/*
* X.509 Time Types
* (C) 1999-2007 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/

#include <botan/asn1_time.h>
#include <botan/der_enc.h>
#include <botan/ber_dec.h>
#include <botan/charset.h>
#include <botan/parsing.h>
#include <botan/calendar.h>
#include <sstream>
#include <iomanip>

namespace Botan {

/*
* Create an X509_Time
*/
X509_Time::X509_Time(const std::string& time_str)
   {
   set_to(time_str);
   }

/*
* Create a X509_Time from a time point
*/
X509_Time::X509_Time(const std::chrono::system_clock::time_point& time)
   {
   calendar_point cal = calendar_value(time);

   year   = cal.year;
   month  = cal.month;
   day    = cal.day;
   hour   = cal.hour;
   minute = cal.minutes;
   second = cal.seconds;

   tag = (year >= 2050) ? GENERALIZED_TIME : UTC_TIME;
   }

/*
* Create an X509_Time
*/
X509_Time::X509_Time(const std::string& t_spec, ASN1_Tag t) : tag(t)
   {
   set_to(t_spec, tag);
   }

/*
* Set the time with a human readable string
*/
void X509_Time::set_to(const std::string& time_str)
   {
   if(time_str == "")
      {
      year = month = day = hour = minute = second = 0;
      tag = NO_OBJECT;
      return;
      }

   std::vector<std::string> params;
   std::string current;

   for(size_t j = 0; j != time_str.size(); ++j)
      {
      if(Charset::is_digit(time_str[j]))
         current += time_str[j];
      else
         {
         if(current != "")
            params.push_back(current);
         current.clear();
         }
      }
   if(current != "")
      params.push_back(current);

   if(params.size() < 3 || params.size() > 6)
      throw Invalid_Argument("Invalid time specification " + time_str);

   year   = to_u32bit(params[0]);
   month  = to_u32bit(params[1]);
   day    = to_u32bit(params[2]);
   hour   = (params.size() >= 4) ? to_u32bit(params[3]) : 0;
   minute = (params.size() >= 5) ? to_u32bit(params[4]) : 0;
   second = (params.size() == 6) ? to_u32bit(params[5]) : 0;

   tag = (year >= 2050) ? GENERALIZED_TIME : UTC_TIME;

   if(!passes_sanity_check())
      throw Invalid_Argument("Invalid time specification " + time_str);
   }

/*
* Set the time with an ISO time format string
*/
void X509_Time::set_to(const std::string& t_spec, ASN1_Tag spec_tag)
   {
   if(spec_tag == GENERALIZED_TIME)
      {
      if(t_spec.size() != 13 && t_spec.size() != 15)
         throw Invalid_Argument("Invalid GeneralizedTime: " + t_spec);
      }
   else if(spec_tag == UTC_TIME)
      {
      if(t_spec.size() != 11 && t_spec.size() != 13)
         throw Invalid_Argument("Invalid UTCTime: " + t_spec);
      }
   else
      {
      throw Invalid_Argument("Invalid time tag " + std::to_string(spec_tag) + " val " + t_spec);
      }

   if(t_spec[t_spec.size()-1] != 'Z')
      throw Invalid_Argument("Invalid time encoding: " + t_spec);

   const size_t YEAR_SIZE = (spec_tag == UTC_TIME) ? 2 : 4;

   std::vector<std::string> params;
   std::string current;

   for(size_t j = 0; j != YEAR_SIZE; ++j)
      current += t_spec[j];
   params.push_back(current);
   current.clear();

   for(size_t j = YEAR_SIZE; j != t_spec.size() - 1; ++j)
      {
      current += t_spec[j];
      if(current.size() == 2)
         {
         params.push_back(current);
         current.clear();
         }
      }

   year   = to_u32bit(params[0]);
   month  = to_u32bit(params[1]);
   day    = to_u32bit(params[2]);
   hour   = to_u32bit(params[3]);
   minute = to_u32bit(params[4]);
   second = (params.size() == 6) ? to_u32bit(params[5]) : 0;
   tag    = spec_tag;

   if(spec_tag == UTC_TIME)
      {
      if(year >= 50) year += 1900;
      else           year += 2000;
      }

   if(!passes_sanity_check())
      throw Invalid_Argument("Invalid time specification " + t_spec);
   }

/*
* DER encode a X509_Time
*/
void X509_Time::encode_into(DER_Encoder& der) const
   {
   if(tag != GENERALIZED_TIME && tag != UTC_TIME)
      throw Invalid_Argument("X509_Time: Bad encoding tag");

   der.add_object(tag, UNIVERSAL,
                  Charset::transcode(as_string(),
                                     LOCAL_CHARSET,
                                     LATIN1_CHARSET));
   }

/*
* Decode a BER encoded X509_Time
*/
void X509_Time::decode_from(BER_Decoder& source)
   {
   BER_Object ber_time = source.get_next_object();

   set_to(Charset::transcode(ASN1::to_string(ber_time),
                             LATIN1_CHARSET,
                             LOCAL_CHARSET),
          ber_time.type_tag);
   }

/*
* Return a string representation of the time
*/
std::string X509_Time::as_string() const
   {
   if(time_is_set() == false)
      throw Invalid_State("X509_Time::as_string: No time set");

   u32bit full_year = year;

   if(tag == UTC_TIME)
      {
      if(year < 1950 || year >= 2050)
         throw Encoding_Error("X509_Time: The time " + readable_string() +
                              " cannot be encoded as a UTCTime");

      full_year = (year >= 2000) ? (year - 2000) : (year - 1900);
      }

   std::string repr = std::to_string(full_year*10000000000 +
                                     month*100000000 +
                                     day*1000000 +
                                     hour*10000 +
                                     minute*100 +
                                     second) + "Z";

   u32bit desired_size = (tag == UTC_TIME) ? 13 : 15;

   while(repr.size() < desired_size)
      repr = "0" + repr;

   return repr;
   }

/*
* Return if the time has been set somehow
*/
bool X509_Time::time_is_set() const
   {
   return (year != 0);
   }

/*
* Return a human readable string representation
*/
std::string X509_Time::readable_string() const
   {
   if(time_is_set() == false)
      throw Invalid_State("X509_Time::readable_string: No time set");

   // desired format: "%04d/%02d/%02d %02d:%02d:%02d UTC"
   std::stringstream output;
      {
      using namespace std;
      output << setfill('0')
             << setw(4) << year << "/" << setw(2) << month << "/" << setw(2) << day
             << " "
             << setw(2) << hour << ":" << setw(2) << minute << ":" << setw(2) << second
             << " UTC";
      }
   return output.str();
   }

/*
* Do a general sanity check on the time
*/
bool X509_Time::passes_sanity_check() const
   {
   if(year < 1950 || year > 2100)
      return false;
   if(month == 0 || month > 12)
      return false;
   if(day == 0 || day > 31)
      return false;
   if(hour >= 24 || minute > 60 || second > 60)
      return false;
   return true;
   }

/*
* Compare this time against another
*/
s32bit X509_Time::cmp(const X509_Time& other) const
   {
   if(time_is_set() == false)
      throw Invalid_State("X509_Time::cmp: No time set");

   const s32bit EARLIER = -1, LATER = 1, SAME_TIME = 0;

   if(year < other.year)     return EARLIER;
   if(year > other.year)     return LATER;
   if(month < other.month)   return EARLIER;
   if(month > other.month)   return LATER;
   if(day < other.day)       return EARLIER;
   if(day > other.day)       return LATER;
   if(hour < other.hour)     return EARLIER;
   if(hour > other.hour)     return LATER;
   if(minute < other.minute) return EARLIER;
   if(minute > other.minute) return LATER;
   if(second < other.second) return EARLIER;
   if(second > other.second) return LATER;

   return SAME_TIME;
   }

/*
* Compare two X509_Times for in various ways
*/
bool operator==(const X509_Time& t1, const X509_Time& t2)
   { return (t1.cmp(t2) == 0); }
bool operator!=(const X509_Time& t1, const X509_Time& t2)
   { return (t1.cmp(t2) != 0); }

bool operator<=(const X509_Time& t1, const X509_Time& t2)
   { return (t1.cmp(t2) <= 0); }
bool operator>=(const X509_Time& t1, const X509_Time& t2)
   { return (t1.cmp(t2) >= 0); }

bool operator<(const X509_Time& t1, const X509_Time& t2)
   { return (t1.cmp(t2) < 0); }
bool operator>(const X509_Time& t1, const X509_Time& t2)
   { return (t1.cmp(t2) > 0); }

}