use std::io::{self, Write};

use std::{env, fs};

// use chunk::{Chunk, OpCode};
// use vm::VM;

use color_eyre::eyre::{Result, WrapErr};
use error::Error;
use tracing::Level;
use tracing_subscriber::FmtSubscriber;

mod chunk;
mod compiler;
mod error;
mod scanner;
mod value;
mod vm;

fn main() -> Result<()> {
    let level = match env::var("DEBUG") {
        Ok(_) => Level::DEBUG,
        Err(_) => Level::ERROR,
    };
    let subscriber = FmtSubscriber::builder().with_max_level(level).finish();
    tracing::subscriber::set_global_default(subscriber)
        .wrap_err("setting default subscriber failed")?;

    match &env::args().skip(1).collect::<Vec<_>>()[..] {
        [] => repl()?,
        [file] => run(file)?,
        _ => return Err(Error::Usage.into()),
    }

    Ok(())
}

fn repl() -> Result<()> {
    let stdin = io::stdin(); // We get `Stdin` here.
    let mut buffer = String::new();

    loop {
        print!("> ");
        io::stdout().flush()?;

        stdin.read_line(&mut buffer)?;
        if buffer == "\n" {
            return Ok(());
        }

        interpret(&buffer)?;
    }
}

fn interpret(buffer: &str) -> Result<()> {
    todo!()
}

fn run(file: &str) -> Result<()> {
    let contents = fs::read_to_string(file).map_err(|e| Error::ReadFile {
        path: file.to_string(),
        source: e,
    })?;
    interpret(&contents)?;
    Ok(())
}