/* Copyright 2015 OpenMarket Ltd
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
#include "olm/ratchet.hh"
#include "olm/cipher.hh"
#include "unittest.hh"


int main() {

std::uint8_t root_info[] = "Olm";
std::uint8_t ratchet_info[] = "OlmRatchet";
std::uint8_t message_info[] = "OlmMessageKeys";

olm::KdfInfo kdf_info = {
    root_info, sizeof(root_info) - 1,
    ratchet_info, sizeof(ratchet_info) - 1
};

olm::CipherAesSha256 cipher(
    message_info, sizeof(message_info) - 1
);

std::uint8_t random_bytes[] = "0123456789ABDEF0123456789ABCDEF";
olm::Curve25519KeyPair alice_key;
olm::curve25519_generate_key(random_bytes, alice_key);

std::uint8_t shared_secret[] = "A secret";

{ /* Send/Receive test case */
TestCase test_case("Olm Send/Receive");

olm::Ratchet alice(kdf_info, cipher);
olm::Ratchet bob(kdf_info, cipher);

alice.initialise_as_alice(shared_secret, sizeof(shared_secret) - 1, alice_key);
bob.initialise_as_bob(shared_secret, sizeof(shared_secret) - 1, alice_key);

std::uint8_t plaintext[] = "Message";
std::size_t plaintext_length = sizeof(plaintext) - 1;

std::size_t message_length, random_length, output_length;
std::size_t encrypt_length, decrypt_length;
{
    /* Alice sends Bob a message */
    message_length = alice.encrypt_output_length(plaintext_length);
    random_length = alice.encrypt_random_length();
    assert_equals(std::size_t(0), random_length);

    std::uint8_t message[message_length];

    encrypt_length = alice.encrypt(
        plaintext, plaintext_length,
        NULL, 0,
        message, message_length
    );
    assert_equals(message_length, encrypt_length);

    output_length = bob.decrypt_max_plaintext_length(message, message_length);
    std::uint8_t output[output_length];
    decrypt_length = bob.decrypt(
        message, message_length,
        output, output_length
    );
    assert_equals(plaintext_length, decrypt_length);
    assert_equals(plaintext, output, decrypt_length);
}


{
    /* Bob sends Alice a message */
    message_length = bob.encrypt_output_length(plaintext_length);
    random_length = bob.encrypt_random_length();
    assert_equals(std::size_t(32), random_length);

    std::uint8_t message[message_length];
    std::uint8_t random[] = "This is a random 32 byte string.";

    encrypt_length = bob.encrypt(
        plaintext, plaintext_length,
        random, 32,
        message, message_length
    );
    assert_equals(message_length, encrypt_length);

    output_length = alice.decrypt_max_plaintext_length(message, message_length);
    std::uint8_t output[output_length];
    decrypt_length = alice.decrypt(
        message, message_length,
        output, output_length
    );
    assert_equals(plaintext_length, decrypt_length);
    assert_equals(plaintext, output, decrypt_length);
}

} /* Send/receive message test case */

{ /* Out of order test case */

TestCase test_case("Olm Out of Order");

olm::Ratchet alice(kdf_info, cipher);
olm::Ratchet bob(kdf_info, cipher);

alice.initialise_as_alice(shared_secret, sizeof(shared_secret) - 1, alice_key);
bob.initialise_as_bob(shared_secret, sizeof(shared_secret) - 1, alice_key);

std::uint8_t plaintext_1[] = "First Message";
std::size_t plaintext_1_length = sizeof(plaintext_1) - 1;

std::uint8_t plaintext_2[] = "Second Messsage. A bit longer than the first.";
std::size_t plaintext_2_length = sizeof(plaintext_2) - 1;

std::size_t message_1_length, message_2_length, random_length, output_length;
std::size_t encrypt_length, decrypt_length;

{
    /* Alice sends Bob two messages and they arrive out of order */
    message_1_length = alice.encrypt_output_length(plaintext_1_length);
    random_length = alice.encrypt_random_length();
    assert_equals(std::size_t(0), random_length);

    std::uint8_t message_1[message_1_length];
    std::uint8_t random[] = "This is a random 32 byte string.";
    encrypt_length = alice.encrypt(
        plaintext_1, plaintext_1_length,
        random, 32,
        message_1, message_1_length
    );
    assert_equals(message_1_length, encrypt_length);

    message_2_length = alice.encrypt_output_length(plaintext_2_length);
    random_length = alice.encrypt_random_length();
    assert_equals(std::size_t(0), random_length);

    std::uint8_t message_2[message_2_length];
    encrypt_length = alice.encrypt(
        plaintext_2, plaintext_2_length,
        NULL, 0,
        message_2, message_2_length
    );
    assert_equals(message_2_length, encrypt_length);

    output_length = bob.decrypt_max_plaintext_length(
        message_2, message_2_length
    );
    std::uint8_t output_1[output_length];
    decrypt_length = bob.decrypt(
        message_2, message_2_length,
        output_1, output_length
    );
    assert_equals(plaintext_2_length, decrypt_length);
    assert_equals(plaintext_2, output_1, decrypt_length);

    output_length = bob.decrypt_max_plaintext_length(
        message_1, message_1_length
    );
    std::uint8_t output_2[output_length];
    decrypt_length = bob.decrypt(
        message_1, message_1_length,
        output_2, output_length
    );

    assert_equals(plaintext_1_length, decrypt_length);
    assert_equals(plaintext_1, output_2, decrypt_length);
}

} /* Out of order test case */

{ /* More messages */

TestCase test_case("Olm More Messages");

olm::Ratchet alice(kdf_info, cipher);
olm::Ratchet bob(kdf_info, cipher);

alice.initialise_as_alice(shared_secret, sizeof(shared_secret) - 1, alice_key);
bob.initialise_as_bob(shared_secret, sizeof(shared_secret) - 1, alice_key);

std::uint8_t plaintext[] = "These 15 bytes";
assert_equals(std::size_t(15), sizeof(plaintext));
std::uint8_t random[] = "This is a random 32 byte string";

for (unsigned i = 0; i < 8; ++i) {
{
    std::uint8_t msg[alice.encrypt_output_length(sizeof(plaintext))];
    alice.encrypt(
        plaintext, 15, random, 32, msg, sizeof(msg)
    );
    std::uint8_t output[bob.decrypt_max_plaintext_length(msg, sizeof(msg))];
    assert_equals(
        std::size_t(15), bob.decrypt(msg, sizeof(msg), output, sizeof(output))
    );
}
random[31]++;
{
    std::uint8_t msg[bob.encrypt_output_length(sizeof(plaintext))];
    bob.encrypt(
        plaintext, 15, random, 32, msg, sizeof(msg)
    );
    std::uint8_t output[alice.decrypt_max_plaintext_length(msg, sizeof(msg))];
    assert_equals(
        std::size_t(15), alice.decrypt(msg, sizeof(msg), output, sizeof(output))
    );
}
random[31]++;
}

}

}