use core::iter;

use hex_literal::hex;
use hkdf::{Hkdf, HkdfExtract, SimpleHkdf, SimpleHkdfExtract};
use sha1::Sha1;
use sha2::{Sha256, Sha384, Sha512};

struct Test<'a> {
    ikm: &'a [u8],
    salt: &'a [u8],
    info: &'a [u8],
    prk: &'a [u8],
    okm: &'a [u8],
}

// Test Vectors from https://tools.ietf.org/html/rfc5869.
#[test]
#[rustfmt::skip]
fn test_rfc5869_sha256() {
    let tests = [
        Test {
            // Test Case 1
            ikm: &hex!("0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b"),
            salt: &hex!("000102030405060708090a0b0c"),
            info: &hex!("f0f1f2f3f4f5f6f7f8f9"),
            prk: &hex!("
                077709362c2e32df0ddc3f0dc47bba63
                90b6c73bb50f9c3122ec844ad7c2b3e5
            "),
            okm: &hex!("
                3cb25f25faacd57a90434f64d0362f2a
                2d2d0a90cf1a5a4c5db02d56ecc4c5bf
                34007208d5b887185865
            "),
        },
        Test {
            // Test Case 2
            ikm: &hex!("
                000102030405060708090a0b0c0d0e0f
                101112131415161718191a1b1c1d1e1f
                202122232425262728292a2b2c2d2e2f
                303132333435363738393a3b3c3d3e3f
                404142434445464748494a4b4c4d4e4f
            "),
            salt: &hex!("
                606162636465666768696a6b6c6d6e6f
                707172737475767778797a7b7c7d7e7f
                808182838485868788898a8b8c8d8e8f
                909192939495969798999a9b9c9d9e9f
                a0a1a2a3a4a5a6a7a8a9aaabacadaeaf
            "),
            info: &hex!("
                b0b1b2b3b4b5b6b7b8b9babbbcbdbebf
                c0c1c2c3c4c5c6c7c8c9cacbcccdcecf
                d0d1d2d3d4d5d6d7d8d9dadbdcdddedf
                e0e1e2e3e4e5e6e7e8e9eaebecedeeef
                f0f1f2f3f4f5f6f7f8f9fafbfcfdfeff
            "),
            prk: &hex!("
                06a6b88c5853361a06104c9ceb35b45c
                ef760014904671014a193f40c15fc244
            "),
            okm: &hex!("
                b11e398dc80327a1c8e7f78c596a4934
                4f012eda2d4efad8a050cc4c19afa97c
                59045a99cac7827271cb41c65e590e09
                da3275600c2f09b8367793a9aca3db71
                cc30c58179ec3e87c14c01d5c1f3434f
                1d87
            "),
        },
        Test {
            // Test Case 3
            ikm: &hex!("0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b"),
            salt: &hex!(""),
            info: &hex!(""),
            prk: &hex!("
                19ef24a32c717b167f33a91d6f648bdf
                96596776afdb6377ac434c1c293ccb04
            "),
            okm: &hex!("
                8da4e775a563c18f715f802a063c5a31
                b8a11f5c5ee1879ec3454e5f3c738d2d
                9d201395faa4b61a96c8
            "),
        },
    ];
    for Test { ikm, salt, info, prk, okm } in tests.iter() {
        let salt = if salt.is_empty() {
            None
        } else {
            Some(&salt[..])
        };
        let (prk2, hkdf) = Hkdf::<Sha256>::extract(salt, ikm);
        let mut okm2 = vec![0u8; okm.len()];
        assert!(hkdf.expand(&info[..], &mut okm2).is_ok());

        assert_eq!(prk2[..], prk[..]);
        assert_eq!(okm2[..], okm[..]);

        okm2.iter_mut().for_each(|b| *b = 0);
        let hkdf = Hkdf::<Sha256>::from_prk(prk).unwrap();
        assert!(hkdf.expand(&info[..], &mut okm2).is_ok());
        assert_eq!(okm2[..], okm[..]);
    }
}

#[test]
#[rustfmt::skip]
fn test_rfc5869_sha1() {
    let tests = [
        Test {
            // Test Case 4
            ikm: &hex!("0b0b0b0b0b0b0b0b0b0b0b"),
            salt: &hex!("000102030405060708090a0b0c"),
            info: &hex!("f0f1f2f3f4f5f6f7f8f9"),
            prk: &hex!("9b6c18c432a7bf8f0e71c8eb88f4b30baa2ba243"),
            okm: &hex!("
                085a01ea1b10f36933068b56efa5ad81
                a4f14b822f5b091568a9cdd4f155fda2
                c22e422478d305f3f896
            "),
        },
        Test {
            // Test Case 5
            ikm: &hex!("
                000102030405060708090a0b0c0d0e0f
                101112131415161718191a1b1c1d1e1f
                202122232425262728292a2b2c2d2e2f
                303132333435363738393a3b3c3d3e3f
                404142434445464748494a4b4c4d4e4f
            "),
            salt: &hex!("
                606162636465666768696a6b6c6d6e6f
                707172737475767778797a7b7c7d7e7f
                808182838485868788898a8b8c8d8e8f
                909192939495969798999a9b9c9d9e9f
                a0a1a2a3a4a5a6a7a8a9aaabacadaeaf
            "),
            info: &hex!("
                b0b1b2b3b4b5b6b7b8b9babbbcbdbebf
                c0c1c2c3c4c5c6c7c8c9cacbcccdcecf
                d0d1d2d3d4d5d6d7d8d9dadbdcdddedf
                e0e1e2e3e4e5e6e7e8e9eaebecedeeef
                f0f1f2f3f4f5f6f7f8f9fafbfcfdfeff
            "),
            prk: &hex!("8adae09a2a307059478d309b26c4115a224cfaf6"),
            okm: &hex!("
                0bd770a74d1160f7c9f12cd5912a06eb
                ff6adcae899d92191fe4305673ba2ffe
                8fa3f1a4e5ad79f3f334b3b202b2173c
                486ea37ce3d397ed034c7f9dfeb15c5e
                927336d0441f4c4300e2cff0d0900b52
                d3b4
            "),
        },
        Test {
            // Test Case 6
            ikm: &hex!("0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b"),
            salt: &hex!(""),
            info: &hex!(""),
            prk: &hex!("da8c8a73c7fa77288ec6f5e7c297786aa0d32d01"),
            okm: &hex!("
                0ac1af7002b3d761d1e55298da9d0506
                b9ae52057220a306e07b6b87e8df21d0
                ea00033de03984d34918
            "),
        },
        Test {
            // Test Case 7
            ikm: &hex!("0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c"),
            salt: &hex!(""), // "Not Provided"
            info: &hex!(""),
            prk: &hex!("2adccada18779e7c2077ad2eb19d3f3e731385dd"),
            okm: &hex!("
                2c91117204d745f3500d636a62f64f0a
                b3bae548aa53d423b0d1f27ebba6f5e5
                673a081d70cce7acfc48
            "),
        },
    ];
    for Test { ikm, salt, info, prk, okm } in tests.iter() {
        let salt = if salt.is_empty() {
            None
        } else {
            Some(&salt[..])
        };
        let (prk2, hkdf) = Hkdf::<Sha1>::extract(salt, ikm);
        let mut okm2 = vec![0u8; okm.len()];
        assert!(hkdf.expand(&info[..], &mut okm2).is_ok());

        assert_eq!(prk2[..], prk[..]);
        assert_eq!(okm2[..], okm[..]);

        okm2.iter_mut().for_each(|b| *b = 0);
        let hkdf = Hkdf::<Sha1>::from_prk(prk).unwrap();
        assert!(hkdf.expand(&info[..], &mut okm2).is_ok());
        assert_eq!(okm2[..], okm[..]);
    }
}

const MAX_SHA256_LENGTH: usize = 255 * (256 / 8); // =8160

#[test]
fn test_lengths() {
    let hkdf = Hkdf::<Sha256>::new(None, &[]);
    let mut longest = vec![0u8; MAX_SHA256_LENGTH];
    assert!(hkdf.expand(&[], &mut longest).is_ok());
    // Runtime is O(length), so exhaustively testing all legal lengths
    // would take too long (at least without --release). Only test a
    // subset: the first 500, the last 10, and every 100th in between.
    let range = 500..MAX_SHA256_LENGTH - 10;
    let lengths = (0..MAX_SHA256_LENGTH + 1).filter(|len| !range.contains(len) || *len % 100 == 0);

    for length in lengths {
        let mut okm = vec![0u8; length];
        assert!(hkdf.expand(&[], &mut okm).is_ok());
        assert_eq!(okm.len(), length);
        assert_eq!(okm[..], longest[..length]);
    }
}

#[test]
fn test_max_length() {
    let hkdf = Hkdf::<Sha256>::new(Some(&[]), &[]);
    let mut okm = vec![0u8; MAX_SHA256_LENGTH];
    assert!(hkdf.expand(&[], &mut okm).is_ok());
}

#[test]
fn test_max_length_exceeded() {
    let hkdf = Hkdf::<Sha256>::new(Some(&[]), &[]);
    let mut okm = vec![0u8; MAX_SHA256_LENGTH + 1];
    assert!(hkdf.expand(&[], &mut okm).is_err());
}

#[test]
fn test_unsupported_length() {
    let hkdf = Hkdf::<Sha256>::new(Some(&[]), &[]);
    let mut okm = vec![0u8; 90000];
    assert!(hkdf.expand(&[], &mut okm).is_err());
}

#[test]
fn test_prk_too_short() {
    use sha2::digest::Digest;

    let output_len = Sha256::output_size();
    let prk = vec![0; output_len - 1];
    assert!(Hkdf::<Sha256>::from_prk(&prk).is_err());
}

#[test]
#[rustfmt::skip]
fn test_derive_sha1_with_none() {
    let ikm = hex!("0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c");
    let salt = None;
    let info = hex!("");
    let (prk, hkdf) = Hkdf::<Sha1>::extract(salt, &ikm[..]);
    let mut okm = [0u8; 42];
    assert!(hkdf.expand(&info[..], &mut okm).is_ok());

    assert_eq!(
        prk[..],
        hex!("2adccada18779e7c2077ad2eb19d3f3e731385dd")[..]
    );
    assert_eq!(
        okm[..],
        hex!("
            2c91117204d745f3500d636a62f64f0a
            b3bae548aa53d423b0d1f27ebba6f5e5
            673a081d70cce7acfc48
        ")[..],
    );
}

#[test]
fn test_expand_multi_info() {
    let info_components = &[
        &b"09090909090909090909090909090909090909090909"[..],
        &b"8a8a8a8a8a8a8a8a8a8a8a8a8a8a8a8a8a8a8a8a8a"[..],
        &b"0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0"[..],
        &b"4c4c4c4c4c4c4c4c4c4c4c4c4c4c4c4c4c4c4"[..],
        &b"1d1d1d1d1d1d1d1d1d1d1d1d1d1d1d1d1d"[..],
    ];

    let (_, hkdf_ctx) = Hkdf::<Sha256>::extract(None, b"some ikm here");

    // Compute HKDF-Expand on the concatenation of all the info components
    let mut oneshot_res = [0u8; 16];
    hkdf_ctx
        .expand(&info_components.concat(), &mut oneshot_res)
        .unwrap();

    // Now iteratively join the components of info_components until it's all 1 component. The value
    // of HKDF-Expand should be the same throughout
    let mut num_concatted = 0;
    let mut info_head = Vec::new();

    while num_concatted < info_components.len() {
        info_head.extend(info_components[num_concatted]);

        // Build the new input to be the info head followed by the remaining components
        let input: Vec<&[u8]> = iter::once(info_head.as_slice())
            .chain(info_components.iter().cloned().skip(num_concatted + 1))
            .collect();

        // Compute and compare to the one-shot answer
        let mut multipart_res = [0u8; 16];
        hkdf_ctx
            .expand_multi_info(&input, &mut multipart_res)
            .unwrap();
        assert_eq!(multipart_res, oneshot_res);

        num_concatted += 1;
    }
}

#[test]
fn test_extract_streaming() {
    let ikm_components = &[
        &b"09090909090909090909090909090909090909090909"[..],
        &b"8a8a8a8a8a8a8a8a8a8a8a8a8a8a8a8a8a8a8a8a8a"[..],
        &b"0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0"[..],
        &b"4c4c4c4c4c4c4c4c4c4c4c4c4c4c4c4c4c4c4"[..],
        &b"1d1d1d1d1d1d1d1d1d1d1d1d1d1d1d1d1d"[..],
    ];
    let salt = b"mysalt";

    // Compute HKDF-Extract on the concatenation of all the IKM components
    let (oneshot_res, _) = Hkdf::<Sha256>::extract(Some(&salt[..]), &ikm_components.concat());

    // Now iteratively join the components of ikm_components until it's all 1 component. The value
    // of HKDF-Extract should be the same throughout
    let mut num_concatted = 0;
    let mut ikm_head = Vec::new();

    while num_concatted < ikm_components.len() {
        ikm_head.extend(ikm_components[num_concatted]);

        // Make a new extraction context and build the new input to be the IKM head followed by the
        // remaining components
        let mut extract_ctx = HkdfExtract::<Sha256>::new(Some(&salt[..]));
        let input = iter::once(ikm_head.as_slice())
            .chain(ikm_components.iter().cloned().skip(num_concatted + 1));

        // Stream in the IKM input in the chunks specified
        for ikm in input {
            extract_ctx.input_ikm(ikm);
        }

        // Finalize and compare to the one-shot answer
        let (multipart_res, _) = extract_ctx.finalize();
        assert_eq!(multipart_res, oneshot_res);

        num_concatted += 1;
    }

    let mut num_concatted = 0;
    let mut ikm_head = Vec::new();

    while num_concatted < ikm_components.len() {
        ikm_head.extend(ikm_components[num_concatted]);

        // Make a new extraction context and build the new input to be the IKM head followed by the
        // remaining components
        let mut extract_ctx = SimpleHkdfExtract::<Sha256>::new(Some(&salt[..]));
        let input = iter::once(ikm_head.as_slice())
            .chain(ikm_components.iter().cloned().skip(num_concatted + 1));

        // Stream in the IKM input in the chunks specified
        for ikm in input {
            extract_ctx.input_ikm(ikm);
        }

        // Finalize and compare to the one-shot answer
        let (multipart_res, _) = extract_ctx.finalize();
        assert_eq!(multipart_res, oneshot_res);

        num_concatted += 1;
    }
}

/// Define test
macro_rules! new_test {
    ($name:ident, $test_name:expr, $hkdf:ty) => {
        #[test]
        fn $name() {
            use blobby::Blob4Iterator;

            fn run_test(ikm: &[u8], salt: &[u8], info: &[u8], okm: &[u8]) -> Option<&'static str> {
                let prk = <$hkdf>::new(Some(salt), ikm);
                let mut got_okm = vec![0; okm.len()];

                if prk.expand(info, &mut got_okm).is_err() {
                    return Some("prk expand");
                }
                if got_okm != okm {
                    return Some("mismatch in okm");
                }
                None
            }

            let data = include_bytes!(concat!("data/", $test_name, ".blb"));

            for (i, row) in Blob4Iterator::new(data).unwrap().enumerate() {
                let [ikm, salt, info, okm] = row.unwrap();
                if let Some(desc) = run_test(ikm, salt, info, okm) {
                    panic!(
                        "\n\
                         Failed test №{}: {}\n\
                         ikm:\t{:?}\n\
                         salt:\t{:?}\n\
                         info:\t{:?}\n\
                         okm:\t{:?}\n",
                        i, desc, ikm, salt, info, okm
                    );
                }
            }
        }
    };
}

new_test!(wycheproof_sha1, "wycheproof-sha1", Hkdf::<Sha1>);
new_test!(wycheproof_sha256, "wycheproof-sha256", Hkdf::<Sha256>);
new_test!(wycheproof_sha384, "wycheproof-sha384", Hkdf::<Sha384>);
new_test!(wycheproof_sha512, "wycheproof-sha512", Hkdf::<Sha512>);

new_test!(
    wycheproof_sha1_simple,
    "wycheproof-sha1",
    SimpleHkdf::<Sha1>
);
new_test!(
    wycheproof_sha256_simple,
    "wycheproof-sha256",
    SimpleHkdf::<Sha256>
);
new_test!(
    wycheproof_sha384_simple,
    "wycheproof-sha384",
    SimpleHkdf::<Sha384>
);
new_test!(
    wycheproof_sha512_simple,
    "wycheproof-sha512",
    SimpleHkdf::<Sha512>
);

#[test]
fn test_debug_impls() {
    fn needs_debug<T: std::fmt::Debug>() {}
    needs_debug::<Hkdf<Sha256>>();
    needs_debug::<HkdfExtract<Sha256>>();
}