package Classes;

/**
 * @author Michael Wilhelm
 * @since 1.0
 * @version 1.0
 */
public class Bitmap {

    private final short VERSION = 2;
    String filename = "";
    byte[] array = null;

    public String fileID="";
    public short version=0;
    public int width=0;
    public int height=0;

    public short numberOfColors=0;
    public int[] colors=null;


    public void readBitmap(String filename, byte[] array) {
        this.filename = filename;
        this.array = array;
        if (!readHeader()) {
            System.err.println("Fehlerhafter Header");
        }
        else {
            System.out.println("Header okay");
        }
        if (!readMeasurements()) {
            System.err.println("Fehlerhafter Breiten/Höhen");
        }
        else {
            System.out.println("Breiten/Höhen okay");
        }
        if (!readColors()) {
            System.err.println("Fehlerhafte Farben");
        }
        else {
            System.out.println("Farben okay");
        }
        System.out.println(this);
        printColors();
    } // readBitmap

    private boolean readColors() {
        numberOfColors = getShort(12);
        if (numberOfColors<=0) {
            return false;
        }
        colors = new int[numberOfColors];
        for (int i=0; i<colors.length; i++) {
            colors[i] = getInt3Bytes(14+3*i);
        }
        return true;
    }  // readColors

    private boolean readMeasurements() {
        width = getInt4Bytes(4);
        height = getInt4Bytes(8);
        return width>0 && height>0;
    }

    /**
     * description read the header: fileID and version
     * @return true if the header is okay
     */
    private boolean readHeader() {
        // FileID  MW   0x4D  0x57
        int id1 = array[0];
        int id2 = array[1];
        if (id1==0x4D && id2==0x57) {
            char ch1 = (char)id1;
            char ch2 = (char)id2;
            fileID = Character.toString(ch1)+Character.toString(ch2);
        }
        else {
            return false;
        }
        version = getShort(2);
        if (version != VERSION) {
            return false;
        }
        return true;
    } // readHeader

    private short getShort(int offset) {
        short sh = (short) (array[offset]<<8 | array[offset+1]);
        return sh;
    }
    private int getInt4Bytes(int offset) {
        int intValue = (int) (array[offset]<<24 | array[offset+1]<<16 |
                array[offset+2]<<8 | array[offset+3]);
        return intValue;
    }
    private int getInt3Bytes(int offset) {
        int i1 = array[offset];
        if (i1<0) i1+=256;
        int i2 = array[offset+1];
        if (i2<0) i2+=256;
        int i3 = array[offset+2];
        if (i3<0) i3+=256;
        int intValue = (int) (i1<<16 | i2<<8 | i3);
        return intValue;
    }

    @Override public String toString() {
        return "Bitmap{" +
                "filename='" + filename + '\'' +
                ", fileID='" + fileID + '\'' +
                ", version=" + version +
                ", width=" + width +
                ", height=" + height +
                '}';
    }

    public void printColors() {
        System.out.println("Anzahl der Farben: "+numberOfColors);
        for (int color:colors){
            System.out.print( color>>16 & 0xFF );
            System.out.print( "  ");
            System.out.print( color>>8 & 0xFF );
            System.out.print( "  ");
            System.out.println( color & 0xFF );
        }
    }
}