use crsn::asm::error::Error;
use crsn::asm::instr::op::{AsmModule, ParseOpResult};
use crsn::asm::instr::Op;
use crsn::asm::parse::arg_parser::ArgParser;

use crate::defs::StackOp;

#[derive(Debug, Clone)]
pub struct StackOps {
    _internal: ()
}

impl StackOps {
    pub fn new() -> Box<dyn AsmModule> {
        Box::new(Self {
            _internal: ()
        })
    }
}

impl AsmModule for StackOps {
    fn name(&self) -> &'static str {
        "stacks"
    }

    fn parse_op(&self, keyword: &str, mut args: ArgParser) -> Result<ParseOpResult, Error> {
        Ok(ParseOpResult::Parsed(Op::Ext(Box::new(match keyword {
            "push" => {
                StackOp::Push {
                    num: args.next_rd()?,
                    src: args.next_rd()?,
                }
            }

            "pop" => {
                StackOp::Pop {
                    dst: args.next_wr()?,
                    num: args.next_rd()?,
                }
            }

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