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

  Copyright (C) 2007 Brockmann Consult

  Author: Ralf Quast
          Uwe Schulzweida

*/

/*
   This module contains the following operators:

      Seascount   seascount         Seasonal counts
*/

#include <cdi.h>

#include "cdo_season.h"
#include "datetime.h"
#include "process_int.h"
#include "field_functions.h"

class Seascount : public Process
{
public:
  using Process::Process;
  inline static CdoModule module = {
    .name = "Seascount",
    .operators = { { "seascount" } },
    .aliases = {},
    .mode = EXPOSED,     // Module mode: 0:intern 1:extern
    .number = CDI_BOTH,  // Allowed number type
    .constraints = { 1, 1, NoRestriction },
  };
  inline static RegisterEntry<Seascount> registration = RegisterEntry<Seascount>(module);

  CdiDateTime vDateTime0{};
  int seas0 = 0;
  int oldmon = 0;

  CdoStreamID streamID1;
  CdoStreamID streamID2;

  int taxisID1;
  int taxisID2;

  VarList varList1;
  FieldVector2D varsData1;

public:
  void
  init() override
  {
    operator_check_argc(0);

    streamID1 = cdo_open_read(0);

    auto vlistID1 = cdo_stream_inq_vlist(streamID1);
    auto vlistID2 = vlistDuplicate(vlistID1);

    taxisID1 = vlistInqTaxis(vlistID1);
    taxisID2 = taxisDuplicate(taxisID1);
    vlistDefTaxis(vlistID2, taxisID2);

    streamID2 = cdo_open_write(1);
    cdo_def_vlist(streamID2, vlistID2);

    varList1 = VarList(vlistID1);

    field2D_init(varsData1, varList1, FIELD_VEC);
  }

  void
  run() override
  {
    auto maxFields = varList1.maxFields();
    std::vector<FieldInfo> fieldInfoList(maxFields);
    Field field;

    auto seasonStart = get_season_start();

    int tsID = 0;
    int otsID = 0;
    while (true)
      {
        int numFields = 0;
        int numSets = 0;
        auto newseas = false;
        while (true)
          {
            numFields = cdo_stream_inq_timestep(streamID1, tsID);
            if (numFields == 0) break;

            auto vDateTime = taxisInqVdatetime(taxisID1);

            auto month = decode_month(vDateTime.date);
            auto newmon = month;
            if (seasonStart == SeasonStart::DEC && newmon == 12) newmon = 0;

            auto seas = month_to_season(month);

            if (numSets == 0)
              {
                seas0 = seas;
                oldmon = newmon;
              }

            if (newmon < oldmon) newseas = true;

            if ((seas != seas0) || newseas)
              {
                cdo_add_steps(-1);
                break;
              }

            oldmon = newmon;

            for (int fieldID = 0; fieldID < numFields; ++fieldID)
              {
                auto [varID, levelID] = cdo_inq_field(streamID1);
                const auto &var = varList1.vars[varID];

                if (tsID == 0) fieldInfoList[fieldID].set(varID, levelID);

                auto fieldsize = varsData1[varID][levelID].size;

                if (numSets == 0)
                  {
                    for (size_t i = 0; i < fieldsize; ++i) varsData1[varID][levelID].vec_d[i] = varsData1[varID][levelID].missval;
                    varsData1[varID][levelID].numMissVals = fieldsize;
                  }

                field.init(var);
                cdo_read_field(streamID1, field);

                field2_count(varsData1[varID][levelID], field);
              }

            vDateTime0 = vDateTime;
            numSets++;
            tsID++;
          }

        if (numFields == 0 && numSets == 0) break;

        taxisDefVdatetime(taxisID2, vDateTime0);
        cdo_def_timestep(streamID2, otsID);

        for (int fieldID = 0; fieldID < maxFields; ++fieldID)
          {
            auto [varID, levelID] = fieldInfoList[fieldID].get();
            if (otsID && varList1.vars[varID].isConstant) continue;

            cdo_def_field(streamID2, varID, levelID);
            cdo_write_field(streamID2, varsData1[varID][levelID].vec_d.data(), varsData1[varID][levelID].numMissVals);
          }

        if (numFields == 0) break;
        otsID++;
      }
  }

  void
  close() override
  {
    cdo_stream_close(streamID2);
    cdo_stream_close(streamID1);
  }
};
