use digest::{core_api::BlockSizeUser, Digest, FixedOutputReset};
use dsa::{Components, Signature, SigningKey, VerifyingKey};
use num_bigint::BigUint;
use num_traits::Num;
use sha1::Sha1;
use sha2::{Sha224, Sha256, Sha384, Sha512};
use signature::DigestSigner;

const MESSAGE: &[u8] = b"sample";
const MESSAGE_2: &[u8] = b"test";

fn dsa_1024_signing_key() -> SigningKey {
    let p = BigUint::from_str_radix(
        "86F5CA03DCFEB225063FF830A0C769B9DD9D6153AD91D7CE27F787C43278B447\
                E6533B86B18BED6E8A48B784A14C252C5BE0DBF60B86D6385BD2F12FB763ED88\
                73ABFD3F5BA2E0A8C0A59082EAC056935E529DAF7C610467899C77ADEDFC846C\
                881870B7B19B2B58F9BE0521A17002E3BDD6B86685EE90B3D9A1B02B782B1779",
        16,
    )
    .unwrap();
    let q = BigUint::from_str_radix("996F967F6C8E388D9E28D01E205FBA957A5698B1", 16).unwrap();
    let g = BigUint::from_str_radix(
        "07B0F92546150B62514BB771E2A0C0CE387F03BDA6C56B505209FF25FD3C133D\
            89BBCD97E904E09114D9A7DEFDEADFC9078EA544D2E401AEECC40BB9FBBF78FD\
            87995A10A1C27CB7789B594BA7EFB5C4326A9FE59A070E136DB77175464ADCA4\
            17BE5DCE2F40D10A46A3A3943F26AB7FD9C0398FF8C76EE0A56826A8A88F1DBD",
        16,
    )
    .unwrap();

    let x = BigUint::from_str_radix("411602CB19A6CCC34494D79D98EF1E7ED5AF25F7", 16).unwrap();
    let y = BigUint::from_str_radix(
        "5DF5E01DED31D0297E274E1691C192FE5868FEF9E19A84776454B100CF16F653\
            92195A38B90523E2542EE61871C0440CB87C322FC4B4D2EC5E1E7EC766E1BE8D\
            4CE935437DC11C3C8FD426338933EBFE739CB3465F4D3668C5E473508253B1E6\
            82F65CBDC4FAE93C2EA212390E54905A86E2223170B44EAA7DA5DD9FFCFB7F3B",
        16,
    )
    .unwrap();

    let components = Components::from_components(p, q, g).expect("Invalid components");
    let verifying_key =
        VerifyingKey::from_components(components, y).expect("Invalid verifying key");

    SigningKey::from_components(verifying_key, x).expect("Invalid signing key")
}

fn dsa_2048_signing_key() -> SigningKey {
    let p = BigUint::from_str_radix(
        "9DB6FB5951B66BB6FE1E140F1D2CE5502374161FD6538DF1648218642F0B5C48\
        C8F7A41AADFA187324B87674FA1822B00F1ECF8136943D7C55757264E5A1A44F\
        FE012E9936E00C1D3E9310B01C7D179805D3058B2A9F4BB6F9716BFE6117C6B5\
        B3CC4D9BE341104AD4A80AD6C94E005F4B993E14F091EB51743BF33050C38DE2\
        35567E1B34C3D6A5C0CEAA1A0F368213C3D19843D0B4B09DCB9FC72D39C8DE41\
        F1BF14D4BB4563CA28371621CAD3324B6A2D392145BEBFAC748805236F5CA2FE\
        92B871CD8F9C36D3292B5509CA8CAA77A2ADFC7BFD77DDA6F71125A7456FEA15\
        3E433256A2261C6A06ED3693797E7995FAD5AABBCFBE3EDA2741E375404AE25B",
        16,
    )
    .unwrap();
    let q = BigUint::from_str_radix(
        "F2C3119374CE76C9356990B465374A17F23F9ED35089BD969F61C6DDE9998C1F",
        16,
    )
    .unwrap();
    let g = BigUint::from_str_radix(
        "5C7FF6B06F8F143FE8288433493E4769C4D988ACE5BE25A0E24809670716C613\
        D7B0CEE6932F8FAA7C44D2CB24523DA53FBE4F6EC3595892D1AA58C4328A06C4\
        6A15662E7EAA703A1DECF8BBB2D05DBE2EB956C142A338661D10461C0D135472\
        085057F3494309FFA73C611F78B32ADBB5740C361C9F35BE90997DB2014E2EF5\
        AA61782F52ABEB8BD6432C4DD097BC5423B285DAFB60DC364E8161F4A2A35ACA\
        3A10B1C4D203CC76A470A33AFDCBDD92959859ABD8B56E1725252D78EAC66E71\
        BA9AE3F1DD2487199874393CD4D832186800654760E1E34C09E4D155179F9EC0\
        DC4473F996BDCE6EED1CABED8B6F116F7AD9CF505DF0F998E34AB27514B0FFE7",
        16,
    )
    .unwrap();

    let x = BigUint::from_str_radix(
        "69C7548C21D0DFEA6B9A51C9EAD4E27C33D3B3F180316E5BCAB92C933F0E4DBC",
        16,
    )
    .unwrap();
    let y = BigUint::from_str_radix(
        "667098C654426C78D7F8201EAC6C203EF030D43605032C2F1FA937E5237DBD94\
        9F34A0A2564FE126DC8B715C5141802CE0979C8246463C40E6B6BDAA2513FA61\
        1728716C2E4FD53BC95B89E69949D96512E873B9C8F8DFD499CC312882561ADE\
        CB31F658E934C0C197F2C4D96B05CBAD67381E7B768891E4DA3843D24D94CDFB\
        5126E9B8BF21E8358EE0E0A30EF13FD6A664C0DCE3731F7FB49A4845A4FD8254\
        687972A2D382599C9BAC4E0ED7998193078913032558134976410B89D2C171D1\
        23AC35FD977219597AA7D15C1A9A428E59194F75C721EBCBCFAE44696A499AFA\
        74E04299F132026601638CB87AB79190D4A0986315DA8EEC6561C938996BEADF",
        16,
    )
    .unwrap();

    let components = Components::from_components(p, q, g).expect("Invalid components");
    let verifying_key =
        VerifyingKey::from_components(components, y).expect("Invalid verifying key");

    SigningKey::from_components(verifying_key, x).expect("Invalid signing key")
}

/// Generate a signature given the unhashed message and a private key
fn generate_signature<D>(signing_key: SigningKey, data: &[u8]) -> Signature
where
    D: Digest + BlockSizeUser + FixedOutputReset,
{
    signing_key.sign_digest(<D as Digest>::new().chain_update(data))
}

/// Generate a signature using the 1024-bit DSA key
fn generate_1024_signature<D>(data: &[u8]) -> Signature
where
    D: Digest + BlockSizeUser + FixedOutputReset,
{
    generate_signature::<D>(dsa_1024_signing_key(), data)
}

/// Generate a signature using the 2048-bit DSA key
fn generate_2048_signature<D>(data: &[u8]) -> Signature
where
    D: Digest + BlockSizeUser + FixedOutputReset,
{
    generate_signature::<D>(dsa_2048_signing_key(), data)
}

/// Create a signature container from the two components in their textual hexadecimal form
fn from_str_signature(r: &str, s: &str) -> Signature {
    Signature::from_components(
        BigUint::from_str_radix(r, 16).unwrap(),
        BigUint::from_str_radix(s, 16).unwrap(),
    )
    .unwrap()
}

/// Return the RFC 6979 test cases
///
/// # Returns
///
/// Vector of tuples.
/// First element is the message appended to the panic upon signature mismatch, the second one is the expected signature and the third element is a function
/// that generates an RFC-6979 signature using the `dsa` crate
fn cases() -> Vec<(Signature, Box<dyn Fn() -> Signature>)> {
    vec![
        // sha1, 1024, "sample"
        (
            from_str_signature(
                "2E1A0C2562B2912CAAF89186FB0F42001585DA55",
                "29EFB6B0AFF2D7A68EB70CA313022253B9A88DF5",
            ),
            Box::new(|| generate_1024_signature::<Sha1>(MESSAGE)),
        ),
        // sha1, 1024, "test"
        (
            from_str_signature(
                "42AB2052FD43E123F0607F115052A67DCD9C5C77",
                "183916B0230D45B9931491D4C6B0BD2FB4AAF088",
            ),
            Box::new(|| generate_1024_signature::<Sha1>(MESSAGE_2)),
        ),
        // sha224, 1024, "sample"
        (
            from_str_signature(
                "4BC3B686AEA70145856814A6F1BB53346F02101E",
                "410697B92295D994D21EDD2F4ADA85566F6F94C1",
            ),
            Box::new(|| generate_1024_signature::<Sha224>(MESSAGE)),
        ),
        // sha224, 1024, "test"
        (
            from_str_signature(
                "6868E9964E36C1689F6037F91F28D5F2C30610F2",
                "49CEC3ACDC83018C5BD2674ECAAD35B8CD22940F",
            ),
            Box::new(|| generate_1024_signature::<Sha224>(MESSAGE_2)),
        ),
        // sha256, 1024, "sample"
        (
            from_str_signature(
                "81F2F5850BE5BC123C43F71A3033E9384611C545",
                "4CDD914B65EB6C66A8AAAD27299BEE6B035F5E89",
            ),
            Box::new(|| generate_1024_signature::<Sha256>(MESSAGE)),
        ),
        // sha256, 1024, "test"
        (
            from_str_signature(
                "22518C127299B0F6FDC9872B282B9E70D0790812",
                "6837EC18F150D55DE95B5E29BE7AF5D01E4FE160",
            ),
            Box::new(|| generate_1024_signature::<Sha256>(MESSAGE_2)),
        ),
        // sha384, 1024, "sample"
        (
            from_str_signature(
                "07F2108557EE0E3921BC1774F1CA9B410B4CE65A",
                "54DF70456C86FAC10FAB47C1949AB83F2C6F7595",
            ),
            Box::new(|| generate_1024_signature::<Sha384>(MESSAGE)),
        ),
        // sha384, 1024, "test"
        (
            from_str_signature(
                "854CF929B58D73C3CBFDC421E8D5430CD6DB5E66",
                "91D0E0F53E22F898D158380676A871A157CDA622",
            ),
            Box::new(|| generate_1024_signature::<Sha384>(MESSAGE_2)),
        ),
        // sha512, 1024, "sample"
        (
            from_str_signature(
                "16C3491F9B8C3FBBDD5E7A7B667057F0D8EE8E1B",
                "02C36A127A7B89EDBB72E4FFBC71DABC7D4FC69C",
            ),
            Box::new(|| generate_1024_signature::<Sha512>(MESSAGE)),
        ),
        // sha512, 1024, "test"
        (
            from_str_signature(
                "8EA47E475BA8AC6F2D821DA3BD212D11A3DEB9A0",
                "7C670C7AD72B6C050C109E1790008097125433E8",
            ),
            Box::new(|| generate_1024_signature::<Sha512>(MESSAGE_2)),
        ),
        // sha1, 2048, "sample"
        (
            from_str_signature(
                "3A1B2DBD7489D6ED7E608FD036C83AF396E290DBD602408E8677DAABD6E7445A",
                "D26FCBA19FA3E3058FFC02CA1596CDBB6E0D20CB37B06054F7E36DED0CDBBCCF",
            ),
            Box::new(|| generate_2048_signature::<Sha1>(MESSAGE)),
        ),
        // sha1, 2048, "test"
        (
            from_str_signature(
                "C18270A93CFC6063F57A4DFA86024F700D980E4CF4E2CB65A504397273D98EA0",
                "414F22E5F31A8B6D33295C7539C1C1BA3A6160D7D68D50AC0D3A5BEAC2884FAA",
            ),
            Box::new(|| generate_2048_signature::<Sha1>(MESSAGE_2)),
        ),
        // sha224, 2048, "sample"
        (
            from_str_signature(
                "DC9F4DEADA8D8FF588E98FED0AB690FFCE858DC8C79376450EB6B76C24537E2C",
                "A65A9C3BC7BABE286B195D5DA68616DA8D47FA0097F36DD19F517327DC848CEC",
            ),
            Box::new(|| generate_2048_signature::<Sha224>(MESSAGE)),
        ),
        // sha224, 2048, "test"
        (
            from_str_signature(
                "272ABA31572F6CC55E30BF616B7A265312018DD325BE031BE0CC82AA17870EA3",
                "E9CC286A52CCE201586722D36D1E917EB96A4EBDB47932F9576AC645B3A60806",
            ),
            Box::new(|| generate_2048_signature::<Sha224>(MESSAGE_2)),
        ),
        // sha256, 2048, "sample"
        (
            from_str_signature(
                "EACE8BDBBE353C432A795D9EC556C6D021F7A03F42C36E9BC87E4AC7932CC809",
                "7081E175455F9247B812B74583E9E94F9EA79BD640DC962533B0680793A38D53",
            ),
            Box::new(|| generate_2048_signature::<Sha256>(MESSAGE)),
        ),
        // sha256, 2048, "test"
        (
            from_str_signature(
                "8190012A1969F9957D56FCCAAD223186F423398D58EF5B3CEFD5A4146A4476F0",
                "7452A53F7075D417B4B013B278D1BB8BBD21863F5E7B1CEE679CF2188E1AB19E",
            ),
            Box::new(|| generate_2048_signature::<Sha256>(MESSAGE_2)),
        ),
        // sha384, 2048, "sample"
        (
            from_str_signature(
                "B2DA945E91858834FD9BF616EBAC151EDBC4B45D27D0DD4A7F6A22739F45C00B",
                "19048B63D9FD6BCA1D9BAE3664E1BCB97F7276C306130969F63F38FA8319021B",
            ),
            Box::new(|| generate_2048_signature::<Sha384>(MESSAGE)),
        ),
        // sha384, 2048, "test"
        (
            from_str_signature(
                "239E66DDBE8F8C230A3D071D601B6FFBDFB5901F94D444C6AF56F732BEB954BE",
                "6BD737513D5E72FE85D1C750E0F73921FE299B945AAD1C802F15C26A43D34961",
            ),
            Box::new(|| generate_2048_signature::<Sha384>(MESSAGE_2)),
        ),
        // sha512, 2048, "sample"
        (
            from_str_signature(
                "2016ED092DC5FB669B8EFB3D1F31A91EECB199879BE0CF78F02BA062CB4C942E",
                "D0C76F84B5F091E141572A639A4FB8C230807EEA7D55C8A154A224400AFF2351",
            ),
            Box::new(|| generate_2048_signature::<Sha512>(MESSAGE)),
        ),
        // sha512, 2048, "test"
        (
            from_str_signature(
                "89EC4BB1400ECCFF8E7D9AA515CD1DE7803F2DAFF09693EE7FD1353E90A68307",
                "C9F0BDABCC0D880BB137A994CC7F3980CE91CC10FAF529FC46565B15CEA854E1",
            ),
            Box::new(|| generate_2048_signature::<Sha512>(MESSAGE_2)),
        ),
    ]
}

#[test]
fn rfc6979_signatures() {
    for (idx, (expected, gen_fn)) in cases().into_iter().enumerate() {
        assert_eq!(expected, gen_fn(), "{}th test case", idx);
    }
}