package uk.ac.leeds.ccg.dbffile;

import java.io.*;
import java.util.*;
import java.lang.*;
import java.net.*;
import cmp.LEDataStream.*;

/**
 *
 * This class represents a DBF (or DBase) file.<p>
 * Construct it with a URL (including the .dbf)
 * this causes the header and field definitions to be read.<p>
 * Later queries return rows or columns of the database.
 *<hr>
 * @author <a href="mailto:ian@geog.leeds.ac.uk">Ian Turton</a> Centre for
 * Computaional Geography, University of Leeds, LS2 9JT, 1998.
 * <br>
 * mod to getStringCol by James Macgill.
 */
public final class DbfNet implements DbfConsts{
    static final boolean DEBUG=true;
    int dbf_id;
    int last_update_d,last_update_m,last_update_y;
    int last_rec;
    int data_offset;
    int rec_size;
    StringBuffer records[];
    int position=0;
    boolean hasmemo;
    LEDataInputStream dFile;
    int filesize,numfields;
    public DbfFieldDef fielddef[];
    
    /**
     * Constructor, opens the file and reads the header infomation.
     * @param file The file to be opened, includes path and .dbf
     * @exception java.io.IOException If the file can't be opened.
     * @exception DbfFileException If there is an error reading header.
     */
    public DbfNet(URL url) throws java.io.IOException,DbfFileException{
        if(DEBUG)System.out.println("---->uk.ac.leeds.ccg.dbffile.DbfNet constructed. Will identify itself as DbN->");
        URLConnection uc = url.openConnection();
        InputStream in = uc.getInputStream();
        LEDataInputStream sfile = new LEDataInputStream(in);
        init(sfile);
    }
    
    public DbfNet(InputStream in) throws java.io.IOException,DbfFileException{
        if(DEBUG)System.out.println("---->uk.ac.leeds.ccg.dbffile.DbfNet constructed. Will identify itself as DbN->");
        LEDataInputStream sfile = new LEDataInputStream(in);
        init(sfile);
    }
    
    public DbfNet(String name) throws java.io.IOException,DbfFileException{
        if(DEBUG)System.out.println("---->uk.ac.leeds.ccg.dbffile.DbfNet constructed. Will identify itself as DbN->");
        URL url = new URL(name);
        URLConnection uc = url.openConnection();
        InputStream in = uc.getInputStream();
        LEDataInputStream sfile = new LEDataInputStream(in);
        init(sfile);
    }
    /**
     * Returns the date of the last update of the file as a string.
     */
    public String getLastUpdate(){
        String date=last_update_d+"/"+last_update_m+"/"+last_update_y;
        return date;
    }
    
    /**
     * Returns the number of records in the database file.
     */
    public int getLastRec(){
        return last_rec;
    }
    /**
     * Returns the size of the records in the database file.
     */
    public int getRecSize(){
        return  rec_size;
    }
    /**
     * Returns the number of fields in the records in the database file.
     */
    public int getNumFields(){
        return numfields;
    }
    
    /**
     * looks up the field number for the given named column
     * @param name A String for the name to look up
     * @return int The col number for the field, -1 if field could not be found
     */
    public int getFieldNumber(String name){
        for(int i=0;i<numfields;i++){
            //System.out.println(i);
            // System.out.println(fielddef[i].fieldname.toString()+" "+name);
            if(name.trim().equalsIgnoreCase(fielddef[i].fieldname.toString().trim())){
                return i;
            }
        }
        return -1;//not found
    }
    /**
     * Returns the size  of the database file.
     */
    public int getFileSize(){
        return  filesize;
    }
    public StringBuffer getFieldName(int col){
        if(fielddef.length - 1 < col) throw new IllegalArgumentException("DbN->column number specified is invalid. It's higher than the amount of columns available");
        return  fielddef[col].fieldname;
    }
    public char getFieldType(int col){
        if(fielddef.length - 1 < col) throw new IllegalArgumentException("DbN->column number specified is invalid. It's higher than the amount of columns available");
        return fielddef[col].fieldtype;
    }
    
    /**
     * initailizer, allows the use of multiple constructers in later
     * versions.
     */
    
    private void init(LEDataInputStream sfile)throws
    IOException,DbfFileException {
        DbfFileHeader head = new DbfFileHeader(sfile);
        int widthsofar;
        
        dFile=sfile;
        
        fielddef = new DbfFieldDef[numfields];
        widthsofar=1;
        for(int index=0;index<numfields;index++){
            fielddef[index] = new DbfFieldDef(widthsofar);
            widthsofar+=fielddef[index].fieldlen;
        }
        //System.out.println("Skippint two bytes");
        sfile.skipBytes(1); // end of field defs marker
        records=GrabFile();
    }
    /**
     * Internal Class to hold information from the header of the file
     */
    final class DbfFileHeader{
        
        
        /**
         * Reads the header of a dbf file.
         * @param LEDataInputStream file Stream attached to the input file
         * @exception IOException read error.
         */
        public  DbfFileHeader(LEDataInputStream file) throws IOException {
            getDbfFileHeader(file);
        }
        private void getDbfFileHeader(LEDataInputStream file) throws IOException {
            
            int len;
            dbf_id=(int)file.readUnsignedByte();
            if(DEBUG)System.out.print("DbN->Header id ");
            if(DEBUG)System.out.println(dbf_id);
            if(dbf_id==3) hasmemo=true;
            else hasmemo=false;
            
            last_update_y=(int)file.readUnsignedByte();
            last_update_m=(int)file.readUnsignedByte();
            last_update_d=(int)file.readUnsignedByte();
            if(DEBUG)System.out.print("DbN->last update ");
            if(DEBUG)System.out.print(last_update_d);
            if(DEBUG)System.out.print("/");
            if(DEBUG)System.out.print(last_update_m);
            if(DEBUG)System.out.print("/");
            if(DEBUG)System.out.println(last_update_y);
            
            last_rec=file.readInt();
            if(DEBUG)System.out.print("DbN->last rec ");
            if(DEBUG)System.out.println(last_rec);
            
            data_offset=file.readShort();
            //data_offset=0;
            //System.out.println("x = "+file.readUnsignedByte()+" " +
            //file.readUnsignedByte());
            if(DEBUG)System.out.print("DbN->data offset ");
            if(DEBUG)System.out.println(data_offset);
            
            rec_size=file.readShort();
            if(DEBUG)System.out.print("DbN->rec_size ");
            if(DEBUG)System.out.println(rec_size);
            
            filesize=(rec_size * last_rec) + data_offset+1;
            numfields = (data_offset - DBF_BUFFSIZE -1)/DBF_BUFFSIZE;
            
            if(DEBUG)System.out.print("DbN->num fields ");
            if(DEBUG)System.out.println(numfields);
            if(DEBUG)System.out.print("DbN->file size ");
            if(DEBUG)System.out.println(filesize);
            file.skipBytes(20);
        }
        
    }
    /**
     * Internal class to hold infomation about the fields in the file
     */
    final class DbfFieldDef{
        public StringBuffer fieldname = new StringBuffer(DBF_NAMELEN);
        public char fieldtype;
        public int  fieldstart;
        public int  fieldlen;
        public int  fieldnumdec;
        DbfFieldDef(int pos) throws IOException {
            byte[] strbuf = new byte[DBF_NAMELEN]; // <---- byte array buffer fo storing string's byte data
            int j=-1;
            int term =-1;
            for(int i=0;i<DBF_NAMELEN;i++){
                byte b = dFile.readByte();
                if(b==0){
                    if(term== -1 )
                        term=j;
                    continue;
                }
                j++;
                strbuf[j] = b; // <---- read string's byte data
            }
            if(term==-1) term=j;
            String name = new String(strbuf, 0, term+1);
            if(DEBUG)System.out.println("DbN->Loaded as "+name);
            fieldname.append(name); // <- append byte array to String Buffer
            if(DEBUG)System.out.println("DbN->Fieldname "+fieldname);
            fieldtype=(char)dFile.readUnsignedByte();
            fieldstart=pos;
            dFile.skipBytes(4);
            switch(fieldtype){
                case 'C':
                case 'c':
                case 'L':
                case 'M':
                case 'G':
                case 'N':
                case 'n':
                    fieldlen=(int)dFile.readUnsignedByte();
                    fieldnumdec=(int)dFile.readUnsignedByte();
                    fieldnumdec=0;
                    break;
                case 'F':
                case 'f':
                    fieldlen=(int)dFile.readUnsignedByte();
                    fieldnumdec=(int)dFile.readUnsignedByte();
                    break;
                default:
                    System.out.println("DbN->Help - wrong field type: "+fieldtype);
            }
            if(DEBUG)System.out.println("DbN->Fieldtype "+fieldtype+" width "+fieldlen+
            "."+fieldnumdec);
            
            dFile.skipBytes(14);
            
            
        }
    }
    /**
     * gets the next record and returns it as a string. This method works on
     * a sequential stream and can not go backwards. Only useful if you want
     * to read the whole file in one.
     * @exception java.io.IOException on read error.
     */
    public  StringBuffer GetNextDbfRec()throws java.io.IOException{
        return records[position++];
    }
    
    private StringBuffer GrabNextDbfRec()throws java.io.IOException{
        //modifed for two byte character sets.
        //StringBuffer record = new StringBuffer(rec_size+numfields);
        byte[] strbuf = new byte[rec_size+numfields];
        for(int i=0;i< rec_size;i++){
            // we could do some checking here.
            strbuf[i] = dFile.readByte();
            
        }
        StringBuffer record = new StringBuffer(new String(strbuf));
        //System.out.println(record);
        return record;
    }
    
    private StringBuffer[] GrabFile() throws java.io.IOException{
        StringBuffer records[] = new StringBuffer[last_rec];
        for(int i=0;i<last_rec;i++) {
            records[i]=GrabNextDbfRec();
        }
        return records;
    }
    
    
    
    
    
    /**
     * fetches the <i>row</i>th row of the file
     * @param row - the row to fetch
     * @exception java.io.IOException on read error.
     */
    public StringBuffer GetDbfRec(int row)throws java.io.IOException{
        StringBuffer record;// = new StringBuffer(rec_size);
        if(DEBUG)System.out.println("DbN->GetDbfRec("+row+") "+records[row]);
        return record = new StringBuffer(records[row].toString());
    }
    /**
     * fetches the <i>row</i>th row of the file and parses it into an vector
     * of objects.
     * @param row - the row to fetch
     * @exception java.io.IOException on read error.
     */
    public Vector ParseDbfRecord(int row)throws java.io.IOException{
        return ParseRecord(GetDbfRec(row));
    }
    /**
     * Parses the record stored in the StringBuffer rec into a vector of
     * objects
     * @param StringBuffer rec - the record to be parsed.
     */
    
    public Vector ParseRecord(StringBuffer rec){
        Vector record=new Vector(numfields);
        String t;
        Integer I=new Integer(0);
        Float F=new Float(0.0);
        t = rec.toString();
        for(int i=0;i<numfields;i++){
            if(DEBUG)System.out.println("DbN->type "+fielddef[i].fieldtype);
            if(DEBUG)System.out.println("DbN->start "+fielddef[i].fieldstart);
            if(DEBUG)System.out.println("DbN->len "+fielddef[i].fieldlen);
            if(DEBUG)System.out.println(t.substring(fielddef[i].fieldstart,
            fielddef[i].fieldstart+fielddef[i].fieldlen));
            switch(fielddef[i].fieldtype){
                case 'C':
                    record.addElement(t.substring(fielddef[i].fieldstart,
                    fielddef[i].fieldstart+fielddef[i].fieldlen));
                    break;
                case 'N':
                    try{
                        record.addElement(I.decode(t.substring(
                        fielddef[i].fieldstart,fielddef[i].fieldstart+fielddef[i].fieldlen)));
                    }catch(java.lang.NumberFormatException e){
                        record.addElement(new Integer(0));
                    }
                    break;
                case 'F':
                    try{
                        record.addElement(F.valueOf(t.substring(
                        fielddef[i].fieldstart,fielddef[i].fieldstart+fielddef[i].fieldlen)));
                    }catch(java.lang.NumberFormatException e){
                        record.addElement(new Float(0.0));
                    }
                    
                    break;
                default:
                    if(DEBUG)System.out.println("DbN->Oh - don't know how to parse "
                    +fielddef[i].fieldtype);
                    
            }
        }
        return record;
    }
    
    /**
     * Fetches a column of Integers from the database file.
     * @param int col - the column to fetch
     * @exception java.io.IOException - on read error
     * @exception DbfFileException - column is not an Integer.
     */
    public Integer[] getIntegerCol(int col )
    throws java.io.IOException,DbfFileException {
        return getIntegerCol(col,0,last_rec);
    }
    /**
     * Fetches a part column of Integers from the database file.
     * @param int col - the column to fetch
     * @param int start - the row to start fetching from
     * @param int end - the row to stop fetching at.
     * @exception java.io.IOException - on read error
     * @exception DbfFileException - column is not an Integer.
     */
    public Integer[] getIntegerCol(int col, int start, int end)
    throws java.io.IOException,DbfFileException {
        Integer column[]=new Integer[end-start];
        String record = new String();
        StringBuffer sb = new StringBuffer(numfields);
        int k=0,i=0;
        if(col>=numfields)
            throw new DbfFileException("DbN->No Such Column in file: "+col);
        if(fielddef[col].fieldtype!='N')
            throw new DbfFileException("DbN->Column "+col+" is not Integer");
        if(start<0)
            throw new DbfFileException("DbN->Start must be >= 0");
        if(end>last_rec)
            throw new DbfFileException("DbN->End must be <= "+last_rec);
        // move to start of data
        try{
            for(i=start;i<end;i++){
                sb.setLength(0);
                sb=GetDbfRec(i);
                record=sb.toString();
                try{
                    column[i-start]=new Integer(record.substring(fielddef[col].fieldstart,
                    fielddef[col].fieldstart+fielddef[col].fieldlen));
                }catch(java.lang.NumberFormatException e){
                    column[i-start]=new Integer(0);
                }
            }
        }
        catch(java.io.EOFException e){
            System.err.println("DbN->"+e);
            System.err.println("DbN->record "+i+" byte "+k+" file pos "
            );}
        catch(java.io.IOException e){
            System.err.println("DbN->"+e);
            System.err.println("DbN->record "+i+" byte "+k+" file pos "
            );}
        return column;
    }
    /**
     * Fetches a column of Floats from the database file.
     * @param int col - the column to fetch
     * @exception java.io.IOException - on read error
     * @exception DbfFileException - column is not an Integer.
     */
    public Float[] getFloatCol(int col) throws DbfFileException,
    java.io.IOException{
        return getFloatCol(col,0,last_rec);
    }
    /**
     * Fetches a part column of Floats from the database file.
     * @param int col - the column to fetch
     * @param int start - the row to start fetching from
     * @param int end - the row to stop fetching at.
     * @exception java.io.IOException - on read error
     * @exception DbfFileException - column is not an Integer.
     */
    public Float[] getFloatCol(int col,int start,int end)
    throws DbfFileException, java.io.IOException{
        Float column[]=new Float[end-start];
        String record,st;
        StringBuffer sb = new StringBuffer(rec_size);
        int k=0,i=0;
        if(col>=numfields)
            throw new DbfFileException("DbN->No Such Column in file: "+col);
        if(fielddef[col].fieldtype!='F')
            throw new DbfFileException("DbN->Column "+col+" is not Float or Numeric it is of type "
            +fielddef[col].fieldtype);
        if(start<0)
            throw new DbfFileException("DbN->Start must be >= 0");
        if(end>last_rec)
            throw new DbfFileException("End must be <= "+last_rec);
        // move to start of data
        try{
            for(i=start;i<end;i++){
                sb.setLength(0);
                sb=GetDbfRec(i);
                record=sb.toString();
                st=new String(record.substring(fielddef[col].fieldstart,
                fielddef[col].fieldstart+fielddef[col].fieldlen));
                if(st.indexOf('.')==-1){
                    st=st+".0";
                }
                try{
                    column[i-start]=new Float(st);
                }
                catch(NumberFormatException nfe){
                    column[i-start]=new Float(0.0);
                }
            }
        }
        catch(java.io.EOFException e){
            System.err.println("DbN->"+e);
            System.err.println("DbN->record "+i+" byte "+k+" file pos ");}
        catch(java.io.IOException e){
            System.err.println("DbN->"+e);
            System.err.println("DbN->record "+i+" byte "+k+" file pos ");}
        
        return column;
    }
    /**
     * Fetches a column of Strings from the database file.
     * @param int col - the column to fetch
     * @exception java.io.IOException - on read error
     * @exception DbfFileException - column is not an Integer.
     */
    public String[] getStringCol(int col) throws DbfFileException,
    java.io.IOException{
        return getStringCol(col,0,last_rec);
    }
    /**
     * Fetches a part column of Strings from the database file.
     * @param int col - the column to fetch
     * @param int start - the row to start fetching from
     * @param int end - the row to stop fetching at.
     * @exception java.io.IOException - on read error
     * @exception DbfFileException - column is not an Integer.
     */
    public String[] getStringCol(int col,int start,int end)
    throws DbfFileException, java.io.IOException{
        String column[]=new String[end-start];
        String record = new String();
        StringBuffer sb = new StringBuffer(numfields);
        int k=0,i=0;
        if(col>=numfields)
            throw new DbfFileException("DbN->No Such Column in file: "+col);
        //if(fielddef[col].fieldtype!='C')
        //throw new DbfFileException("Column "+col+" is not a String");
        if(start<0)
            throw new DbfFileException("DbN->Start must be >= 0");
        if(end>last_rec)
            throw new DbfFileException("DbN->End must be <= "+last_rec);
        // move to start of data
        try{
            for(i=start;i<end;i++){
                //sb.setLength(0);
                byte[] strbuf = new byte[rec_size];
                
                sb=GetDbfRec(i);
                record=sb.toString();
                //column[i-start]=new String(record.substring(fielddef[col].fieldstart,
                //fielddef[col].fieldstart+fielddef[col].fieldlen));
                // replaced to fix bug #547080 
                column[i-start]=new String(record.getBytes(), fielddef[col].fieldstart,fielddef
                [col].fieldlen).trim();
            }
        }
        catch(java.io.EOFException e){
            System.err.println(e);
            System.err.println("DbN->record "+i+" byte "+k+" file pos ");}
        catch(java.io.IOException e){
            System.err.println(e);
            System.err.println("DbN->record "+i+" byte "+k+" file pos ");}
        return column;
    }
    
    
    
    
    
}