use std::{
	error::Error,
	path::PathBuf,
	sync::Arc,
	time::Duration,
};

use handlebars::Handlebars;
use hyper::{
	StatusCode,
};
use reqwest::Client;
use serde::Deserialize;
use tokio::{
	time::delay_for,
};

use crate::{
	http_serde,
	prefix_match,
};

pub mod file_server;

struct ServerState {
	config: Config,
	opt: Opt,
	handlebars: Handlebars <'static>,
	client: Client,
}

fn status_reply (c: http_serde::StatusCode, body: &str) -> http_serde::Response 
{
	let mut r = http_serde::Response::default ();
	r.status_code (c)
	.body_bytes (body.as_bytes ().to_vec ());
	r
}

async fn handle_req_resp <'a> (
	state: Arc <ServerState>,
	req_resp: reqwest::Response
) {
	//println! ("Step 1");
	
	if req_resp.status () != StatusCode::OK {
		// TODO: Error handling
		return;
	}
	
	let body = req_resp.bytes ().await.unwrap ();
	let wrapped_reqs: Vec <http_serde::WrappedRequest> = match rmp_serde::from_read_ref (&body)
	{
		Ok (x) => x,
		_ => return,
	};
	
	for wrapped_req in wrapped_reqs.into_iter () {
		let state = state.clone ();
		
		tokio::spawn (async move {
			let (req_id, parts) = (wrapped_req.id, wrapped_req.req);
			
			let response = if let Some (uri) = prefix_match (&parts.uri, "/files") {
				let default_root = PathBuf::from ("./");
				let file_server_root: &std::path::Path = state.config.file_server_root
				.as_ref ()
				.unwrap_or (&default_root);
				
				file_server::serve_all (
					&state.handlebars, 
					file_server_root,
					parts.method, 
					uri, 
					&parts.headers
				).await
			}
			else {
				status_reply (http_serde::StatusCode::NotFound, "404 Not Found")
			};
			
			let mut resp_req = state.client
			.post (&format! ("{}/7ZSFUKGV/http_response/{}", state.config.relay_url, req_id))
			.header (crate::PTTH_MAGIC_HEADER, base64::encode (rmp_serde::to_vec (&response.parts).unwrap ()));
			
			if let Some (body) = response.body {
				resp_req = resp_req.body (reqwest::Body::wrap_stream (body));
			}
			
			//println! ("Step 6");
			if let Err (e) = resp_req.send ().await {
				println! ("Err: {:?}", e);
			}
		});
	}
}

#[derive (Default, Deserialize)]
pub struct ConfigFile {
	pub name: String,
	pub api_key: String,
	pub relay_url: String,
	pub file_server_root: Option <PathBuf>,
}

#[derive (Default)]
pub struct Config {
	pub relay_url: String,
	pub file_server_root: Option <PathBuf>,
}

#[derive (Clone)]
pub struct Opt {
	
}

pub async fn main (config_file: ConfigFile, opt: Opt) 
-> Result <(), Box <dyn Error>> 
{
	use std::convert::TryInto;
	
	if crate::password_is_bad (config_file.api_key.clone ()) {
		panic! ("API key is too weak, server can't use it");
	}
	
	let tripcode = base64::encode (blake3::hash (config_file.api_key.as_bytes ()).as_bytes ());
	
	println! ("Our tripcode is {}", tripcode);
	
	let mut headers = reqwest::header::HeaderMap::new ();
	headers.insert ("X-ApiKey", config_file.api_key.try_into ().unwrap ());
	
	let client = Client::builder ()
	.default_headers (headers)
	.build ().unwrap ();
	let handlebars = file_server::load_templates ()?;
	
	let state = Arc::new (ServerState {
		config: Config {
			relay_url: config_file.relay_url,
			file_server_root: config_file.file_server_root,
		},
		opt,
		handlebars,
		client,
	});
	
	let mut backoff_delay = 0;
	
	loop {
		if backoff_delay > 0 {
			delay_for (Duration::from_millis (backoff_delay)).await;
		}
		
		let req_req = state.client.get (&format! ("{}/7ZSFUKGV/http_listen/{}", state.config.relay_url, config_file.name));
		
		let err_backoff_delay = std::cmp::min (30_000, backoff_delay * 2 + 500);
		
		let req_resp = match req_req.send ().await {
			Err (e) => {
				eprintln! ("Err: {:?}", e);
				backoff_delay = err_backoff_delay;
				continue;
			},
			Ok (r) => {
				backoff_delay = 0;
				r
			},
		};
		
		if req_resp.status () != StatusCode::OK {
			eprintln! ("{}", req_resp.status ());
			eprintln! ("{}", String::from_utf8 (req_resp.bytes ().await.unwrap ().to_vec ()).unwrap ());
			backoff_delay = err_backoff_delay;
			continue;
		}
		
		// Spawn another task for each request so we can 
		// immediately listen for the next connection
		
		let state = state.clone ();
		
		tokio::spawn (async move {
			handle_req_resp (state, req_resp).await;
		});
	}
}