// Copyright 2018-2024 the Deno authors. All rights reserved. MIT license.

use std::rc::Rc;

use deno_core::error::bad_resource;
use deno_core::error::bad_resource_id;
use deno_core::error::AnyError;
use deno_core::op2;
use deno_core::OpState;
use deno_core::ResourceId;
use deno_http::http_create_conn_resource;
use deno_net::io::TcpStreamResource;
use deno_net::ops_tls::TlsStreamResource;

pub const UNSTABLE_FEATURE_NAME: &str = "http";

deno_core::extension!(deno_http_runtime, ops = [op_http_start],);

#[op2(fast)]
#[smi]
fn op_http_start(
  state: &mut OpState,
  #[smi] tcp_stream_rid: ResourceId,
) -> Result<ResourceId, AnyError> {
  if let Ok(resource_rc) = state
    .resource_table
    .take::<TcpStreamResource>(tcp_stream_rid)
  {
    // This TCP connection might be used somewhere else. If it's the case, we cannot proceed with the
    // process of starting a HTTP server on top of this TCP connection, so we just return a bad
    // resource error. See also: https://github.com/denoland/deno/pull/16242
    let resource = Rc::try_unwrap(resource_rc)
      .map_err(|_| bad_resource("TCP stream is currently in use"))?;
    let (read_half, write_half) = resource.into_inner();
    let tcp_stream = read_half.reunite(write_half)?;
    let addr = tcp_stream.local_addr()?;
    return http_create_conn_resource(state, tcp_stream, addr, "http");
  }

  if let Ok(resource_rc) = state
    .resource_table
    .take::<TlsStreamResource>(tcp_stream_rid)
  {
    // This TLS connection might be used somewhere else. If it's the case, we cannot proceed with the
    // process of starting a HTTP server on top of this TLS connection, so we just return a bad
    // resource error. See also: https://github.com/denoland/deno/pull/16242
    let resource = Rc::try_unwrap(resource_rc)
      .map_err(|_| bad_resource("TLS stream is currently in use"))?;
    let (read_half, write_half) = resource.into_inner();
    let tls_stream = read_half.unsplit(write_half);
    let addr = tls_stream.local_addr()?;
    return http_create_conn_resource(state, tls_stream, addr, "https");
  }

  #[cfg(unix)]
  if let Ok(resource_rc) = state
    .resource_table
    .take::<deno_net::io::UnixStreamResource>(tcp_stream_rid)
  {
    super::check_unstable(state, UNSTABLE_FEATURE_NAME, "Deno.serveHttp");

    // This UNIX socket might be used somewhere else. If it's the case, we cannot proceed with the
    // process of starting a HTTP server on top of this UNIX socket, so we just return a bad
    // resource error. See also: https://github.com/denoland/deno/pull/16242
    let resource = Rc::try_unwrap(resource_rc)
      .map_err(|_| bad_resource("UNIX stream is currently in use"))?;
    let (read_half, write_half) = resource.into_inner();
    let unix_stream = read_half.reunite(write_half)?;
    let addr = unix_stream.local_addr()?;
    return http_create_conn_resource(state, unix_stream, addr, "http+unix");
  }

  Err(bad_resource_id())
}