/*
  This file is part of CDO. CDO is a collection of Operators to manipulate and analyse Climate model Data.

  Author: Cedrick Ansorge

*/

/*
  This module contains the following operators:

  Eofcoeff             eofcoeff             process eof coefficients
*/

#include <cdi.h>

#include "cdo_options.h"
#include "process_int.h"
#include "cdo_vlist.h"
#include "util_files.h"
#include "util_string.h"

// NO MISSING VALUE SUPPORT ADDED SO FAR

class Eofcoeff : public Process
{
public:
  using Process::Process;
  inline static CdoModule module = {
    .name = "Eofcoeff",
    .operators = { { "eofcoeff", EofcoeffHelp } },
    .aliases = {},
    .mode = EXPOSED,     // Module mode: 0:intern 1:extern
    .number = CDI_REAL,  // Allowed number type
    .constraints = { 2, OBASE, OnlyFirst },
  };
  inline static RegisterEntry<Eofcoeff> registration = RegisterEntry<Eofcoeff>(module);

  double missval1 = -999, missval2;
  int varID, levelID;
  int numFields;
  size_t numMissVals;

  CdoStreamID streamID1;
  CdoStreamID streamID2;

  int taxisID2;
  int taxisID3;

  int vlistID1;
  int vlistID2;
  int vlistID3;

  VarList varList1;
  VarList varList2;

  int gridID1;
  int eofID;
  size_t gridsize;
  int neof;
  int numVars;
  int numLevels;

  std::vector<CdoStreamID> streamIDs;

  FieldVector3D eof;
  std::string fileSuffix;

public:
  void
  init() override
  {
    streamID1 = cdo_open_read(0);
    streamID2 = cdo_open_read(1);

    vlistID1 = cdo_stream_inq_vlist(streamID1);
    vlistID2 = cdo_stream_inq_vlist(streamID2);
    vlistID3 = vlistDuplicate(vlistID2);

    varList1 = VarList(vlistID1);
    varList2 = VarList(vlistID2);

    // taxisID1 = vlistInqTaxis(vlistID1);
    taxisID2 = vlistInqTaxis(vlistID2);
    taxisID3 = taxisDuplicate(taxisID2);

    gridID1 = varList1.vars[0].gridID;
    int gridID2 = varList2.vars[0].gridID;

    gridsize = vlistGridsizeMax(vlistID1);
    if (gridsize != vlistGridsizeMax(vlistID2))
      cdo_abort("Gridsize of input files does not match! %zu and %zu", gridsize, vlistGridsizeMax(vlistID2));

    if (vlistNumGrids(vlistID2) > 1 || vlistNumGrids(vlistID1) > 1) cdo_abort("Too many different grids in input!");

    numVars = (varList1.numVars() == varList2.numVars()) ? varList1.numVars() : -1;
    numLevels = varList1.vars[0].nlevels;

    if (gridID1 != gridID2) cdo_compare_grids(gridID1, gridID2);

    fileSuffix = FileUtils::gen_suffix(cdo_inq_filetype(streamID1), vlistID1, cdo_get_stream_name(0));

    eof = FieldVector3D(numVars);
    for (varID = 0; varID < numVars; ++varID) eof[varID].resize(numLevels);

    eofID = 0;
  }

  void
  run() override
  {
    while (1)
      {
        numFields = cdo_stream_inq_timestep(streamID1, eofID);
        if (numFields == 0) break;

        for (int fieldID = 0; fieldID < numFields; ++fieldID)
          {
            cdo_inq_field(streamID1, &varID, &levelID);
            missval1 = varList1.vars[varID].missval;
            eof[varID][levelID].resize((eofID == 0) ? 1 : eofID + 1);
            eof[varID][levelID][eofID].grid = gridID1;
            eof[varID][levelID][eofID].missval = missval1;
            eof[varID][levelID][eofID].resize(gridsize);
            ranges::fill(eof[varID][levelID][eofID].vec_d, missval1);

            if (varID >= numVars) cdo_abort("Internal error - varID >= nvars");
            if (levelID >= numLevels) cdo_abort("Internal error - levelID >= nlevs");

            cdo_read_field(streamID1, eof[varID][levelID][eofID].vec_d.data(), &numMissVals);
            eof[varID][levelID][eofID].numMissVals = numMissVals;
          }
        eofID++;
      }

    neof = eofID;

    if (Options::cdoVerbose) cdo_print("%s contains %i eof's", cdo_get_stream_name(0), neof);
    // Create 1x1 Grid for output
    auto gridID3 = gridCreate(GRID_LONLAT, 1);
    gridDefXsize(gridID3, 1);
    gridDefYsize(gridID3, 1);
    double xvals = 0.0, yvals = 0.0;
    gridDefXvals(gridID3, &xvals);
    gridDefYvals(gridID3, &yvals);

    // Create var-list and time-axis for output

    auto ngrids = vlistNumGrids(vlistID3);
    for (int i = 0; i < ngrids; ++i) vlistChangeGridIndex(vlistID3, i, gridID3);

    vlistDefTaxis(vlistID3, taxisID3);
    for (varID = 0; varID < numVars; ++varID) vlistDefVarTimetype(vlistID3, varID, TIME_VARYING);

    // open streams for eofcoeff output
    streamIDs = std::vector<CdoStreamID>(neof);
    for (eofID = 0; eofID < neof; eofID++)
      {
        auto fileName = cdo_get_obase() + string_format("%5.5i", eofID);
        if (fileSuffix.size() > 0) fileName += fileSuffix;

        streamIDs[eofID] = cdo_open_write(fileName.c_str());

        if (Options::cdoVerbose)
          cdo_print("opened %s ('w')  as stream%i for %i. eof", fileName, streamIDs[eofID]->get_id(), eofID + 1);

        cdo_def_vlist(streamIDs[eofID], vlistID3);
      }

    // ALLOCATE temporary fields for data read and write
    Field in, out;
    in.resize(gridsize);
    in.grid = gridID1;
    out.missval = missval1;
    out.numMissVals = 0;
    out.resize(1);

    int tsID = 0;
    while (1)
      {
        numFields = cdo_stream_inq_timestep(streamID2, tsID);
        if (numFields == 0) break;

        cdo_taxis_copy_timestep(taxisID3, taxisID2);
        /*for ( eofID=0; eofID<neof; eofID++)
          {
            fprintf(stderr, "defining ts %i\n", tsID);
            cdo_def_timestep(streamIDs[eofID],tsID);
          }
        */
        for (int fieldID = 0; fieldID < numFields; ++fieldID)
          {
            cdo_inq_field(streamID2, &varID, &levelID);
            missval2 = varList2.vars[varID].missval;
            cdo_read_field(streamID2, in.vec_d.data(), &in.numMissVals);

            for (eofID = 0; eofID < neof; eofID++)
              {
                if (fieldID == 0) cdo_def_timestep(streamIDs[eofID], tsID);
                // if ( fieldID == 0 ) fprintf(stderr, "ts%i rec%i eof%i\n", tsID, fieldID, eofID);
                out.vec_d[0] = 0;
                out.grid = gridID3;
                out.missval = missval2;
                for (size_t i = 0; i < gridsize; ++i)
                  {
                    if (!fp_is_equal(in.vec_d[i], missval2) && !fp_is_equal(eof[varID][levelID][eofID].vec_d[i], missval1))
                      {
                        // out.vec_d[0] += w[i]*in.vec_d[i]*eof[varID][levelID][eofID].vec_d[i];
                        out.vec_d[0] += in.vec_d[i] * eof[varID][levelID][eofID].vec_d[i];
                      }
                  }
                if (!fp_is_equal(out.vec_d[0], 0.))
                  numMissVals = 0;
                else
                  {
                    numMissVals = 1;
                    out.vec_d[0] = missval2;
                  }

                cdo_def_field(streamIDs[eofID], varID, levelID);
                // fprintf(stderr, "%d %d %d %d %d %g\n", streamIDs[eofID],tsID, fieldID, varID, levelID,*out.vec_d.data());
                cdo_write_field(streamIDs[eofID], out.vec_d.data(), numMissVals);
              }
            if (varID >= numVars) cdo_abort("Internal error - varID >= nvars");
            if (levelID >= numLevels) cdo_abort("Internal error - levelID >= nlevs");
          }

        tsID++;
      }
  }

  void
  close() override
  {
    for (eofID = 0; eofID < neof; eofID++) cdo_stream_close(streamIDs[eofID]);

    cdo_stream_close(streamID2);
    cdo_stream_close(streamID1);
  }
};
