use crsn::asm::data::literal::Value;
use crsn::asm::error::CrsnError;
use crsn::asm::instr::op::OpKind;
use crsn::asm::parse::arg_parser::TokenParser;
use crsn::module::{CrsnExtension, ParseRes};
use crsn::runtime::fault::Fault;
use crsn::runtime::run_thread::{RunState, ThreadInfo};
use crsn::sexp::SourcePosition;
use crate::parse::{BUF_IOMODE_STACK, BUF_IOMODE_REVERSE_STACK, BUF_IOMODE_QUEUE, BUF_IOMODE_REVERSE_QUEUE};
use crsn::asm::data::Wr;

mod defs;
mod parse;
mod exec;

#[derive(Debug, Clone)]
pub struct BufOps;

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

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

    fn parse_op<'a>(&self, pos: &SourcePosition, keyword: &str, args: TokenParser<'a>) -> Result<ParseRes<'a, OpKind>, CrsnError> {
        parse::parse(pos, keyword, args)
    }

    fn drop_obj(&self, _ti: &ThreadInfo, state: &mut RunState, handle: Value) -> Result<Option<()>, Fault> {
        exec::drop_obj(state, handle)
    }

    /// Run-time method called to read an object (using the object handle syntax)
    fn read_obj(&self, state: &mut RunState, handle: Value)
                -> Result<Option<Value>, Fault>
    {
        exec::read_obj(state, handle)
    }

    /// Run-time method called to write an object (using the object handle syntax)
    fn write_obj(&self, state: &mut RunState, handle: Value, value: Value) -> Result<Option<()>, Fault>
    {
        exec::write_obj(state, handle, value)
    }

    /// Get value of an extension-provided constant.
    /// This constant may be an object handle, or a constant value used as argument in some other instruction.
    fn get_constant_value<'a>(&self, name: &str) -> Option<Value>
    {
        match name {
            "BFIO_STACK" => Some(BUF_IOMODE_STACK),
            "BFIO_RSTACK" => Some(BUF_IOMODE_REVERSE_STACK),
            "BFIO_QUEUE" => Some(BUF_IOMODE_QUEUE),
            "BFIO_RQUEUE" => Some(BUF_IOMODE_REVERSE_QUEUE),
            _ => None
        }
    }

    /// Run-time method called to read all values from an object ("lds" using the object handle syntax)
    fn read_obj_all(&self, state: &mut RunState, whandle: Wr, rhandle: Value)
                    -> Result<Option<()>, Fault>
    {
        exec::read_obj_all(state, whandle, rhandle)
    }
}