use std::io::{BufWriter, BufReader, Read};
use doby::{
    cli,
    crypto::{EncryptionParams, DobyCipher},
    MAGIC_BYTES,
    decrypt,
    encrypt,
};

fn main() {
    if let Some(cli_args) = cli::parse() {
        let mut reader = BufReader::with_capacity(cli_args.block_size, cli_args.reader);
        let mut writer = BufWriter::with_capacity(cli_args.block_size, cli_args.writer);

        let mut magic_bytes = vec![0; MAGIC_BYTES.len()];
        match reader.read(&mut magic_bytes) {
            Ok(n) => {
                if n < magic_bytes.len() {
                    magic_bytes.truncate(n);
                }
                if magic_bytes == MAGIC_BYTES && !cli_args.force_encrypt { //we probably want to decrypt
                    match EncryptionParams::read(&mut reader) {
                        Ok(params) => {
                            match params {
                                Some(params) => {
                                    match DobyCipher::new(cli_args.password, &params) {
                                        Ok(cipher) => {
                                            match decrypt(&mut reader, &mut writer, cipher, cli_args.block_size) {
                                                Ok(verified) => {
                                                    if !verified {
                                                        eprintln!("WARNING: HMAC verification failed !\nEither your password is incorrect or the ciphertext has been corrupted.\nBe careful, the data could have been altered by an attacker.");
                                                    }
                                                }
                                                Err(e) => eprintln!("I/O error while decrypting: {}", e)
                                            }
                                        }
                                        Err(e) => eprintln!("Invalid argon2 params: {}", e)
                                    }
                                }
                                None => eprintln!("Invalid cipher")
                            }
                        }
                        Err(e) => eprintln!("I/O error while reading headers: {}", e)
                    }
                } else { //otherwise, encrypt
                    let params = EncryptionParams::new(cli_args.argon2_params, cli_args.cipher);
                    match DobyCipher::new(cli_args.password, &params) {
                        Ok(cipher) => {
                            if let Err(e) = encrypt(
                                &mut reader,
                                &mut writer,
                                &params,
                                cipher,
                                cli_args.block_size, 
                                Some(magic_bytes)
                            ) {
                                eprintln!("I/O error while encrypting: {}", e);
                            }
                        }
                        Err(e) => eprintln!("Invalid argon2 params: {}", e)
                    }
                }
            }
            Err(e) => eprintln!("I/O error while reading magic bytes: {}", e),
        }
    }
}