/*
* Various string utils and parsing functions
* (C) 1999-2007,2013,2014 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/

#include <botan/parsing.h>
#include <botan/exceptn.h>
#include <botan/charset.h>
#include <botan/get_byte.h>
#include <set>
#include <stdexcept>

namespace Botan {

u32bit to_u32bit(const std::string& str)
   {
   try
      {
      return std::stoul(str, nullptr);
      }
   catch(std::exception&)
      {
      throw std::runtime_error("Could not read '" + str + "' as decimal string");
      }
   }

/*
* Convert a string into a time duration
*/
u32bit timespec_to_u32bit(const std::string& timespec)
   {
   if(timespec == "")
      return 0;

   const char suffix = timespec[timespec.size()-1];
   std::string value = timespec.substr(0, timespec.size()-1);

   u32bit scale = 1;

   if(Charset::is_digit(suffix))
      value += suffix;
   else if(suffix == 's')
      scale = 1;
   else if(suffix == 'm')
      scale = 60;
   else if(suffix == 'h')
      scale = 60 * 60;
   else if(suffix == 'd')
      scale = 24 * 60 * 60;
   else if(suffix == 'y')
      scale = 365 * 24 * 60 * 60;
   else
      throw Decoding_Error("timespec_to_u32bit: Bad input " + timespec);

   return scale * to_u32bit(value);
   }

/*
* Parse a SCAN-style algorithm name
*/
std::vector<std::string> parse_algorithm_name(const std::string& namex)
   {
   if(namex.find('(') == std::string::npos &&
      namex.find(')') == std::string::npos)
      return std::vector<std::string>(1, namex);

   std::string name = namex, substring;
   std::vector<std::string> elems;
   size_t level = 0;

   elems.push_back(name.substr(0, name.find('(')));
   name = name.substr(name.find('('));

   for(auto i = name.begin(); i != name.end(); ++i)
      {
      char c = *i;

      if(c == '(')
         ++level;
      if(c == ')')
         {
         if(level == 1 && i == name.end() - 1)
            {
            if(elems.size() == 1)
               elems.push_back(substring.substr(1));
            else
               elems.push_back(substring);
            return elems;
            }

         if(level == 0 || (level == 1 && i != name.end() - 1))
            throw Invalid_Algorithm_Name(namex);
         --level;
         }

      if(c == ',' && level == 1)
         {
         if(elems.size() == 1)
            elems.push_back(substring.substr(1));
         else
            elems.push_back(substring);
         substring.clear();
         }
      else
         substring += c;
      }

   if(substring != "")
      throw Invalid_Algorithm_Name(namex);

   return elems;
   }

std::vector<std::string> split_on(const std::string& str, char delim)
   {
   return split_on_pred(str, [delim](char c) { return c == delim; });
   }

std::vector<std::string> split_on_pred(const std::string& str,
                                       std::function<bool (char)> pred)
   {
   std::vector<std::string> elems;
   if(str == "") return elems;

   std::string substr;
   for(auto i = str.begin(); i != str.end(); ++i)
      {
      if(pred(*i))
         {
         if(substr != "")
            elems.push_back(substr);
         substr.clear();
         }
      else
         substr += *i;
      }

   if(substr == "")
      throw Invalid_Argument("Unable to split string: " + str);
   elems.push_back(substr);

   return elems;
   }

/*
* Join a string
*/
std::string string_join(const std::vector<std::string>& strs, char delim)
   {
   std::string out = "";

   for(size_t i = 0; i != strs.size(); ++i)
      {
      if(i != 0)
         out += delim;
      out += strs[i];
      }

   return out;
   }

/*
* Parse an ASN.1 OID string
*/
std::vector<u32bit> parse_asn1_oid(const std::string& oid)
   {
   std::string substring;
   std::vector<u32bit> oid_elems;

   for(auto i = oid.begin(); i != oid.end(); ++i)
      {
      char c = *i;

      if(c == '.')
         {
         if(substring == "")
            throw Invalid_OID(oid);
         oid_elems.push_back(to_u32bit(substring));
         substring.clear();
         }
      else
         substring += c;
      }

   if(substring == "")
      throw Invalid_OID(oid);
   oid_elems.push_back(to_u32bit(substring));

   if(oid_elems.size() < 2)
      throw Invalid_OID(oid);

   return oid_elems;
   }

/*
* X.500 String Comparison
*/
bool x500_name_cmp(const std::string& name1, const std::string& name2)
   {
   auto p1 = name1.begin();
   auto p2 = name2.begin();

   while((p1 != name1.end()) && Charset::is_space(*p1)) ++p1;
   while((p2 != name2.end()) && Charset::is_space(*p2)) ++p2;

   while(p1 != name1.end() && p2 != name2.end())
      {
      if(Charset::is_space(*p1))
         {
         if(!Charset::is_space(*p2))
            return false;

         while((p1 != name1.end()) && Charset::is_space(*p1)) ++p1;
         while((p2 != name2.end()) && Charset::is_space(*p2)) ++p2;

         if(p1 == name1.end() && p2 == name2.end())
            return true;
         }

      if(!Charset::caseless_cmp(*p1, *p2))
         return false;
      ++p1;
      ++p2;
      }

   while((p1 != name1.end()) && Charset::is_space(*p1)) ++p1;
   while((p2 != name2.end()) && Charset::is_space(*p2)) ++p2;

   if((p1 != name1.end()) || (p2 != name2.end()))
      return false;
   return true;
   }

/*
* Convert a decimal-dotted string to binary IP
*/
u32bit string_to_ipv4(const std::string& str)
   {
   std::vector<std::string> parts = split_on(str, '.');

   if(parts.size() != 4)
      throw Decoding_Error("Invalid IP string " + str);

   u32bit ip = 0;

   for(auto part = parts.begin(); part != parts.end(); ++part)
      {
      u32bit octet = to_u32bit(*part);

      if(octet > 255)
         throw Decoding_Error("Invalid IP string " + str);

      ip = (ip << 8) | (octet & 0xFF);
      }

   return ip;
   }

/*
* Convert an IP address to decimal-dotted string
*/
std::string ipv4_to_string(u32bit ip)
   {
   std::string str;

   for(size_t i = 0; i != sizeof(ip); ++i)
      {
      if(i)
         str += ".";
      str += std::to_string(get_byte(i, ip));
      }

   return str;
   }

std::string erase_chars(const std::string& str, const std::set<char>& chars)
   {
   std::string out;

   for(auto c: str)
      if(chars.count(c) == 0)
         out += c;

   return out;
   }

std::string replace_chars(const std::string& str,
                          const std::set<char>& chars,
                          char to_char)
   {
   std::string out = str;

   for(size_t i = 0; i != out.size(); ++i)
      if(chars.count(out[i]))
         out[i] = to_char;

   return out;
   }

std::string replace_char(const std::string& str, char from_char, char to_char)
   {
   std::string out = str;

   for(size_t i = 0; i != out.size(); ++i)
      if(out[i] == from_char)
         out[i] = to_char;

   return out;
   }

}