/** @file

  ProxyClientSession - Base class for protocol client sessions.

  @section license License

  Licensed to the Apache Software Foundation (ASF) under one
  or more contributor license agreements.  See the NOTICE file
  distributed with this work for additional information
  regarding copyright ownership.  The ASF licenses this file
  to you under the Apache License, Version 2.0 (the
  "License"); you may not use this file except in compliance
  with the License.  You may obtain a copy of the License at

      http://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.
 */

#ifndef __PROXY_CLIENT_SESSION_H__
#define __PROXY_CLIENT_SESSION_H__

#include "ts/ink_platform.h"
#include "ts/ink_resolver.h"
#include "P_Net.h"
#include "InkAPIInternal.h"
#include "http/HttpServerSession.h"

// Emit a debug message conditional on whether this particular client session
// has debugging enabled. This should only be called from within a client session
// member function.
#define DebugSsn(ssn, tag, ...) DebugSpecific((ssn)->debug(), tag, __VA_ARGS__)

class ProxyClientTransaction;
struct AclRecord;

class ProxyClientSession : public VConnection
{
public:
  ProxyClientSession();

  virtual void destroy();
  virtual void start() = 0;

  virtual void new_connection(NetVConnection *new_vc, MIOBuffer *iobuf, IOBufferReader *reader, bool backdoor) = 0;

  virtual void
  ssn_hook_append(TSHttpHookID id, INKContInternal *cont)
  {
    this->api_hooks.append(id, cont);
  }

  virtual void
  ssn_hook_prepend(TSHttpHookID id, INKContInternal *cont)
  {
    this->api_hooks.prepend(id, cont);
  }

  virtual NetVConnection *get_netvc() const = 0;
  virtual void release_netvc()              = 0;

  APIHook *
  ssn_hook_get(TSHttpHookID id) const
  {
    return this->api_hooks.get(id);
  }

  void *
  get_user_arg(unsigned ix) const
  {
    ink_assert(ix < countof(user_args));
    return this->user_args[ix];
  }

  void
  set_user_arg(unsigned ix, void *arg)
  {
    ink_assert(ix < countof(user_args));
    user_args[ix] = arg;
  }

  // Return whether debugging is enabled for this session.
  bool
  debug() const
  {
    return this->debug_on;
  }

  bool
  hooks_enabled() const
  {
    return this->hooks_on;
  }

  bool
  has_hooks() const
  {
    return this->api_hooks.has_hooks() || http_global_hooks->has_hooks();
  }

  // Initiate an API hook invocation.
  void do_api_callout(TSHttpHookID id);

  static int64_t next_connection_id();
  virtual int get_transact_count() const = 0;

  // Override if your session protocol allows this
  virtual bool
  is_transparent_passthrough_allowed()
  {
    return false;
  }

  // Override if your session protocol cares
  virtual void
  set_half_close_flag(bool flag)
  {
  }
  virtual bool
  get_half_close_flag() const
  {
    return false;
  }

  // Indicate we are done with a transaction
  virtual void release(ProxyClientTransaction *trans) = 0;

  /// acl record - cache IpAllow::match() call
  const AclRecord *acl_record;

  int64_t
  connection_id() const
  {
    return con_id;
  }

  virtual void
  attach_server_session(HttpServerSession *ssession, bool transaction_done = true)
  {
  }

  virtual HttpServerSession *
  get_server_session() const
  {
    return NULL;
  }

  /// DNS resolution preferences.
  HostResStyle host_res_style;

  virtual int state_api_callout(int event, void *edata);

  TSHttpHookID
  get_hookid() const
  {
    return api_hookid;
  }

  ink_hrtime ssn_start_time;
  ink_hrtime ssn_last_txn_time;

  virtual void
  set_active_timeout(ink_hrtime timeout_in)
  {
  }
  virtual void
  set_inactivity_timeout(ink_hrtime timeout_in)
  {
  }
  virtual void
  cancel_inactivity_timeout()
  {
  }

protected:
  // XXX Consider using a bitwise flags variable for the following flags, so that we can make the best
  // use of internal alignment padding.

  // Session specific debug flag.
  bool debug_on;
  bool hooks_on;

  int64_t con_id;

private:
  APIHookScope api_scope;
  TSHttpHookID api_hookid;
  APIHook *api_current;
  HttpAPIHooks api_hooks;
  void *user_args[HTTP_SSN_TXN_MAX_USER_ARG];

  ProxyClientSession(ProxyClientSession &);                  // noncopyable
  ProxyClientSession &operator=(const ProxyClientSession &); // noncopyable

  void handle_api_return(int event);

  friend void TSHttpSsnDebugSet(TSHttpSsn, int);
};

#endif // __PROXY_CLIENT_SESSION_H__