use std::fmt::{Debug, Display, Formatter};
use std::fmt;

use crate::asm::data::{RdData, Register};
use crate::asm::data::literal::Value;
use crate::runtime::run_thread::RunState;
use crate::runtime::fault::Fault;

/// Data source argument (read-only)
#[derive(Clone, Copy, Eq, PartialEq)]
pub struct Rd(pub RdData);

impl Rd {
    pub const fn new(src: RdData) -> Self {
        Rd(src)
    }
    pub const fn immediate(val: Value) -> Rd {
        Rd(RdData::Immediate(val))
    }

    pub fn is_immediate_equal(self, other: Value) -> bool {
        match self.0 {
            RdData::Immediate(val) => {
                val == other
            }
            _ => false
        }
    }
}

impl From<&Rd> for Rd {
    fn from(a: &Rd) -> Self {
        *a
    }
}

impl Display for Rd {
    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
        write!(f, "{}", self.0) // TODO mask, when implemented
    }
}

impl Debug for Rd {
    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
        write!(f, "Rd({})", self.0)
    }
}


/// Reference an object through a handle
#[derive(Clone, Copy, Eq, PartialEq)]
pub enum RdObj {
    Reg(Register),
    Imm(Value),
}

impl RdObj {
    pub const fn from_reg(reg: Register) -> Self {
        RdObj::Reg(reg)
    }

    pub const fn from_value(value: Value) -> Self {
        RdObj::Imm(value)
    }

    pub fn read(self, state: &mut RunState) -> Result<Value, Fault> {
        Ok(match self {
            RdObj::Reg(r) => state.read(Rd::new(RdData::Register(r)))?,
            RdObj::Imm(v) => v,
        })
    }
}

impl From<&RdObj> for RdObj {
    fn from(a: &RdObj) -> Self {
        *a
    }
}

impl Display for RdObj {
    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
        match self {
            RdObj::Reg(r) => write!(f, "@{}", r),
            RdObj::Imm(v) => write!(f, "@{:#x}", v)
        }
    }
}

impl Debug for RdObj {
    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
        match self {
            RdObj::Reg(r) => write!(f, "Obj({})", r),
            RdObj::Imm(v) => write!(f, "Obj({:#x})", v)
        }
    }
}