use crsn::asm::error::CrsnError;
use crsn::asm::instr::op::OpKind;
use crsn::asm::parse::arg_parser::TokenParser;
use crsn::module::ParseRes;
use crsn::sexp::{SourcePosition, Sexp, Atom};

use crate::defs::{BufOps, BufValue, BufIoMode};
use crsn::asm::data::Rd;
use crsn::asm::parse::parse_data::parse_rd;
use crsn::asm::data::literal::Value;

pub const BUF_IOMODE_STACK : Value = 1;
pub const BUF_IOMODE_REVERSE_STACK : Value = 2;
pub const BUF_IOMODE_QUEUE : Value = 3;
pub const BUF_IOMODE_REVERSE_QUEUE : Value = 4;

pub(crate) fn parse<'a>(_pos: &SourcePosition, keyword: &str, mut args: TokenParser<'a>) -> Result<ParseRes<'a, OpKind>, CrsnError> {
    Ok(ParseRes::ext(match keyword {
        "mkbf" => {
            let dst = args.next_wr()?;

            let value = match args.next() {
                None => {
                    BufValue::Zeros(Rd::new_imm(0))
                }
                Some(tok @ Sexp::Atom(Atom::S(_), _)) |
                Some(tok @ Sexp::Atom(Atom::I(_), _)) |
                Some(tok @ Sexp::Atom(Atom::U(_), _)) => {
                    BufValue::Zeros(parse_rd(tok, args.pcx)?)
                }
                Some(Sexp::Atom(Atom::QS(s), _)) => {
                    BufValue::Chars(s)
                }
                Some(Sexp::List(list, _)) => {
                    let mut vals = vec![];
                    for v in list {
                        vals.push(parse_rd(v, args.pcx)?);
                    }
                    BufValue::Values(vals)
                }
                Some(other) => {
                    return Err(CrsnError::Parse("Expected quoted string or a tuple of values".into(), other.pos().clone()));
                }
            };

            BufOps::New { dst, value }
        }

        "bfio" => {
            let obj = args.next_rdobj()?;
            let (mode, modepos) = args.next_value()?;
            BufOps::SetIoMode {
                obj,
                mode: match mode {
                    BUF_IOMODE_STACK => BufIoMode::Stack,
                    BUF_IOMODE_REVERSE_STACK => BufIoMode::ReverseStack,
                    BUF_IOMODE_QUEUE => BufIoMode::Queue,
                    BUF_IOMODE_REVERSE_QUEUE => BufIoMode::ReverseQueue,
                    _ => return Err(CrsnError::Parse("Bad buffer iomode".into(), modepos))
                }
            }
        }

        "bfrd" => {
            let dst = args.next_wr()?;
            let obj = args.next_rdobj()?;
            let idx = args.next_rd()?;
            BufOps::Read { dst, obj, idx }
        }

        "bfwr" => {
            let obj = args.next_rdobj()?;
            let idx = args.next_rd()?;
            let value = args.next_rd()?;
            BufOps::Write { obj, idx, value }
        }

        "bfsz" => {
            let dst = args.next_wr()?;
            let obj = args.next_rdobj()?;
            BufOps::GetLen { dst, obj }
        }

        "bfins" => {
            let obj = args.next_rdobj()?;
            let idx = args.next_rd()?;
            let value = args.next_rd()?;
            BufOps::Insert { obj, idx, value }
        }

        "bfrm" => {
            let dst = args.next_wr()?;
            let obj = args.next_rdobj()?;
            let idx = args.next_rd()?;
            BufOps::Remove { dst, obj, idx }
        }

        "bfpush" => {
            BufOps::Push {
                obj: args.next_rdobj()?,
                src: args.next_rd()?,
            }
        }

        "bfpop" => {
            BufOps::Pop {
                dst: args.next_wr()?,
                obj: args.next_rdobj()?,
            }
        }

        "bfrpush" => {
            BufOps::Insert {
                obj: args.next_rdobj()?,
                idx: Rd::new_imm(0),
                value: args.next_rd()?,
            }
        }

        "bfrpop" => {
            BufOps::Remove {
                dst: args.next_wr()?,
                obj: args.next_rdobj()?,
                idx: Rd::new_imm(0),
            }
        }

        "bfrsz" => {
            BufOps::Resize {
                obj: args.next_rdobj()?,
                len: args.next_rd()?,
            }
        }

        "bfrev" => {
            BufOps::Reverse {
                obj: args.next_rdobj()?,
            }
        }

        "bfapp" => {
            BufOps::AppendBuf {
                obj: args.next_rdobj()?,
                obj2: args.next_rdobj()?,
            }
        }

        "bfprep" => {
            BufOps::PrependBuf {
                obj: args.next_rdobj()?,
                obj2: args.next_rdobj()?,
            }
        }

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