/* Copyright (C) 2018 Open Information Security Foundation

 *

 * You can copy, redistribute or modify this Program under the terms of

 * the GNU General Public License version 2 as published by the Free

 * Software Foundation.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * version 2 along with this program; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA

 * 02110-1301, USA.

 */

use nom7::{

    bytes::streaming::{take, take_until},

    combinator::map_res,

    IResult,

};

use std;

fn parse_len(input: &str) -> Result<u32, std::num::ParseIntError> {

    input.parse::<u32>()

}

pub fn parse_message(i: &[u8]) -> IResult<&[u8], String> {

    let (i, len) = map_res(map_res(take_until(":"), std::str::from_utf8), parse_len)(i)?;

    let (i, _sep) = take(1_usize)(i)?;

    let (i, msg) = map_res(take(len as usize), std::str::from_utf8)(i)?;

    let result = msg.to_string();

    Ok((i, result))

}

#[cfg(test)]

mod tests {

    use super::*;

    use nom7::Err;

    /// Simple test of some valid data.

    #[test]

    fn test_parse_valid() {

        let buf = b"12:Hello World!4:Bye.";

        let result = parse_message(buf);

        match result {

            Ok((remainder, message)) => {

                // Check the first message.

                assert_eq!(message, "Hello World!");

                // And we should have 6 bytes left.

                assert_eq!(remainder.len(), 6);

            }

            Err(Err::Incomplete(_)) => {

                panic!("Result should not have been incomplete.");

            }

            Err(Err::Error(err)) | Err(Err::Failure(err)) => {

                panic!("Result should not be an error: {:?}.", err);

            }

        }

    }

}