use std::{io::Write, sync::atomic::Ordering};

use matrix::{value::Value, vm::Interupt};
use rustyline::{Config, EditMode, ColorMode, Editor, CompletionType};

use crate::{State, helper::MatrixHelper};

pub struct Repl<'a> {
    state: State<'a>
}

impl<'a> Repl<'a> {

    pub fn new(state: State<'a>) -> Self {
        Self { state }
    }

    pub fn run(&mut self)  {

        let interupt = self.state.vm.borrow().interupt();
        ctrlc::set_handler(move || {
            interupt.store(Interupt::KeyboardInterupt as usize, Ordering::SeqCst);
        }).unwrap();

        let config = Config::builder()
            .check_cursor_position(true)
            .completion_type(CompletionType::List)
            .edit_mode(EditMode::Emacs)
            .color_mode(if self.state.color { ColorMode::Enabled } else { ColorMode::Disabled })
            .build();

        let helper = MatrixHelper::new(self.state.vm.clone());

        let mut rl = Editor::with_config(config).unwrap();
        rl.set_helper(Some(helper));

        loop {
            let Ok(line) = rl.readline(">> ") else {
                break;
            };
            if let Err(_) = rl.add_history_entry(&line) {
                break;
            };
            match self.state.execute(line) {
                Err(err) => crate::error(err, &self.state),
                Ok(val) => {
                    if val != Value::Nil {
                        if self.state.color {
                            println!("{val:#}");
                        } else {
                            println!("{val}");
                        }
                    }
                }
            }
            let _ = std::io::stdout().flush();
        }
    }

}