use std::{fs::File, io::Read, iter::once};

use jaq_interpret::{Error, Native, ParseCtx, Val};
use tracing::{debug, error, trace};

use super::macros::*;

pub fn load(jaq: &mut ParseCtx) {
	trace!("jaq: add hash filter");
	jaq.insert_native(
		"hash".into(),
		0,
		Native::new({
			move |_, (_, val)| {
				let string = match &val {
					Val::Str(v) => v.to_string(),
					_ => return_err!(Err(Error::str("expected string but got {val:?}"))),
				};

				Box::new(once(Ok(Val::Str(
					blake3::hash(string.as_bytes()).to_hex().to_string().into(),
				))))
			}
		}),
	);

	trace!("jaq: add file_hash filter");
	jaq.insert_native(
		"file_hash".into(),
		0,
		Native::new({
			move |_, (_, val)| {
				let path = match &val {
					Val::Str(v) => v.to_string(),
					_ => return_err!(Err(Error::str("expected string but got {val:?}"))),
				};

				Box::new(once(Ok(match File::open(&path) {
					Ok(mut file) => {
						const BUFFER_SIZE: usize = 1024 * 1024;
						let mut hasher = blake3::Hasher::new();
						let mut buf = vec![0; BUFFER_SIZE];
						while let Ok(bytes) = file.read(&mut buf) {
							debug!("jaq: read {bytes} bytes from {path:?}");
							if bytes == 0 {
								break;
							}
							hasher.update(&buf[..bytes]);
							buf = vec![0; BUFFER_SIZE];
						}

						Val::Str(hasher.finalize().to_hex().to_string().into())
					}
					Err(err) => {
						error!("jaq: failed to open file {path:?}: {err:?}");
						Val::Null
					}
				})))
			}
		}),
	);
}