use sexp::{Atom, Sexp};

use crate::asm::data::literal::{Label, RoutineName};
use crate::asm::data::reg::parse_reg;
use crate::asm::error::CrsnError;
use crate::asm::instr::op::OpKind;
use crate::asm::parse::arg_parser::TokenParser;
use crate::asm::parse::parse_data::{parse_constant_name, parse_label, parse_rd, parse_reg_alias, parse_value};
use crate::asm::parse::sexp_expect::expect_string_atom;
use crate::builtin::defs::{Barrier, BuiltinOp};
use crate::module::{CrsnExtension, ParseRes};

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

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

impl CrsnExtension for BuiltinOps {
    fn name(&self) -> &'static str {
        "builtin"
    }

    fn parse_op<'a>(&self, keyword: &str, mut args: TokenParser<'a>) -> Result<ParseRes<'a, OpKind>, CrsnError> {
        let pcx = args.pcx;

        Ok(ParseRes::Parsed(OpKind::BuiltIn(match keyword {
            "nop" => {
                BuiltinOp::Nop
            }

            "halt" => {
                BuiltinOp::Halt
            }

            "sleep" => {
                BuiltinOp::Sleep {
                    micros: args.next_rd()?,
                }
            }

            "sym" => {
                let alias = parse_reg_alias(args.next())?;
                trace!("alias={:?}", alias);
                let register = parse_reg(&args.next_string()?)?;
                trace!("register={:?}", alias);

                let mut pstate = pcx.state.borrow_mut();
                if pstate.reg_aliases.contains_key(&alias) {
                    return Err(CrsnError::Parse(format!("Register alias \"{}\" already defined!", alias).into()));
                }

                if pstate.constants.contains_key(&alias) {
                    return Err(CrsnError::Parse(format!("Name \"{}\" already used for a constant!", alias).into()));
                }

                if pstate.reg_aliases.iter().find(|x| x.1 == &register).is_some() {
                    return Err(CrsnError::Parse(format!("Register \"{}\" already aliased!", register).into()));
                }

                pstate.reg_aliases.insert(alias, register);

                return Ok(ParseRes::ParsedNone);
            }

            "unsym" => {
                let alias = parse_reg_alias(args.next())?;

                let mut pstate = pcx.state.borrow_mut();
                if pstate.reg_aliases.remove(&alias).is_none() {
                    return Err(CrsnError::Parse(format!("Register alias \"{}\" not defined!", alias).into()));
                }
                return Ok(ParseRes::ParsedNone);
            }

            "def" => {
                let name = parse_constant_name(args.next())?;
                let value = parse_value(args.next())?;

                let mut pstate = pcx.state.borrow_mut();
                if pstate.constants.contains_key(&name) {
                    return Err(CrsnError::Parse(format!("Constant \"{}\" already defined!", name).into()));
                }

                if pstate.reg_aliases.contains_key(&name) {
                    return Err(CrsnError::Parse(format!("Name \"{}\" already used for a register alias!", name).into()));
                }

                pstate.constants.insert(name, value);

                return Ok(ParseRes::ParsedNone);
            }

            "undef" => {
                let name = parse_constant_name(args.next())?;

                let mut pstate = pcx.state.borrow_mut();
                if pstate.constants.remove(&name).is_none() {
                    return Err(CrsnError::Parse(format!("Constant \"{}\" not defined!", name).into()));
                }
                return Ok(ParseRes::ParsedNone);
            }

            "j" => {
                let dest = parse_label(args.next())?;
                BuiltinOp::Jump(dest)
            }

            "fj" => {
                let dest = parse_label(args.next())?;
                BuiltinOp::FarJump(dest)
            }

            "call" => {
                let dest = RoutineName { name: args.next_string()?, arity: args.len() as u8 };

                let mut call_args = vec![];
                for t in args {
                    call_args.push(parse_rd(Some(t), pcx)?);
                }
                BuiltinOp::Call(dest, call_args)
            }

            "ret" => {
                let mut ret_vals = vec![];
                for t in args {
                    ret_vals.push(parse_rd(Some(t), pcx)?);
                }
                BuiltinOp::Ret(ret_vals)
            }

            "routine" => {
                let name = args.next_string()?;
                BuiltinOp::Routine(parse_routine_name(name)?)
            }

            "skip" => {
                BuiltinOp::Skip(args.next_rd()?)
            }

            "barrier" => {
                BuiltinOp::Barrier {
                    kind: Barrier::Standalone,
                    msg: match args.next() {
                        None => None,
                        Some(s) => Some(expect_string_atom(Some(s))?.into()),
                    },
                }
            }

            "fault" => {
                BuiltinOp::Fault(match args.next() {
                    None => None,
                    Some(s) => Some(expect_string_atom(Some(s))?.into()),
                })
            }

            "ld" => {
                BuiltinOp::Move {
                    dst: args.next_wr()?,
                    src: args.next_rd()?,
                }
            }

            "sst" => {
                BuiltinOp::StoreStatus {
                    dst: args.next_wr()?,
                }
            }

            "sld" => {
                BuiltinOp::LoadStatus {
                    src: args.next_rd()?,
                }
            }

            "drop" => {
                BuiltinOp::Drop(args.next_rdobj()?)
            }

            "far" => {
                if let Some(Sexp::Atom(Atom::S(ref label))) = args.peek() {
                    if let Some(label) = label.strip_prefix(':') {
                        let label = Label::Named(label.to_string());
                        BuiltinOp::FarLabel(label)
                    } else {
                        return Ok(ParseRes::Unknown(args));
                    }
                } else {
                    return Ok(ParseRes::Unknown(args));
                }
            }

            other => {
                if let Some(label) = other.strip_prefix(':') {
                    let label = Label::Named(label.to_string());
                    BuiltinOp::Label(label)
                } else {
                    return Ok(ParseRes::Unknown(args));
                }
            }
        })))
    }
}

pub(crate) fn parse_routine_name(name: String) -> Result<RoutineName, CrsnError> {
    let (name, arity) = if let Some(n) = name.find('/') {
        (
            (&name[0..n]).to_string(),
            (&name[(n + 1)..]).parse::<u8>()?
        )
    } else {
        (name, 0)
    };

    Ok(RoutineName { name, arity })
}