#ifndef GDALVECTORSTREAM_H
#define GDALVECTORSTREAM_H

// WIP https://gdal.org/development/rfc/rfc86_column_oriented_api.html
// written by Dewey Dunnington and the GDAL project
// https://github.com/paleolimbot/sf/tree/stream-reading

#include <Rcpp.h>
#include <ogrsf_frmts.h>
#include "common/common_vapour.h"
#if GDAL_VERSION_NUM >= GDAL_COMPUTE_VERSION(3,6,0)
#include <ogr_recordbatch.h>
#endif

using namespace Rcpp;

namespace gdalvectorstream {

#if GDAL_VERSION_NUM >= GDAL_COMPUTE_VERSION(3,6,0)


class GDALStreamWrapper {
public:
  static void Make(struct ArrowArrayStream* stream, Rcpp::List shelter,
                   struct ArrowArrayStream* stream_out) {
    stream_out->get_schema = &get_schema_wrap;
    stream_out->get_next = &get_next_wrap;
    stream_out->get_last_error = &get_last_error_wrap;
    stream_out->release = &release_wrap;
    stream_out->private_data = new GDALStreamWrapper(stream, shelter);
  }

  ~GDALStreamWrapper() {
    stream_.release(&stream_);
    GDALDataset* poDS = (GDALDataset*)R_ExternalPtrAddr(shelter_[0]);
    GDALClose(poDS);
    R_SetExternalPtrAddr(shelter_[0], nullptr);
  }

private:
  // The parent stream as returned from GDAL
  struct ArrowArrayStream stream_;
  Rcpp::List shelter_;

  GDALStreamWrapper(struct ArrowArrayStream* stream, Rcpp::List shelter):
    shelter_(shelter) {
    memcpy(&stream_, stream, sizeof(struct ArrowArrayStream));
    stream->release = nullptr;
  }

  int get_schema(struct ArrowSchema* out) {
    return stream_.get_schema(&stream_, out);
  }

  int get_next(struct ArrowArray* out) {
    return stream_.get_next(&stream_, out);
  }

  const char* get_last_error() {
    return stream_.get_last_error(&stream_);
  }

  static int get_schema_wrap(struct ArrowArrayStream* stream, struct ArrowSchema* out) {
    return reinterpret_cast<GDALStreamWrapper*>(stream->private_data)->get_schema(out);
  }

  static int get_next_wrap(struct ArrowArrayStream* stream, struct ArrowArray* out) {
    return reinterpret_cast<GDALStreamWrapper*>(stream->private_data)->get_next(out);
  }

  static const char* get_last_error_wrap(struct ArrowArrayStream* stream) {
    return reinterpret_cast<GDALStreamWrapper*>(stream->private_data)->get_last_error();
  }

  static void release_wrap(struct ArrowArrayStream* stream) {
    delete reinterpret_cast<GDALStreamWrapper*>(stream->private_data);
    stream->release = nullptr;
  }
};


static void finalize_dataset_xptr(SEXP dataset_xptr) {
  GDALDataset *poDS = (GDALDataset*)R_ExternalPtrAddr(dataset_xptr);
  if (poDS != nullptr) {
    GDALClose(poDS);
  }
}

inline Rcpp::List ogr_layer_setup(Rcpp::CharacterVector datasource,
                                  Rcpp::CharacterVector layer,
                               Rcpp::CharacterVector query,
                               std::vector<std::string> options,
                               bool quiet,
                               std::vector<std::string> drivers,
                               Rcpp::NumericVector ex,

                               int width) {
  // adapted from the OGR tutorial @ www.gdal.org
  std::vector <char *> open_options;
  if (options.size() > 0) {
     open_options = string_to_charptr(options);
  }

  std::vector <char *> drivers_v = string_to_charptr(drivers);
  GDALDataset *poDS;

  poDS = (GDALDataset *) GDALOpenEx( datasource[0], GDAL_OF_VECTOR | GDAL_OF_READONLY,
          drivers.size() ? drivers_v.data() : NULL,
          open_options.size() ? open_options.data() : NULL,
          NULL );

  if( poDS == NULL ) {

    Rcpp::stop("Cannot open %s; ", datasource);
  }

  // Will close the dataset if some early return/exception prevents GDALClose() from being
  // called/allows the result to be accessed by the caller.
  Rcpp::RObject dataset_xptr = R_MakeExternalPtr(poDS, R_NilValue, R_NilValue);
  R_RegisterCFinalizer(dataset_xptr, &finalize_dataset_xptr);


  if (layer.size() == 0 && Rcpp::CharacterVector::is_na(query[0])) { // no layer specified
    switch (poDS->GetLayerCount()) {
    case 0: { // error:
    Rcpp::stop("No layers in datasource.");
  }
    case 1: { // silent:
      OGRLayer *poLayer = poDS->GetLayer(0);
      layer = Rcpp::CharacterVector::create(poLayer->GetName());
      break;
    }
    default: { // select first layer: message + warning:
      OGRLayer *poLayer = poDS->GetLayer(0);
      layer = Rcpp::CharacterVector::create(poLayer->GetName());
      if (! quiet) { // #nocov start
        Rcpp::Rcout << "Multiple layers are present in data source " << datasource[0] << ", ";
        Rcpp::Rcout << "reading layer `" << layer[0] << "'." << std::endl;
        Rcpp::Rcout << "Use `st_layers' to list all layer names and their type in a data source." << std::endl;
        Rcpp::Rcout << "Set the `layer' argument in `st_read' to read a particular layer." << std::endl;
      } // #nocov end
      Rcpp::Function warning("warning");
      warning("automatically selected the first layer in a data source containing more than one.");
    }
    }
  }


  OGRPolygon poly;
  OGRLinearRing ring;

  if (ex.length() == 4) {
        if (ex[1] <= ex[0] || ex[3] <= ex[2]) {
          if (ex[1] <= ex[0]) {
            Rcpp::warning("extent filter invalid (xmax <= xmin), ignoring");
          }
          if (ex[3] <= ex[2]) {
            Rcpp::warning("extent filter invalid (ymax <= ymin), ignoring");
          }
        } else {
          ring.addPoint(ex[0], ex[2]); //xmin, ymin
          ring.addPoint(ex[0], ex[3]); //xmin, ymax
          ring.addPoint(ex[1], ex[3]); //xmax, ymax
          ring.addPoint(ex[1], ex[2]); //xmax, ymin
          ring.closeRings();
          poly.addRing(&ring);
          if (Rcpp::CharacterVector::is_na(query[0]) ) {
            query[0] =  CPLSPrintf("SELECT * FROM %s", (char *) layer[0]);
          }
        }
  }

  OGRLayer *poLayer;
  if (! Rcpp::CharacterVector::is_na(query[0])) {// [[Rcpp::export]]
  // FIXME we need dialect here
    poLayer = poDS->ExecuteSQL(query[0], &poly, NULL);
    if (poLayer == NULL)
      Rcpp::stop("Query execution failed, cannot open layer.\n"); // #nocov
    if (layer.size())
      Rcpp::warning("argument layer is ignored when query is specified\n"); // #nocov
  } else
    poLayer = 	poDS->GetLayerByName(layer[0]);
  if (poLayer == NULL) {
    Rcpp::Rcout << "Cannot open layer " << layer[0] << std::endl;
    Rcpp::stop("Opening layer failed.\n");
  }

  if (! quiet) {
    if (! Rcpp::CharacterVector::is_na(query[0]))
      Rcpp::Rcout << "Reading query `" << query[0] << "'" << std::endl << "from data source ";
    else
      Rcpp::Rcout << "Reading layer `" << layer[0] << "' from data source ";
    // if (LENGTH(datasource[0]) > (width - (34 + LENGTH(layer[0]))))
    Rcpp::String ds(datasource(0));
    if (layer.size()) {
      Rcpp::String la(layer(0));
      if (strlen(ds.get_cstring()) > (width - (34 + strlen(la.get_cstring()))))
        Rcpp::Rcout << std::endl << "  ";
    }
    Rcpp::Rcout << "`" << datasource[0] << "' ";
    if (((int) strlen(ds.get_cstring())) > (width - 25))
      Rcpp::Rcout << std::endl << "  ";
    Rcpp::Rcout << "using driver `" << poDS->GetDriverName() << "'" << std::endl;                       // #nocov
  }

  // Keeps the dataset external pointer alive as long as the layer external pointer is alive
  Rcpp::RObject layer_xptr = R_MakeExternalPtr(poLayer, R_NilValue, dataset_xptr);
  Rprintf("%s", "ogr_layer_setup:\n");
  return Rcpp::List::create(dataset_xptr, layer_xptr);
}

inline Rcpp::List read_gdal_stream(
    Rcpp::RObject stream_xptr,
    Rcpp::CharacterVector datasource,
    Rcpp::CharacterVector layer,
    Rcpp::CharacterVector query,
    std::vector<std::string> options,
    bool quiet,
    std::vector<std::string> drivers,
    Rcpp::NumericVector extent,
    bool dsn_exists,
    Rcpp::CharacterVector fid_column,
    int width) {

  const char* array_stream_options[] = {"INCLUDE_FID=NO", nullptr};
  if (fid_column.size() == 1) {
    array_stream_options[0] = "INCLUDE_FID=YES";
  }

  Rcpp::List prep = ogr_layer_setup(datasource, layer, query,
                                        options,
                                        quiet,
                                        drivers,
                                        extent,
                                        width);
  
  OGRLayer* poLayer = (OGRLayer*)R_ExternalPtrAddr(prep[1]);
  auto stream_out = reinterpret_cast<struct ArrowArrayStream*>(
    R_ExternalPtrAddr(stream_xptr));

  //OGRSpatialReference* crs = poLayer->GetSpatialRef();
  OGRLayerH hLayer = reinterpret_cast<OGRLayerH>(poLayer);
  
  OGRSpatialReferenceH hSRS = OGR_L_GetSpatialRef(hLayer);

  char* wkt_out;
  
  std::string wkt_str;
  if (OSRExportToWkt(hSRS, &wkt_out) != OGRERR_NONE) {
    Rcpp::stop("error export SRS to Wkt"); 
  }
  wkt_str = wkt_out;
  CPLFree(wkt_out);
  
  struct ArrowArrayStream stream_temp;
  if (!poLayer->GetArrowStream(&stream_temp, array_stream_options)) {
    Rcpp::stop("Failed to open ArrayStream from Layer");
  }

  GDALStreamWrapper::Make(&stream_temp, prep, stream_out);


  // The reported feature count is incorrect if there is a query
  double num_features;
  if (query.size() == 0) {
    num_features = (double) poLayer->GetFeatureCount(false);
  } else {
    num_features = -1;
  }



  return Rcpp::List::create(wkt_str, Rcpp::NumericVector::create(num_features));
}

#else

inline Rcpp::List read_gdal_stream(
    Rcpp::RObject stream_xptr,
    Rcpp::CharacterVector datasource,
    Rcpp::CharacterVector layer,
    Rcpp::CharacterVector query,
    std::vector<std::string> options,
    bool quiet,
    std::vector<std::string> drivers,
    Rcpp::NumericVector extent,
    bool dsn_exists,
    Rcpp::CharacterVector fid_column,
    int width) {
  Rcpp::stop("read_stream() requires GDAL >= 3.6");
}

#endif

} // gdalvectorstream


#endif
