/*
  SWWReader

  Reader of SWW files from within OpenSceneGraph.

  copyright (C) 2004-2005 Geoscience Australia
*/

#include <SWWReader.h>
#include <cstdlib>
#include <string>
#include <fstream>
#include <netcdf.h>
#include <osg/Notify>

#include <osgDB/Registry>
#include <osgDB/ReadFile>
#include <osgDB/FileNameUtils>

#include <stdlib.h>
#include <stdio.h>
#include <gdal_priv.h>


// compile time defaults
#define DEFAULT_CULLANGLE 85.0
#define DEFAULT_ALPHAMIN 0.8
#define DEFAULT_ALPHAMAX 1.0
#define DEFAULT_HEIGHTMIN 0.0
#define DEFAULT_HEIGHTMAX 1.0
#define DEFAULT_BEDSLOPEOFFSET 0.0
#define DEFAULT_CULLONSTART false


// only constructor, requires netcdf file
SWWReader::SWWReader(const std::string& filename)
{
   // assume failure until end of constructor
   _valid = false;

   // state initialization
   _state.bedslopetexturefilename = NULL;

   // netcdf filename
   _state.swwfilename = new std::string(filename);

   // netcdf open
   _status.push_back( nc_open(filename.c_str(), NC_NOWRITE, &_ncid) );
   if (this->_statusHasError()) return;

   // dimension ids
   _status.push_back( nc_inq_dimid(_ncid, "number_of_volumes", &_nvolumesid) );
   _status.push_back( nc_inq_dimid(_ncid, "number_of_vertices", &_nverticesid) );
   _status.push_back( nc_inq_dimid(_ncid, "number_of_points", &_npointsid) );
   _status.push_back( nc_inq_dimid(_ncid, "number_of_timesteps", &_ntimestepsid) );
   if (this->_statusHasError()) return;

   // dimension values
   _status.push_back( nc_inq_dimlen(_ncid, _nvolumesid, &_nvolumes) );
   _status.push_back( nc_inq_dimlen(_ncid, _nverticesid, &_nvertices) );
   _status.push_back( nc_inq_dimlen(_ncid, _npointsid, &_npoints) );
   _status.push_back( nc_inq_dimlen(_ncid, _ntimestepsid, &_ntimesteps) );
   if (this->_statusHasError()) return;

   // variable ids
   _status.push_back( nc_inq_varid (_ncid, "x", &_xid) );
   _status.push_back( nc_inq_varid (_ncid, "y", &_yid) );
   _status.push_back( nc_inq_varid (_ncid, "z", &_zid) );
   _status.push_back( nc_inq_varid (_ncid, "volumes", &_volumesid) );
   _status.push_back( nc_inq_varid (_ncid, "time", &_timeid) );
   _status.push_back( nc_inq_varid (_ncid, "stage", &_stageid) );
   if (this->_statusHasError()) return;

   // allocation of variable arrays, destructor responsible for cleanup
   _px = new float[_npoints];
   _py = new float[_npoints];
   _pz = new float[_npoints];
   _ptime = new float[_ntimesteps];
   _pvolumes = new unsigned int[_nvertices * _nvolumes];
   _pstage = new float[_npoints];

   // loading variables from netcdf file
   _status.push_back( nc_get_var_float (_ncid, _xid, _px) );  // x vertices
   _status.push_back( nc_get_var_float (_ncid, _yid, _py) );  // y vertices
   _status.push_back( nc_get_var_float (_ncid, _zid, _pz) );  // bedslope heights
   _status.push_back( nc_get_var_float (_ncid, _timeid, _ptime) );  // time array
   _status.push_back( nc_get_var_int (_ncid, _volumesid, (int *) _pvolumes) );  // triangle indices
   if (this->_statusHasError()) return;


   osg::notify(osg::INFO) << "[SWWReader] number of volumes: " << _nvolumes <<  std::endl;
   osg::notify(osg::INFO) << "[SWWReader] number of vertices: " << _nvertices <<  std::endl;
   osg::notify(osg::INFO) << "[SWWReader] number of points: " << _npoints <<  std::endl;
   osg::notify(osg::INFO) << "[SWWReader] number of timesteps: " << _ntimesteps <<  std::endl;


   // sww file can optionally contain bedslope texture image filename
   size_t attlen; // length of text attribute (if it exists)
   if( nc_inq_attlen(_ncid, NC_GLOBAL, "texture", &attlen) != NC_ENOTATT )
   {
      char* texfilename;
      if( (texfilename = (char*) malloc(attlen+1)) != NULL){
         int status;
         status = nc_get_att_text(_ncid, NC_GLOBAL, "texture", texfilename);
         if( status == NC_NOERR )
         {
            texfilename[attlen] = '\0';  // ensure string is terminated, not a requirement for netcdf attributes
            osg::notify(osg::INFO) << "[SWWReader] embedded image filename: " << texfilename <<  std::endl;

            // if sww isn't in current directory, need to prepend sww path to the bedslope texture
            if( osgDB::getFilePath(filename) == "" )
               setBedslopeTexture( std::string(texfilename) );
            else
               setBedslopeTexture( osgDB::getFilePath(filename) + std::string("/") + std::string(texfilename) );
         }
         free( texfilename );
      }
   }

   // sww file can optionally contain georeference offset
   int status1 = nc_get_att_float(_ncid, NC_GLOBAL, "xllcorner", &_xllcorner);
   int status2 = nc_get_att_float(_ncid, NC_GLOBAL, "yllcorner", &_yllcorner);
   if( status1 == NC_NOERR && status2 == NC_NOERR)
   {
      osg::notify(osg::INFO) << "[SWWReader] xllcorner: " << _xllcorner <<  std::endl;
      osg::notify(osg::INFO) << "[SWWReader] yllcorner: " << _yllcorner <<  std::endl;
   }
   else
   {
      _xllcorner = 0.0;  // default value
      _yllcorner = 0.0;
   }


   // alpha-scaling defaults, can be overridden after construction by command line parameters
   _state.alphamin = DEFAULT_ALPHAMIN;
   _state.alphamax = DEFAULT_ALPHAMAX;
   _state.heightmin = DEFAULT_HEIGHTMIN;
   _state.heightmax = DEFAULT_HEIGHTMAX;

   // steepness culling default, can be overridden after construction by command line parameter
   _state.cullangle = DEFAULT_CULLANGLE;
   _state.culling = DEFAULT_CULLONSTART;

   // loop index
   size_t iv;

   // vertex indices
   unsigned int v1index, v2index, v3index;

   // bedslope range and resultant scale factors (note, these don't take into
   // account any xllcorner, yllcorner offsets - used during texture coord assignment)
   float xmin, xmax, xrange;
   float ymin, ymax, yrange;
   float zmin, zmax, zrange;
   float aspect_ratio;
   xmin = _px[0]; 
   xmax = _px[0];
   ymin = _py[0]; 
   ymax = _py[0];
   zmin = _pz[0]; 
   zmax = _pz[0];
   for( iv=1; iv < _npoints; iv++ )
   {
      if( _px[iv] < xmin ) xmin = _px[iv];
      if( _px[iv] > xmax ) xmax = _px[iv];
      if( _py[iv] < ymin ) ymin = _py[iv];
      if( _py[iv] > ymax ) ymax = _py[iv];
      if( _pz[iv] < zmin ) zmin = _pz[iv];
      if( _pz[iv] > zmax ) zmax = _pz[iv];
   }

   xrange = xmax - xmin;
   yrange = ymax - ymin;
   zrange = zmax - zmin;
   aspect_ratio = xrange/yrange;
   _xscale = 1.0 / xrange;
   _yscale = 1.0 / yrange;
    
   // handle case of a flat bed that doesn't necessarily pass through z=0
   _zscale = (zrange == 0.0) ? 1.0 : 1.0/zrange;

   _xoffset = xmin;
   _yoffset = ymin;
   _zoffset = zmin;
   _xcenter = 0.5;
   _ycenter = 0.5;
   _zcenter = 0.0;

   if( aspect_ratio > 1.0 )
   {
      _scale = 1.0/xrange;
      _ycenter /= aspect_ratio;
   }
   else
   {
      _scale = 1.0/yrange;
      _xcenter *= aspect_ratio;
   }

   osg::notify(osg::INFO) << "[SWWReader] xmin: " << xmin <<  std::endl;
   osg::notify(osg::INFO) << "[SWWReader] xmax: " << xmax <<  std::endl;
   osg::notify(osg::INFO) << "[SWWReader] xrange: " << xrange <<  std::endl;
   osg::notify(osg::INFO) << "[SWWReader] xscale: " << _xscale <<  std::endl;
   osg::notify(osg::INFO) << "[SWWReader] xcenter: " << _xcenter <<  std::endl;
   osg::notify(osg::INFO) <<  std::endl;

   osg::notify(osg::INFO) << "[SWWReader] ymin: " << ymin <<  std::endl;
   osg::notify(osg::INFO) << "[SWWReader] ymax: " << ymax <<  std::endl;
   osg::notify(osg::INFO) << "[SWWReader] yrange: " << yrange <<  std::endl;
   osg::notify(osg::INFO) << "[SWWReader] yscale: " << _yscale <<  std::endl;
   osg::notify(osg::INFO) << "[SWWReader] ycenter: " << _ycenter <<  std::endl;
   osg::notify(osg::INFO) <<  std::endl;

   osg::notify(osg::INFO) << "[SWWReader] zmin: " << zmin <<  std::endl;
   osg::notify(osg::INFO) << "[SWWReader] zmax: " << zmax <<  std::endl;
   osg::notify(osg::INFO) << "[SWWReader] zrange: " << zrange <<  std::endl;
   osg::notify(osg::INFO) << "[SWWReader] zscale: " << _zscale <<  std::endl;
   osg::notify(osg::INFO) << "[SWWReader] zcenter: " << _zcenter <<  std::endl;
   osg::notify(osg::INFO) <<  std::endl;

   // compute triangle connectivity, a list (indexed by vertex number) 
   // of lists (indices of triangles sharing this vertex)
   _connectivity = std::vector<triangle_list>(_npoints);
   for (iv=0; iv < _nvolumes; iv++)
   {
      v1index = _pvolumes[3*iv+0];
      v2index = _pvolumes[3*iv+1];
      v3index = _pvolumes[3*iv+2];
      _connectivity.at(v1index).push_back(iv);
      _connectivity.at(v2index).push_back(iv);
      _connectivity.at(v3index).push_back(iv);
   }

   // bedslope vertex array, shifting and scaling vertices to unit cube
   // centred about the origin
   _bedslopevertices = new osg::Vec3Array;
   for (iv=0; iv < _npoints; iv++)
      _bedslopevertices->push_back( osg::Vec3( (_px[iv]-_xoffset)*_scale - _xcenter, 
                                               (_py[iv]-_yoffset)*_scale - _ycenter, 
                                               (_pz[iv]-_zoffset)*_scale - _zcenter - DEFAULT_BEDSLOPEOFFSET) );

   // bedslope index array, pvolumes array indexes into x, y and z
   _bedslopeindices = new osg::DrawElementsUInt(osg::PrimitiveSet::TRIANGLES, _nvolumes*_nvertices);
   for (iv=0; iv < _nvolumes*_nvertices; iv++)
      (*_bedslopeindices)[iv] = _pvolumes[iv];


   // calculate bedslope primitive normal and centroid arrays
   _bedslopenormals = new osg::Vec3Array;
   _bedslopecentroids = new osg::Vec3Array;
   osg::Vec3 v1, v2, v3, side1, side2, nrm;
   for (iv=0; iv < _nvolumes; iv++)
   {
      v1index = _pvolumes[3*iv+0];
      v2index = _pvolumes[3*iv+1];
      v3index = _pvolumes[3*iv+2];

      v1 = _bedslopevertices->at(v1index);
      v2 = _bedslopevertices->at(v2index);
      v3 = _bedslopevertices->at(v3index);

      side1 = v2 - v1;
      side2 = v3 - v2;
      nrm = side1^side2;
      nrm.normalize();

      _bedslopenormals->push_back( nrm );
      _bedslopecentroids->push_back( (v1+v2+v3)/3.0 );
   }

   // success!
   _valid = true;

}



SWWReader::~SWWReader()
{
   _status.push_back( nc_close(_ncid) );
   delete[]( _px, _py, _pz, _ptime, _pvolumes, _pstage );
}



void SWWReader::setBedslopeTexture( std::string filename )
{
   osg::notify(osg::INFO) << "[SWWReader::setBedslopetexture] filename: " << filename <<  std::endl;
   _state.bedslopetexturefilename = new std::string(filename);
   _bedslopegeodata.hasData = false;

   // GDAL Geospatial Image Library
   GDALDataset *pGDAL;
   GDALAllRegister();
   pGDAL = (GDALDataset *) GDALOpen( filename.c_str(), GA_ReadOnly );
   if( pGDAL == NULL )
      osg::notify(osg::INFO) << "[SWWReader::setBedslopetexture] GDAL unable to open file: " << filename <<  std::endl;
   else
   {
      osg::notify(osg::INFO) << "[SWWReader::setBedslopetexture] GDAL Driver: "
			     << pGDAL->GetDriver()->GetDescription() << "/" 
			     << pGDAL->GetDriver()->GetMetadataItem( GDAL_DMD_LONGNAME ) 
			     << std::endl;

      _bedslopegeodata.xresolution = pGDAL->GetRasterXSize();
      _bedslopegeodata.yresolution = pGDAL->GetRasterYSize();
      osg::notify(osg::INFO) << "[SWWReader::setBedslopetexture] xresolution: " << _bedslopegeodata.xresolution <<  std::endl;
      osg::notify(osg::INFO) << "[SWWReader::setBedslopetexture] yresolution: " << _bedslopegeodata.yresolution <<  std::endl;

      // check if image contains geodata
      double geodata[6];
      if( pGDAL->GetGeoTransform( geodata ) == CE_None )
      {
         _bedslopegeodata.xorigin = geodata[0];
         _bedslopegeodata.yorigin = geodata[3];
         _bedslopegeodata.rotation = geodata[2];
         _bedslopegeodata.xpixel = geodata[1];
         _bedslopegeodata.ypixel = geodata[5];
         _bedslopegeodata.hasData = true;

         osg::notify(osg::INFO) << "[SWWReader::setBedslopetexture] xorigin: " << _bedslopegeodata.xorigin <<  std::endl;
         osg::notify(osg::INFO) << "[SWWReader::setBedslopetexture] yorigin: " << _bedslopegeodata.yorigin <<  std::endl;
         osg::notify(osg::INFO) << "[SWWReader::setBedslopetexture] xpixel: " << _bedslopegeodata.xpixel <<  std::endl;
         osg::notify(osg::INFO) << "[SWWReader::setBedslopetexture] ypixel: " << _bedslopegeodata.ypixel <<  std::endl;
         osg::notify(osg::INFO) << "[SWWReader::setBedslopetexture] rotation: " << _bedslopegeodata.rotation <<  std::endl;
      }
   }
}



osg::Image* SWWReader::getBedslopeTexture()
{
   return osgDB::readImageFile( _state.bedslopetexturefilename->c_str() );
}



osg::ref_ptr<osg::Vec2Array> SWWReader::getBedslopeTextureCoords()
{
   _bedslopetexcoords = new osg::Vec2Array;
   if( _bedslopegeodata.hasData )  // georeferenced bedslope texture
   {
      float xorigin = _bedslopegeodata.xorigin;
      float yorigin = _bedslopegeodata.yorigin;
      float xrange = _bedslopegeodata.xpixel * _bedslopegeodata.xresolution;
      float yrange = _bedslopegeodata.ypixel * _bedslopegeodata.yresolution;
      for( unsigned int iv=0; iv < _npoints; iv++ )
         _bedslopetexcoords->push_back( osg::Vec2( (_px[iv] + _xllcorner - xorigin)/xrange, 
                                                   (_py[iv] + _yllcorner - yorigin)/yrange ) );
   }
   else
   {
      // decaled using (x,y) locations scaled by extents into range [0,1]
      for( unsigned int iv=0; iv < _npoints; iv++ )
         _bedslopetexcoords->push_back( osg::Vec2( (_px[iv]-_xoffset)*_xscale, (_py[iv]-_yoffset)*_yscale ) );
   }

   return _bedslopetexcoords;
}



osg::ref_ptr<osg::Vec3Array> SWWReader::getStageVertexArray(unsigned int index)
{
   size_t start[2], count[2], iv;
   const ptrdiff_t stride[2] = {1,1};
   start[0] = index;
   start[1] = 0;
   count[0] = 1;
   count[1] = _npoints;

   // empty array for storing list of steep triangles
   osg::ref_ptr<osg::IntArray> steeptri = new osg::IntArray;

   // stage heights from netcdf file (x and y are same as bedslope)
   int status = nc_get_vars_float (_ncid, _stageid, start, count, stride, _pstage);

   // load stage vertex array, scaling and shifting vertices to lie in the unit cube
   _stagevertices = new osg::Vec3Array;
   for (iv=0; iv < _npoints; iv++)
      _stagevertices->push_back( osg::Vec3( (_px[iv]-_xoffset)*_scale - _xcenter, 
                                            (_py[iv]-_yoffset)*_scale - _ycenter, 
                                            (_pstage[iv]-_zoffset)*_scale - _zcenter) );

   // stage index, per primitive normal and centroid arrays
   _stageprimitivenormals = new osg::Vec3Array;
   _stagecentroids = new osg::Vec3Array;
   osg::Vec3 v1b, v2b, v3b;
   osg::Vec3 v1s, v2s, v3s;
   osg::Vec3 side1, side2, nrm;
   unsigned int v1index, v2index, v3index;

   // cullangle given in degrees, test is against dot product
   float cullthreshold = cos(osg::DegreesToRadians(_state.cullangle));

   // over all stage triangles
   for (iv=0; iv < _nvolumes; iv++)
   {
      v1index = _pvolumes[3*iv+0];
      v2index = _pvolumes[3*iv+1];
      v3index = _pvolumes[3*iv+2];

      v1s = _stagevertices->at(v1index);
      v2s = _stagevertices->at(v2index);
      v3s = _stagevertices->at(v3index);
      v1b = _bedslopevertices->at(v1index);
      v2b = _bedslopevertices->at(v2index);
      v3b = _bedslopevertices->at(v3index);

      // current triangle primitive normal
      side1 = v2s - v1s;
      side2 = v3s - v2s;
      nrm = side1^side2;
      nrm.normalize();

      // store centroid and primitive normal
      _stagecentroids->push_back( (v1s+v2s+v3s)/3.0 );
      _stageprimitivenormals->push_back( nrm );

      // identify steep triangles, store index
      if( fabs(nrm * osg::Vec3f(0,0,1)) < cullthreshold )
         steeptri->push_back( iv );
   }

   // stage height above bedslope mapped as alpha value
   //      alpha = min( a(h-hmin) + alphamin, alphamax),  h >= hmin
   //      alpha = 0,                                     h < hmin
   // where a = (alphamax-alphamin)/(hmax-hmin)
   float alpha, height, alphascale;
   alphascale = (_state.alphamax - _state.alphamin) / (_state.heightmax - _state.heightmin);
   _stagecolors = new osg::Vec4Array;
   for (iv=0; iv < _npoints; iv++)
   {
      // water height above corresponding bedslope
      height = _stagevertices->at(iv).z() - _bedslopevertices->at(iv).z();
	
      if (height < _state.heightmin)
         alpha = 0.0;
      else 
      {
         alpha = alphascale * (height - _state.heightmin) + _state.alphamin;
         if( alpha > _state.alphamax ) 
            alpha = _state.alphamax;
      }

      _stagecolors->push_back( osg::Vec4( 1.0, 1.0, 1.0, alpha ) );
   }

   // steep triangle vertices should have alpha=0, overwrite such vertex colours
   if( _state.culling )
   {
      //std::cout << "culling on step: " << index << "  steeptris: " << steeptri->size() << std::endl;
      for (iv=0; iv < steeptri->size() ; iv++)
      {
         int tri = steeptri->at(iv);
         v1index = _pvolumes[3*tri+0];
         v2index = _pvolumes[3*tri+1];
         v3index = _pvolumes[3*tri+2];

         _stagecolors->at(v1index) = osg::Vec4( 1, 1, 1, 0 );
         _stagecolors->at(v2index) = osg::Vec4( 1, 1, 1, 0 );
         _stagecolors->at(v3index) = osg::Vec4( 1, 1, 1, 0 );
      }
   }

   // per-vertex normals calculated as average of primitive normals
   // from contributing triangles
   _stagevertexnormals = new osg::Vec3Array;
   int num_shared_triangles, triangle_index;
   for (iv=0; iv < _npoints; iv++)
   {
      nrm.set(0,0,0);
      num_shared_triangles = _connectivity.at(iv).size();
      for (int i=0; i<num_shared_triangles; i++ )
      {
         triangle_index = _connectivity.at(iv).at(i);
         nrm += _stageprimitivenormals->at(triangle_index);
      }

      nrm = nrm / num_shared_triangles;  // average
      nrm.normalize();
      _stagevertexnormals->push_back(nrm);
   }

   return _stagevertices;
}




bool SWWReader::_statusHasError()
{
   bool haserror = false;  // assume success, trap failure

   std::vector<int>::iterator iter;
   for (iter=_status.begin(); iter != _status.end(); iter++)
   {
      if (*iter != NC_NOERR)
      {
         osg::notify(osg::WARN) << nc_strerror(*iter) <<  std::endl;
         haserror = true;
         nc_close(_ncid);
         break;
      }
   }

   // on return start gathering result values afresh
   _status.clear();

   return haserror;
}