/** Serene --- Yet an other Lisp
*
* Copyright (c) 2020  Sameer Rahmani <lxsameer@gnu.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 2 of the License.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
use crate::core::read_eval_print;
use crate::runtime::RT;
use rustyline::error::ReadlineError;
use rustyline::Editor;

pub fn repl(rt: RT) {
    let mut rl = Editor::<()>::new();
    let history = rt.history_file_path();

    if rl.load_history(&history).is_err() && rt.is_debug() {
        println!("No previous history.");
    }

    loop {
        let prompt = format!("{}> ", rt.current_ns().name);
        let readline = rl.readline(&prompt);
        match readline {
            Ok(line) => {
                rl.add_history_entry(line.as_str());
                read_eval_print(&rt, &line);
            }
            Err(ReadlineError::Interrupted) => {
                println!("CTRL-C");
                break;
            }
            Err(ReadlineError::Eof) => {
                println!("CTRL-D");
                break;
            }
            Err(err) => {
                println!("Error: {:?}", err);
                break;
            }
        }
    }
    rl.save_history(&history).unwrap();
}