#include "shim/trace/sha256.h"

#include <cstring>
#include <string>

#include "check.h"

using shim::Sha256;

static std::string hex_of(const std::string& s) {
    char h[65];
    Sha256::digest_hex(s.data(), s.size(), h);
    return h;
}

int main() {
    // FIPS 180-2 vectors + the harness's empty-string value (mkfixture test_float_and_bigint_forms).
    CHECK_STR(hex_of(""), "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855");
    CHECK_STR(hex_of("abc"), "ba7816bf8f01cfea414140de5dae2223b00361a396177a9cb410ff61f20015ad");
    CHECK_STR(hex_of("abcdbcdecdefdefgefghfghighijhijkijkljklmklmnlmnomnopnopq"),
              "248d6a61d20638b8e5c026930c3e6039a33ce45964ff2167f6ecedd419db06c1");
    CHECK_STR(hex_of(std::string(1000000, 'a')), "cdc76e5c9914fb9281a1c7e284d73e67f1809a48a497200e046d39ccc7112cd0");
    CHECK_STR(hex_of(std::string("\x00\xff", 2)), "06eb7d6a69ee19e5fbdf749018d3d2abfa04bcbd1365db312eb86dc7169389b8");

    // Incremental updates across block boundaries equal the one-shot digest.
    const std::string big(1000000, 'a');
    Sha256 s;
    std::size_t pos = 0;
    const std::size_t steps[] = {1, 63, 64, 65, 1000, 4096, 55, 56, 57, 100000};
    while (pos < big.size()) {
        for (std::size_t st : steps) {
            const std::size_t n = (pos + st > big.size()) ? big.size() - pos : st;
            s.update(big.data() + pos, n);
            pos += n;
            if (pos >= big.size()) break;
        }
    }
    std::uint8_t d[32];
    s.finish(d);
    char h[65];
    Sha256::to_hex(d, h);
    CHECK_STR(std::string(h), "cdc76e5c9914fb9281a1c7e284d73e67f1809a48a497200e046d39ccc7112cd0");

    // Exactly 55 / 56 / 64 bytes (padding edge cases) agree with themselves chunked.
    for (std::size_t n : {55u, 56u, 63u, 64u, 65u, 119u, 120u, 128u}) {
        const std::string m(n, 'x');
        Sha256 a;
        a.update(m.data(), 20);
        a.update(m.data() + 20, n - 20);
        std::uint8_t da[32];
        a.finish(da);
        std::uint8_t db[32];
        Sha256::digest(m.data(), n, db);
        CHECK(std::memcmp(da, db, 32) == 0);
    }
    return tracetest::finish("shim_trace_sha256");
}