/*****************************************************************************
 * 
 * This file is part of Mapnik (c++ mapping toolkit)
 *
 * Copyright (C) 2009 Artem Pavlenko
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *
 *****************************************************************************/
//$Id$

#include <mapnik/datasource.hpp>
#include <mapnik/wkb.hpp>

#include "connection_manager.hpp"
#include "cursorresultset.hpp"
// boost
#include <boost/cstdint.hpp>
#include <boost/optional.hpp>
#include <boost/scoped_ptr.hpp>
#include <boost/shared_ptr.hpp>
#include <boost/lexical_cast.hpp>
#include <boost/format.hpp>
#include <boost/algorithm/string/replace.hpp>
#include <boost/program_options.hpp>

//stl
#include <iostream>
#include <fstream>

namespace mapnik {

   struct blob_to_hex
   {
      std::string operator() (const char* blob, unsigned size)
      {
         std::string buf;
         buf.reserve(size*2);
         std::ostringstream s(buf);
         s.seekp(0);
         char hex[3];
         std::memset(hex,0,3);
         for ( unsigned pos=0; pos < size; ++pos)
         {  
            std::sprintf (hex, "%02X", int(blob[pos]) & 0xff);
            s << hex;
         }
         return s.str();
      }
   };

   bool valid_envelope(mapnik::Envelope<double> const& e)
   {
      return (e.minx() < e.maxx() && e.miny() < e.maxy()) ;
   }

   template <typename Connection, typename OUT>
   void pgsql2sqlite(Connection conn, std::string const& table_name, OUT & out, unsigned tolerance)
   {
      using namespace mapnik;
   
      boost::shared_ptr<ResultSet> rs = conn->executeQuery("select * from " + table_name + " limit 0;");
      int count = rs->getNumFields();

      std::ostringstream select_sql;
   
      select_sql << "select ";
   
      for (int i=0; i<count; ++i)
      {
         if (i!=0) select_sql << ",";
         select_sql << "\"" <<  rs->getFieldName(i) << "\"";
      }
   
      select_sql << " from " << table_name ;
   
      std::ostringstream geom_col_sql;
      geom_col_sql << "select f_geometry_column,srid,type from geometry_columns ";
      geom_col_sql << "where f_table_name='" << table_name << "'";
   
      rs = conn->executeQuery(geom_col_sql.str());
   
      int srid = -1;
      std::string geom_col = "UNKNOWN";
      std::string geom_type = "UNKNOWN";
   
      if ( rs->next())
      {
         try 
         {
            srid = boost::lexical_cast<int>(rs->getValue("srid"));
         }
         catch (boost::bad_lexical_cast &ex)
         {
            std::clog << ex.what() << std::endl;
         }
         geom_col = rs->getValue("f_geometry_column");
         geom_type = rs->getValue("type");
      }
   
      // add AsBinary(<geometry_column>) modifier
      std::string select_sql_str = select_sql.str();
      if (tolerance > 0)
      {
         std::string from =  "\"" + geom_col + "\"";
         std::string to   = (boost::format("AsBinary(Simplify(%1%,%2%)) as %1%") % geom_col % tolerance).str();
         boost::algorithm::replace_all(select_sql_str,from ,to);
      }
      else
      {
         boost::algorithm::replace_all(select_sql_str, "\"" + geom_col + "\"","AsBinary(" + geom_col+") as " + geom_col);
      }
   
      std::cout << select_sql_str << "\n";
   
      std::ostringstream cursor_sql;
      std::string cursor_name("my_cursor");
   
      cursor_sql << "DECLARE " << cursor_name << " BINARY INSENSITIVE NO SCROLL CURSOR WITH HOLD FOR " << select_sql_str << " FOR READ ONLY";
      conn->execute(cursor_sql.str());
   
      boost::shared_ptr<CursorResultSet> cursor(new CursorResultSet(conn,cursor_name,10000));
   
      unsigned num_fields = cursor->getNumFields();
   
      std::ostringstream create_sql;
      create_sql << "create table " << table_name << "(PK_UID INTEGER PRIMARY KEY AUTOINCREMENT,";
   
      int geometry_oid = -1;
   
      for ( unsigned pos = 0; pos < num_fields ; ++pos)
      {
         if (pos > 0) create_sql << ",";
         if (geom_col == cursor->getFieldName(pos))
         {
            geometry_oid = cursor->getTypeOID(pos);
            create_sql << "'" << cursor->getFieldName(pos) << "' BLOB";
         }
         else
         {
            create_sql << "'" << cursor->getFieldName(pos) << "' TEXT";
         }
      }
   
      create_sql << ");";
   
   
      std::cout << "client_encoding=" << conn->client_encoding() << "\n";
      std::cout << "geometry_column=" << geom_col << "(" << geom_type 
                <<  ") srid=" << srid << " oid=" << geometry_oid << "\n";
   
   
      // begin
      out << "begin;\n";
   
      out << create_sql.str() << "\n";
   
      // spatial index sql
      out << "create virtual table idx_"<< table_name << "_" << geom_col << " using rtree(pkid, xmin, xmax, ymin, ymax);\n";
   
      blob_to_hex hex;
      int pkid = 0;
      while (cursor->next())
      {
         ++pkid;
      
         std::ostringstream insert_sql;
         insert_sql << "insert into " <<  table_name << " values(" << pkid;

         bool empty_geom = true;
      
         for (unsigned pos=0 ; pos < num_fields; ++pos)
         {
            insert_sql << ",";
            if (! cursor->isNull(pos))
            {
               int size=cursor->getFieldLength(pos);
               int oid = cursor->getTypeOID(pos);
               const char* buf=cursor->getValue(pos);
            
               switch (oid)
               {
                  case 25:
                  case 1042:
                  case 1043:
                  {
                     std::string text(buf);
                     boost::algorithm::replace_all(text,"'","''");
                     insert_sql << "'"<< text << "'"; 
                     break;
                  }
                  case 23:
                     insert_sql << int4net(buf);
                     break;
                  default:  
                  {
                     if (oid == geometry_oid)
                     {
                        mapnik::Feature feat(pkid);
                        geometry_utils::from_wkb(feat,buf,size,false,wkbGeneric);
                        if (feat.num_geometries() > 0)
                        {
                           geometry2d const& geom=feat.get_geometry(0);
                           Envelope<double> bbox = geom.envelope();
                           if (valid_envelope(bbox))
                           {
                              out << "insert into idx_" << table_name << "_" << geom_col << " values (" ;
                              out << pkid << "," << bbox.minx() << "," << bbox.maxx();
                              out << "," << bbox.miny() << "," << bbox.maxy() << ");\n";
                              empty_geom = false;
                           }
                        }
                     
                        insert_sql << "X'" << hex(buf,size) << "'";
                     
                     }
                     else 
                     {
                        insert_sql << "NULL";
                     }
                     break;
                  }
               }    
            }
            else 
            {
               insert_sql << "NULL";
            } 
         }
         insert_sql << ");";
      
         if (!empty_geom) out << insert_sql.str() << "\n";
      
         if (pkid % 1000 == 0)
         {
            std::cout << "\r processing " << pkid << " features";
            std::cout.flush();
         }
         if (pkid % 100000 == 0)
         {
            out << "commit;\n";
            out << "begin;\n";
         }
      }
      // commit
      out << "commit;\n";
      std::cout << "\r processed " << pkid << " features";
      std::cout << "\n Done!" << std::endl;
   }
}