use std::{
	fs,
	io::Write,
	net::{SocketAddr, TcpListener, TcpStream},
	path::{Path, PathBuf},
	result,
	str::FromStr,
};

use clap::Parser;

use crate::{buffer::ByteBuffer, cli::CliArgs};

mod buffer;
mod cli;

type Result<T> = result::Result<T, ()>;

fn main() -> Result<()> {
	env_logger::init();

	let args = CliArgs::parse();

	let ip = args.ip.unwrap_or_default();
	let port = args.port.unwrap_or_default();
	let export = fs::canonicalize(args.export).expect("failed to get absolute export path");
	let allowed = args.allowed_devices;

	let socket = SocketAddr::from_str(&format!("{ip}:{port}")).unwrap();
	let listener = TcpListener::bind(socket).unwrap();

	for stream in listener.incoming() {
		match stream {
			Ok(conn) => handle_connection(conn, export.clone(), allowed.clone())?,
			Err(e) => eprintln!("Something went wrong while listening {e}"),
		}
	}

	Ok(())
}

fn handle_connection(
	mut conn: TcpStream,
	export: PathBuf,
	allowed_devices: Option<Vec<String>>,
) -> Result<()> {
	let mut paths = vec![];
	let mut buffer = ByteBuffer::default();

	let remote_ip = conn
		.peer_addr()
		.expect("Could not get remote IP address")
		.ip();

	if let Some(allowed_devices) = allowed_devices {
		for allowed in allowed_devices {
			let allowed_net = ipnet::IpNet::from_str(&allowed).unwrap();

			let is_allowed = allowed_net.contains(&remote_ip);
			if !is_allowed {
				log::error!("{remote_ip} tried to connect but is not allowed");
				return Ok(());
			}
		}
	}

	walk_dir(&export, &mut paths);

	let export_path = export
		.as_path()
		.to_str()
		.expect("invalid export path, aborting");

	let files_sent = paths.len();

	log::info!("Sending {files_sent} files to {remote_ip}");

	buffer.write_usize(files_sent);

	for file in paths {
		let mut path = file.replace(export_path, "");
		if path.starts_with("/") {
			path.remove(0);
		}

		log::debug!("Sending {path}");

		buffer.write_string(&path);

		match fs::read(file) {
			Ok(data) => {
				buffer.write_usize(data.len());
				buffer.write_bytes(&data);
			}
			Err(_) => {
				buffer.write_usize(0);
				eprintln!("No file found");
			}
		};
	}

	let _ = conn.write_all(&buffer);
	let _ = conn.flush();

	Ok(())
}

fn walk_dir<P: AsRef<Path>>(path: P, file_paths: &mut Vec<String>) {
	for entry in fs::read_dir(path).unwrap().flatten() {
		if entry.path().is_dir() {
			walk_dir(entry.path(), file_paths);
			continue;
		}

		let file_path = entry.path().to_str().unwrap().to_string();

		file_paths.push(file_path);
	}
}

#[cfg(test)]
mod tests {
	use std::io::Read;

	use super::*;

	const IP: &str = "0.0.0.0";
	const PORT: &str = "9696";

	#[test]
	fn test_connection() {
		let conn = TcpStream::connect(format!("{IP}:{PORT}"));
		assert!(conn.is_ok());

		let mut conn = conn.unwrap();
		let mut buffer = ByteBuffer::default();

		let bytes_read = conn.read_to_end(&mut buffer);
		assert!(bytes_read.is_ok());

		let file_name = buffer.read_string();
		assert_eq!(file_name, "examples/test.md");

		// let content = buffer.read_bytes(buffer.unread_len());
		// println!("{}", String::from_utf8(content).unwrap());
	}
}