#ifndef _DATETIME_H
#define _DATETIME_H

#include <ctime>
#include <sstream>

struct interval_t
{
  unsigned int years;
  unsigned int months;
  unsigned int seconds;
  std::time_t  begin;
  std::time_t  end;

  interval_t(int _seconds = 0, int _months = 0, int _years = 0,
	     std::time_t _begin = 0, std::time_t _end = 0)
    : years(_years), months(_months), seconds(_seconds),
      begin(_begin), end(_end) {
  }
  interval_t(const std::string& desc)
    : years(0), months(0), seconds(0), begin(0), end(0) {
    std::istringstream stream(desc);
    parse(stream);
  }

  operator bool() const {
    return seconds > 0 || months > 0 || years > 0;
  }

  void start(const std::time_t moment) {
    begin = first(moment);
  }
  std::time_t first(const std::time_t moment = 0) const;
  std::time_t increment(const std::time_t) const;

  void parse(std::istream& in);
};

extern std::time_t  now;
extern int	    now_year;
extern char         input_format[128];
extern const char * formats[];

bool parse_date_mask(const char * date_str, struct std::tm * result);
bool parse_date(const char * date_str, std::time_t * result,
		const int year = -1);
bool quick_parse_date(const char * date_str, std::time_t * result);

class datetime_error : public std::exception {
  std::string reason;
 public:
  datetime_error(const std::string& _reason) throw() : reason(_reason) {}
  virtual ~datetime_error() throw() {}

  virtual const char* what() const throw() {
    return reason.c_str();
  }
};

#endif // _DATETIME_H