use rustyline::error::ReadlineError;
use talc_lang::{Parser, Vm, Symbol, value::{Value, Function}, compiler::repl};
use std::{rc::Rc, io::Write};

fn main() -> Result<(), Box<dyn std::error::Error>> {
	let parser = Parser::new();
	let mut vm = Vm::new(256);
	let mut globals = Vec::new();

	let prev1_sym = Symbol::get("_");
	let prev2_sym = Symbol::get("__");
	let prev3_sym = Symbol::get("___");

	vm.set_global(prev1_sym, Value::Nil);
	vm.set_global(prev2_sym, Value::Nil);
	vm.set_global(prev3_sym, Value::Nil);

	let mut rl = rustyline::DefaultEditor::new()?;

	loop {
		let line = rl.readline(">> ");
		let line = match line {
			Ok(line) => line,
			Err(ReadlineError::Eof) => break,
			Err(ReadlineError::Interrupted) => continue,
			Err(e) => {
				eprintln!("Error: {e}");
				continue
			},
		};

		let ex = match parser.parse(&line) {
			Ok(ex) => ex,
			Err(e) => { eprintln!("Error: {e}"); continue },
		};

		let (f, g) = repl(&ex, &globals);
		globals = g;
		let func = Rc::new(f);

		Function::disasm_recursive(func.clone(), &mut std::io::stdout())?;
		std::io::stdout().flush()?;

		match vm.run(func) {
			Ok(v) => {
				vm.set_global(prev3_sym, vm.get_global(prev2_sym).unwrap().clone());
				vm.set_global(prev2_sym, vm.get_global(prev1_sym).unwrap().clone());
				vm.set_global(prev1_sym, v.clone());
				if v != Value::Nil {
					println!("{v:#}");
				}
			}
			Err(e) => eprintln!("{e}"),
		}
	}

	Ok(())
}