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/*
 * Copyright (c) 1998-2018 John Caron and University Corporation for Atmospheric Research/Unidata
 * See LICENSE for license information.
 */
package ucar.nc2.dataset.conv;

import ucar.nc2.Attribute;
import ucar.nc2.constants.CF;
import ucar.nc2.dataset.*;
import ucar.nc2.time.Calendar;
import ucar.nc2.units.SimpleUnit;
import ucar.nc2.Variable;
import ucar.nc2.constants.AxisType;
import ucar.nc2.util.CancelTask;

import java.io.IOException;
import java.util.List;

/**
 * COARDS Convention.
 * see http://ferret.wrc.noaa.gov/noaa_coop/coop_cdf_profile.html
 *
 * @author caron
 */

public class COARDSConvention extends CoordSysBuilder {

  /*
  The COARDS standard offers limited support for climatological time. For compatibility with COARDS, time coordinates should also be
  recognised as climatological if they have a units attribute of time-units relative to midnight on 1 January in year 0
  i.e. since 0-1-1 in udunits syntax , and provided they refer to the real-world calendar. We do not recommend this convention because
   (a) it does not provide any information about the intervals used to compute the climatology, and
   (b) there is no standard for how dates since year 1 will be encoded with units having a reference time in year 0,
  since this year does not exist; consequently there may be inconsistencies among software packages in the interpretation of the
  time coordinates. Year 0 may be a valid year in non-real-world calendars, and therefore cannot be used to signal climatological
  time in such cases.
   */

  public static boolean isMine(String hasName) {
    if (hasName.equalsIgnoreCase("COARDS")) return true;
    List names = breakupConventionNames(hasName);
    for (String name : names) {
      if (name.equalsIgnoreCase("COARDS")) return true;
    }
    return false;
  }


  public COARDSConvention() {
    this.conventionName = "COARDS";
  }

  protected boolean checkTimeVarForCalendar (Variable var) {
    boolean hasChanged = false;
    String unit = var.getUnitsString();
    if (unit != null) {
      unit = unit.trim();
      if (SimpleUnit.isDateUnit(unit)) {
        Attribute calAttr = var.findAttributeIgnoreCase(CF.CALENDAR);
        if (calAttr == null) {
          calAttr = new Attribute(CF.CALENDAR, Calendar.gregorian.toString());
          var.addAttribute(calAttr);
          hasChanged = true;
        }
      }
    }
    return hasChanged;
  }

  @Override
  public void augmentDataset(NetcdfDataset ds, CancelTask cancelTask) throws IOException {
    boolean hasChanged = false;
    boolean hasChangedThisTime;
    for (Variable var : ds.getVariables()) {
      hasChangedThisTime = checkTimeVarForCalendar(var);
      if (hasChangedThisTime) {
        hasChanged = true;
      }
    }
    if (hasChanged) {
      ds.finish();
    }
  }

  protected boolean checkForMeter = true;

  // we assume that coordinate axes get identified by being coordinate variables
  protected AxisType getAxisType( NetcdfDataset ncDataset, VariableEnhanced v) {

    String unit = v.getUnitsString();
    if (unit == null)
      return null;
    unit = unit.trim();
    
    if( unit.equalsIgnoreCase("degrees_east") ||
            unit.equalsIgnoreCase("degrees_E") ||
            unit.equalsIgnoreCase("degreesE") ||
            unit.equalsIgnoreCase("degree_east") ||
            unit.equalsIgnoreCase("degree_E") ||
            unit.equalsIgnoreCase("degreeE"))
      return AxisType.Lon;

    if ( unit.equalsIgnoreCase("degrees_north") ||
            unit.equalsIgnoreCase("degrees_N") ||
            unit.equalsIgnoreCase("degreesN") ||
            unit.equalsIgnoreCase("degree_north") ||
            unit.equalsIgnoreCase("degree_N") ||
            unit.equalsIgnoreCase("degreeN"))
      return AxisType.Lat;

    if (SimpleUnit.isDateUnit(unit)) {
      return AxisType.Time;
    }
    // look for other z coordinate
    if (SimpleUnit.isCompatible("mbar", unit))
      return AxisType.Pressure;
    if (unit.equalsIgnoreCase("level") || unit.equalsIgnoreCase("layer") || unit.equalsIgnoreCase("sigma_level"))
      return AxisType.GeoZ;

    String positive = ncDataset.findAttValueIgnoreCase((Variable) v, CF.POSITIVE, null);
    if (positive != null) {
      if (SimpleUnit.isCompatible("m", unit))
        return AxisType.Height;
      else
        return AxisType.GeoZ;
    }

    // a bad idea, but CDC SST relies on it :
    // :Source = "NOAA/National Climatic Data Center";
   // :Contact = "Dick Reynolds, email: [email protected] & Chunying Liu, email: [email protected]";
   //:netcdf_Convention = "COARDS";
   // if (checkForMeter && SimpleUnit.isCompatible("m", unit))
   //   return AxisType.Height;

    return null;
  }

}