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use crypto::aes;
use crypto::blockmodes;
use crypto::buffer::{RefReadBuffer, RefWriteBuffer};
use crypto::hmac::Hmac;
use crypto::pbkdf2::pbkdf2;
use crypto::sha1::Sha1;

pub const AES_BLOCK_SIZE: usize = 16;
pub const AES_MAC_SIZE: usize = 12;
pub const AES128_SEED_SIZE: usize = 16;
pub const AES256_SEED_SIZE: usize = 32;

/// Size of AES-128 key, 16 bytes
pub const AES128_KEY_SIZE: usize = 16;

/// Size of AES-256 key, 32 bytes
pub const AES256_KEY_SIZE: usize = 32;

/// Enum to provide asociated parameters with each size of the AES algorithm
pub enum AesSizes {
    Aes128,
    Aes256,
}

impl AesSizes {
    pub fn seed_size(&self) -> usize {
        match &self {
            AesSizes::Aes128 => return AES128_SEED_SIZE,
            AesSizes::Aes256 => return AES256_SEED_SIZE,
        }
    }

    pub fn block_size(&self) -> usize {
        return AES_BLOCK_SIZE;
    }

    pub fn key_size(&self) -> aes::KeySize {
        match &self {
            AesSizes::Aes128 => return aes::KeySize::KeySize128,
            AesSizes::Aes256 => return aes::KeySize::KeySize256,
        }
    }

    pub fn mac_size(&self) -> usize {
        return AES_MAC_SIZE;
    }
}

pub fn pbkdf2_sha1(key: &[u8], salt: &[u8], seed_size: usize) -> Vec<u8> {
    let iteration_count = 0x1000;
    let mut hmacker = Hmac::new(Sha1::new(), key);
    let mut seed: Vec<u8> = vec![0; seed_size];
    pbkdf2(&mut hmacker, salt, iteration_count, &mut seed);
    return seed;
}

pub fn decrypt_aes_ecb(
    key: &[u8],
    ciphertext: &[u8],
    aes_sizes: &AesSizes,
) -> Vec<u8> {
    let mut decryptor =
        aes::ecb_decryptor(aes_sizes.key_size(), key, blockmodes::NoPadding);
    let mut plaintext: Vec<u8> = vec![0; ciphertext.len()];
    decryptor
        .decrypt(
            &mut RefReadBuffer::new(ciphertext),
            &mut RefWriteBuffer::new(&mut plaintext),
            true,
        )
        .unwrap();

    return plaintext;
}

pub fn encrypt_aes_cbc(
    key: &[u8],
    plaintext: &[u8],
    aes_sizes: &AesSizes,
) -> Vec<u8> {
    let mut encryptor = aes::cbc_encryptor(
        aes_sizes.key_size(),
        key,
        &vec![0; aes_sizes.block_size()],
        blockmodes::NoPadding,
    );

    let mut ciphertext: Vec<u8> = vec![0; plaintext.len()];
    encryptor
        .encrypt(
            &mut RefReadBuffer::new(plaintext),
            &mut RefWriteBuffer::new(&mut ciphertext),
            true,
        )
        .unwrap();

    return ciphertext;
}