use crsn::asm::data::{Rd, Wr};
use crsn::asm::error::CrsnError;
use crsn::asm::instr::op::OpKind;
use crsn::asm::parse::arg_parser::TokenParser;
use crsn::module::ParseRes;

use crate::defs::ArithOp;

pub(crate) fn parse<'a>(keyword: &str, mut args: TokenParser<'a>) -> Result<ParseRes<'a, OpKind>, CrsnError> {
    Ok(ParseRes::ext(match keyword {
        "cmp" => {
            ArithOp::Compare {
                a: args.next_rd()?,
                b: args.next_rd()?,
            }
        }

        "tst" => {
            let arg = args.next_rd()?;
            ArithOp::Test { a: arg }
        }

        "inc" => {
            let dst = args.next_wr()?;
            ArithOp::Add {
                dst,
                a: dst.as_rd(),
                b: Rd::immediate(1),
            }
        }

        "dec" => {
            let dst = args.next_wr()?;
            ArithOp::Sub {
                dst,
                a: dst.as_rd(),
                b: Rd::immediate(1),
            }
        }

        "add" => {
            match args.len() {
                3 => {
                    ArithOp::Add {
                        dst: args.next_wr()?,
                        a: args.next_rd()?,
                        b: args.next_rd()?,
                    }
                }
                2 => {
                    let dst = args.next_wr()?;
                    ArithOp::Add {
                        dst,
                        a: dst.as_rd(),
                        b: args.next_rd()?,
                    }
                }
                _ => {
                    return Err(CrsnError::Parse("Add requires 2 or 3 arguments".into()));
                }
            }
        }

        "sub" => {
            match args.len() {
                3 => {
                    ArithOp::Sub {
                        dst: args.next_wr()?,
                        a: args.next_rd()?,
                        b: args.next_rd()?,
                    }
                }
                2 => {
                    let dst = args.next_wr()?;
                    ArithOp::Sub {
                        dst,
                        a: dst.as_rd(),
                        b: args.next_rd()?,
                    }
                }
                _ => {
                    return Err(CrsnError::Parse("Sub requires 2 or 3 arguments".into()));
                }
            }
        }

        "mul" => {
            match args.len() {
                3 => {
                    ArithOp::Mul {
                        dst: args.next_wr()?,
                        a: args.next_rd()?,
                        b: args.next_rd()?,
                    }
                }
                2 => {
                    let dst = args.next_wr()?;
                    ArithOp::Mul {
                        dst,
                        a: dst.as_rd(),
                        b: args.next_rd()?,
                    }
                }
                _ => {
                    return Err(CrsnError::Parse("Mul requires 2 or 3 arguments".into()));
                }
            }
        }

        "divr" => {
            match args.len() {
                3 => {
                    let dst = args.next_wr()?;
                    let rem = args.next_wr()?;
                    let div = args.next_rd()?;
                    ArithOp::Div {
                        dst,
                        rem,
                        a: dst.as_rd(),
                        div,
                    }
                }
                4 => {
                    ArithOp::Div {
                        dst: args.next_wr()?,
                        rem: args.next_wr()?,
                        a: args.next_rd()?,
                        div: args.next_rd()?,
                    }
                }
                _ => {
                    return Err(CrsnError::Parse("DivR requires 3 or 4 arguments".into()));
                }
            }
        }

        "div" => {
            match args.len() {
                3 => {
                    ArithOp::Div {
                        dst: args.next_wr()?,
                        rem: Wr::discard(),
                        a: args.next_rd()?,
                        div: args.next_rd()?,
                    }
                }
                2 => {
                    let dst = args.next_wr()?;
                    let div = args.next_rd()?;
                    ArithOp::Div {
                        dst,
                        rem: Wr::discard(),
                        a: dst.as_rd(),
                        div,
                    }
                }
                _ => {
                    return Err(CrsnError::Parse("Div requires 2 or 3 arguments".into()));
                }
            }
        }

        "mod" => {
            match args.len() {
                3 => {
                    ArithOp::Mod {
                        dst: args.next_wr()?,
                        a: args.next_rd()?,
                        div: args.next_rd()?,
                    }
                }
                2 => {
                    let dst = args.next_wr()?;
                    let div = args.next_rd()?;
                    ArithOp::Mod {
                        dst,
                        a: dst.as_rd(),
                        div,
                    }
                }
                _ => {
                    return Err(CrsnError::Parse("Mod requires 2 or 3 arguments".into()));
                }
            }
        }

        "and" => {
            match args.len() {
                3 => {
                    ArithOp::And {
                        dst: args.next_wr()?,
                        a: args.next_rd()?,
                        b: args.next_rd()?,
                    }
                }
                2 => {
                    let dst = args.next_wr()?;
                    ArithOp::And {
                        dst,
                        a: dst.as_rd(),
                        b: args.next_rd()?,
                    }
                }
                _ => {
                    return Err(CrsnError::Parse("And requires 2 or 3 arguments".into()));
                }
            }
        }

        "or" => {
            match args.len() {
                3 => {
                    ArithOp::Or {
                        dst: args.next_wr()?,
                        a: args.next_rd()?,
                        b: args.next_rd()?,
                    }
                }
                2 => {
                    let dst = args.next_wr()?;
                    ArithOp::Or {
                        dst,
                        a: dst.as_rd(),
                        b: args.next_rd()?,
                    }
                }
                _ => {
                    return Err(CrsnError::Parse("Or requires 2 or 3 arguments".into()));
                }
            }
        }

        "xor" => {
            match args.len() {
                3 => {
                    ArithOp::Xor {
                        dst: args.next_wr()?,
                        a: args.next_rd()?,
                        b: args.next_rd()?,
                    }
                }
                2 => {
                    let dst = args.next_wr()?;
                    ArithOp::Xor {
                        dst,
                        a: dst.as_rd(),
                        b: args.next_rd()?,
                    }
                }
                _ => {
                    return Err(CrsnError::Parse("Xor requires 2 or 3 arguments".into()));
                }
            }
        }

        "cpl" => {
            match args.len() {
                2 => {
                    ArithOp::Cpl {
                        dst: args.next_wr()?,
                        a: args.next_rd()?,
                    }
                }
                1 => {
                    let dst = args.next_wr()?;
                    ArithOp::Cpl {
                        dst,
                        a: dst.as_rd(),
                    }
                }
                _ => {
                    return Err(CrsnError::Parse("Cpl requires 1 or 2 arguments".into()));
                }
            }
        }

        "rol" => {
            match args.len() {
                3 => {
                    ArithOp::Rol {
                        dst: args.next_wr()?,
                        a: args.next_rd()?,
                        n: args.next_rd()?,
                    }
                }
                2 => {
                    let dst = args.next_wr()?;
                    ArithOp::Rol {
                        dst,
                        a: dst.as_rd(),
                        n: args.next_rd()?,
                    }
                }
                1 => {
                    let dst = args.next_wr()?;
                    ArithOp::Rol {
                        dst,
                        a: dst.as_rd(),
                        n: Rd::immediate(1),
                    }
                }
                _ => {
                    return Err(CrsnError::Parse("Rol requires 1, 2 or 3 arguments".into()));
                }
            }
        }

        "ror" => {
            match args.len() {
                3 => {
                    ArithOp::Ror {
                        dst: args.next_wr()?,
                        a: args.next_rd()?,
                        n: args.next_rd()?,
                    }
                }
                2 => {
                    let dst = args.next_wr()?;
                    ArithOp::Ror {
                        dst,
                        a: dst.as_rd(),
                        n: args.next_rd()?,
                    }
                }
                1 => {
                    let dst = args.next_wr()?;
                    ArithOp::Ror {
                        dst,
                        a: dst.as_rd(),
                        n: Rd::immediate(1),
                    }
                }
                _ => {
                    return Err(CrsnError::Parse("Ror requires 1, 2 or 3 arguments".into()));
                }
            }
        }

        "lsl" | "asl" => {
            match args.len() {
                3 => {
                    ArithOp::Lsl {
                        dst: args.next_wr()?,
                        a: args.next_rd()?,
                        n: args.next_rd()?,
                    }
                }
                2 => {
                    let dst = args.next_wr()?;
                    ArithOp::Lsl {
                        dst,
                        a: dst.as_rd(),
                        n: args.next_rd()?,
                    }
                }
                1 => {
                    let dst = args.next_wr()?;
                    ArithOp::Lsl {
                        dst,
                        a: dst.as_rd(),
                        n: Rd::immediate(1),
                    }
                }
                _ => {
                    return Err(CrsnError::Parse("Lsl requires 1, 2 or 3 arguments".into()));
                }
            }
        }

        "lsr" => {
            match args.len() {
                3 => {
                    ArithOp::Lsr {
                        dst: args.next_wr()?,
                        a: args.next_rd()?,
                        n: args.next_rd()?,
                    }
                }
                2 => {
                    let dst = args.next_wr()?;
                    ArithOp::Lsr {
                        dst,
                        a: dst.as_rd(),
                        n: args.next_rd()?,
                    }
                }
                1 => {
                    let dst = args.next_wr()?;
                    ArithOp::Lsr {
                        dst,
                        a: dst.as_rd(),
                        n: Rd::immediate(1),
                    }
                }
                _ => {
                    return Err(CrsnError::Parse("Lsr requires 1, 2 or 3 arguments".into()));
                }
            }
        }

        "asr" => {
            match args.len() {
                3 => {
                    ArithOp::Asr {
                        dst: args.next_wr()?,
                        a: args.next_rd()?,
                        n: args.next_rd()?,
                    }
                }
                2 => {
                    let dst = args.next_wr()?;
                    ArithOp::Asr {
                        dst,
                        a: dst.as_rd(),
                        n: args.next_rd()?,
                    }
                }
                1 => {
                    let dst = args.next_wr()?;
                    ArithOp::Asr {
                        dst,
                        a: dst.as_rd(),
                        n: Rd::immediate(1),
                    }
                }
                _ => {
                    return Err(CrsnError::Parse("Asr requires 1, 2 or 3 arguments".into()));
                }
            }
        }

        _other => {
            return Ok(ParseRes::Unknown(args));
        }
    }))
}