//! SHA-256 vectors. Do not edit: these define the required behaviour.
//!
//! The lengths 55, 56, 63, 64 and 65 sit on either side of the padding boundaries of SHA-256,
//! which is where implementations go wrong. Expected values come from `sha256sum`.

use proto::{Sha256, sha256};

const VECTORS: &[(usize, &str)] = &[
    (
        0,
        "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855",
    ),
    (
        1,
        "ca978112ca1bbdcafac231b39a23dc4da786eff8147c4e72b9807785afee48bb",
    ),
    (
        55,
        "9f4390f8d30c2dd92ec9f095b65e2b9ae9b0a925a5258e241c9f1e910f734318",
    ),
    (
        56,
        "b35439a4ac6f0948b6d6f9e3c6af0f5f590ce20f1bde7090ef7970686ec6738a",
    ),
    (
        63,
        "7d3e74a05d7db15bce4ad9ec0658ea98e3f06eeecf16b4c6fff2da457ddc2f34",
    ),
    (
        64,
        "ffe054fe7ae0cb6dc65c3af9b61d5209f439851db43d0ba5997337df154668eb",
    ),
    (
        65,
        "635361c48bb9eab14198e76ea8ab7f1a41685d6ad62aa9146d301d4f17eb0ae0",
    ),
    (
        119,
        "31eba51c313a5c08226adf18d4a359cfdfd8d2e816b13f4af952f7ea6584dcfb",
    ),
    (
        127,
        "c57e9278af78fa3cab38667bef4ce29d783787a2f731d4e12200270f0c32320a",
    ),
    (
        128,
        "6836cf13bac400e9105071cd6af47084dfacad4e5e302c94bfed24e013afb73e",
    ),
    (
        1000,
        "41edece42d63e8d9bf515a9ba6932e1c20cbc9f5a5d134645adb5db1b9737ea3",
    ),
];

/// `n` bytes of the letter `a`.
fn letters(n: usize) -> Vec<u8> {
    vec![b'a'; n]
}

#[test]
fn abc() {
    let want = "ba7816bf8f01cfea414140de5dae2223b00361a396177a9cb410ff61f20015ad";
    assert_eq!(sha256(b"abc").unwrap().to_hex(), want);
}

#[test]
fn lengths_around_the_padding_boundaries() {
    for (n, want) in VECTORS {
        assert_eq!(sha256(&letters(*n)).unwrap().to_hex(), *want, "{n} bytes");
    }
}

#[test]
fn input_in_two_pieces_gives_the_same_hash() {
    for (n, want) in VECTORS {
        let data = letters(*n);
        for split in [0, 1, 55, 56, 63, 64, 65, *n / 2, *n] {
            let split = split.min(*n);
            let mut h = Sha256::new();
            h.update(&data[..split]).unwrap();
            h.update(&data[split..]).unwrap();
            assert_eq!(
                h.finish().unwrap().to_hex(),
                *want,
                "{n} bytes split at {split}"
            );
        }
    }
}

#[test]
fn one_million_letters() {
    let want = "cdc76e5c9914fb9281a1c7e284d73e67f1809a48a497200e046d39ccc7112cd0";
    assert_eq!(sha256(&letters(1_000_000)).unwrap().to_hex(), want);
    let mut h = Sha256::default();
    for _ in 0..1000 {
        h.update(&letters(1000)).unwrap();
    }
    assert_eq!(h.finish().unwrap().to_hex(), want);
}