RedControl/src/main/java/net/brokenmoon/redcontrol/blockentities/DriveEntity.java

package net.brokenmoon.redcontrol.blockentities;

import com.simon816.j65el02.device.ByteDiskDriver;
import com.simon816.j65el02.device.DiskDriver;
import com.simon816.j65el02.device.FileDiskDriver;
import net.brokenmoon.redcontrol.RedControl;
import net.minecraft.block.BlockState;
import net.minecraft.block.entity.BlockEntityType;
import net.minecraft.util.math.BlockPos;

import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.file.Paths;

public class DriveEntity extends Peripheral{

    private static final int SECTOR_SIZE = 0x80;

    private final DiskDriver driver;
    private final byte[] diskName = new byte[SECTOR_SIZE];
    private final byte[] diskSerial = new byte[SECTOR_SIZE];
    private final ByteBuffer buffer;

    private int sector;
    private int command;

    public DriveEntity(BlockPos pos, BlockState state) {
        super(RedControl.DRIVE_BLOCK_ENTITY, pos, state, 2);

        this.driver = new ByteDiskDriver(RedControl.images.get("basic.img"), "Forth", "FORTH");
        this.buffer = ByteBuffer.allocateDirect(SECTOR_SIZE);
        byte[] name = driver.getDriveName();
        byte[] serial = driver.getDriveSerial();
        System.arraycopy(name, 0, this.diskName, 0, name.length);
        System.arraycopy(serial, 0, this.diskSerial, 0, serial.length);
    }

    @Override
    public void write(int address, int data) {
        switch (address) {
            case 0x80: // Sector number (lo)
                this.sector = (this.sector & 0xff00) | data;
                break;
            case 0x81: // Sector number (hi)
                this.sector = (data << 8) | (this.sector & 0xff);
                break;
            case 0x82: // Disk command
                this.command = data;
                break;
            default: // Disk sector buffer
                if (address >= 0 && address <= 0x7f) {
                    this.buffer.put(address, (byte) data);
                }
        }
    }


    @Override
    public int read(int address) {
        switch (address) {
            case 0x80: // Sector number (lo)
                return this.sector & 0xff;
            case 0x81: // Sector number (hi)
                return (this.sector >> 8) & 0xff;
            case 0x82: // Disk command
                return this.command;
            default: // Disk sector buffer
                if (address >= 0 && address <= 0x7f) {
                    return this.buffer.get(address);
                }
                return 0;
        }
    }

    @Override
    public void update() {
        try {
            switch (this.command) {
                case 0x01: // Read Disk Name
                    this.buffer.clear();
                    this.buffer.put(this.diskName);
                    this.command = 0;
                    break;
                case 0x02: // Write Disk Name
                    this.buffer.position(0);
                    this.buffer.get(this.diskName);
                    this.driver.writeDiskName(this.diskName);
                    this.command = 0;
                    break;
                case 0x03: // Read Disk Serial
                    this.buffer.clear();
                    this.buffer.put(this.diskSerial);
                    this.command = 0;
                    break;
                case 0x04: // Read Disk Sector
                    if (this.sector >= 0x800) {
                        this.command = 0xff;
                        break;
                    }
                    this.driver.seek(this.sector << 7);
                    this.buffer.position(0);
                    this.driver.read(this.buffer);
                    this.command = 0;
                    break;
                case 0x05: // Write Disk Sector
                    if (this.sector >= 0x800) {
                        this.command = 0xff;
                        break;
                    }
                    this.driver.seek(this.sector << 7);
                    this.buffer.position(0);
                    this.driver.write(this.buffer);
                    this.command = 0;
                    break;
            }
        } catch (Exception e) {
            this.command = 0xff;
            e.printStackTrace();
        }
    }
}