package org.hapiserver.source;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.Iterator;
import java.util.logging.Level;
import java.util.logging.Logger;
import org.hapiserver.HapiRecord;

/**
 * Bootstrap method for getting server going, used to test its functionality in initial development.  It still serves
 * as a nice demo of how a source can be added to the server.
 * Each record of the dataset at
 * https://cdaweb.gsfc.nasa.gov/pub/data/wind/swe/ascii/2-min/wind_swe_2m_sw2022.asc
 * are formatted like so:
 * (i4.4," ", f11.6," ", i4.2,18(" ",f7.1),2(" ",f9.3),14(" ",f7.1),2(" ",f9.3)," ",f6.1,7(" ",f7.1)," ",f9.3,10(" ",f9.3),2(" ", f11.6))
 * 
 * @author jbf
 */
public class WindSwe2mIterator implements Iterator<HapiRecord> {

    private static final Logger logger= Logger.getLogger("hapi.windswe");
    
    int currentYear;
    int stopYear;
    
    int currentMonth;
    
    URL currentUrl;
    BufferedReader readerCurrentYear;
    
    String nextRecord=null;
    
    /**
     * create a new iterator.  The dataHome should be a local file reference, 
     * but can also be a remote website.  The startTime and stopTime must correspond
     * to one file, and the granule iterator should ensure this.
     * 
     * @param dataHome the URL containing the files, like https://cdaweb.gsfc.nasa.gov/pub/data/wind/swe/ascii/2-min/
     * @param startTime
     * @param stopTime 
     */
    public WindSwe2mIterator( String dataHome, int[] startTime, int[] stopTime ) {
        
        currentYear= startTime[0];
        currentMonth= startTime[1];
        
        try {
            currentUrl= new URL( String.format( dataHome+"/wind_swe_2m_sw%4d%02d.asc",
                currentYear, currentMonth ) );
        } catch (MalformedURLException ex) {
            throw new RuntimeException(ex);
        }
        
        try {
            readerCurrentYear= new BufferedReader( new InputStreamReader( currentUrl.openStream() ) );
        } catch ( IOException ex ) {
            throw new RuntimeException(ex);
        }
        
        readNextRecord();
        
        if ( nextRecord==null ) {
            try {
                readerCurrentYear.close();
            } catch (IOException ex) {
                logger.log(Level.SEVERE, null, ex);
            }
        }
    }

    private void readNextRecord() {
        try {
            nextRecord= readerCurrentYear.readLine();
            if ( nextRecord==null ) {
                readerCurrentYear.close();
            }
        } catch ( IOException ex ) {
            logger.log(Level.SEVERE, null, ex);
        }
    }
    
    @Override
    public boolean hasNext() {
        return nextRecord!=null;
    }

    @Override
    public HapiRecord next() {
        
        final String localNextRecord= nextRecord;
        
        readNextRecord();
        
        return new HapiRecord() {
            @Override
            public String getIsoTime(int i) {
                if ( i==0 ) {
                    final int year= Integer.parseInt( localNextRecord.substring(0,4) );
                    double fdoy= Double.parseDouble( localNextRecord.substring(5,16) );
                    final int doy= (int)fdoy;
                    double fsec= ( fdoy - doy ) * 86400;
                    final int hr= (int)( fsec / 3600. );
                    fsec= fsec - hr*3600;
                    final int mn= (int)( fsec / 60 );
                    fsec= fsec - mn*60;
                    final double ffsec= fsec;
                    return String.format( "%04d-%03dT%02d:%02d:%09.6fZ", year, doy, hr, mn, ffsec );
                } else {
                    throw new IllegalArgumentException("implementation error");
                }
            }

            @Override
            public String[] getIsoTimeArray(int i) {
                throw new IllegalArgumentException("implementation error");
            }

            @Override
            public String getString(int i) {
                throw new IllegalArgumentException("implementation error");
            }

            @Override
            public String[] getStringArray(int i) {
                throw new IllegalArgumentException("implementation error");
            }

            @Override
            public double getDouble(int i) {
                if ( i==1 ) {
                    // it's field 12
                    return Double.parseDouble( localNextRecord.substring(85,93) );
                } else {
                    throw new IllegalArgumentException("implementation error");
                }
            }

            @Override
            public double[] getDoubleArray(int i) {
                if ( i==2 ) { // it's field 54,55,56
                    double d1= Double.parseDouble(localNextRecord.substring(440,449) );
                    double d2= Double.parseDouble(localNextRecord.substring(450,459) );
                    double d3= Double.parseDouble(localNextRecord.substring(460,469) );
                    return new double[] { d1, d2, d3 };
                } else {
                    throw new IllegalArgumentException("implementation error");
                }
                
            }

            @Override
            public int getInteger(int i) {
                throw new IllegalArgumentException("implementation error");
            }

            @Override
            public int[] getIntegerArray(int i) {
                throw new IllegalArgumentException("implementation error");
            }

            @Override
            public String getAsString(int i) {
                throw new IllegalArgumentException("implementation error");
            }

            @Override
            public int length() {
                return 3;
            }
        };
    }
    
}