package example;

import sega.dreamcast.gdrom.GdromProtocol;
import sega.dreamcast.gdrom.G1IF;
import java.misc.Memory;
import filesystem.iso9660.VolumeParser;
import filesystem.iso9660.ExtentReader;
import filesystem.iso9660.DirectoryRecordHandler;
import filesystem.iso9660.DirectoryRecord;
import jvm.internal.Loader;

class GdromExtentReader implements ExtentReader {
    public void readInto(byte[] buf, int extent) {
        int starting_address = extent + 150;
        System.out.print("starting_address: ");
        System.out.println(starting_address);
        GdromProtocol.cdReadPIO(buf, starting_address, 1);
    }
}

class GdromDirectoryRecordHandler implements DirectoryRecordHandler {
    int address;
    int[] addresses;
    public int addresses_ix;
    static byte[] class_ext;

    static {
        class_ext = new byte[] { 'C', 'L', 'A', ';', '1' }; // CLA;1
    }

    public GdromDirectoryRecordHandler(int address, int[] addresses) {
        this.address = address;
        this.addresses = addresses;
        this.addresses_ix = 0;
    }

    // transfer_length is in bytes
    public static void startG1DMA(int start_address, int transfer_length) {
        int gdstar = start_address & ~(0b111 << 29);

        Memory.putU4(G1IF.GDAPRO, 0x8843407F);
        Memory.putU4(G1IF.G1GDRC, 0x00001001);
        Memory.putU4(G1IF.GDSTAR, gdstar);
        Memory.putU4(G1IF.GDLEN, transfer_length);
        Memory.putU4(G1IF.GDDIR, 1);
        Memory.putU4(G1IF.GDEN, 1);
        Memory.putU4(G1IF.GDST, 1);
    }

    public boolean drIsClass(DirectoryRecord dr) {
        int length = dr.lengthOfFileIdentifier();

        if (length < 6)
            return false;

        byte[] buf = dr.array;
        int offset = dr.offset + DirectoryRecord.FILE_IDENTIFIER_START;

        int ix = 0;
        for (int i = length - 5; i < length; i++) {
            System.out.print(ix);
            System.out.print(" ");
            if (buf[offset + i] != class_ext[ix]) {
                return false;
            }
            ix += 1;
        }
        System.out.println();
        return true;
    }

    public void handle(DirectoryRecord dr) {
        int extent = dr.locationOfExtent(); // sector number
        int length = dr.dataLength(); // bytes

        if (drIsClass(dr)) {
            System.out.println("class found");
        } else {
            System.out.println("is not class");
            return;
        }

        // round up to nearest multiple of 2048
        length = (length + 2047) & ~(2047);

        System.out.print("start G1 DMA: address:");
        System.out.print(address);
        System.out.print(" length: ");
        System.out.println(length);

        System.out.println("read dma");

        Memory.putU4(G1IF.GDEN, 0);

        int sectors = length >> 11; // division by 2048
        GdromProtocol.cdReadDMA(extent + 150, sectors);

        System.out.println("start dma");
        startG1DMA(address, length);

        System.out.println("wait gdst");
        while ((Memory.getU4(G1IF.GDST) & 1) != 0);
        System.out.println("transfer complete");

        addresses[addresses_ix] = 0xa0000000 | address;
        addresses_ix += 1;
        address += length;
    }
}

class GdromTest {
    public static void main() {
        // assume gdrom is already unlocked

        int data_track_fad = GdromProtocol.tocGetDataTrackFad();

        int[] buffer_addresses = new int[0x3000]; // maximum 12,288 class files

        int loader_buffer_address = Loader.getBuffer();
        GdromDirectoryRecordHandler handler = new GdromDirectoryRecordHandler(loader_buffer_address, buffer_addresses);
        GdromExtentReader reader = new GdromExtentReader();

        VolumeParser parser = new VolumeParser(data_track_fad - 150, reader, handler);
        System.out.println("::parser parse::");
        parser.parse();

        Loader.load(buffer_addresses, handler.addresses_ix);
    }
}