// Copyright 2015-2017 Brian Smith.
//
// Permission to use, copy, modify, and/or distribute this software for any
// purpose with or without fee is hereby granted, provided that the above
// copyright notice and this permission notice appear in all copies.
//
// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHORS DISCLAIM ALL WARRANTIES
// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY
// SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
// OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
// CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

extern crate alloc;

use ring::{agreement, error, rand, test, test_file};

#[test]
fn agreement_traits() {
    use alloc::vec::Vec;

    let rng = rand::SystemRandom::new();
    let private_key =
        agreement::EphemeralPrivateKey::generate(&agreement::ECDH_P256, &rng).unwrap();

    test::compile_time_assert_send::<agreement::EphemeralPrivateKey>();
    test::compile_time_assert_sync::<agreement::EphemeralPrivateKey>();

    assert_eq!(
        format!("{:?}", &private_key),
        "EphemeralPrivateKey { algorithm: Algorithm { curve: P256 } }"
    );

    let public_key = private_key.compute_public_key().unwrap();

    test::compile_time_assert_clone::<agreement::PublicKey>();
    test::compile_time_assert_send::<agreement::PublicKey>();
    test::compile_time_assert_sync::<agreement::PublicKey>();

    // Verify `PublicKey` implements `Debug`.
    //
    // TODO: Test the actual output.
    let _: &dyn core::fmt::Debug = &public_key;

    test::compile_time_assert_clone::<agreement::UnparsedPublicKey<&[u8]>>();
    test::compile_time_assert_copy::<agreement::UnparsedPublicKey<&[u8]>>();
    test::compile_time_assert_sync::<agreement::UnparsedPublicKey<&[u8]>>();

    test::compile_time_assert_clone::<agreement::UnparsedPublicKey<Vec<u8>>>();
    test::compile_time_assert_sync::<agreement::UnparsedPublicKey<Vec<u8>>>();

    let unparsed_public_key =
        agreement::UnparsedPublicKey::new(&agreement::X25519, &[0x01, 0x02, 0x03]);

    assert_eq!(
        format!("{:?}", unparsed_public_key),
        r#"UnparsedPublicKey { algorithm: Algorithm { curve: Curve25519 }, bytes: "010203" }"#
    );
}

#[test]
fn agreement_agree_ephemeral() {
    let rng = rand::SystemRandom::new();

    test::run(test_file!("agreement_tests.txt"), |section, test_case| {
        assert_eq!(section, "");

        let curve_name = test_case.consume_string("Curve");
        let alg = alg_from_curve_name(&curve_name);
        let peer_public = agreement::UnparsedPublicKey::new(alg, test_case.consume_bytes("PeerQ"));

        match test_case.consume_optional_string("Error") {
            None => {
                let my_private = test_case.consume_bytes("D");
                let my_private = {
                    let rng = test::rand::FixedSliceRandom { bytes: &my_private };
                    agreement::EphemeralPrivateKey::generate(alg, &rng)?
                };
                let my_public = test_case.consume_bytes("MyQ");
                let output = test_case.consume_bytes("Output");

                assert_eq!(my_private.algorithm(), alg);

                let computed_public = my_private.compute_public_key().unwrap();
                assert_eq!(computed_public.as_ref(), &my_public[..]);

                assert_eq!(my_private.algorithm(), alg);

                let result =
                    agreement::agree_ephemeral(my_private, &peer_public, (), |key_material| {
                        assert_eq!(key_material, &output[..]);
                        Ok(())
                    });
                assert_eq!(result, Ok(()));
            }

            Some(_) => {
                // In the no-heap mode, some algorithms aren't supported so
                // we have to skip those algorithms' test cases.
                let dummy_private_key = agreement::EphemeralPrivateKey::generate(alg, &rng)?;
                fn kdf_not_called(_: &[u8]) -> Result<(), ()> {
                    panic!(
                        "The KDF was called during ECDH when the peer's \
                         public key is invalid."
                    );
                }
                assert!(agreement::agree_ephemeral(
                    dummy_private_key,
                    &peer_public,
                    (),
                    kdf_not_called
                )
                .is_err());
            }
        }

        Ok(())
    });
}

#[test]
fn test_agreement_ecdh_x25519_rfc_iterated() {
    let mut k = h("0900000000000000000000000000000000000000000000000000000000000000");
    let mut u = k.clone();

    fn expect_iterated_x25519(
        expected_result: &str,
        range: core::ops::Range<usize>,
        k: &mut Vec<u8>,
        u: &mut Vec<u8>,
    ) {
        for _ in range {
            let new_k = x25519(k, u);
            *u = k.clone();
            *k = new_k;
        }
        assert_eq!(&h(expected_result), k);
    }

    expect_iterated_x25519(
        "422c8e7a6227d7bca1350b3e2bb7279f7897b87bb6854b783c60e80311ae3079",
        0..1,
        &mut k,
        &mut u,
    );
    expect_iterated_x25519(
        "684cf59ba83309552800ef566f2f4d3c1c3887c49360e3875f2eb94d99532c51",
        1..1_000,
        &mut k,
        &mut u,
    );

    // The spec gives a test vector for 1,000,000 iterations but it takes
    // too long to do 1,000,000 iterations by default right now. This
    // 10,000 iteration vector is self-computed.
    expect_iterated_x25519(
        "2c125a20f639d504a7703d2e223c79a79de48c4ee8c23379aa19a62ecd211815",
        1_000..10_000,
        &mut k,
        &mut u,
    );

    if cfg!(feature = "slow_tests") {
        expect_iterated_x25519(
            "7c3911e0ab2586fd864497297e575e6f3bc601c0883c30df5f4dd2d24f665424",
            10_000..1_000_000,
            &mut k,
            &mut u,
        );
    }
}

fn x25519(private_key: &[u8], public_key: &[u8]) -> Vec<u8> {
    x25519_(private_key, public_key).unwrap()
}

fn x25519_(private_key: &[u8], public_key: &[u8]) -> Result<Vec<u8>, error::Unspecified> {
    let rng = test::rand::FixedSliceRandom { bytes: private_key };
    let private_key = agreement::EphemeralPrivateKey::generate(&agreement::X25519, &rng)?;
    let public_key = agreement::UnparsedPublicKey::new(&agreement::X25519, public_key);
    agreement::agree_ephemeral(
        private_key,
        &public_key,
        error::Unspecified,
        |agreed_value| Ok(Vec::from(agreed_value)),
    )
}

fn h(s: &str) -> Vec<u8> {
    match test::from_hex(s) {
        Ok(v) => v,
        Err(msg) => {
            panic!("{} in {}", msg, s);
        }
    }
}

fn alg_from_curve_name(curve_name: &str) -> &'static agreement::Algorithm {
    if curve_name == "P-256" {
        &agreement::ECDH_P256
    } else if curve_name == "P-384" {
        &agreement::ECDH_P384
    } else if curve_name == "X25519" {
        &agreement::X25519
    } else {
        panic!("Unsupported curve: {}", curve_name);
    }
}
