/*
 * nghttp2 - HTTP/2 C Library
 *
 * Copyright (c) 2016 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 "shrpx_api_downstream_connection.h"

#include "shrpx_client_handler.h"
#include "shrpx_upstream.h"
#include "shrpx_downstream.h"
#include "shrpx_worker.h"
#include "shrpx_connection_handler.h"

namespace shrpx {

APIDownstreamConnection::APIDownstreamConnection(Worker *worker)
    : worker_(worker), abandoned_(false) {}

APIDownstreamConnection::~APIDownstreamConnection() {}

int APIDownstreamConnection::attach_downstream(Downstream *downstream) {
  if (LOG_ENABLED(INFO)) {
    DCLOG(INFO, this) << "Attaching to DOWNSTREAM:" << downstream;
  }

  downstream_ = downstream;

  return 0;
}

void APIDownstreamConnection::detach_downstream(Downstream *downstream) {
  if (LOG_ENABLED(INFO)) {
    DCLOG(INFO, this) << "Detaching from DOWNSTREAM:" << downstream;
  }
  downstream_ = nullptr;
}

int APIDownstreamConnection::send_reply(unsigned int http_status,
                                        const StringRef &body) {
  abandoned_ = true;

  auto upstream = downstream_->get_upstream();

  auto &resp = downstream_->response();

  resp.http_status = http_status;

  auto &balloc = downstream_->get_block_allocator();

  auto content_length = util::make_string_ref_uint(balloc, body.size());

  resp.fs.add_header_token(StringRef::from_lit("content-length"),
                           content_length, false, http2::HD_CONTENT_LENGTH);

  if (upstream->send_reply(downstream_, body.byte(), body.size()) != 0) {
    return -1;
  }

  return 0;
}

int APIDownstreamConnection::push_request_headers() {
  auto &req = downstream_->request();

  if (req.path != StringRef::from_lit("/api/v1alpha1/backend/replace")) {
    send_reply(404, StringRef::from_lit("404 Not Found"));

    return 0;
  }

  return 0;
}

int APIDownstreamConnection::push_upload_data_chunk(const uint8_t *data,
                                                    size_t datalen) {
  if (abandoned_) {
    return 0;
  }

  auto output = downstream_->get_request_buf();

  // TODO limit the maximum payload size
  output->append(data, datalen);

  // We don't have to call Upstream::resume_read() here, because
  // request buffer is effectively unlimited.  Actually, we cannot
  // call it here since it could recursively call this function again.

  return 0;
}

int APIDownstreamConnection::end_upload_data() {
  if (abandoned_) {
    return 0;
  }

  auto output = downstream_->get_request_buf();

  struct iovec iov;
  auto iovcnt = output->riovec(&iov, 1);

  constexpr auto body = StringRef::from_lit("200 OK");
  constexpr auto error_body = StringRef::from_lit("400 Bad Request");

  if (iovcnt == 0) {
    send_reply(200, body);

    return 0;
  }

  Config config{};
  config.conn.downstream = std::make_shared<DownstreamConfig>();
  const auto &downstreamconf = config.conn.downstream;

  auto src = get_config()->conn.downstream;

  downstreamconf->timeout = src->timeout;
  downstreamconf->connections_per_host = src->connections_per_host;
  downstreamconf->connections_per_frontend = src->connections_per_frontend;
  downstreamconf->request_buffer_size = src->request_buffer_size;
  downstreamconf->response_buffer_size = src->response_buffer_size;
  downstreamconf->family = src->family;

  std::set<StringRef> include_set;

  for (auto first = reinterpret_cast<const uint8_t *>(iov.iov_base),
            last = first + iov.iov_len;
       first != last;) {
    auto eol = std::find(first, last, '\n');
    if (eol == last) {
      break;
    }

    if (first == eol || *first == '#') {
      first = ++eol;
      continue;
    }

    auto eq = std::find(first, eol, '=');
    if (eq == eol) {
      send_reply(400, error_body);
      return 0;
    }

    if (parse_config(&config, StringRef{first, eq}, StringRef{eq + 1, eol},
                     include_set) != 0) {
      send_reply(400, error_body);
      return 0;
    }

    first = ++eol;
  }

  auto &tlsconf = get_config()->tls;
  if (configure_downstream_group(&config, get_config()->http2_proxy, true,
                                 tlsconf) != 0) {
    send_reply(400, error_body);
    return 0;
  }

  auto conn_handler = worker_->get_connection_handler();

  conn_handler->send_replace_downstream(downstreamconf);

  send_reply(200, body);

  return 0;
}

void APIDownstreamConnection::pause_read(IOCtrlReason reason) {}

int APIDownstreamConnection::resume_read(IOCtrlReason reason, size_t consumed) {
  return 0;
}

void APIDownstreamConnection::force_resume_read() {}

int APIDownstreamConnection::on_read() { return 0; }

int APIDownstreamConnection::on_write() { return 0; }

void APIDownstreamConnection::on_upstream_change(Upstream *uptream) {}

bool APIDownstreamConnection::poolable() const { return false; }

DownstreamAddrGroup *
APIDownstreamConnection::get_downstream_addr_group() const {
  return nullptr;
}

} // namespace shrpx