use cmake::Config;

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

/// Allow x86_64 <-> aarch64 cross compilation on macOS
/// https://cmake.org/cmake/help/latest/command/try_run.html#behavior-when-cross-compiling
fn setup_macos_cross_compile(config: &mut Config) {
	let host_triple = std::env::var("HOST").unwrap();
	let target_triple = std::env::var("TARGET").unwrap();

	let host_triple = host_triple.split('-').collect::<Vec<_>>();
	let target_triple = target_triple.split('-').collect::<Vec<_>>();

	if host_triple[1] == "apple"
		&& target_triple[1] == "apple"
		&& host_triple[0] != target_triple[0]
	{
		config.define("SEAL_MEMSET_S_FOUND_EXITCODE", "0");
		config.define("SEAL_MEMSET_S_FOUND_EXITCODE__TRYRUN_OUTPUT", "");
		config.define("SEAL___BUILTIN_CLZLL_FOUND_EXITCODE", "0");
		config.define("SEAL___BUILTIN_CLZLL_FOUND_EXITCODE__TRYRUN_OUTPUT", "");
		config.define("SEAL__ADDCARRY_U64_FOUND_EXITCODE", "0");
		config.define("SEAL__ADDCARRY_U64_FOUND_EXITCODE__TRYRUN_OUTPUT", "");
		config.define("SEAL__SUBBORROW_U64_FOUND_EXITCODE", "0");
		config.define("SEAL__SUBBORROW_U64_FOUND_EXITCODE__TRYRUN_OUTPUT", "");
	}
}

fn compile_native(profile: &str, out_path: &Path) {
	let hexl = if std::env::var("CARGO_FEATURE_HEXL").is_ok() {
		"ON"
	} else {
		"OFF"
	};

	let forbid_transparent_ciphertexts =
		if std::env::var("CARGO_FEATURE_TRANSPARENT_CIPHERTEXTS").is_ok() {
			"OFF"
		} else {
			"ON"
		};

	let mut builder = Config::new("SEAL");

	builder
		.define("CMAKE_BUILD_TYPE", profile)
		.define("CMAKE_CXX_FLAGS_RELEASE", "-DNDEBUG -O3")
		.define("CMAKE_C_FLAGS_RELEASE", "-DNDEBUG -O3")
		.define("SEAL_USE_GAUSSIAN_NOISE", "ON")
		.define("SEAL_BUILD_STATIC_SEAL_C", "ON")
		.define("SEAL_USE_INTEL_HEXL", hexl)
		.define("SEAL_BUILD_DEPS", "ON")
		.define("SEAL_BUILD_SEAL_C", "ON")
		.define("SEAL_BUILD_BENCH", "OFF")
		.define("SEAL_BUILD_EXAMPLES", "OFF")
		.define("SEAL_BUILD_TESTS", "OFF")
		.define("SEAL_USE_CXX17", "ON")
		.define("SEAL_USE_INTRIN", "ON")
		.define("SEAL_USE_MSGSL", "OFF")
		.define("SEAL_USE_ZLIB", "ON")
		.define("SEAL_USE_ZSTD", "ON")
		.define(
			"SEAL_THROW_ON_TRANSPARENT_CIPHERTEXT",
			forbid_transparent_ciphertexts,
		);

	setup_macos_cross_compile(&mut builder);

	let dst = builder.build();

	let out_path_suffix = if std::env::var("CARGO_CFG_WINDOWS").is_ok() {
		profile
	} else {
		""
	};

	// Tell cargo to look for shared libraries in the specified directory
	println!(
		"cargo:rustc-link-search=native={}/build/lib/{}",
		dst.display(),
		out_path_suffix
	);

	// Tell cargo to tell rustc to link the static library seal.
	println!("cargo:rustc-link-lib=static=sealc-4.0");
	println!("cargo:rustc-link-lib=static=seal-4.0");

	println!("-I{}", out_path.join("include").display());
}

fn main() {
	// debug/release
	let profile = std::env::var("PROFILE").expect("Failed to get build profile");
	let out_path = PathBuf::from(std::env::var("OUT_DIR").unwrap());
	let target = std::env::var("TARGET").expect("Failed to get target");

	println!("cargo:rerun-if-changed=SEAL");

	let profile = if profile == "release" {
		"Release"
	} else if profile == "debug" {
		"Debug"
	} else {
		panic!("Unknown profile type {}", profile);
	};

	compile_native(profile, &out_path);

	let mut builder = bindgen::builder()
		.clang_arg(format!("-I{}", out_path.join("include/SEAL-3.7").display()))
		.clang_arg("-ISEAL/native/src")
		.clang_arg("-xc++")
		.clang_arg("-std=c++17");

	if target == "wasm32-unknown-emscripten" {
		// Bindgen appears to be broken under wasm. Just generate bindings with
		// the host's target.
		builder = builder
			.clang_arg("-target")
			.clang_arg("aarch64-apple-darwin")
			.detect_include_paths(false);
	}

	let builder = builder
		.detect_include_paths(true)
		.header("bindgen_wrapper.h")
		.parse_callbacks(Box::new(bindgen::CargoCallbacks::new()))
		.allowlist_function("BatchEncoder_.*")
		.allowlist_function("Ciphertext_.*")
		.allowlist_function("CKKSEncoder_.*")
		.allowlist_function("CoeffModulus_.*")
		.allowlist_function("ContextData_.*")
		.allowlist_function("Decryptor_.*")
		.allowlist_function("EPQ_.*")
		.allowlist_function("EncParams_.*")
		.allowlist_function("Encryptor_.*")
		.allowlist_function("Evaluator_.*")
		.allowlist_function("GaloisKeys_.*")
		.allowlist_function("KeyGenerator_.*")
		.allowlist_function("KSwitchKeys_.*")
		.allowlist_function("MemoryManager_.*")
		.allowlist_function("MemoryPoolHandle_.*")
		.allowlist_function("Modulus_.*")
		.allowlist_function("Plaintext_.*")
		.allowlist_function("PublicKey_.*")
		.allowlist_function("RelinKeys_.*")
		.allowlist_function("SEALContext_.*")
		.allowlist_function("SecretKey_.*")
		.allowlist_function("Serialization_.*")
		.allowlist_function("PolynomialArray_.*")
		.allowlist_function("ValCheck_.*");

	let bindings = builder.generate().expect("Failed to generate bindings");

	bindings
		.write_to_file(out_path.join("bindings.rs"))
		.expect("Failed to write bindings");
}