use self::parser::message;

use log::*;

use netbuf;

use std::io::{Read, Result};

pub mod messages;

mod parser;

#[cfg(test)]

pub mod test;

pub struct ProtocolDecoder {

    buf: netbuf::Buf,

    is_recovering: bool,

}

impl ProtocolDecoder {

    pub fn new() -> ProtocolDecoder {

        ProtocolDecoder {

            buf: netbuf::Buf::new(),

            is_recovering: false,

        }

    }

    fn recover(&mut self) -> bool {

        self.is_recovering = match parser::malformed_message(&self.buf[..]) {

            Ok((tail, ())) => {

                let length = tail.len();

                self.buf.consume(self.buf.len() - length);

                false

            }

            _ => {

                self.buf.consume(self.buf.len());

                true

            }

        };

        !self.is_recovering

    }

    pub fn read_from<R: Read>(&mut self, stream: &mut R) -> Result<usize> {

        let count = self.buf.read_from(stream)?;

        if count > 0 && self.is_recovering {

            self.recover();

        }

        Ok(count)

    }

    pub fn extract_messages(&mut self) -> Vec<messages::HwProtocolMessage> {

        let mut messages = vec![];

        if !self.is_recovering {

            while !self.buf.is_empty() {

                match parser::message(&self.buf[..]) {

                    Ok((tail, message)) => {

                        messages.push(message);

                        let length = tail.len();

                        self.buf.consume(self.buf.len() - length);

                    }

                    Err(nom::Err::Incomplete(_)) => break,

                    Err(nom::Err::Failure(e)) | Err(nom::Err::Error(e)) => {

                        debug!("Invalid message: {:?}", e);

                        if !self.recover() || self.buf.is_empty() {

                            break;

                        }

                    }

                }

            }

        }

        messages

    }

}