/// test dataset
const DATA: [&[u8]; 8] = [
    // empty slice
    b"",
    // single-byte
    b"x",
    // common ascii pangram
    b"The quick brown fox jumps over the lazy dog",
    // ascii with punctuation and digits
    b"Rust v1.65.0 - Memory Safety, Speed, Concurrency!",
    // simple unicode (utf-8) greeting
    "こんにちは世界".as_bytes(),
    // pseudo-random bytes with embedded nuls
    &[
        0x3C, 0xA7, 0x5D, 0xE1, 0x4F, 0x99, 0x00, 0x20, 0x7F, 0xB3, 0xCD, 0x8A, 0x10, 0x55, 0xAA,
        0xFF, 0x5E, 0xA3, 0x1F, 0xC8, 0x72, 0x4D, 0x99, 0x00, 0xB7, 0x3C, 0x8E, 0xAD, 0x26, 0xF1,
    ],
    // long run of identical bytes (1 KiB of ascii 'A')
    &[b'A'; 1024],
    // very large slice (10 MiB of zeroes)
    &[0u8; 10 * 1024 * 1024],
];

/// lengths of the test dataset
const DATA_LENGTHS: [u64; 8] = [
    DATA[0].len() as u64,
    DATA[1].len() as u64,
    DATA[2].len() as u64,
    DATA[3].len() as u64,
    DATA[4].len() as u64,
    DATA[5].len() as u64,
    DATA[6].len() as u64,
    DATA[7].len() as u64,
];

/// anything but the lengths of the test dataset
pub const DATA_LENGTHS_BAD: [u64; 8] = [36, 12, 1, 0, 9, 24, 13, 10];

/// known good hashes of the test dataset
///
/// using `BLAKE2b`, 512 bit, with unpadded Base64 (standard variant)
pub const HASHES_STD_GOOD: [&str; 8] = [
    // empty slice
    "eGoC90IBWQPGxv2FJVLScpEvR0DhWEdhiobiF/cfVBnSXhAxr+5YUxOJZESTTrBLkDpoWxRIt1XVb3Aa/pvizg",
    // single-byte
    "CQk3etNREMr7KQnhhWcrfyco0fUJT4rWjW+sYnS/H0mUhagOo2TATtAG0pRZ6jy3xgAoDi+D4DJSmQb4iuMNCg",
    // common ascii pangram
    "qK3Uvd39k+SHfSdG5igXsRY2Sh+nvBSNlQkLxzM7NnP4JAHPeqLkyx7NkCluPxTLVBP47Xe+cwRbE5FM3NapGA",
    // ascii with punctuation and digits
    "NOtceHp9LrSYpXvSP3ayPbgMUyX4hynBYt4KtHuwJDsv1ELco5QeUj9aJTYTqbw4KzRKY+RjsbR26N3smUeCmA",
    // simple unicode (utf-8) greeting
    "h3xQg25wr/XqaXgqXWJivbVgN89XQoZUN/JcSZB0jxOtkbVStY7hnO+pm3PnLv6yZ4ZDLrxzYpoBk05BR7Wo1A",
    // pseudo-random bytes with embedded nuls
    "kiUYjOegDM9n1ryWtZhukpTuZ8oZbhi2onpXNl6pg16R+JZj5ty4uJZs44YbCu0A9m35Xs3bi/mxfbSulbo5Rg",
    // long run of identical bytes (1 kib of ascii 'a')
    "xwGOG01h2kco4CgjJlD9T2v5bM8XVuCrYzKTM4D0s7rCnOH+HR1H2S2Tmg43M+ym1A+AEPTE4J7iGljgntTdZA",
    // very large slice (10 mib of zeroes)
    "xsHH9h63e1+254TSCQoWCl6L5eGOo0Zg+ubtQC8Inwj7dwW7oxg0kYCrnkuTRj+7bVYNjlRSDOa8OIdInp73wA",
];

/// known bad version of `HASHES_STD_GOOD`
pub const HASHES_STD_BAD: [&str; 8] = [
    // off by one character (last “z” -> “y”)
    "eGoC90IBWQPGxv2FJVLScpEvR0DhWEdhiobiF/cfVBnSXhAxr+5YUxOJZESTTrBLkDpoWxRIt1XVb3Aa/pviyg",
    // truncated by dropping the final 4 chars
    "CQk3etNREMr7KQnhhWcrfyco0fUJT4rWjW+sYnS/H0mUhagOo2TATtAG0pRZ6jy3xgAoDi+D4DJSmQb4iu",
    // contains a non‐Base64 character (“#”)
    "qK3Uvd39k+SHfSdG5igXsRY2Sh+nvBSNlQkLxzM7NnP4JAHPeqLkyx7NkCluPxTLVBP47Xe+cwRbE5FM3NapG#",
    // too long, extra “AA” at end
    "NOtceHp9LrSYpXvSP3ayPbgMUyX4hynBYt4KtHuwJDsv1ELco5QeUj9aJTYTqbw4KzRKY+RjsbR26N3smUeCmAAA",
    // one byte altered at the front (“h” -> “H”)
    "H3xQg25wr/XqaXgqXWJivbVgN89XQoZUN/JcSZB0jxOtkbVStY7hnO+pm3PnLv6yZ4ZDLrxzYpoBk05BR7Wo1A",
    // garbled mid‐section
    "kiUYjOegDM9n1ryWtZhukpTuZ8oZbhi2onpXYZ6pg16R+JZj5ty4uJZs44YbCu0A9m35Xs3bi/mxfbSulbo5Rg",
    // entirely different length (too short)
    "xwGOG01h2kco4CgjJlD9T2v5bM8XVuCrYzKTM4D0s7rCnO",
    // correct length, but all “A”s (obviously wrong)
    "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA",
];

// /// known good hashes of the test dataset
// ///
// /// using BLAKE2b, 128 bit, with unpadded Base64 (url safe variant)
// const HASHES_URL_GOOD: [&str; 8] = [
//     // empty slice
//     "########################################################",
//     // single-byte
//     "########################################################",
//     // common ascii pangram
//     "",
//     // ascii with punctuation and digits
//     "",
//     // simple unicode (utf-8) greeting
//     "",
//     // pseudo-random bytes with embedded nuls
//     "",
//     // long run of identical bytes (1 kib of ascii 'a')
//     "",
//     // very large slice (10 mib of zeroes)
//     "",
// ];

pub fn data() -> impl Iterator<Item = &'static [u8]> {
    DATA.iter().copied()
}

pub fn cases() -> impl Iterator<Item = (&'static [u8], u64)> {
    data().zip(DATA_LENGTHS)
}

pub fn cases_with<T>(addons: T) -> impl Iterator<Item = (&'static [u8], u64, T::Item)>
where
    T: IntoIterator,
{
    cases()
        .zip(addons)
        .map(|((data, len), addon)| (data, len, addon))
}