#[cfg(feature="use-serde")]
#[macro_use] extern crate serde_derive;
#[cfg(feature="use-serde")]
extern crate serde;
//#[cfg(feature="use-serde")]
//use serde::{Serialize, Deserialize};

extern crate yaxpeax_arch;

use yaxpeax_arch::{Arch, Decoder, LengthedInstruction};

use std::fmt;

#[derive(Debug)]
pub enum Opcode {
    NOP
}

#[derive(Debug)]
pub struct Instruction {
    pub opcode: Opcode
}

impl Default for Instruction {
    fn default() -> Self {
        Instruction {
            opcode: Opcode::NOP
        }
    }
}

impl LengthedInstruction for Instruction {
    type Unit = <PIC24 as Arch>::Address;
    fn min_size() -> Self::Unit {
        3
    }
    fn len(&self) -> Self::Unit {
        3 // ish
    }
}

#[derive(Debug, PartialEq)]
pub enum DecodeError {
    ExhaustedInput,
    InvalidOpcode,
    InvalidOperand,
}

impl fmt::Display for DecodeError {
    fn fmt(&self, f:  &mut fmt::Formatter) -> fmt::Result {
        match self {
            DecodeError::ExhaustedInput => write!(f, "exhausted input"),
            DecodeError::InvalidOpcode => write!(f, "invalid opcode"),
            DecodeError::InvalidOperand => write!(f, "invalid operand"),
        }
    }
}

impl yaxpeax_arch::DecodeError for DecodeError {
    fn data_exhausted(&self) -> bool { self == &DecodeError::ExhaustedInput }
    fn bad_opcode(&self) -> bool { self == &DecodeError::InvalidOpcode }
    fn bad_operand(&self) -> bool { self == &DecodeError::InvalidOperand }
}

impl yaxpeax_arch::Instruction for Instruction {
    // TODO: this is wrong!!
    fn well_defined(&self) -> bool { true }
}

#[derive(Default, Debug)]
pub struct InstDecoder {}

impl Decoder<Instruction> for InstDecoder {
    type Error = DecodeError;

    fn decode_into<T: IntoIterator<Item=u8>>(&self, instr: &mut Instruction, bytes: T) -> Result<(), Self::Error> {
        match bytes.into_iter().next() {
            Some(0x00) => {
                instr.opcode = Opcode::NOP;
                Ok(())
            },
            _ => Err(DecodeError::ExhaustedInput)
        }
    }
}

#[cfg(feature="use-serde")]
#[derive(Debug, Serialize, Deserialize)]
pub struct PIC24;

#[cfg(not(feature="use-serde"))]
#[derive(Debug)]
pub struct PIC24;

impl Arch for PIC24 {
    type Address = u32;
    type Instruction = Instruction;
    type DecodeError = DecodeError;
    type Decoder = InstDecoder;
    type Operand = ();
}