()
}

fn out_dir() -> PathBuf {
    std::path::Path::new(&std::env::var("OUT_DIR").unwrap())
        .canonicalize()
        .unwrap()
}

fn path_to_string(path: impl AsRef<Path>) -> String {
    path.as_ref().to_str().unwrap().to_string()
}

fn lto_enabled() -> bool {
    std::env::var("CARGO_FEATURE_LTO").is_ok()
}