use std::io::Result;

extern crate byteorder;
use byteorder::{BigEndian, ByteOrder};


pub trait HoldingRegisters {
    fn get<A: Into<u16>>(&mut self, addr: A) -> Result<u16>;
    fn gets<A: Into<u16>, D: From<u16>>(&mut self, start_addr: A, buff: &mut [D]) -> Result<()>;
    fn set<A: Into<u16>, D: Into<u16>>(&mut self, addr: A, data: D) -> Result<()>;
    fn sets<A: Into<u16>, D: Into<u16> + Copy>(&mut self, start_addr: A, buff: &[D]) -> Result<()>;
}

pub trait RawHoldingRegisters<'a> {
    type Data: RawData + 'a;
    fn put<A: Into<u16>>(&'a mut self, start_addr: A, registers: u16, bytes: u8) -> Self::Data;
    fn pop<A: Into<u16>>(&'a mut self, start_addr: A, registers: u16) -> Self::Data;
}

impl<'a, T: RawHoldingRegisters<'a>> HoldingRegisters for T {
    fn get<A: Into<u16>>(&mut self, addr: A) -> Result<u16> {
        let raw = self.pop(addr, 1);
        raw.query()?;
        Ok(BigEndian::read_u16(raw.as_slice()))
    }

    fn gets<A: Into<u16>, D: From<u16>>(&mut self, start_addr: A, buff: &mut [D]) -> Result<()> {
        Ok(())
    }

    fn set<A: Into<u16>, D: Into<u16>>(&mut self, addr: A, data: D) -> Result<()> {
        Ok(())
    }

    fn sets<A: Into<u16>, D: Into<u16> + Copy>(&mut self, start_addr: A, buff: &[D]) -> Result<()> {
        Ok(())
    }
}

pub trait RawData {
    fn query(&mut self) -> Result<()>;
    fn as_slice(&self) -> &[u8];
    fn as_mut_slice(&mut self) -> &mut [u8];
}