//! This module provides access to libsodium

use super::{check_init, secbuf::SecBuf};
use crate::error::SodiumError;

/// Used to set the size of nonce var in the enc fns
pub const NONCEBYTES: usize =
    rust_sodium_sys::crypto_aead_xchacha20poly1305_ietf_NPUBBYTES as usize;
/// Used with the size of the message to set the size of the cipher and decripted message
///
/// Note: look at the test cases to see how it is used
pub const ABYTES: usize = rust_sodium_sys::crypto_aead_xchacha20poly1305_ietf_ABYTES as usize;

/// Generate symmetric cipher text given a message, secret, and optional auth data
///
/// @param {SecBuf} message - data to encrypt
///
/// @param {SecBuf} secret - symmetric secret key
///
/// @param {SecBuf} adata - optional additional authenticated data
///
/// @param {SecBuf} nonce - sometimes called initialization vector (iv)
///
/// @param {SecBuf} cipher - Empty Buffer (needed when you want to Decrypt the meassage)
pub fn enc(
    message: &mut SecBuf,
    secret: &mut SecBuf,
    adata: Option<&mut SecBuf>,
    nonce: &mut SecBuf,
    cipher: &mut SecBuf,
) -> Result<(), SodiumError> {
    check_init();
    let my_adata_locker;
    let mut my_adata = std::ptr::null();
    let mut my_ad_len = 0 as libc::c_ulonglong;

    if let Some(s) = adata {
        my_adata_locker = s.read_lock();
        my_adata = raw_ptr_char_immut!(my_adata_locker);
        my_ad_len = my_adata_locker.len() as libc::c_ulonglong;
    }

    let mut cipher = cipher.write_lock();
    let message = message.read_lock();
    let nonce = nonce.read_lock();
    let secret = secret.read_lock();

    unsafe {
        rust_sodium_sys::crypto_aead_xchacha20poly1305_ietf_encrypt(
            raw_ptr_char!(cipher),
            std::ptr::null_mut(),
            raw_ptr_char_immut!(message),
            message.len() as libc::c_ulonglong,
            my_adata,
            my_ad_len,
            std::ptr::null_mut(),
            raw_ptr_char_immut!(nonce),
            raw_ptr_char_immut!(secret),
        );
    }
    Ok(())
}

/// Decrypt symmetric cipher text given a nonce, secret, and optional auth data
/// ****
/// @param {SecBuf} decrypted_message - Empty Buffer to be used as output to return the result
///
/// @param {SecBuf} secret - symmetric secret key
///
/// @param {Buffer} adata - optional additional authenticated data
///
/// @param {Buffer} nonce - sometimes called initialization vector (iv)
///
/// @param {Buffer} cipher - the cipher text
pub fn dec(
    decrypted_message: &mut SecBuf,
    secret: &mut SecBuf,
    adata: Option<&mut SecBuf>,
    nonce: &mut SecBuf,
    cipher: &mut SecBuf,
) -> Result<(), SodiumError> {
    check_init();
    let my_adata_locker;
    let mut my_adata = std::ptr::null();
    let mut my_ad_len = 0 as libc::c_ulonglong;

    if let Some(s) = adata {
        my_adata_locker = s.read_lock();
        my_adata = raw_ptr_char_immut!(my_adata_locker);
        my_ad_len = my_adata_locker.len() as libc::c_ulonglong;
    }

    let mut decrypted_message = decrypted_message.write_lock();
    let cipher = cipher.read_lock();
    let nonce = nonce.read_lock();
    let secret = secret.read_lock();

    unsafe {
        rust_sodium_sys::crypto_aead_xchacha20poly1305_ietf_decrypt(
            raw_ptr_char!(decrypted_message),
            std::ptr::null_mut(),
            std::ptr::null_mut(),
            raw_ptr_char_immut!(cipher),
            cipher.len() as libc::c_ulonglong,
            my_adata,
            my_ad_len,
            raw_ptr_char_immut!(nonce),
            raw_ptr_char_immut!(secret),
        );
    }
    Ok(())
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn it_should_with_auth_aead_encrypt_and_decrypt() {
        let mut message = SecBuf::with_secure(8);
        message.randomize();

        let mut secret = SecBuf::with_secure(32);
        secret.randomize();

        let mut adata = SecBuf::with_secure(16);
        adata.randomize();

        let mut nonce = SecBuf::with_insecure(16);
        nonce.randomize();

        let mut cipher = SecBuf::with_insecure(message.len() + ABYTES);

        enc(
            &mut message,
            &mut secret,
            Some(&mut adata),
            &mut nonce,
            &mut cipher,
        )
        .unwrap();

        let mut decrypted_message = SecBuf::with_insecure(cipher.len() - ABYTES);

        dec(
            &mut decrypted_message,
            &mut secret,
            Some(&mut adata),
            &mut nonce,
            &mut cipher,
        )
        .unwrap();

        {
            let message = message.read_lock();
            let decrypted_message = decrypted_message.read_lock();
            assert_eq!(
                format!("{:?}", *message),
                format!("{:?}", *decrypted_message)
            );
        }
    }

    #[test]
    fn it_should_with_none_aead_encrypt_and_decrypt() {
        let mut message = SecBuf::with_secure(16);
        message.randomize();

        let mut secret = SecBuf::with_secure(32);
        secret.randomize();

        let mut nonce = SecBuf::with_insecure(NONCEBYTES);
        nonce.randomize();

        let cip_len = message.len() + ABYTES;
        let mut cipher = SecBuf::with_insecure(cip_len);
        enc(&mut message, &mut secret, None, &mut nonce, &mut cipher).unwrap();

        let dec_len = cip_len - ABYTES;
        let mut decrypted_message = SecBuf::with_insecure(dec_len);
        dec(
            &mut decrypted_message,
            &mut secret,
            None,
            &mut nonce,
            &mut cipher,
        )
        .unwrap();
        let message = message.read_lock();
        let decrypted_message = decrypted_message.read_lock();
        assert_eq!(
            format!("{:?}", *message),
            format!("{:?}", *decrypted_message)
        );
    }
    #[test]
    fn it_should_with_bad_aead_encrypt_and_decrypt() {
        let mut message = SecBuf::with_secure(16);
        message.randomize();

        let mut secret = SecBuf::with_secure(32);
        secret.randomize();

        let mut adata = SecBuf::with_secure(16);
        adata.randomize();

        let mut adata1 = SecBuf::with_secure(16);
        adata1.randomize();

        let mut nonce = SecBuf::with_insecure(NONCEBYTES);
        nonce.randomize();

        let cip_len = message.len() + ABYTES;
        let mut cipher = SecBuf::with_insecure(cip_len);
        enc(
            &mut message,
            &mut secret,
            Some(&mut adata),
            &mut nonce,
            &mut cipher,
        )
        .unwrap();
        let dec_len = cip_len - ABYTES;
        let mut decrypted_message = SecBuf::with_insecure(dec_len);
        dec(
            &mut decrypted_message,
            &mut secret,
            Some(&mut adata1),
            &mut nonce,
            &mut cipher,
        )
        .unwrap();
        let decrypted_message = decrypted_message.read_lock();
        assert_eq!(
            "[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]",
            format!("{:?}", *decrypted_message)
        );
    }
}