/*
 * nghttp2 - HTTP/2 C Library
 *
 * Copyright (c) 2014 Tatsuhiro Tsujikawa
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
 * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */
#include "asio_http2_impl.h"

#include <boost/asio/ssl.hpp>

#include <openssl/ssl.h>

#include <nghttp2/nghttp2.h>

#include "asio_server.h"
#include "util.h"
#include "ssl.h"

namespace nghttp2 {

namespace asio_http2 {

namespace server {

http2::http2()
  : impl_(util::make_unique<http2_impl>())
{}

http2::~http2()
{}

void http2::listen(const std::string& address, uint16_t port, request_cb cb)
{
  impl_->listen(address, port, std::move(cb));
}

void http2::num_threads(size_t num_threads)
{
  impl_->num_threads(num_threads);
}

void http2::tls(std::string private_key_file,
                std::string certificate_file)
{
  impl_->tls(std::move(private_key_file), std::move(certificate_file));
}

void http2::num_concurrent_tasks(size_t num_concurrent_tasks)
{
  impl_->num_concurrent_tasks(num_concurrent_tasks);
}

void http2::backlog(int backlog)
{
  impl_->backlog(backlog);
}

http2_impl::http2_impl()
  : num_threads_(1),
    num_concurrent_tasks_(1),
    backlog_(-1)
{}

namespace {
std::array<unsigned char, NGHTTP2_PROTO_VERSION_ID_LEN + 1>&
get_alpn_token()
{
  static std::array<unsigned char, NGHTTP2_PROTO_VERSION_ID_LEN + 1> token;

  token[0] = NGHTTP2_PROTO_VERSION_ID_LEN;
  std::copy(NGHTTP2_PROTO_VERSION_ID,
            NGHTTP2_PROTO_VERSION_ID + NGHTTP2_PROTO_VERSION_ID_LEN,
            std::begin(token) + 1);
  return token;
}
} // namespace

void http2_impl::listen(const std::string& address, uint16_t port,
                        request_cb cb)
{
  std::unique_ptr<boost::asio::ssl::context> ssl_ctx;

  if(!private_key_file_.empty() && !certificate_file_.empty()) {
    ssl_ctx = util::make_unique<boost::asio::ssl::context>
      (boost::asio::ssl::context::sslv23);

    ssl_ctx->use_private_key_file(private_key_file_,
                                 boost::asio::ssl::context::pem);
    ssl_ctx->use_certificate_chain_file(certificate_file_);

    auto ctx = ssl_ctx->native_handle();

    SSL_CTX_set_options(ctx,
                        SSL_OP_ALL | SSL_OP_NO_SSLv2 | SSL_OP_NO_SSLv3 |
                        SSL_OP_NO_COMPRESSION |
                        SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION |
                        SSL_OP_SINGLE_ECDH_USE |
                        SSL_OP_NO_TICKET |
                        SSL_OP_CIPHER_SERVER_PREFERENCE);
    SSL_CTX_set_mode(ctx, SSL_MODE_AUTO_RETRY);
    SSL_CTX_set_mode(ctx, SSL_MODE_RELEASE_BUFFERS);
    SSL_CTX_set_mode(ctx, SSL_MODE_ENABLE_PARTIAL_WRITE);

    SSL_CTX_set_cipher_list(ctx, ssl::DEFAULT_CIPHER_LIST);

    auto ecdh = EC_KEY_new_by_curve_name(NID_X9_62_prime256v1);
    if(ecdh) {
      SSL_CTX_set_tmp_ecdh(ctx, ecdh);
      EC_KEY_free(ecdh);
    }

    SSL_CTX_set_next_protos_advertised_cb
      (ctx,
       [](SSL *s, const unsigned char **data, unsigned int *len, void *arg) {
        auto& token = get_alpn_token();

        *data = token.data();
        *len = token.size();

        return SSL_TLSEXT_ERR_OK;
      }, nullptr);
  }

  server(address, port, num_threads_, num_concurrent_tasks_,
         std::move(cb), std::move(ssl_ctx), backlog_).run();
}

void http2_impl::num_threads(size_t num_threads)
{
  num_threads_ = num_threads;
}

void http2_impl::tls(std::string private_key_file,
                     std::string certificate_file)
{
  private_key_file_ = std::move(private_key_file);
  certificate_file_ = std::move(certificate_file);
}

void http2_impl::num_concurrent_tasks(size_t num_concurrent_tasks)
{
  num_concurrent_tasks_ = num_concurrent_tasks;
}

void http2_impl::backlog(int backlog)
{
  backlog_ = backlog;
}

} // namespace server

template<typename T, typename F>
std::shared_ptr<util::Defer<T, F>> defer_shared(T&& t, F f)
{
  return std::make_shared<util::Defer<T, F>>(std::forward<T>(t),
                                             std::forward<F>(f));
}

read_cb file_reader(const std::string& path)
{
  auto fd = open(path.c_str(), O_RDONLY);
  if(fd == -1) {
    return read_cb();
  }

  return file_reader_from_fd(fd);
}

read_cb file_reader_from_fd(int fd)
{
  auto d = defer_shared(static_cast<int>(fd), close);

  return [fd, d](uint8_t *buf, size_t len) -> read_cb::result_type
    {
      int rv;
      while((rv = read(fd, buf, len)) == -1 && errno == EINTR);

      if(rv == -1) {
        return std::make_pair(-1, false);
      }

      if(rv == 0) {
        return std::make_pair(rv, true);
      }

      return std::make_pair(rv, false);
    };
}

bool check_path(const std::string& path)
{
  return util::check_path(path);
}

std::string percent_decode(const std::string& s)
{
  return util::percentDecode(std::begin(s), std::end(s));
}

std::string http_date(int64_t t)
{
  return util::http_date(t);
}

} // namespace asio_http2

} // namespace nghttp2