#![feature(let_chains, impl_trait_in_assoc_type)]
use std::{str::FromStr, sync::Arc};

#[cfg(feature = "full")]
use async_compression::futures::bufread as async_comp;
use bytes::Bytes;
use cfg_if::cfg_if;
#[cfg(feature = "full")]
use futures_util::future::Either;
use futures_util::TryStreamExt;
use http::{
	header::{InvalidHeaderName, InvalidHeaderValue},
	method::InvalidMethod,
	uri::{InvalidUri, InvalidUriParts},
	HeaderName, HeaderValue, Method, Request, Response,
};
use hyper::{body::Incoming, Uri};
use hyper_util_wasm::client::legacy::Client;
#[cfg(feature = "full")]
use io_stream::{EpoxyIoStream, EpoxyUdpStream};
use js_sys::{Array, Function, Object, Reflect};
use stream_provider::{StreamProvider, StreamProviderService};
use thiserror::Error;
use utils::{
	asyncread_to_readablestream_stream, convert_body, entries_of_object, is_null_body, is_redirect,
	object_get, object_set, IncomingBody, UriExt, WasmExecutor,
};
use wasm_bindgen::prelude::*;
use wasm_streams::ReadableStream;
use web_sys::ResponseInit;
#[cfg(feature = "full")]
use websocket::EpoxyWebSocket;
#[cfg(feature = "full")]
use wisp_mux::StreamType;

#[cfg(feature = "full")]
mod io_stream;
mod stream_provider;
mod tokioio;
mod utils;
#[cfg(feature = "full")]
mod websocket;
mod ws_wrapper;

type HttpBody = http_body_util::Full<Bytes>;

#[derive(Debug, Error)]
pub enum EpoxyError {
	#[error("Invalid DNS name: {0:?}")]
	InvalidDnsName(#[from] futures_rustls::rustls::pki_types::InvalidDnsNameError),
	#[error("Wisp: {0:?}")]
	Wisp(#[from] wisp_mux::WispError),
	#[error("IO: {0:?}")]
	Io(#[from] std::io::Error),
	#[error("HTTP: {0:?}")]
	Http(#[from] http::Error),
	#[error("Hyper client: {0:?}")]
	HyperClient(#[from] hyper_util_wasm::client::legacy::Error),
	#[error("Hyper: {0:?}")]
	Hyper(#[from] hyper::Error),
	#[error("HTTP ToStr: {0:?}")]
	ToStr(#[from] http::header::ToStrError),
	#[cfg(feature = "full")]
	#[error("Getrandom: {0:?}")]
	GetRandom(#[from] getrandom::Error),
	#[cfg(feature = "full")]
	#[error("Fastwebsockets: {0:?}")]
	FastWebSockets(#[from] fastwebsockets::WebSocketError),

	#[error("Invalid URL scheme")]
	InvalidUrlScheme,
	#[error("No URL host found")]
	NoUrlHost,
	#[error("No URL port found")]
	NoUrlPort,
	#[error("Invalid request body")]
	InvalidRequestBody,
	#[error("Invalid request")]
	InvalidRequest,
	#[error("Invalid websocket response status code")]
	WsInvalidStatusCode,
	#[error("Invalid websocket upgrade header")]
	WsInvalidUpgradeHeader,
	#[error("Invalid websocket connection header")]
	WsInvalidConnectionHeader,
	#[error("Invalid websocket payload")]
	WsInvalidPayload,
	#[error("Invalid payload")]
	InvalidPayload,

	#[error("Invalid certificate store")]
	InvalidCertStore,
	#[error("WebSocket failed to connect")]
	WebSocketConnectFailed,

	#[error("Failed to construct response headers object")]
	ResponseHeadersFromEntriesFailed,
	#[error("Failed to construct response object")]
	ResponseNewFailed,
	#[error("Failed to construct define_property object")]
	DefinePropertyObjFailed,
	#[error("Failed to set raw header item")]
	RawHeaderSetFailed,
}

impl From<EpoxyError> for JsValue {
	fn from(value: EpoxyError) -> Self {
		JsError::from(value).into()
	}
}

impl From<InvalidUri> for EpoxyError {
	fn from(value: InvalidUri) -> Self {
		http::Error::from(value).into()
	}
}

impl From<InvalidUriParts> for EpoxyError {
	fn from(value: InvalidUriParts) -> Self {
		http::Error::from(value).into()
	}
}

impl From<InvalidHeaderName> for EpoxyError {
	fn from(value: InvalidHeaderName) -> Self {
		http::Error::from(value).into()
	}
}

impl From<InvalidHeaderValue> for EpoxyError {
	fn from(value: InvalidHeaderValue) -> Self {
		http::Error::from(value).into()
	}
}

impl From<InvalidMethod> for EpoxyError {
	fn from(value: InvalidMethod) -> Self {
		http::Error::from(value).into()
	}
}

#[derive(Debug)]
enum EpoxyResponse {
	Success(Response<Incoming>),
	Redirect((Response<Incoming>, http::Request<HttpBody>)),
}

#[cfg(feature = "full")]
enum EpoxyCompression {
	Brotli,
	Gzip,
}

#[wasm_bindgen]
pub struct EpoxyClientOptions {
	pub wisp_v2: bool,
	pub udp_extension_required: bool,
	#[wasm_bindgen(getter_with_clone)]
	pub websocket_protocols: Vec<String>,
	pub redirect_limit: usize,
	#[wasm_bindgen(getter_with_clone)]
	pub user_agent: String,
}

#[wasm_bindgen]
impl EpoxyClientOptions {
	#[wasm_bindgen(constructor)]
	pub fn new_default() -> Self {
		Self::default()
	}
}

impl Default for EpoxyClientOptions {
	fn default() -> Self {
		Self {
            wisp_v2: false,
            udp_extension_required: false,
            websocket_protocols: Vec::new(),
            redirect_limit: 10,
            user_agent: "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/127.0.0.0 Safari/537.36".to_string(),
        }
	}
}

#[wasm_bindgen(getter_with_clone)]
pub struct EpoxyHandlers {
	pub onopen: Function,
	pub onclose: Function,
	pub onerror: Function,
	pub onmessage: Function,
}

#[cfg(feature = "full")]
#[wasm_bindgen]
impl EpoxyHandlers {
	#[wasm_bindgen(constructor)]
	pub fn new(
		onopen: Function,
		onclose: Function,
		onerror: Function,
		onmessage: Function,
	) -> Self {
		Self {
			onopen,
			onclose,
			onerror,
			onmessage,
		}
	}
}

#[wasm_bindgen(inspectable)]
pub struct EpoxyClient {
	stream_provider: Arc<StreamProvider>,
	client: Client<StreamProviderService, HttpBody>,

	pub redirect_limit: usize,
	#[wasm_bindgen(getter_with_clone)]
	pub user_agent: String,
}

#[wasm_bindgen]
impl EpoxyClient {
	#[wasm_bindgen(constructor)]
	pub fn new(
		wisp_url: String,
		certs: Array,
		options: EpoxyClientOptions,
	) -> Result<EpoxyClient, EpoxyError> {
		let wisp_url: Uri = wisp_url.try_into()?;
		if wisp_url.scheme_str() != Some("wss") && wisp_url.scheme_str() != Some("ws") {
			return Err(EpoxyError::InvalidUrlScheme);
		}

		let stream_provider = Arc::new(StreamProvider::new(wisp_url.to_string(), certs, &options)?);

		let service = StreamProviderService(stream_provider.clone());
		let client = Client::builder(WasmExecutor)
			.http09_responses(true)
			.http1_title_case_headers(true)
			.http1_preserve_header_case(true)
			.build(service);

		Ok(Self {
			stream_provider,
			client,
			redirect_limit: options.redirect_limit,
			user_agent: options.user_agent,
		})
	}

	pub async fn replace_stream_provider(&self) -> Result<(), EpoxyError> {
		self.stream_provider.replace_client().await
	}

	#[cfg(feature = "full")]
	pub async fn connect_websocket(
		&self,
		handlers: EpoxyHandlers,
		url: String,
		protocols: Vec<String>,
		headers: JsValue,
	) -> Result<EpoxyWebSocket, EpoxyError> {
		EpoxyWebSocket::connect(self, handlers, url, protocols, headers, &self.user_agent).await
	}

	#[cfg(feature = "full")]
	pub async fn connect_tcp(
		&self,
		handlers: EpoxyHandlers,
		url: String,
	) -> Result<EpoxyIoStream, EpoxyError> {
		let url: Uri = url.try_into()?;
		let host = url.host().ok_or(EpoxyError::NoUrlHost)?;
		let port = url.port_u16().ok_or(EpoxyError::NoUrlPort)?;
		match self
			.stream_provider
			.get_asyncread(StreamType::Tcp, host.to_string(), port)
			.await
		{
			Ok(stream) => Ok(EpoxyIoStream::connect(Either::Right(stream), handlers)),
			Err(err) => {
				let _ = handlers
					.onerror
					.call1(&JsValue::null(), &err.to_string().into());
				Err(err)
			}
		}
	}

	#[cfg(feature = "full")]
	pub async fn connect_tls(
		&self,
		handlers: EpoxyHandlers,
		url: String,
	) -> Result<EpoxyIoStream, EpoxyError> {
		let url: Uri = url.try_into()?;
		let host = url.host().ok_or(EpoxyError::NoUrlHost)?;
		let port = url.port_u16().ok_or(EpoxyError::NoUrlPort)?;
		match self
			.stream_provider
			.get_tls_stream(host.to_string(), port)
			.await
		{
			Ok(stream) => Ok(EpoxyIoStream::connect(Either::Left(stream), handlers)),
			Err(err) => {
				let _ = handlers
					.onerror
					.call1(&JsValue::null(), &err.to_string().into());
				Err(err)
			}
		}
	}

	#[cfg(feature = "full")]
	pub async fn connect_udp(
		&self,
		handlers: EpoxyHandlers,
		url: String,
	) -> Result<EpoxyUdpStream, EpoxyError> {
		let url: Uri = url.try_into()?;
		let host = url.host().ok_or(EpoxyError::NoUrlHost)?;
		let port = url.port_u16().ok_or(EpoxyError::NoUrlPort)?;
		match self
			.stream_provider
			.get_stream(StreamType::Udp, host.to_string(), port)
			.await
		{
			Ok(stream) => Ok(EpoxyUdpStream::connect(stream, handlers)),
			Err(err) => {
				let _ = handlers
					.onerror
					.call1(&JsValue::null(), &err.to_string().into());
				Err(err)
			}
		}
	}

	async fn send_req_inner(
		&self,
		req: http::Request<HttpBody>,
		should_redirect: bool,
	) -> Result<EpoxyResponse, EpoxyError> {
		let new_req = if should_redirect {
			Some(req.clone())
		} else {
			None
		};

		let res = self.client.request(req).await;
		match res {
			Ok(res) => {
				if is_redirect(res.status().as_u16())
					&& let Some(mut new_req) = new_req
					&& let Some(location) = res.headers().get("Location")
					&& let Ok(redirect_url) = new_req.uri().get_redirect(location)
					&& let Some(redirect_url_authority) = redirect_url.clone().authority()
				{
					*new_req.uri_mut() = redirect_url;
					new_req.headers_mut().insert(
						"Host",
						HeaderValue::from_str(redirect_url_authority.as_str())?,
					);
					Ok(EpoxyResponse::Redirect((res, new_req)))
				} else {
					Ok(EpoxyResponse::Success(res))
				}
			}
			Err(err) => Err(err.into()),
		}
	}

	async fn send_req(
		&self,
		req: http::Request<HttpBody>,
		should_redirect: bool,
	) -> Result<(hyper::Response<Incoming>, Uri, bool), EpoxyError> {
		let mut redirected = false;
		let mut current_url = req.uri().clone();
		let mut current_resp: EpoxyResponse = self.send_req_inner(req, should_redirect).await?;
		for _ in 0..self.redirect_limit {
			match current_resp {
				EpoxyResponse::Success(_) => break,
				EpoxyResponse::Redirect((_, req)) => {
					redirected = true;
					current_url = req.uri().clone();
					current_resp = self.send_req_inner(req, should_redirect).await?
				}
			}
		}

		match current_resp {
			EpoxyResponse::Success(resp) => Ok((resp, current_url, redirected)),
			EpoxyResponse::Redirect((resp, _)) => Ok((resp, current_url, redirected)),
		}
	}

	pub async fn fetch(
		&self,
		url: String,
		options: Object,
	) -> Result<web_sys::Response, EpoxyError> {
		let url: Uri = url.try_into()?;
		// only valid `Scheme`s are HTTP and HTTPS, which are the ones we support
		url.scheme().ok_or(EpoxyError::InvalidUrlScheme)?;

		let host = url.host().ok_or(EpoxyError::NoUrlHost)?;

		let request_method = object_get(&options, "method")
			.and_then(|x| x.as_string())
			.unwrap_or_else(|| "GET".to_string());
		let request_method: Method = Method::from_str(&request_method)?;

		let request_redirect = object_get(&options, "redirect")
			.map(|x| {
				!matches!(
					x.as_string().unwrap_or_default().as_str(),
					"error" | "manual"
				)
			})
			.unwrap_or(true);

		let mut body_content_type: Option<String> = None;
		let body = match object_get(&options, "body") {
			Some(buf) => {
				let (body, req) = convert_body(buf)
					.await
					.map_err(|_| EpoxyError::InvalidRequestBody)?;
				body_content_type = req.headers().get("Content-Type").ok().flatten();
				Bytes::from(body.to_vec())
			}
			None => Bytes::new(),
		};

		let headers = object_get(&options, "headers").and_then(|val| {
			if web_sys::Headers::instanceof(&val) {
				Some(entries_of_object(&Object::from_entries(&val).ok()?))
			} else if val.is_truthy() {
				Some(entries_of_object(&Object::from(val)))
			} else {
				None
			}
		});

		let mut request_builder = Request::builder().uri(url.clone()).method(request_method);

		// Generic InvalidRequest because this only returns None if the builder has some error
		// which we don't know
		let headers_map = request_builder
			.headers_mut()
			.ok_or(EpoxyError::InvalidRequest)?;

		cfg_if! {
			if #[cfg(feature = "full")] {
				headers_map.insert("Accept-Encoding", HeaderValue::from_static("gzip, br"));
			} else {
				headers_map.insert("Accept-Encoding", HeaderValue::from_static("identity"));
			}
		}
		headers_map.insert("Connection", HeaderValue::from_static("keep-alive"));
		headers_map.insert("User-Agent", HeaderValue::from_str(&self.user_agent)?);
		headers_map.insert("Host", HeaderValue::from_str(host)?);

		if body.is_empty() {
			headers_map.insert("Content-Length", HeaderValue::from_static("0"));
		}

		if let Some(content_type) = body_content_type {
			headers_map.insert("Content-Type", HeaderValue::from_str(&content_type)?);
		}

		if let Some(headers) = headers {
			for hdr in headers {
				headers_map.insert(
					HeaderName::from_str(&hdr[0])?,
					HeaderValue::from_str(&hdr[1])?,
				);
			}
		}

		let (response, response_uri, redirected) = self
			.send_req(request_builder.body(HttpBody::new(body))?, request_redirect)
			.await?;

		let response_headers: Array = response
			.headers()
			.iter()
			.filter_map(|val| {
				Some(Array::of2(
					&val.0.as_str().into(),
					&val.1.to_str().ok()?.into(),
				))
			})
			.collect();
		let response_headers = Object::from_entries(&response_headers)
			.map_err(|_| EpoxyError::ResponseHeadersFromEntriesFailed)?;

		let response_headers_raw = response.headers().clone();

		let mut response_builder = ResponseInit::new();
		response_builder
			.headers(&response_headers)
			.status(response.status().as_u16())
			.status_text(response.status().canonical_reason().unwrap_or_default());

		cfg_if! {
			if #[cfg(feature = "full")] {
				let response_stream = if !is_null_body(response.status().as_u16()) {
					let compression = match response
						.headers()
						.get("Content-Encoding")
						.and_then(|val| val.to_str().ok())
						.unwrap_or_default()
					{
						"gzip" => Some(EpoxyCompression::Gzip),
						"br" => Some(EpoxyCompression::Brotli),
						_ => None,
					};

					let response_body = IncomingBody::new(response.into_body()).into_async_read();
					let decompressed_body = match compression {
						Some(alg) => match alg {
							EpoxyCompression::Gzip => {
								Either::Left(Either::Left(async_comp::GzipDecoder::new(response_body)))
							}
							EpoxyCompression::Brotli => {
								Either::Left(Either::Right(async_comp::BrotliDecoder::new(response_body)))
							}
						},
						None => Either::Right(response_body),
					};
					Some(ReadableStream::from_stream(asyncread_to_readablestream_stream(decompressed_body)).into_raw())
				} else {
					None
				};
			} else {
				let response_stream = if !is_null_body(response.status().as_u16()) {
					let response_body = IncomingBody::new(response.into_body()).into_async_read();
					Some(ReadableStream::from_stream(asyncread_to_readablestream_stream(response_body)).into_raw())
				} else {
					None
				};
			}
		}

		let resp = web_sys::Response::new_with_opt_readable_stream_and_init(
			response_stream.as_ref(),
			&response_builder,
		)
		.map_err(|_| EpoxyError::ResponseNewFailed)?;

		Object::define_property(
			&resp,
			&"url".into(),
			&utils::define_property_obj(response_uri.to_string().into(), false)
				.map_err(|_| EpoxyError::DefinePropertyObjFailed)?,
		);

		Object::define_property(
			&resp,
			&"redirected".into(),
			&utils::define_property_obj(redirected.into(), false)
				.map_err(|_| EpoxyError::DefinePropertyObjFailed)?,
		);

		let raw_headers = Object::new();
		for (k, v) in response_headers_raw.iter() {
			let k: JsValue = k.to_string().into();
			let v: JsValue = v.to_str()?.to_string().into();
			if let Ok(jv) = Reflect::get(&raw_headers, &k) {
				if jv.is_array() {
					let arr = Array::from(&jv);
					arr.push(&v);
					object_set(&raw_headers, &k, &arr)?;
				} else if jv.is_truthy() {
					object_set(&raw_headers, &k, &Array::of2(&jv, &v))?;
				} else {
					object_set(&raw_headers, &k, &v)?;
				}
			}
		}
		Object::define_property(
			&resp,
			&"rawHeaders".into(),
			&utils::define_property_obj(raw_headers.into(), false)
				.map_err(|_| EpoxyError::DefinePropertyObjFailed)?,
		);

		Ok(resp)
	}
}