package org.autoplot.hapiserver;

import java.io.IOException;
import java.io.OutputStream;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.charset.Charset;
import java.util.Collections;
import java.util.logging.Level;
import java.util.logging.Logger;
import org.das2.datum.Units;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import org.das2.qds.DataSetUtil;
import org.das2.qds.QDataSet;
import org.das2.qds.SemanticOps;
import org.das2.qstream.AsciiTimeTransferType;
import org.das2.qstream.TransferType;

/**
 * Format to doubles.
 * @author jbf
 */
public class BinaryDataFormatter implements DataFormatter {
  
    private static final Logger logger= Logger.getLogger("hapi");    
    
    TransferType[] transferTypes;
    ByteBuffer b;
    int bufferSize;
    
    public BinaryDataFormatter( ) {
    }
        
    @Override
    public void initialize( JSONObject info, OutputStream out, QDataSet record) {
        try {
            transferTypes= new TransferType[record.length()];
            bufferSize= 0;
            
            int totalFields= 0;
            JSONArray parameters= info.getJSONArray("parameters");
            for ( int i=0; i<parameters.length(); i++ ) {
                JSONObject parameter= parameters.getJSONObject(i);
                TransferType tt;
                final String stype = parameter.getString("type");
                Units u= SemanticOps.getUnits(record.slice(i));
                if ( stype.equals("isotime") ) {
                    if ( !parameter.has("length") ) throw new RuntimeException("required tag length is missing");
                    final int len= parameter.getInt("length");
                    final TransferType delegate= AsciiTimeTransferType.getForName( "time"+(len-1), Collections.singletonMap(QDataSet.UNITS,(Object)u) );
                    final byte NULL= 0;
                    tt= new TransferType() {
                        @Override
                        public void write(double d, ByteBuffer buffer) {
                            delegate.write(d, buffer);
                            buffer.put(NULL);
                        }
                        @Override
                        public double read(ByteBuffer buffer) {
                            throw new UnsupportedOperationException("Not supported."); 
                        }
                        @Override
                        public int sizeBytes() {
                            return len;
                        }
                        @Override
                        public boolean isAscii() {
                            return false;
                        }
                        @Override
                        public String name() {
                            return "string"+len;
                        }   
                    };
                } else if ( stype.equals("string") ) {
                    if ( !parameter.has("length") ) throw new RuntimeException("required tag length is missing");
                    final int len= parameter.getInt("length");
                    final Units units= u;
                    final byte[] zeros= new byte[len];
                    for ( int i2=0; i2<zeros.length; i2++ ) zeros[i2]= 0;
                    tt= new TransferType() {
                        @Override
                        public void write(double d, ByteBuffer buffer) {
                            String s= units.createDatum(d).toString();
                            byte[] bytes= s.getBytes( Charset.forName("UTF-8") );  
                            if ( bytes.length<len ) {
                                buffer.put( bytes, 0, Math.min(bytes.length,len) );  //TODO: we could be in the middle of a letter.
                                buffer.put( zeros, bytes.length, len-bytes.length );
                            } else {
                                // find last full character
                                int ipos= len-1;
                                while ( ipos>0 && bytes[ipos]<0 ) ipos--;  // unicode characters > 127 are multi-byte.
                                buffer.put( bytes, 0, ipos );  //TODO: we could be in the middle of a UTF-8 letter.
                            }
                        }
                        @Override
                        public double read(ByteBuffer buffer) {
                            throw new UnsupportedOperationException("Not supported."); 
                        }
                        @Override
                        public int sizeBytes() {
                            return len;
                        }
                        @Override
                        public boolean isAscii() {
                            return false;
                        }
                        @Override
                        public String name() {
                            return "string"+len;
                        }   
                    };
                } else if ( stype.equals("double") || stype.equals("integer")) {
                    tt= TransferType.getForName(stype, Collections.singletonMap(QDataSet.UNITS,(Object)u) );
                } else {
                    throw new IllegalArgumentException("server is misconfigured, using unsupported type: "+stype );
                }
                int nfields;
                if ( parameter.has("size") ) {
                    JSONArray ja= (JSONArray)parameter.get("size");
                    int prod= 1;
                    for ( int j=0; j<ja.length(); j++ ) {
                        prod*= ja.getInt(j);
                    }
                    nfields= prod;
                } else {
                    nfields= 1;
                }
                for ( int j=0; j<nfields; j++ ) {
                    transferTypes[totalFields+j]= tt;
                }
                totalFields+= nfields;
                bufferSize+= nfields * tt.sizeBytes();
            }

            b= TransferType.allocate( bufferSize, ByteOrder.LITTLE_ENDIAN );
            
        } catch (JSONException ex) {
            logger.log(Level.SEVERE, null, ex);
        }
    }
    
    @Override
    public void sendRecord( OutputStream out, QDataSet record ) throws IOException {

        for ( int i=0; i<record.length(); i++ ) {
            QDataSet d= record.slice(i);
            transferTypes[i].write( d.value(), b );
        }
        byte[] bytes= b.array();
        
        out.write( bytes );
        
        b.flip();
                
    }
    
    /**
     * perform any final operations to the stream.  This 
     * DOES NOT close the stream!
     * @param out 
     */
    @Override
    public void finalize( OutputStream out ) {
        
    } 
    
}