package solarsim.io;

import solarsim.common.Vector;
import java.io.IOException;
import java.io.InputStream;

/**
 * Clasa Wrapper pentru InputStream care permite citirea de valori care au fost scrise de programul in C
 * @author Marius Ion
 */
public class MyInputStreamReader {

    private InputStream in;

    public MyInputStreamReader(InputStream in) {
        this.in = in;
    }

    /**
     * Citeste un double scris in binar (8 octeti) din streamul de intrare
     * @return numarul citit citit
     * @throws IOException cand s-a produs o eroare la citirea din InputStream-ul incapsulat
     */
    public double readDouble() throws IOException {
        byte [] buf = new byte[8];
        while( in.available() < 8 )
            try {
                Thread.currentThread().sleep(1000);
            } catch (InterruptedException ex) {}
        in.read(buf, 0, 8);
        return arr2double(buf, 0);
    }

    /**
     * Citeste un float scris in binar (4 octeti) din streamul de intrare
     * @return numarul citit citit
     * @throws IOException cand s-a produs o eroare la citirea din InputStream-ul incapsulat
     */
    public double readFloat() throws IOException {
        byte [] buf = new byte[4];
        while( in.available() < 4 )
            try {
                Thread.currentThread().sleep(1000);
            } catch (InterruptedException ex) {}
        in.read(buf, 0, 4);
        return arr2float(buf, 0);
    }

    /**
     * Citeste un int scris in binar (4 octeti) din streamul de intrare
     * @return numarul citit
     * @throws IOException cand s-a produs o eroare la citirea din InputStream-ul incapsulat
     */
    public int readInt() throws IOException {
        byte [] buf = new byte[4];
        while( in.available() < 4 )
            try {
                Thread.currentThread().sleep(1000);
            } catch (InterruptedException ex) {}
        in.read(buf, 0, 4);
        return arr2int(buf);
    }

    /**
     * Citeste un Vector scris in binar (3 double) din streamul de intrare
     * @return Vectorul citit
     * @throws IOException cand s-a produs o eroare la citirea din InputStream-ul incapsulat
     */
    public Vector readVector() throws IOException {
        Vector v = new Vector();
        v.x = readDouble();
        v.y = readDouble();
        v.z = readDouble();
        readDouble();
        return v;
    }

    /**
     * Citeste un Vector scris in binar (3 float) din streamul de intrare
     * @return Vectorul citit
     * @throws IOException cand s-a produs o eroare la citirea din InputStream-ul incapsulat
     */
    public Vector readFloatVector() throws IOException {
        Vector v = new Vector();
        v.x = (double)readFloat();
        v.y = (double)readFloat();
        v.z = (double)readFloat();
        readFloat();
        return v;
    }

    private int arr2int (byte[] arr) {
        int i = 0;
        int len = 4;
        int cnt = 0;
        byte[] tmp = new byte[len];
        for (i = 0; i < len; i++) {
            tmp[cnt] = arr[i];
            cnt++;
        }
        int accum = 0;
        i = 0;
        for ( int shiftBy = 0; shiftBy < 32; shiftBy += 8 ) {
            accum |= ( (int)( tmp[i] & 0xff ) ) << shiftBy;
            i++;
        }
        return accum;
    }

    private double arr2float (byte[] arr, int start) {
        int i = 0;
        int len = 4;
        int cnt = 0;
        byte[] tmp = new byte[len];
        for (i = start; i < (start + len); i++) {
            tmp[cnt] = arr[i];
            cnt++;
        }
        int accum = 0;
        i = 0;
        for ( int shiftBy = 0; shiftBy < 32; shiftBy += 8 ) {
            accum |= ( (long)( tmp[i] & 0xff ) ) << shiftBy;
            i++;
        }
        return Float.intBitsToFloat(accum);
    }

    private double arr2double (byte[] arr, int start) {
        int i = 0;
        int len = 8;
        int cnt = 0;
        byte[] tmp = new byte[len];
        for (i = start; i < (start + len); i++) {
            tmp[cnt] = arr[i];
            cnt++;
        }
        long accum = 0;
        i = 0;
        for ( int shiftBy = 0; shiftBy < 64; shiftBy += 8 ) {
            accum |= ( (long)( tmp[i] & 0xff ) ) << shiftBy;
            i++;
        }
        return Double.longBitsToDouble(accum);
    }

}