use crate::vm::{addr::Addr, reg::Reg};

macro_rules! instructions {
    {
        $($variant:ident = $value:expr),* $(,)?
    } => {

        $(
            pub const $variant: InstOp = $value;
        )*

        pub fn inst_name(op: InstOp) -> Option<&'static str> {
            match op {
                $(
                    $value => Some(stringify!($variant)),
                )*
                _ => None,
            }
        }
    };
}
pub type InstOp = u16;

instructions! {
    ADD   = 0x0000,
    SUB   = 0x0001,
    MUL   = 0x0002,
    DIV   = 0x0003,
    MOD   = 0x0004,
    AND   = 0x0005,
    OR    = 0x0006,
    XOR   = 0x0007,
    SHL   = 0x0008,
    SHR   = 0x0009,
    INEG  = 0x000a,
    INV   = 0x000b,
    NOT   = 0x000c,
    CMPEQ = 0x1000,
    CMPLT = 0x1001,
    JMP   = 0x1002,
    JZ    = 0x1003,
    JNZ   = 0x1004,
    MOV   = 0x2000,
    HALT  = 0xF000,
    NOP   = 0xF001,
    DUMP  = 0xF002,
}

#[derive(Debug, Clone, Copy)]
pub enum Inst {
    Add(Dest, Source),
    Sub(Dest, Source),
    Mul(Dest, Source),
    Div(Dest, Source),
    Mod(Dest, Source),
    And(Dest, Source),
    Or(Dest, Source),
    Xor(Dest, Source),
    Shl(Dest, Source),
    Shr(Dest, Source),
    INeg(Dest, Source),
    Inv(Dest, Source),
    Not(Dest, Source),
    CmpEq(Source, Source),
    CmpLt(Source, Source),
    Jmp(Source),
    Jz(Source),
    Jnz(Source),
    Mov(Dest, Source),
    Halt,
    Nop,
    Dump,
}

impl Inst {
    pub fn op(&self) -> InstOp {
        match self {
            Inst::Add(_, _) => ADD,
            Inst::Sub(_, _) => SUB,
            Inst::Mul(_, _) => MUL,
            Inst::Div(_, _) => DIV,
            Inst::Mod(_, _) => MOD,
            Inst::And(_, _) => AND,
            Inst::Or(_, _) => OR,
            Inst::Xor(_, _) => XOR,
            Inst::Shl(_, _) => SHL,
            Inst::Shr(_, _) => SHL,
            Inst::INeg(_, _) => INEG,
            Inst::Inv(_, _) => INV,
            Inst::Not(_, _) => NOT,
            Inst::CmpEq(_, _) => CMPEQ,
            Inst::CmpLt(_, _) => CMPLT,
            Inst::Jmp(_) => JMP,
            Inst::Jz(_) => JZ,
            Inst::Jnz(_) => JNZ,
            Inst::Mov(_, _) => MOV,
            Inst::Halt => HALT,
            Inst::Nop => NOP,
            Inst::Dump => DUMP,
        }
    }

    pub fn len(&self) -> usize {
        match self {
            Inst::Add(dest, source)
                | Inst::Sub(dest, source)
                | Inst::Mul(dest, source)
                | Inst::Div(dest, source)
                | Inst::Mod(dest, source)
                | Inst::And(dest, source)
                | Inst::Or(dest, source)
                | Inst::Xor(dest, source)
                | Inst::Shl(dest, source)
                | Inst::Shr(dest, source)
                | Inst::INeg(dest, source)
                | Inst::Inv(dest, source)
                | Inst::Not(dest, source)
                | Inst::Mov(dest, source) => { 3 + dest.len() + source.len() }
            Inst::CmpEq(s1, s2)
                | Inst::CmpLt(s1, s2) => { 3 + s1.len() + s2.len() }
            Inst::Jmp(v)
                | Inst::Jz(v)
                | Inst::Jnz(v) => { 3 + v.len() }
            Inst::Halt
                | Inst::Nop
                | Inst::Dump => { 2 }
        }
    }
}

#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum Source {
    Addr64(Addr),
    Addr32(Addr),
    Addr16(Addr),
    Addr8(Addr),
    Reg(Reg),
    Imm(u64),
}

impl Source {
    pub fn len(&self) -> usize {
        match self {
            Source::Addr64(_) | Source::Addr32(_) | Source::Addr16(_) | Source::Addr8(_) => 8,
            Source::Reg(_) => 1,
            Source::Imm(_) => 8,
        }
    }
}

#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum Dest {
    Addr64(Addr),
    Addr32(Addr),
    Addr16(Addr),
    Addr8(Addr),
    Reg(Reg),
}

impl Dest {
    pub fn len(&self) -> usize {
        match self {
            Dest::Addr64(_) | Dest::Addr32(_) | Dest::Addr16(_) | Dest::Addr8(_) => 8,
            Dest::Reg(_) => 1,
        }
    }
}

pub const DEST_ADDR64: u8 = 0b0000;
pub const DEST_ADDR32: u8 = 0b0001;
pub const DEST_ADDR16: u8 = 0b0010;
pub const DEST_ADDR8: u8 = 0b0011;
pub const DEST_REG: u8 = 0b0100;

pub const SOURCE_ADDR64: u8 = 0b0000;
pub const SOURCE_ADDR32: u8 = 0b0001;
pub const SOURCE_ADDR16: u8 = 0b0010;
pub const SOURCE_ADDR8: u8 = 0b0011;
pub const SOURCE_REG: u8 = 0b0100;
pub const SOURCE_IMM64: u8 = 0b0101;
pub const SOURCE_IMM32: u8 = 0b0110;
pub const SOURCE_IMM16: u8 = 0b0111;
pub const SOURCE_IMM8: u8 = 0b1000;