/*
 * Copyright (C) 2011 Stefan Sayer
 *
 * This file is part of SEMS, a free SIP media server.
 *
 * SEMS is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * For a license to use the SEMS software under conditions
 * other than those described here, or to purchase support for this
 * software, please contact iptel.org by e-mail at the following addresses:
 *    info@iptel.org
 *
 * SEMS is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#include "AmPlugIn.h"
#include "log.h"
#include "AmArg.h"
#include "AmSipHeaders.h"

#include "CCParallelCalls.h"
#include "SBCCallControlAPI.h"

#include <string.h>

#define SBCVAR_PARALLEL_CALLS_UUID "uuid"

unsigned int CCParallelCalls::refuse_code = 402;
string CCParallelCalls::refuse_reason = "Too Many Simultaneous Calls";

CCParallelCalls::CCParallelCalls()
{
}

CCParallelCalls::~CCParallelCalls() { }

int CCParallelCalls::onLoad() {
  AmConfigReader cfg;

  if(cfg.loadFile(AmConfig::ModConfigPath + string(MOD_NAME ".conf"))) {
    INFO(MOD_NAME "configuration  file (%s) not found, "
  	 "assuming default configuration is fine\n",
  	 (AmConfig::ModConfigPath + string(MOD_NAME ".conf")).c_str());
    return 0;
  }
  
  refuse_reason = cfg.hasParameter("refuse_reason") ?
    cfg.getParameter("refuse_reason") : refuse_reason;

  if (cfg.hasParameter("refuse_code")) {
    if (str2int(cfg.getParameter("refuse_code"), refuse_code)) {
      ERROR("refuse_code '%s' not understood\n", cfg.getParameter("refuse_code").c_str());
      return -1;
    }
  }

  return 0;
}

void CCParallelCalls::invoke(const string& method, const AmArg& args, AmArg& ret)
{
  // DBG("CCParallelCalls: %s(%s)\n", method.c_str(), AmArg::print(args).c_str());

  if(method == "start"){
    SBCCallProfile* call_profile =
      dynamic_cast<SBCCallProfile*>(args[CC_API_PARAMS_CALL_PROFILE].asObject());

    start(args[CC_API_PARAMS_CC_NAMESPACE].asCStr(),
	  args[CC_API_PARAMS_LTAG].asCStr(), call_profile,
	  args[CC_API_PARAMS_CFGVALUES], ret);
    
  } else if(method == "connect"){
    // no action

  } else if(method == "end"){
    args[CC_API_PARAMS_TIMESTAMPS].assertArrayFmt("iiiiii");
    SBCCallProfile* call_profile =
      dynamic_cast<SBCCallProfile*>(args[CC_API_PARAMS_CALL_PROFILE].asObject());

    end(args[CC_API_PARAMS_CC_NAMESPACE].asCStr(),
	args[CC_API_PARAMS_LTAG].asCStr(), call_profile);

  } else if(method == CC_INTERFACE_MAND_VALUES_METHOD){
    ret.push("uuid");
  } else if(method == "_list"){
    ret.push("start");
    ret.push("connect");
    ret.push("end");
  }
  else
    throw AmDynInvoke::NotImplemented(method);
}

void CCParallelCalls::start(const string& cc_namespace,
			    const string& ltag, SBCCallProfile* call_profile,
			    const AmArg& values, AmArg& res) {
#define REFUSE_WITH_SERVER_INTERNAL_ERROR				\
  res.push(AmArg());							\
  AmArg& res_cmd = res[0];						\
  res_cmd[SBC_CC_ACTION] = SBC_CC_REFUSE_ACTION;			\
  res_cmd[SBC_CC_REFUSE_CODE] = 500;					\
  res_cmd[SBC_CC_REFUSE_REASON] = SIP_REPLY_SERVER_INTERNAL_ERROR;	\
  return;

  if (!call_profile) {
    ERROR("internal: call_profile object not found in parameters\n");
    REFUSE_WITH_SERVER_INTERNAL_ERROR;
    return;
  }

  if (!values.hasMember("uuid") || !isArgCStr(values["uuid"]) ||
      !strlen(values["uuid"].asCStr())) {
    ERROR("configuration error: uuid missing for parallel calls call control!\n");
    REFUSE_WITH_SERVER_INTERNAL_ERROR;
  }

  string uuid = values["uuid"].asCStr();

  call_profile->cc_vars[cc_namespace+"::"+SBCVAR_PARALLEL_CALLS_UUID] = uuid;

  unsigned int max_calls = 1; // default
  if (values.hasMember("max_calls") && isArgCStr(values["max_calls"])) {
    if (str2int(values["max_calls"].asCStr(), max_calls)) {
      ERROR("max_calls '%s' could not be interpreted!\n", values["max_calls"].asCStr());
      REFUSE_WITH_SERVER_INTERNAL_ERROR;
    }
  }

  DBG("enforcing limit of %i calls for uuid '%s'\n", max_calls, uuid.c_str());

  bool do_limit = !max_calls;
  unsigned int current_calls = 0;
  if (max_calls) {
    call_control_calls_mut.lock();
    map<string, unsigned int>::iterator it=call_control_calls.find(uuid);
    if (it==call_control_calls.end()) {
      call_control_calls[uuid] = current_calls = 1;
    } else {
      if (it->second < max_calls) {
	it->second++;
      } else {
	do_limit = true;
      }
      current_calls = it->second;
    }
  }

  call_control_calls_mut.unlock();

  DBG("uuid %s has %u active calls (limit = %s)\n",
      uuid.c_str(), current_calls, do_limit?"true":"false");

  if (do_limit) {
    res.push(AmArg());
    AmArg& res_cmd = res[0];
    res_cmd[SBC_CC_ACTION] = SBC_CC_REFUSE_ACTION;
    res_cmd[SBC_CC_REFUSE_CODE] = (int)refuse_code;
    res_cmd[SBC_CC_REFUSE_REASON] = refuse_reason;
  }

#undef REFUSE_WITH_SERVER_INTERNAL_ERROR
}

void CCParallelCalls::end(const string& cc_namespace, const string& ltag,
			  SBCCallProfile* call_profile) {
  if (!call_profile) {
    ERROR("internal: call_profile object not found in parameters\n");
    return;
  }

  SBCVarMapIteratorT vars_it =
    call_profile->cc_vars.find(cc_namespace+"::"+SBCVAR_PARALLEL_CALLS_UUID);
  if (vars_it == call_profile->cc_vars.end() || !isArgCStr(vars_it->second)) {
    ERROR("internal: could not find UUID for ending call '%s'\n", ltag.c_str());
    return;
  }
  string uuid = vars_it->second.asCStr();
  call_profile->cc_vars.erase(cc_namespace+"::"+SBCVAR_PARALLEL_CALLS_UUID);

  unsigned int new_call_count  = 0;

  call_control_calls_mut.lock();
  if (call_control_calls[uuid] > 1) {
    new_call_count = --call_control_calls[uuid];
  }  else {
    call_control_calls.erase(uuid);
  }
  call_control_calls_mut.unlock();

  DBG("uuid '%s' now has %u active calls\n", uuid.c_str(), new_call_count);
}

CCParallelCalls* CCParallelCalls::_instance=0;

CCParallelCalls* CCParallelCalls::instance()
{
    if(!_instance)
	_instance = new CCParallelCalls();
    return _instance;
}

class CCParallelCallsFactory : public AmDynInvokeFactory
{
public:
    CCParallelCallsFactory(const string& name)
      : AmDynInvokeFactory(name) { }

    AmDynInvoke* getInstance(){
	return CCParallelCalls::instance();
    }

    int onLoad(){
      if (CCParallelCalls::instance()->onLoad())
	return -1;

      DBG("parallel call control loaded.\n");

      return 0;
    }
};
EXPORT_PLUGIN_CLASS_FACTORY(CCParallelCallsFactory,MOD_NAME);