/* -*- C++ -*-
 * src/lemon/error.h - Part of LEMON, a generic C++ optimization library
 *
 * Copyright (C) 2004 Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
 * (Egervary Combinatorial Optimization Research Group, EGRES).
 *
 * Permission to use, modify and distribute this software is granted
 * provided that this copyright notice appears in all copies. For
 * precise terms see the accompanying LICENSE file.
 *
 * This software is provided "AS IS" with no warranty of any kind,
 * express or implied, and with no claim as to its suitability for any
 * purpose.
 *
 */

#ifndef LEMON_ERROR_H
#define LEMON_ERROR_H

//! \ingroup misc
//! \file
//! \brief Basic error handling (signaling) routines.

#include <exception>
#include <string>
#include <sstream>

#include <boost/shared_ptr.hpp>

namespace lemon {

  /// Exception-safe convenient "error message" class.
  class ErrorMessage {
  protected:
  ///\e 
    boost::shared_ptr<std::ostringstream> buf;
    
  ///\e 
    bool init() throw() {
      try {
	buf.reset(new std::ostringstream);
      }
      catch(...) {
	buf.reset();
      }
      return buf;
    }

  public:

  ///\e 
    ErrorMessage() throw() { init(); }

  ///\e 
    ErrorMessage(const char *message) throw() {
      init();
      *this << message;
    }

  ///\e 
    ErrorMessage(const std::string &message) throw() {
      init();
      *this << message;
    }

  ///\e 
    template <typename T>
    ErrorMessage& operator<<(const T &t) throw() {
      if( !buf ) return *this;

      try {
	*buf << t;
      }
      catch(...) {
	buf.reset();
      }
    }

  ///\e 
    const char* message() throw() {
      if( !buf ) return 0;

      const char* mes = 0;
      try {
	mes = buf->str().c_str();
      }
      catch(...) {}
      return mes;
    }
    
  };

  /**
   * \brief Generic exception class.
   *
   * Base class for exceptions used in LEMON.
   */
  class Exception : public std::exception, public ErrorMessage {
  public:
  ///\e 
    Exception() throw() {}
  ///\e 
    explicit Exception(const std::string &s) throw()
      : ErrorMessage(s) {}
  ///\e 
    virtual ~Exception() throw() {}
    
  ///\e 
    virtual const char* what() const throw() {
      const char *mes = message();
      if( mes ) return mes;
      return "lemon::Exception";
    }
  };

  ///\e 
  class LogicError : public Exception {
  ///\e 
    explicit LogicError(const std::string &s)
      : Exception(s) {}
  };

  ///\e 
  class RuntimeError : public Exception {
  ///\e 
    explicit RuntimeError(const std::string &s)
      : Exception(s) {}
  };

  ///\e 
  class RangeError : public RuntimeError {
  ///\e 
    explicit RangeError(const std::string &s)
      : RuntimeError(s) {}
  };

  ///\e 
  class IOError : public RuntimeError {
  ///\e 
    explicit IOError(const std::string &s)
      : RuntimeError(s) {}
  };

  ///\e 
  class DataFormatError : public IOError {
  ///\e 
    explicit DataFormatError(const std::string &message)
      : IOError(message) : line(0) {}
  ///\e 
    DataFormatError(const std::string &file_name, int line_num,
		    const std::string &message)
      : IOError(message), line(line_num) { set_file(file_name); }

  ///\e 
    void set_line(int line_num) { line=line_num; }
  ///\e 
    void set_file(const std::string &file_name) {
      try {
	file.reset(new std::string);
	*file = file_name;
      }
      catch(...) {
	file.reset();
      }
    }

  ///\e 
    virtual const char* what() const {
      const char *mes = 0;
      try {
	std::ostringstream ostr;
	ostr << IOError::what();
	if( file || line ) {
	  ostr << " (";
	  if( file ) ostr << "in file" << *file;
	  if( line ) ostr << " at line" << line;
	}
	mes = ostr.str().c_str();
      }
      catch(...) {}
      if( mes ) return mes;
      return "lemon::DataFormatError";
    }
  };



  /****************  Macros  ****************/


  /**
   * \brief Macro for assertions with customizable message
   */

# define lemon_assert(exp, msg) \
    if(!(exp)) { \
      std::cerr << __FILE__ ":" << __LINE__ << ": " << (msg) << std::endl; \
      abort; \
    }


  /**
   * \brief Macro for mark not yet implemented features.
   *
   * \todo Is this the right place for this? It should be used only in
   * modules under development.
   */

# define FIXME(msg) lemon_assert(0, "FIXME: " msg)

}
#endif // LEMON_ERROR_H