/*******************************************************************************
 *
 * TRIQS: a Toolbox for Research in Interacting Quantum Systems
 *
 * Copyright (C) 2012 by M. Ferrero, O. Parcollet
 *
 * TRIQS 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 3 of the License, or (at your option) any later
 * version.
 *
 * TRIQS 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
 * TRIQS. If not, see <http://www.gnu.org/licenses/>.
 *
 ******************************************************************************/
#ifndef TRIQS_UTILITY_CRASH_LOGGER_H
#define TRIQS_UTILITY_CRASH_LOGGER_H
#include "./first_include.hpp"
#include <string>
#include <exception>
#include <stdexcept>
#include <functional>
#include <vector>
#include <iostream>
#include "./typeid_name.hpp"
#include "./scope_guard.hpp"
#include "../h5.hpp"

namespace triqs { namespace utility {

 /**
  * Usage :
  *
  * Suppose we have objects a,b,c ... which are all H5_Serializable
  * Then :
  *  { // a scope, whatever
  *    auto log = crash_logger("dump.h5");
  *    log(a,"a")(b,"b")(c,"c"); // <---- pls make a macro here !
  *    // ... do some work
  *    log.dismiss();
  *  }
  *
  * Now : if the calculation proceeds correctly, nothing happens. log is destroyed.
  * if however the calculation does not reach the dismiss, e.g. an exception occurs
  * then log is destroyed without a dismiss and it will dump all objects in the hdf5 file.
  *
  * "some work" can be as complex as needed...
  *
  */
class crash_logger {
 std::string filename_;
 std::vector<scope_guard<std::function<void()>>> guards;
 std::vector<std::string> names;
 public :
 ///
 crash_logger(std::string filename) : filename_(filename){}
 crash_logger(const crash_logger&) = delete;
 crash_logger(crash_logger&&) = default;
 crash_logger& operator=(const crash_logger&) = delete;
 crash_logger& operator=(crash_logger && x) { using std::swap; swap(guards, x.guards); swap(names,x.names); return *this;}
 ///
 template<typename Obj> crash_logger & operator()(Obj const & obj, std::string name) {
  names.push_back(name);
  guards.emplace_back([&obj,this, name](){
    using triqs::h5::h5_write; // to have the proper overload for scalar type !!
    try { h5_write( h5::group(H5::H5File(this->filename_.c_str(),H5F_ACC_RDWR)), name, obj); }
    catch(H5::Exception const & e) { std::cerr  << "An hdf5 exception has occurred in crash_logger : I can not recover : error is " <<std::endl ; e.printError();}
    catch(...) { std::cerr  << "An exception has occurred in crash_logger for an object of type " << typeid_name(obj) << " named " << name<< std::endl ; }
    }); //end lambda
  return *this;
 }
 ///
 ~crash_logger() {
  try {
   if ((guards.size()>0) && (guards.front().active())) {
    std::cerr << "crash_logger : I am destroyed without being dismissed. Dumping the objects : ";
    for (auto & x : names) std::cerr<< "\""<< x <<"\" ";
    std::cerr<< std::endl;
    H5::H5File(this->filename_.c_str(),H5F_ACC_TRUNC); // create the file
   }
  }
  catch(...) {} // just in case ... destructor can not throw
 }
 ///
 void dismiss() {for (auto & g : guards) g.dismiss();}
};


}}
#endif