// This file is Copyright its original authors, visible in version control
// history.
//
// This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
// or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
// You may not use this file except in accordance with one or both of these
// licenses.

use bitcoin::secp256k1::{KeyPair, PublicKey, Secp256k1, SecretKey, self};
use crate::utils::test_logger;
use core::convert::{Infallible, TryFrom};
use lightning::blinded_path::BlindedPath;
use lightning::sign::EntropySource;
use lightning::ln::PaymentHash;
use lightning::ln::features::BlindedHopFeatures;
use lightning::offers::invoice::{BlindedPayInfo, UnsignedBolt12Invoice};
use lightning::offers::parse::Bolt12SemanticError;
use lightning::offers::refund::Refund;
use lightning::util::ser::Writeable;

#[inline]
pub fn do_test<Out: test_logger::Output>(data: &[u8], _out: Out) {
	if let Ok(refund) = Refund::try_from(data.to_vec()) {
		let mut bytes = Vec::with_capacity(data.len());
		refund.write(&mut bytes).unwrap();
		assert_eq!(data, bytes);

		let secp_ctx = Secp256k1::new();
		let keys = KeyPair::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap());
		let pubkey = PublicKey::from(keys);
		let mut buffer = Vec::new();

		if let Ok(invoice) = build_response(&refund, pubkey, &secp_ctx) {
			invoice
				.sign::<_, Infallible>(
					|message| Ok(secp_ctx.sign_schnorr_no_aux_rand(message.as_ref().as_digest(), &keys))
				)
				.unwrap()
				.write(&mut buffer)
				.unwrap();
		}
	}
}

struct Randomness;

impl EntropySource for Randomness {
	fn get_secure_random_bytes(&self) -> [u8; 32] { [42; 32] }
}

fn pubkey(byte: u8) -> PublicKey {
	let secp_ctx = Secp256k1::new();
	PublicKey::from_secret_key(&secp_ctx, &privkey(byte))
}

fn privkey(byte: u8) -> SecretKey {
	SecretKey::from_slice(&[byte; 32]).unwrap()
}

fn build_response<T: secp256k1::Signing + secp256k1::Verification>(
	refund: &Refund, signing_pubkey: PublicKey, secp_ctx: &Secp256k1<T>
) -> Result<UnsignedBolt12Invoice, Bolt12SemanticError> {
	let entropy_source = Randomness {};
	let paths = vec![
		BlindedPath::new_for_message(&[pubkey(43), pubkey(44), pubkey(42)], &entropy_source, secp_ctx).unwrap(),
		BlindedPath::new_for_message(&[pubkey(45), pubkey(46), pubkey(42)], &entropy_source, secp_ctx).unwrap(),
	];

	let payinfo = vec![
		BlindedPayInfo {
			fee_base_msat: 1,
			fee_proportional_millionths: 1_000,
			cltv_expiry_delta: 42,
			htlc_minimum_msat: 100,
			htlc_maximum_msat: 1_000_000_000_000,
			features: BlindedHopFeatures::empty(),
		},
		BlindedPayInfo {
			fee_base_msat: 1,
			fee_proportional_millionths: 1_000,
			cltv_expiry_delta: 42,
			htlc_minimum_msat: 100,
			htlc_maximum_msat: 1_000_000_000_000,
			features: BlindedHopFeatures::empty(),
		},
	];

	let payment_paths = payinfo.into_iter().zip(paths.into_iter()).collect();
	let payment_hash = PaymentHash([42; 32]);
	refund.respond_with(payment_paths, payment_hash, signing_pubkey)?.build()
}

pub fn refund_deser_test<Out: test_logger::Output>(data: &[u8], out: Out) {
	do_test(data, out);
}

#[no_mangle]
pub extern "C" fn refund_deser_run(data: *const u8, datalen: usize) {
	do_test(unsafe { std::slice::from_raw_parts(data, datalen) }, test_logger::DevNull {});
}