#![feature(let_chains)]

mod generator;

use clap::{Command, arg, command};
use debounced::debounced;
use futures::FutureExt;
use generator::{FileWatcher, content_base_path};
use log::info;
use std::cell::RefCell;
use std::rc::Rc;
use std::time::Duration;
use tokio::pin;
use tokio_stream::StreamExt;
use tokio_stream::wrappers::UnboundedReceiverStream;

#[tokio::main]
async fn main() {
    env_logger::init();

    let matches = command!()
        .subcommand_required(true)
        .arg_required_else_help(true)
        .subcommand(
            Command::new("gen")
                .arg(arg!(--watch "Watch the site directory and regenerate on changes")),
        )
        .subcommand(
            Command::new("serve")
                .arg(arg!(--watch "Watch the site directory and regenerate on changes")),
        )
        .get_matches();

    if cfg!(debug_assertions) {
        info!("Running in dev mode");
    } else {
        info!("Running in release mode");
    }

    match matches.subcommand() {
        Some(("gen", matches)) => {
            let watcher = Rc::new(RefCell::new(FileWatcher::new()));

            let mut graph = generator::generate(Rc::clone(&watcher))
                .await
                .expect("generating");

            if matches.contains_id("watch") {
                let (tx, rx) = tokio::sync::mpsc::unbounded_channel::<()>();

                watcher.borrow_mut().watch(content_base_path(), move || {
                    tx.send(()).expect("sending regenerate signal");
                });

                let mut debounced =
                    debounced(UnboundedReceiverStream::new(rx), Duration::from_millis(100));

                let watch = FileWatcher::start(watcher).fuse();

                let regenerate = async move {
                    while let Some(_) = debounced.next().await {
                        info!("Regenerating");
                        graph.evaluate_async().await;
                    }
                }
                .fuse();

                pin!(regenerate, watch);

                loop {
                    futures::select! {
                        watcher_res = watch => {
                            watcher_res.expect("watching files");
                        }
                        _ = regenerate => {
                            info!("regenerate channel closed");
                        }
                    }
                }
            }
        }
        Some(("serve", _matches)) => {
            todo!()
        }
        _ => unreachable!(),
    }
}