/*****************************************************************************
 * 
 * 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 "sqlite.hpp"

#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.hpp>
#include <boost/program_options.hpp>

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

namespace mapnik {

std::string numeric2string(const char* buf)
{
    int16_t ndigits = int2net(buf);
    int16_t weight  = int2net(buf+2);
    int16_t sign    = int2net(buf+4);
    int16_t dscale  = int2net(buf+6);
      
    boost::scoped_array<int16_t> digits(new int16_t[ndigits]); 
    for (int n=0; n < ndigits ;++n)
    {
        digits[n] = int2net(buf+8+n*2);
    }
      
    std::ostringstream ss;
      
    if (sign == 0x4000) ss << "-";
      
    int i = std::max(weight,int16_t(0));
    int d = 0;
    while ( i >= 0)
    {
        if (i <= weight && d < ndigits)
            ss <<  digits[d++];
        else
            ss <<  '0';
        i--;
    }
    if (dscale > 0)
    {
        ss << '.';
        while ( i >= -dscale)
        {
            if (i <= weight && d < ndigits)
                ss <<  digits[d++];
            i--;
        }
    }
    return ss.str();
}
   
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::box2d<double> const& e)
{
    return (e.minx() <= e.maxx() && e.miny() <= e.maxy()) ;
}
   
std::string table_from_sql(std::string const& sql)
{
    std::string table_name = boost::algorithm::to_lower_copy(sql);
    boost::algorithm::replace_all(table_name,"\n"," ");
      
    std::string::size_type idx = table_name.rfind("from");
    if (idx!=std::string::npos)
    {
         
        idx=table_name.find_first_not_of(" ",idx+4);
        if (idx != std::string::npos)
        {
            table_name=table_name.substr(idx);
        }
        idx=table_name.find_first_of(" ),");
        if (idx != std::string::npos)
        {
            table_name = table_name.substr(0,idx);
        }
    }
    return table_name;
}
   
   
template <typename Connection>
void pgsql2sqlite(Connection conn, 
                  std::string const& query, 
                  std::string const& output_table_name, 
                  std::string const& output_filename)
{   
    namespace sqlite = mapnik::sqlite;
    sqlite::database db(output_filename);
      
    boost::shared_ptr<ResultSet> rs = conn->executeQuery("select * from (" + query + ") as query 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 (" << query << ") as query";
   
    std::string table_name = table_from_sql(query);
      
    std::string schema_name="";
    std::string::size_type idx=table_name.find_last_of('.');
    if (idx!=std::string::npos)
    {
        schema_name=table_name.substr(0,idx);
        table_name=table_name.substr(idx+1);
    }
    else
    {
        table_name=table_name.substr(0);
    }
      
    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 << "'";
    if (schema_name.length() > 0)
    {
        geom_col_sql <<" and f_table_schema='"<< schema_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();
    boost::algorithm::replace_all(select_sql_str, "\"" + geom_col + "\"","AsBinary(" + geom_col+") as " + geom_col);

#ifdef MAPNIK_DEBUG
    std::cout << select_sql_str << "\n";
#endif
      
    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();

    if (num_fields == 0) return;
      
    std::string feature_id =  "fid";
   
    std::ostringstream create_sql;
    create_sql << "create table if not exists " << output_table_name << " (" << feature_id << " INTEGER PRIMARY KEY AUTOINCREMENT,";
      
    int geometry_oid = -1;

    std::string output_table_insert_sql = "insert into " + output_table_name + " values (?";
      
    for ( unsigned pos = 0; pos < num_fields ; ++pos)
    {
        if (pos > 0) 
        {
            create_sql << ",";
        }
        output_table_insert_sql +=",?";
        int oid = cursor->getTypeOID(pos);
        if (geom_col == cursor->getFieldName(pos))
        {
            geometry_oid = oid;
            create_sql << "'" << cursor->getFieldName(pos) << "' BLOB";
        }
        else
        {
            create_sql << "'" << cursor->getFieldName(pos);
            switch (oid)
            {
            case 20:
            case 21:
            case 23:
                create_sql << "' INTEGER";
                break;
            case 700:
            case 701:
                create_sql << "' REAL";
                break;
            default:
                create_sql << "' TEXT";
                break;
            }  
           
        }
    }
      
    create_sql << ");";
    output_table_insert_sql +=")";
      
    std::cout << "client_encoding=" << conn->client_encoding() << "\n";
    std::cout << "geometry_column=" << geom_col << "(" << geom_type 
              <<  ") srid=" << srid << " oid=" << geometry_oid << "\n";
   
  
    db.execute("begin;");
    // output table sql
    db.execute(create_sql.str());

    // spatial index sql
    std::string spatial_index_sql = "create virtual table idx_" + output_table_name 
        + "_" + geom_col + " using rtree(pkid, xmin, xmax, ymin, ymax)";
      
    db.execute(spatial_index_sql);
      
    //blob_to_hex hex;
    int pkid = 0;
      
    std::string spatial_index_insert_sql = "insert into idx_" + output_table_name +  "_"  
        +  geom_col + " values (?,?,?,?,?)" ;
      
    sqlite::prepared_statement spatial_index(db,spatial_index_insert_sql);

#ifdef MAPNIK_DEBUG
    std::cout << output_table_insert_sql << "\n";
#endif
      
    sqlite::prepared_statement output_table(db,output_table_insert_sql);
      
    while (cursor->next())
    {
        ++pkid;
         
        sqlite::record_type output_rec;
        output_rec.push_back(sqlite::value_type(pkid));
        bool empty_geom = true;
        const char * buf = 0;
        for (unsigned pos=0 ; pos < num_fields; ++pos)
        {
            if (! cursor->isNull(pos))
            {
                int size=cursor->getFieldLength(pos);
                int oid = cursor->getTypeOID(pos);
                buf=cursor->getValue(pos);
            
                switch (oid)
                {
                case 25:
                case 1042:
                case 1043:
                {
                    std::string text(buf);
                    boost::algorithm::replace_all(text,"'","''");
                    output_rec.push_back(sqlite::value_type(text));
                    break;
                }
                case 23:
                    output_rec.push_back(sqlite::value_type(int4net(buf)));
                    break;
                case 21:
                    output_rec.push_back(sqlite::value_type(int2net(buf)));
                    break;
                case 700:
                {
                    float val;
                    float4net(val,buf);
                    output_rec.push_back(sqlite::value_type(val));
                    break;
                }
                case 701:
                {
                    double val;
                    float8net(val,buf);
                    output_rec.push_back(sqlite::value_type(val));
                    break;
                }
                case 1700:
                {
                    std::string str = numeric2string(buf);
                    try 
                    {
                        double val = boost::lexical_cast<double>(str);
                        output_rec.push_back(sqlite::value_type(val));
                    }
                    catch (boost::bad_lexical_cast & ex)
                    {
                        std::clog << ex.what() << "\n"; 
                    }
                    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);
                            box2d<double> bbox = geom.envelope();
                            if (valid_envelope(bbox))
                            {
                                sqlite::record_type rec;
                             
                                rec.push_back(sqlite::value_type(pkid));
                                rec.push_back(sqlite::value_type(bbox.minx()));
                                rec.push_back(sqlite::value_type(bbox.maxx()));
                                rec.push_back(sqlite::value_type(bbox.miny()));
                                rec.push_back(sqlite::value_type(bbox.maxy()));
                             
                                spatial_index.insert_record(rec);
                                empty_geom = false;
                            }
                        }
                        
                        //output_rec.push_back(sqlite::value_type("X'" + hex(buf,size) + "'"));
                        output_rec.push_back(sqlite::blob(buf,size));
                    }
                    else 
                    {
                        output_rec.push_back(sqlite::null_type());
                    }
                    break;
                }
                }    
            }
            else 
            {
                output_rec.push_back(sqlite::null_type());
            } 
        }
   
        if (!empty_geom) output_table.insert_record(output_rec);
         
        if (pkid % 1000 == 0)
        {
            std::cout << "\r processing " << pkid << " features";
            std::cout.flush();
        }
         
        if (pkid % 100000 == 0)
        {
            db.execute("commit;begin;");           
        }
    }
    // commit
    db.execute("commit;");
    std::cout << "\r processed " << pkid << " features";
    std::cout << "\n Done!" << std::endl;
}
}