use std::path::PathBuf;
use std::sync::Arc;

use futures_util::future::*;
use tokio::sync::watch;

use garage_util::background::*;
use garage_util::config::*;
use garage_util::error::Error;

use garage_api::api_server;
use garage_model::garage::Garage;
use garage_rpc::rpc_server::RpcServer;
use garage_web::web_server;

use crate::admin_rpc::*;

async fn shutdown_signal(send_cancel: watch::Sender<bool>) -> Result<(), Error> {
	// Wait for the CTRL+C signal
	tokio::signal::ctrl_c()
		.await
		.expect("failed to install CTRL+C signal handler");
	info!("Received CTRL+C, shutting down.");
	send_cancel.broadcast(true)?;
	Ok(())
}

async fn wait_from(mut chan: watch::Receiver<bool>) -> () {
	while let Some(exit_now) = chan.recv().await {
		if exit_now {
			return;
		}
	}
}

pub async fn run_server(config_file: PathBuf) -> Result<(), Error> {
	info!("Loading configuration...");
	let config = read_config(config_file).expect("Unable to read config file");

	info!("Opening database...");
	let mut db_path = config.metadata_dir.clone();
	db_path.push("db");
	let db = match sled::open(&db_path) {
		Ok(db) => db,
		Err(e) => {
			warn!("Old DB could not be openned ({}), attempting migration.", e);
			let old = old_sled::open(&db_path).expect("Unable to open old DB for migration");
			let mut new_path = config.metadata_dir.clone();
			new_path.push("db2");
			let new = sled::open(&new_path).expect("Unable to open new DB for migration");
			new.import(old.export());
			if old.checksum().expect("unable to compute old db checksum")
				!= new.checksum().expect("unable to compute new db checksum")
			{
				panic!("db checksums don't match after migration");
			}
			drop(new);
			drop(old);
			std::fs::remove_dir_all(&db_path).expect("Cannot remove old DB folder");
			std::fs::rename(new_path, &db_path)
				.expect("Cannot move new DB folder to correct place");
			sled::open(db_path).expect("Unable to open new DB after migration")
		}
	};

	info!("Initialize RPC server...");
	let mut rpc_server = RpcServer::new(config.rpc_bind_addr.clone(), config.rpc_tls.clone());

	info!("Initializing background runner...");
	let (send_cancel, watch_cancel) = watch::channel(false);
	let background = BackgroundRunner::new(16, watch_cancel.clone());

	let garage = Garage::new(config, db, background.clone(), &mut rpc_server).await;

	info!("Crate admin RPC handler...");
	AdminRpcHandler::new(garage.clone()).register_handler(&mut rpc_server);

	info!("Initializing RPC and API servers...");
	let run_rpc_server = Arc::new(rpc_server).run(wait_from(watch_cancel.clone()));
	let api_server = api_server::run_api_server(garage.clone(), wait_from(watch_cancel.clone()));
	let web_server = web_server::run_web_server(garage.clone(), wait_from(watch_cancel.clone()));

	futures::try_join!(
		garage
			.system
			.clone()
			.bootstrap(
				&garage.config.bootstrap_peers[..],
				garage.config.consul_host.clone(),
				garage.config.consul_service_name.clone()
			)
			.map(|rv| {
				info!("Bootstrap done");
				Ok(rv)
			}),
		run_rpc_server.map(|rv| {
			info!("RPC server exited");
			rv
		}),
		api_server.map(|rv| {
			info!("API server exited");
			rv
		}),
		web_server.map(|rv| {
			info!("Web server exited");
			rv
		}),
		background.run().map(|rv| {
			info!("Background runner exited");
			Ok(rv)
		}),
		shutdown_signal(send_cancel),
	)?;

	info!("Cleaning up...");

	Ok(())
}